3D Bioplotter Research Papers

Three-dimensional (3D) printing has been combined with electrospinning to manufacture multi-layered polymer/glass scaffolds that possess multi-scale porosity, are mechanically robust, release bioactive compounds, degrade at a controlled rate and are biocompatible. Fibrous mats of poly (caprolactone) (PCL) and poly (glycerol sebacate) (PGS) have been directly electrospun on one side of 3D-printed grids of PCL-PGS blends containing bioactive glasses (BGs). The excellent adhesion between layers has resulted in composite scaffolds with a Young’s modulus of 240–310 MPa, higher than that of 3D-printed grids (125–280 MPa, without the electrospun layer). The scaffolds degraded in vitro by releasing PGS and BGs, reaching a…

Tissue engineering, based on a combination of 3D printing, biomaterials blending and stem cell technology, offers the potential to establish customized, transplantable autologous implants using a patient‘s own cells. Graphene, as a two-dimensional (2D) version of carbon, has shown great potential for tissue engineering. Here, we describe a novel combination of graphene with 3D printed alginate (Alg)-based scaffolds for human adipose stem cell (ADSC) support and osteogenic induction. Alg printing was enabled through addition of gelatin (Gel) that was removed after printing, and the 3D structure was then coated with graphene oxide (GO). GO was chemically reduced with a biocompatible…

The printability of bioink and post-printing cell viability is crucial for extrusion-based bioprinting. A proper bioink not only provides mechanical support for structural fidelity, but also serves as suitable three-dimensional (3D) microenvironment for cell encapsulation and protection. In this study, a hydrogel-based composite bioink was developed consisting of gelatin methacryloyl (GelMA) as the continuous phase and decellularised extracellular matrix microgels (DMs) as the discrete phase. A flow-focusing microfluidic system was employed for the fabrication of cell-laden DMs in a high-throughput manner. After gentle mixing of the DMs and GelMA, both rheological characterisations and 3D printing tests showed that the resulting…

Silicate bioceramic scaffolds are of great interest in bone tissue engineering, but the fabrication of silicate bioceramic scaffolds with complex geometries is still challenging. In this study, three-dimensional (3D) porous β-Ca2SiO4 scaffolds have been successfully fabricated from preceramic resin loaded with CaCO3 active filler by 3D printing. The fabricated β-Ca2SiO4 scaffolds had uniform interconnected macropores (ca. 400 μm), high porosity (>78%), enhanced mechanical strength (ca. 5.2 MPa), and excellent apatite mineralization ability. Importantly, the results showed that the increase of sintering temperature significantly enhanced the compressive strength and the scaffolds sintered at higher sintering temperature stimulated the adhesion, proliferation, alkaline phosphatase activity,…

In recent years, tissue engineering has experienced significant advancements, mostly driven by the emergence of additive manufacturing technologies and the integration of biomaterials and cells. This advanced technique enables the creation of intricate structures with diverse components and properties, specifically designed for use in biomedical applications. The primary benefit of this technology is its ability to be customised, which helps minimise post-operative difficulties for patients with orthopaedic diseases and those undergoing tissue transplants. For this purpose, the essential components can be synthesised by the patient’s own cells. However, there are still other obstacles that need to be addressed in order…

Synthesis of bioinks for bioprinting of respiratory tissue requires considerations related to immunogenicity, mechanical properties, printability, and cellular compatibility. Biomaterials can be tailored to provide the appropriate combination of these properties through the synergy of materials with individual pros and cons. Sodium alginate, a water-soluble polymer derived from seaweed, is a cheap yet printable biomaterial with good structural properties; however, it lacks physiological relevance and cell binding sites. Collagen, a common component in the extra cellular matrix of many tissues, is expensive and lacks printability; however, it is highly biocompatible and exhibits sites for cellular binding. This paper presents our…

BACKGROUND: Polylactic acid has good biocompatibility and biodegradability, and has become a new orthopedic fixation material. However, the lack of cell recognition signal of this material is not conducive to cell adhesion and osteogenic differentiation, which limits its application in biomaterials. OBJECTIVE: 3D-printed polylactic acid-nano-hydroxyapatite (nHA)/chitosan (CS) scaffold to evaluate its drug sustained-release and biological properties

Gelatin was widely used as scaffold materials in 3D bio-printing due to its excellent bioactivity and availability and especially that their arginine–glycine–aspartic acid (RGD) sequences could efficiently promote cell adhesion and proliferation. In this study, an electroactive and 3D bio-printable hydrogel was prepared through a two-step chemical cross-linking process. Specifically, residual free amino groups of methacrylated gelatin (GelMA) were cross-linked with the aldehyde groups of dibenzaldehyde-terminated telechelic polyethylene glycol (DF-PEG) via Schiff base bonds, forming a gel at 37 °C. During the subsequent 3D bio-printing process, GelMA underwent UV curing, forming a secondary cross-linked network to the mechanical strength and stability…

Organ-on-a-chip stands as a pivotal platform for skeletal muscle research while constructing 3D skeletal muscle tissues that possess both macroscopic and microscopic structures remains a considerable challenge. This study draws inspiration from LEGO-like assembly, employing a modular approach to construct muscle tissue that integrates biomimetic macroscopic and microscopic structures. Modular LEGO-like hybrid nanofibrous scaffold bricks were fabricated by the combination of 3D printing and electrospinning techniques. Skeletal muscle cells cultured on these modular scaffold bricks exhibited a highly orientated nanofibrous structure. A variety of construction of skeletal muscle tissues further enabled development by various assembling processes. Moreover, skeletal muscle-on-a-chip (SMoC)…

Printing of biologically functional constructs is significant for applications in tissue engineering and regenerative medicine. Designing bioinks remains remarkably challenging due to the multifaceted requirements in terms of the physical, chemical, and biochemical properties of the three-dimensional matrix, such as cytocompatibility, printability, and shape fidelity. In order to promote matrix and materials stiffness, while not sacrificing stress relaxation mechanisms which support cell spreading, migration, and differentiation, this work reports an interpenetrating network (IPN) bioink design. The approach makes use of a chemically defined network, combining physical and chemical crosslinking units with a tunable composition and network density, as well as…

Utilizing tissue-specific extracellular matrices (ECMs) is vital for replicating the composition of native tissues and developing biologically relevant biomaterials. Human- or animal-derived donor tissues and organs are the current gold standard for the source of these ECMs. To overcome the several limitations related to these ECM sources, including the highly limited availability of donor tissues, cell-derived ECM offers an alternative approach for engineering tissue-specific biomaterials, such as bioinks for three-dimensional (3D) bioprinting. 3D bioprinting is a state-of-the-art biofabrication technology that addresses the global need for donor tissues and organs. In fact, there is a vast global demand for human donor…

3D-printed hydrogel scaffolds biomimicking the extracellular matrix (ECM) are key in cartilage tissue engineering as they can enhance the chondrogenic differentiation of mesenchymal stem cells (MSCs) through the presence of active nanoparticles such as graphene oxide (GO). Here, biomimetic hydrogels were developed by cross-linking alginate, gelatin, and chondroitin sulfate biopolymers in the presence of GO as a bioactive filler, with excellent processability for developing bioactive 3D printed scaffolds and for the bioprinting process. A novel bioink based on our hydrogel with embedded human MSCs presented a cell survival rate near 100% after the 3D bioprinting process. The effects of processing…

Nowadays, cartilage tissue engineering (CTE) is considered important due to lack of repair of cartilaginous lesions and the absence of appropriate methods for treatment. In this study, polycaprolactone (PCL) scaffolds were fabricated by three-dimensional (3D) printing and were then coated with fibrin (F) and acellular solubilized extracellular matrix (ECM). After extracting adipose-derived stem cells (ADSCs), 3D-printed scaffolds were characterized and compared to hydrogel groups. After inducing the chondrogenic differentiation in the presence of Piascledine and comparing it with TGF-β3 for 28 days, the expression of genes involved in chondrogenesis (AGG, COLII) and the expression of the hypertrophic gene (COLX) were examined…

Thermosensitive inks are considered an attractive option for the 3D bioprinting of different tissue types, yet comprehensive information on their reliability, preparation, and properties remains lacking. This paper addresses this gap by presenting a twofold aim: firstly, characterizing the preparation, rheology, and printing aspects of two inks that have demonstrated success in skeletal muscle tissue engineering both in vitro and in vivo. The first ink is composed of fibrinogen, gelatin, hyaluronic acid, and glycerol, while the second is a sacrificial ink made of gelatin, hyaluronic acid, and glycerol. Secondly, from this analysis, we demonstrate how thermosensitive and multicomponent inks can…

The pH of a wound site can undergo a significant change from its normal range of 5.4–5.6 to a more alkaline environment of 7.2–8.9 after being infected by microorganisms. Therefore, the development of a smart material that can respond to this shift in pH and release antimicrobial agents for effective treatment of wound infections holds great promise for the future of wound care. In the present work, we produced 3D printed alginate wound dressings doped with calcium phosphate nanoparticles (CaP NPs), referred to as alginate-CaP nanocomposites hereafter. The CaP NPs enabled pH-responsive switching of the degradation and drug release of…

Encapsulating multiple growth factors within a scaffold enhances the regenerative capacity of engineered bone grafts through their localization and controls the spatiotemporal release profile. In this study, we bioprinted hybrid bone grafts with an inherent built-in controlled growth factor delivery system, which would contribute to vascularized bone formation using a single stem cell source, human adipose-derived stem/stromal cells (ASCs) in vitro. The strategy was to provide precise control over the ASC-derived osteogenesis and angiogenesis at certain regions of the graft through the activity of spatially positioned microencapsulated BMP-2 and VEGF within the osteogenic and angiogenic bioink during bioprinting. The 3D-bioprinted…

The 3D bioprinting of complex structures has attracted particular attention in recent years and has been explored in several fields, including dentistry, pharmaceutical technology, medical devices, and tissue/organ engineering. However, it still possesses major challenges, such as decreased cell viability due to the prolongation of the printing time, along with difficulties in preserving the print shape. The 4D bioprinting approach, which is based on controlled shape transformation upon stimulation after 3D bioprinting, is a promising innovative method to overcome these difficulties. Herein, the generation of skeletal muscle tissue-like complex structures is demonstrated by 3D bioprinting of GelMA-based C2C12 mouse myoblast-laden…

Hydrogel skin grafts provide a moist environment and act as a regenerative template to the newly formed tissue. In this study, we developed 3D-bio-printed hydrogels using methacrylated pectin and methacrylated gelatin together with an antibacterial agent (curcumin), a bioactive agent (Vitamin-C) and fibroblast cells. Curcumin release was almost 10 times higher at pH 7.4 than pH 5.0, and it demonstrated antimicrobial affinity against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The developed 3D-bio-printed hydrogels containing cells and bioactive agents demonstrated high cell viability, cell proliferation, and collagen production, and are promising skin graft candidates for the treatment of full-thickness problematic…

The development of the effective 3D printing strategy for diverse functional monomers is still challenging. Moreover, the conventional 3D printing hydrogels are usually soft and fragile due to the lack of an energy dissipation mechanism. Herein, a microsphere mediating ink preparation strategy is developed to provide tailored rheological behavior for various monomer direct ink writings. The chitosan microspheres are used as an exemplary material due to their tunable swelling ratio under the acid-drived electrostatic repulsion of the protonated amino groups. The rheological behaviors of the swollen chitosan microsphere (SCM) are independent on the monomer types, and various functional secondary polymers…

3D bioprinting holds great potential for use in tissue engineering to treat degenerative joint disorders, such as osteoarthritis. However, there is a lack of multifunctional bioinks that can not only support cell growth and differentiation, but also offer protection to cells against injuries caused by the elevated oxidative stress; this conditions is a common characteristic of the microenvironment of the osteoarthritis disease. To mitigate oxidative stress-induced cellular phenotype change and malfunction, an anti-oxidative bioink derived from an alginate dynamic hydrogel was developed in this study. The alginate dynamic hydrogel gelated quickly via the dynamic covalent bond between the phenylboronic acid…

Light-based three-dimensional (3D) bioprinting has been widely studied in tissue engineering. Despite the fact that free-radical chain polymerization-based bioinks like hyaluronic acid methacrylate (HAMA) and gelatin methacryloyl (GelMA) have been extensively explored in 3D bioprinting, the thiol–ene hydrogel system has attracted increasing attention for its ability in building hydrogel scaffolds in an oxygen-tolerant and cell-friendly way. Herein, we report a superfast curing thiol–ene bioink composed of norbornene-modified hyaluronic acid (NorHA) and thiolated gelatin (GelSH) for 3D bioprinting. A new facile approach was first introduced in the synthesis of NorHA, which circumvented the cumbersome steps involved in previous works. Additionally, after…

Complex shaped bone defects that need to be filled are very common in clinic. But after filling, gaps are inevitably left between substitutes and host bone due to the poor conformability of preformed implants, hence hindering bone regeneration. Therefore, based on our previous study, we here used the bioink (named PPG) composed of polyurethane, polyacrylamide, and gelatin with optimized composition ratio to three-dimensionally (3D) print an inorganic/organic composite hydrogel scaffold with self-expandability to fill irregular bone defects and bioactivity to accelerate bone healing through adjusting the content of bioactive ceramic (BC). The results indicated that, the 3D printed BC/PPG scaffold…

Calcium phosphate cement (CPC) is widely used in orthopedics, dentistry and spine surgery because of its excellent biocompatibility, osteoconductivity, arbitrary shaping and self-setting ability. However, slow degradation rate of CPC decreases its bone regeneration efficacy. Herein, poly (lactic co-glycolic acid) microspheres (PLGAm) and wollastonite (WS) were mixed with CPC powder to prepare CPC composite pastes, and then the composite pastes were perfused into poly (lactic co-glycolic acid) network (PLGAnw) to construct composite bone repair materials. The degradation of PLGAnw generated interconnected macropores with the short side of about 468 μm along horizontal axis and the long side of about 785…

In this study, two-component, morphologically composite scaffolds consisting of a 3D-printed component and an electrospun fiber component were fabricated and treated with a nitrogen-argon (N2-Ar) plasma to enhance their surface properties. The 3D-printed component provided mechanical strength, while the electrospun fibrous component acted as a mimic to the extracellular matrix to improve cell-substrate interactions. Two biodegradable polyesters, poly(L-lactide-co–ε-caprolactone) (PLCL) and poly(L-lactide-co-glycolide) (PLGA), were used to create the scaffolds. The resulting 3D/E/N2-Ar scaffolds were characterized in terms of surface properties (morphology, chemical compositions, wettability, roughness, crystallinity), degradation, mechanical properties, and cell cytotoxicity, cell attachment and proliferation, LDH release and cell apoptosis.…

Low-intensity pulsed ultrasound (LIPUS) assisted bone repair is confirmed effective in clinic. Here, a 3D-printed composite poly(DL-lactic acid)/mesoporous bioactive glass scaffold was constructed for particular use in LIPUS-assisted bone tissue engineering. The scaffolds contain dimethyloxallyl glycine (DMOG) loaded microbubbles in pores, which can be released after implanting via LIPUS stimulation. Local DMOG concentrations are modulated through ultrasound power and processing time. The rat bone marrow-derived mesenchymal stem cells (rBMSCs) on these scaffolds with ultrasound treatment show improved proliferation and early osteogenic differentiation.

Cartilage injury is a common occurrence in the modern world. Compared with traditional treatment methods, bio-3D printing technology features better utility in the field of cartilage repair and regeneration, but still faces great challenges. For example, there is currently no means to generate blood vessels inside the scaffolds, and there remains the question of how to improve the biocompatibility of the generated scaffolds, all of which limit the application of bio-3D printing technology in this area. The main objective of this article was to prepare sodium alginate-xanthan gum-hydroxyapatite (SA-XG-HA) porous cartilage scaffolds that can naturally degrade in the human body…

We present a novel additive manufacturing method for NiTi-Nb micro-trusses combining (i) extrusion-based 3D-printing of liquid inks containing NiTi and Nb powders, solvents, and a polymer binder into micro-trusses with 0/90° ABAB layers of parallel, ∼600 µm struts spaced 1 mm apart and (ii) subsequent heat-treatment to remove the binder and solvents, and then bond the NiTi powders using liquid phase sintering via the formation of a transient NiTi-Nb eutectic phase. We investigate the effects of Nb concentration (0, 1.5, 3.1, 6.7 at.% Nb) on the porosity, microstructure, and phase transformations of the printed NiTi-Nb micro-trusses. Micro-trusses with the highest Nb content…

Ureteral stents are commonly used in clinical treatment of ureteral diseases. There were a series of complications, such as biofilms and crusts caused by bacteria after surgery. Therefore, biodegradable with bacteriostatic ureteral scaffolds would be the potential to solve above mentioned problems. In this study, nanosilver (AgNP) was added to the polylactic-co-glycolic acid (PLGA) and polycaprolactone (PCL) to prepare biodegradable antibacterial ureteral scaffold samples by 3D printing. The biocompatibility, antibacterial properties, degradability, and mechanical properties of samples were observed. The samples were under a strong inhibitory effect on both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), and the…

Effective therapeutic approaches to overcome the heterogeneous pro-inflammatory and inhibitory extracellular matrix (ECM) microenvironment are urgently needed to achieve robust structural and functional repair of severely wounded fibrocartilaginous tissues. Herein we developed a dynamic and multifunctional nanohybrid peptide hydrogel (NHPH) through hierarchical self-assembly of peptide amphiphile modified with biodegradable two-dimensional nanomaterials with enzyme-like functions. NHPH is not only injectable, biocompatible, and biodegradable but also therapeutic by catalyzing the scavenging of pro-inflammatory reactive oxygen species and promoting ECM remodeling. In addition, our NHPH method facilitated the structural and functional recovery of the intervertebral disc (IVD) after severe injuries by delivering pro-regenerative…

Scaffolds play a key role in bone tissue engineering (BTE) as they provide a mechanically and biologically supportive template to treat bone defects. Yet, the ideal scaffold structures are far from certain, leaving a lot to be discovered in terms of the scaffold structure–performance relationships. In this study, we investigated the influence of pore size and internal structure on osteoblast performance in vitro. Three-dimensional (3D) scaffolds were printed from polycaprolactone (PCL) reinforced with 30% (wt.) nano-hydroxyapatite (nHAp), with two different internal structures (lattice and staggered) and four pore sizes (0.280, 0.380, 0.420, and 0.550 mm). Scaffolds were seeded with pre-osteoblast…

Tissue-engineered articular cartilage constructs are currently not able to equal native tissues in terms of mechanical and biological properties. A major cause lies in the deficiency in engineering the biomechanical microenvironment (BMME) of articular chondrocytes. In this work, to engineer the BMME of articular chondrocytes, heterogeneous hydrogel structures of gelatin methacrylated (GelMA) containing differential-stiffness domains were first fabricated, and then periodic dynamic mechanical stimulations were applied to the hydrogel structures. The chondrocyte phenotype of ATDC5 cells was enhanced as the spatial differentiation in stiffness was increased in the hydrogel structures and was further strengthened by dynamic mechanical stimulation. It was…

Bioinks for 3D bioprinting of tumor models should not only meet printability requirements but also accurately maintain and support phenotypes of tumor surrounding cells to recapitulate key tumor hallmarks. Collagen is a major extracellular matrix protein for solid tumors, but low viscosity of collagen solution has made 3D bioprinted cancer models challenging. This work produces embedded, bioprinted breast cancer cells and tumor organoid models using low-concentration collagen I based bioinks. The biocompatible and physically crosslinked silk fibroin hydrogel is used to generate the support bath for the embedded 3D printing. The composition of the collagen I based bioink is optimized…

Polysaccharide based hydrogels have been predominantly utilized as ink materials for 3D bioprinting due to biocompatibility and cell responsive features. However, most hydrogels require extensive crosslinking due to poor mechanical properties leading to limited printability. To improve printability without using cytotoxic crosslinkers, thermoresponsive bioinks could be developed. Agarose is a thermoresponsive polysaccharide with upper critical solution temperature (UCST) for sol-gel transition at 35–37 °C. Therefore, we hypothesized that a triad of carboxymethyl cellulose(C)–agarose(A)–gelatin(G) could be a suitable thermoresponsive ink for printing since they undergo instantaneous gelation without any addition of crosslinkers after bioprinting. The blend of agarose-carboxymethyl cellulose was mixed with…

Background There is a great clinical need and it remains a challenge to develop artificial soft tissue constructs that can mimic the biomechanical properties and bioactivity of natural tissue. This is partly due to the lack of suitable biomaterials. Hydrogels made from human placenta offer high bioactivity and represent a potential solution to create animal-free 3D bioprinting systems that are both sustainable and acceptable, as placenta is widely considered medical waste. A combination with silk and gelatin polymers can bridge the biomechanical limitations of human placenta chorion extracellular matrix hydrogels (hpcECM) while maintaining their excellent bioactivity.   Method In this…

Hydrogels show promise in cartilage tissue engineering (CTE) by supporting chondrocytes and maintaining their phenotype and extracellular matrix (ECM) production. Under prolonged mechanical forces, however, hydrogels can be structurally unstable, leading to cell and ECM loss. Furthermore, long periods of mechanical loading might alter the production of cartilage ECM molecules, including glycosaminoglycans (GAGs) and collagen type 2 (Col2), specifically with the negative effect of stimulating fibrocartilage, typified by collagen type 1 (Col1) secretion. Reinforcing hydrogels with 3D-printed Polycaprolactone (PCL) structures offer a solution to enhance the structural integrity and mechanical response of impregnated chondrocytes. This study aimed to assess the…

The development of new biomaterials for bone tissue regeneration with high bioactivity abilities and antibacterial properties is being intensively investigated. We have synthesized nanocomposites formed by mesoporous bioactive glasses (MBGs) in the ternary SiO2, CaO and P2O5 system doped with metallic silver nanoparticles (AgNPs) that were homogenously embedded in the MBG matrices. Ag/MBG nanocomposites have been directly synthesized and silver species were spontaneously reduced to metallic AgNPs by high temperatures (700 °C) obtained of last MBG synthesis step. Three-dimensional silver-containing mesoporous bioactive glass scaffolds were fabricated showing uniformly interconnected ultrapores, macropores and mesopores. The manufacture method consisted of a combination…

Self-setting calcium phosphate cement (CPC) scaffold with interconnected macropores is hard to prepare without compromising its hydration reaction. Herein, an indirect 3D printing method is using to prepare CPC scaffolds. Detailedly, polycaprolactone (PCL)-sacrificed models with different strut sizes are first printed by 3D plotting technique, and then the CPC pastes are perfused into the PCL models and then self-setting. After the removal of the PCL models, the CPC scaffolds with different pore sizes are obtained. It is showed in the results that the prepared CPC scaffolds had uniform shape and 3D interconnected macropore structure. Meanwhile, the compressive strength of CPC…

Nerve conduits may represent a valuable alternative to autograft for the regeneration of long-gap damages. However, no NCs have currently reached market approval for the regeneration of limiting gap lesions, which still represents the very bottleneck of this technology. In recent years, a strong effort has been made to envision an engineered graft to tackle this issue. In our recent work, we presented a novel design of porous/3D-printed chitosan/poly-ε-caprolactone conduits, coupling freeze drying and additive manufacturing technologies to yield conduits with good structural properties. In this work, we studied genipin crosslinking as strategy to improve the physiochemical properties of our…

The repair of nasal cartilage lesions and defects is still a difficult problem in nasal surgery, and nasal cartilage tissue engineering will be an effective way to solve this problem. Hydrogel has excellent application potential in tissue engineering. In order to produce a 3D printable scaffold for cartilage regeneration, we prepared gelatin methacryloyl (GelMA)/hyaluronic acid methacryloyl (HAMA)/bacterial cellulose (BC) composite hydrogel. The composite hydrogel was characterized by swelling, mechanical properties, and printing performance test. Compared with GelMA/HAMA hydrogel, the addition of BC not only significantly enhanced the mechanical properties of the hydrogels, but also improved the printing fidelity. At the…

Decellularized extracellular matrices (ECMs) are being extensively used for tissue engineering purposes and detergents are predominantly used for this. A facile detergent-free decellularization method is developed for dermal matrix and compared it with the most used detergent-based decellularization methods. An optimized, single-step, cost-effective Hypotonic/Hypertonic (H/H) Sodium Chloride (NaCl) solutions-based method is employed to decellularize goat skin that resulted in much higher yield than other methods. The ECM composition, mechanical property, and cytocompatibility are evaluated and compared with other decellularization methods. Furthermore, this H/H-treated decellularized dermal ECM (ddECM) exhibits a residual DNA content of <50 ng mg−1 of dry tissue. Moreover, 85.64 ± 3.01% of glycosaminoglycans…

3D bioprinting enables the fabrication of biomimetic cell-laden constructs for cartilage regeneration, offering exclusive strategies for precise pharmacological screenings in osteoarthritis (OA). Synovial inflammation plays a crucial role in OA’s early stage and progression, characterized by the increased of the synovial pro-inflammatory mediators and cytokines and chondrocyte apoptosis. Therefore, there is an urgent need to develop solutions for effectively managing the primary events associated with OA. To address these issues, a phenolic-based biocompatible ionic liquid approach, combining alginate (ALG), acemannan (ACE), and cholinium caffeate (Ch[Caffeate]), was used to produce easily printable bioinks. Through the use of this strategy 3D constructs…

Fibrosis is shared in multiple diseases with progressive tissue stiffening, organ failure and limited therapeutic options. This unmet need is also due to the lack of adequate pre-clinical models to mimic fibrosis and to be challenged novel by anti-fibrotic therapeutic venues. Here using bioprinting, we designed a novel 3D model where normal human healthy fibroblasts have been encapsulated in type I collagen. After stimulation by Transforming Growth factor beta (TGFβ), embedded cells differentiated into myofibroblasts and enhanced the contractile activity, as confirmed by the high level of α − smooth muscle actin (αSMA) and F-actin expression. As functional assays, SEM…

A modular reinforced bone scaffold with enhanced mechanical properties has recently been developed by our group. It includes: 1) A load-bearing module: a skeleton which is made of a slowly degradable material, undertaking mechanical necessities of the scaffold, and 2) A bio-reactive module: a porous and biodegradable component undertaking biological necessities of the scaffold. The load-bearing module is placed into the bio-reactive module to reinforce it. This paper is dedicated to optimizing the load-bearing module for a certain customized alveolar bone defect. More specifically, a 3D-printed skeleton, made of polycaprolactone (PCL), is optimized based on the boundary conditions of the…

Critical-sized bone defects, caused by congenital disorders or trauma, are defects that will not heal spontaneously and require surgical intervention. Recent advances in biomaterial design for the treatment of such defects focus on improving their osteoinductive properties. Here, we propose a bioactive composite with high ceramic content composed of poly(ethyleneoxide terephthalate)/poly(butylene terephthalate) (1000PEOT70PBT30, PolyActive, PA) and 50 % beta-tricalcium phosphate (β-TCP) with the addition of zinc in a form of a coating on the TCP particles. Due to its essential role in bone homeostasis, we hypothesised that the addition of zinc to the polymer-ceramic composite will further enhance its osteogenic…

Corneal transplantation remains gold standard for the treatment of severe cornea diseases, however, scarcity of donor cornea is a serious bottleneck. 3D bioprinting holds tremendous potential for cornea tissue engineering (TE). One of the key technological challenges is to design bioink compositions with ideal printability and cytocompatibility. Photo-crosslinking and ionic crosslinking are often used for the stabilization of 3D bioprinted structures, which can possess limitations on biological functionality of the printed cells. Here, we developed a hyaluronic acid-based dopamine containing bioink using hydrazone crosslinking chemistry for the 3D bioprinting of corneal equivalents. First, the shear thinning property, viscosity, and mechanical…

Implant-associated infections are not easy to diagnose and very difficult to treat, due to the ability of major pathogens, such as Staphylococcus aureus, to develop biofilms and escape the immune response and antibiotic treatment. We, therefore, aimed to develop a 3D-printed dual rifampicin (Rif)- and vancomycin (Van)-loaded polylacticco-glycolic acid (PLGA) nanoparticles (NPs) delivery system based on hydrogels made of gelatin methacrylate (GelMA). The release of Rif and Van from NPs manufactured from different PLGA molecular weights was studied in phosphate-buffered saline for 21 days. Low molecular weight PLGA NPs exhibited the fastest release of Rif and Van within the first…

More relevant human tissue models are needed to produce reliable results when studying disease mechanisms of genetic diseases and developing or testing novel drugs in cardiac tissue engineering (TE). Three-dimensional (3D) bioprinting enables physiologically relevant positioning of the cells inside the growth matrix according to the detailed digital design. Here we combined human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes (CMs) with methacrylated gelatin (GelMA) and collagen I-based bioink and 3D extrusion bioprinted a cardiac in vitro model for disease modeling and drug screening. Bioprinted constructs were characterized for their rheological properties, swelling behavior, degradation, as well as shape fidelity. The…

Myocardial infarction (MI) is a lethal cardiac disease that causes most of the mortality across the world. MI is a consequence of plaque in the arterial walls of heart, which eventually result in occlusion and ischemia to the myocardial tissues due to inadequate nutrient and oxygen supply. As an efficient alternative to the existing treatment strategies for MI, 3D bioprinting has evolved as an advanced tissue fabrication technique where the cell–laden bioinks are printed layer–by–layer to create functional cardiac patches. In this study, a dual crosslinking strategy has been utilized towards 3D bioprinting of myocardial constructs by using a combination…

The development of suitable bioinks is an important research topic in the field of three-dimensional (3D) bioprinting. Herein, novel hydrogel-based bioinks composed of nanofibrillated cellulose (NFC) and gellan gum (GG) in different NFC/GG mass proportions (90:10, 80:20, 70:30, and 60:40) were developed and characterized. The increase in the content of GG, as well as its combination with NFC, enhanced their rheological properties, increasing both storage (G’) and loss (G”) moduli and the G’ recovery capacity of the hydrogels (from 70.05 ± 3.06 % (90:10) to 82.63 ± 1.21 % (60:40)), as well as their mechanical properties, increasing the compressive stiffness…

Extrusion-based three-dimensional (3D) printing of gelatin is important for additive manufactured tissue engineering scaffolds, but gelatin’s thermal instability has remained an ongoing challenge. The gelatin tends to suddenly collapse at mild temperatures, which is a significant limitation for using it at physiological temperature of 37 °C. Hence, fabrication of a thermo-processable gelatin hydrogel adapted for extrusion-based additive manufacturing is still a challenge. To achieve this, a self-healing nanocomposite double-network (ncDN) gelatin hydrogel was fabricated with high thermo-processability, shear-thinning, mechanical strength, self-healing, self-recovery, and biocompatibility. To do this, amino group-rich gelatin was first created by combining gelatin with carboxyl methyl chitosan.…

Background To investigate the effect of low-intensity pulsed ultrasound (LIPUS) combined with lipid microbubbles on the proliferation and bone regeneration of bone marrow mesenchymal stem cells (BMSCs) in poly (lactic-glycolic acid copolymer) (PLGA)/α-tricalcium phosphate (TCP) 3D-printed scaffolds. Methods BMSCs were irradiated with different LIPUS parameters and microbubble concentrations, and the best acoustic excitation parameters were selected. The expression of type I collagen and the activity of alkaline phosphatase were detected. Alizarin red staining was used to evaluate the calcium salt production during osteogenic differentiation. Results BMSCs proliferation was the most significant under the condition of 0.5% (v/v) lipid microbubble concentration,…

Calcific aortic valve disease (CAVD) is a frequent cardiac pathology in the aging society. Although valvular interstitial cells (VICs) seem to play a crucial role, mechanisms of CAVD are not fully understood. Development of tissue-engineered cellular models by 3D-bioprinting may help to further investigate underlying mechanisms of CAVD. VIC were isolated from ovine aortic valves and cultured in Dulbecco’s modified Eagle’s Medium (DMEM). VIC of passages six to ten were dissolved in a hydrogel consisting of 2% alginate and 8% gelatin with a concentration of 2 × 106 VIC ml−1. Cell-free and VIC-laden hydrogels were printed with an extrusion-based 3D-bioprinter…

Extrusion additive manufacturing is widely used to fabricate polymer-based 3D bone scaffolds. However, the insight views of crystal growths, scaffold features and eventually cell-scaffold interactions are still unknown. In this work, melt and solvent extrusion additive manufacturing techniques are used to produce scaffolds considering highly analogous printing conditions. Results show that the scaffolds produced by these two techniques present distinct physiochemical properties, with melt-printed scaffolds showing stronger mechanical properties and solvent-printed scaffolds showing rougher surface, higher degradation rate, and faster stress relaxation. These differences are attributed to the two different crystal growth kinetics, temperature-induced crystallization (TIC) and strain-induced crystallization (SIC),…

Self-healable degradable networks encounter a growing popularity for biomedical applications due to their ability to recover their properties after damage. Self-healable hydrogels dominate with applications in tissue engineering and drug delivery. On the opposite and despite their potential for medical devices, self-healable elastomers remain scarce, especially if they must be compatible with fused deposition modeling (FDM) 3D-printing and self-heal at physiological temperature under a hydrated state. These unmet challenges are addressed in this work with degradable elastomeric networks based on dynamic imine bonds prepared from multi(aldehyde) and multi(amine) hydrophobic PEG-PLA star-shaped copolymers. The star topology of these copolymers is the…

The parathyroid glands are localized at the back of the thyroid glands in the cervical region and are responsible for regulation of the calcium level in the blood, through specialized cells that sense Ca2+ and secrete parathyroid hormone (PTH) in response to a decline in its serum level. PTH stimulates the skeleton, kidneys and intestines and controls the level of Ca2+ through specialized activities. Iatrogenic removal of the parathyroid gland, as well as damage to its vascular integrity during cauterization are some of the common complications of thyroid surgery. Therefore, regeneration and/or replacement of malfunctioning parathyroid tissue is required. Tissue…

3D bioprinting is a versatile technique that allows the fabrication of living tissue analogs through the layer-by-layer deposition of cell-laden biomaterials, viz. bioinks. In this work, composite alginate hydrogel-based bioinks reinforced with curcumin-loaded particles of cellulose esters (CEpCUR) and laden with human keratinocytes (HaCaT) are developed. The addition of the CEpCUR particles, with sizes of 740 ± 147 nm, improves the rheological properties of the inks, increasing their shear stress and viscosity, while preserving the recovery rate and the mechanical and viscoelastic properties of the resulting fully cross-linked hydrogels. Moreover, the presence of these particles reduces the degradation rate of…

The composite, thermoplastic material composed of polyhydroxybutyrate (PHB) and polylactic acid (PLA) was seeded with stem cells in the experiment. Tests of the polymer were oriented towards biocompatibility in vitro using mesenchymal stem cells isolated from the chorion. PHB/PLA is a currently tested biopolymer for applications in and medicine. Using additive technology, 3D forms of scaffolds in the form of a grid were prepared, which were seeded with stem cells and cultivated in suitable conditions. After an interval of 5 days, the proliferation and viability of the mesenchymal stem cells was tested by the proliferation test. From the results, it…

4D printing of shape memory polymers (SMPs) endows the 3D printed structures with tunable shape-changing behavior and functionalities that opens up new avenues towards intelligent devices. Multiple-SMPs, specially, could memorize more than two shapes that have greatly extended the performance of 4D printed structures. However, the actuation to trigger the shape change of 4D printed multiple-SMPs is usually by direct heating to different temperatures. It hasn’t brought the full superiority of the programmability of multiple-SMPs with distinct responsive regions that could be sequentially and selectively actuated by various stimuli. Besides, the functionality of multi-material based additive manufacturing is another area…

Background Poly(3-caprolactone) (PCL)/β-tricalcium phosphate (β-TCP) composite scaffolds fabricated by three-dimensional (3D) printing are one of the common scaffolds for bone tissue regeneration. However, the main challenge of these 3D printed PCL/β-TCP scaffolds is the fact that many cells pass from porosities during in vitro cell seeding, leading to poor initial cell attachment. This study aimed to demonstrate the fabrication of a new collagen coating process for optimizing the hydrophilic property and cell-substrate interactions. This method may be used for coating collagen on any relevant biomedical constructs made of synthetic polymers to increase their biocompatibility and cell attachment. Materials and methods…

3D Bioprinting plays an irreplaceable role in bone tissue engineering. Shellac and curcumin are two natural compounds that are widely used in the food and pharmaceutical sectors. In this study, a new composite scaffold with good biocompatibility and antibacterial ability was manufactured by adding shellac and curcumin into the traditional bone scaffold through low-temperature three-dimensional printing (LT-3DP), and its impact on the osteoimmune microenvironment was evaluated.

Introduction The use of scaffolds in tissue engineering is becoming increasingly important as solutions need to be found to preserve human tissues such as bone or cartilage. Various factors, including cells, biomaterials, cell and tissue culture conditions, play a crucial role in tissue engineering. The in vivo environment of the cells exerts complex stimuli on the cells, thereby directly influencing cell behavior, including proliferation and differentiation. Therefore, to create suitable replacement or regeneration procedures for human tissues, the conditions of the cells’ natural environment should be well mimicked. Therefore, current research is trying to develop 3-dimensional scaffolds (scaffolds) that can…

Decellularized extracellular matrix hydrogel (dECM-G) has demonstrated its significant tissue-specificity, high biocompatibility, and versatile utilities in tissue engineering. However, the low mechanical stability and fast degradation are major drawbacks for its application in three-dimensional (3D) printing. Herein, we report a hybrid hydrogel system consisting of dECM-Gs and photocrosslinkable gelatin methacrylate (GelMA), which resulted in significantly improved printability and structural fidelity. These premixed hydrogels retained high bioactivity and tissue-specificity due to their containing dECM-Gs. More specifically, it was realized that the hydrogel containing dECM-G derived from porcine peripheral nerves (GelMA/pDNM-G) effectively facilitated neurite growth and Schwann cell migration from two-dimensional cultured…

Human brain organoids present a new paradigm for modeling human brain organogenesis, providing unprecedented insight to the molecular and cellular processes of brain development and maturation. Other potential applications include in vitro models of disease and tissue trauma, as well as three-dimensional (3D) clinically relevant tissues for pharmaceuticals development and cell or tissue replacement. A key requirement for this emerging technology in both research and medicine is the simple, scalable, and reproducible generation of organoids using reliable, economical, and high-throughput culture platforms. Here we describe such a platform using a defined, clinically compliant, and readily available hydrogel generated from gelatin…

Gelatin methacrylate (GelMA) is a widely used biomaterial in tissue engineering and regenerative medicine. GelMA is a chemically modified form of gelatin. Researchers have employed various methods to synthesize GelMA, such as the conventional method (Bulcke et al. 2000), the sequential method (Lee et al. 2015), and facile one-pot (Shirahama et al. 2016) methods to achieve GelMA hydrogels with a wide range of degree of functionalization or methacrylation. However, the impact of these different synthesis methods and their reac- tion parameters on GelMA hydrogels and scaffolds remains to be investigated concerning bioink formulation and 3D printing application. In this study,…

3D bioprinting technology has gained increased attention in the regenerative medicine and tissue engineering communities over the past decade with their attempts to create functional living tissues and organs de novo. While tissues such as skin, bone, and cartilage have been successfully fabricated using 3D bioprinting, there are still many technical and process driven challenges that must be overcome before a complete tissue engineered solution is realized. Although there may never be a single adopted bioprinting process in the scientific community, adherence to optimized bioprinting protocols could reduce variability and improve precision with the goal of ensuring high quality printed…

A modular design composed of 3D-printed polycaprolactone (PCL) as the load-bearing module, and dual porosity gelatin foam as the bio-reactive module, was developed and characterized in this study. Surface treatment of the PCL module through aminolysis-aldehyde process was found to yield a stronger interface bonding compared to NaOH hydrolysis, and therefore was used in the fabrication procedure. The modular scaffold was shown to significantly improve the mechanical properties of the gelatin foam. Both compressive modulus and ultimate strength was found to increase over 10 times when the modular design was employed. The bio-reactive module i.e., gelatin foam, presented a dual…

Cultivated meat harnesses tissue engineering (TE) concepts to create sustainable, edible muscle tissues, for addressing the rising meat product demands and their global consequences. As 3D-printing is a promising method for creating thick and complex structures, two plant-protein-enriched scaffolding compositions were primarily assessed in our work as 3D-printable platforms for bovine satellite cells (BSC) maturation. Mixtures of pea protein isolate (PPI) and soy protein isolate (SPI) with RGD-modified alginate (Alginate(RGD)) were evaluated as prefabricated mold-based and 3D-printed scaffolds for BSC cultivation, and ultimately, as potential bioinks for cellular printing. Mold-based protein enriched scaffolds exhibited elevated stability and stiffness compared to…

Bacterial infection is an important challenge when repairing bone defects with implant materials. The development of functional scaffolds with an intelligent antibacterial function that can be used for bone repair are of great significance. In this study, we used vancomycin (VAN) as a model antibiotic drug and proposed the fabrication of VAN-loaded zeolite imidazole framework-8-functionalized bioglass (ZIF-8@VAN@BG) scaffolds with a pH-responsive antibacterial effect for use in potentially infected bone repair applications. The physicochemical properties, in vitro biological properties and antibacterial properties of the scaffolds were studied. The results showed that the ZIF-8@VAN@BG scaffolds had a 3D porous structure and exhibited…

4D printing is an advanced manufacturing technology combining additive manufacturing with smart materials. Based on light-active shape memory composites, smart medical structures with remote control capability, therapeutic function, and biocompatibility are hopefully fabricated by 4D printing. Here, a multifunctional composite with good mechanical properties, biocompatibility, and light-active shape memory performance is prepared by incorporating gold nanoparticles into a shape memory polyurethane matrix. The composites demonstrate a rapid and stable light-thermal effect, which can achieve localized and controlled breast tumor ablation, providing an approach to hyperthermia treatment for cancer cells. By directly bioprinting the composite melt, a series of 4D-printed structures…

The cultured meat is the solution to reduce resources using in a traditional meat production. It helps produce meat without killing livestock and decrease residue products. The method could also integrate with scaffold’s material which does not derive from animal products. This study aims to investigate the effects of carboxymethyl cellulose (CMC) and apple powder on printability and cytotoxicity as additives in alginate/agarose-based hydrogel. 3D structures of them were printed to find a proper printing condition. From our experiments, the structure could maintain their shapes and uniform line sizes for carboxylmethyl cellulose, but not for apple powder at the 2%…

Regenerative biomaterials play a crucial role in the success of maxillofacial reconstructive procedures. Yet today, limited options are available when choosing polymeric biomaterials to treat critical size bony defects. Further, there is a requirement for 3D printable regenerative biomaterials to fabricate customized structures confined to the defect site. We present here a 3D printable composite formulation consisting of polycaprolactone (PCL) and silk fibroin microfibers and have established a robust protocol for fabricating customized 3D structures of complex geometry with the composite. The 3D printed composite scaffolds demonstrated higher compressive modulus than 3D printed scaffolds of PCL alone. Furthermore, the compressive…

Three-dimensional (3D) printed hydrogel scaffolds enhanced with ceramics have shown potential applications for cartilage regeneration, but leaving biological and mechanical properties to be desired. This paper presents our study on the development of chitosan /alginate scaffolds with nano hydroxyapatite (nHA) by combining 3D printing and impregnating techniques, forming a hybrid, yet novel, structure of scaffolds for potential cartilage regeneration. First, we incorporated nHA into chitosan scaffold printing and studied the printability by examining the difference between the printed scaffolds and their designs. Then, we impregnated alginate with nHA into the printed chitosan scaffolds to forming a hybrid structure of scaffolds;…

The efficiency of nerve guide conduits (NGCs) in repairing peripheral nerve injury is not high enough yet to be a substitute for autografts and is still insufficient for clinical use. To improve this efficiency, 3D electrospun scaffolds (3D/E) of poly(l-lactide-co-ε-caprolactone) (PLCL) and poly(l-lactide-co-glycolide) (PLGA) were designed and fabricated by the combination of 3D printing and electrospinning techniques, resulting in an ideal porous architecture for NGCs. Polypyrrole (PPy) was deposited on PLCL and PLGA scaffolds to enhance biocompatibility for nerve recovery. The designed pore architecture of these “PLCL-3D/E” and “PLGA-3D/E” scaffolds exhibited a combination of nano- and microscale structures. The mean…

Introduction The use of scaffolds in tissue engineering is becoming increasingly important as solutions need to be found for the problem of preserving human tissue, such as bone or cartilage. In this work, scaffolds were printed from the biomaterial known as polycaprolactone (PCL) on a 3D Bioplotter. Both the external and internal geometry were varied to investigate their influence on mechanical stability and biocompatibility. Materials and Methods: An Envisiontec 3D Bioplotter was used to fabricate the scaffolds. First, square scaffolds were printed with variations in the strand width and strand spacing. Then, the filling structure was varied: either lines, waves,…

Direct ink writing (DIW) is a promising extrusion-based 3D printing technology, which employs an ink-deposition nozzle to fabricate 3D scaffold structures with customizable ink formulations for tissue engineering applications. However, determining the optimal DIW process parameters such as temperature, pressure, and speed for the specific ink is essential to achieve high reproducibility of the designed geometry and subsequent mechano-biological performance for different applications, particularly for porous scaffolds of finite sizes (total volume > 1000 mm3) and controlled pore size and porosity. The goal of this study was to evaluate the feasibility of fabricating Polycaprolactone (PCL) and bio-active glass (BG) composite-based…

In the literature, many studies have described the 3D printing of ceramic-based scaffolds (e.g., printing with calcium phosphate cement) in the form of linear structures with layer rotations of 90°, although no right angles can be found in the human body. Therefore, this work focuses on the adaptation of biological shapes, including a layer rotation of only 1°. Sample shapes were printed with calcium phosphate cement using a 3D Bioplotter from EnvisionTec. Both straight and wavy spokes were printed in a round structure with 12 layers. Depending on the strand diameter (200 and 250 µm needle inner diameter) and strand…

An ideal artificial bone implant should have similar mechanical properties and biocompatibility to natural bone, as well as an internal structure that facilitates stomatal penetration. In this work, 3D printing was used to fabricate and investigate artificial bone composites based on HA-ZrO2-PVA. The composites were proportionally configured using zirconia (ZrO2), hydroxyapatite (HA) and polyvinyl alcohol (PVA), where the ZrO2 played a toughening role and PVA solution served as a binder. In order to obtain the optimal 3D printing process parameters for the composites, a theoretical model of the extrusion process of the composites was first established, followed by the optimization…

Flowable photocurable resins can be printed effectively by stereolithographic 3D printing for dental applications; however, the 3D-printed objects’ mechanical properties cannot meet the requirements for the dental restorative materials. In this study, a strong customized crown for tooth repair was first prepared via direct ink writing 3D printing from a high-viscosity hybrid paste of acrylic monomer and multi-scale inorganic particles. The results showed that the hybrid resin-based composites (RBCs) could be printed successfully and smoothly through a metal nozzle with a gradually shrinking channel. The theoretical simulation of finite element methods was consistent with the experiment results. The printed objects…

We report herein the fabrication of a pectin-based scaffold (6 wt% pectin, 3 wt% alginate) with high resolution (small-diameter rods), small pores, and interconnected porosity using a low temperature 3D printing process known as freeze-printing. The ability to successfully print natural polymers has been a long-standing challenge in the field of additive manufacturing of polymeric tissue scaffolds. This is due to the slow evaporation rate of the aqueous solvent, which leads to unstable structures. This problem has been addressed by utilizing the fast solidification rate of the freeze-printing process. Scaffolds with a hgresolution (rod-diameter of 83 ± 14 µm), small…

The excellent rheological property has legitimated the suitability of starch hydrogel for extrusion-based 3D printing. However, the inability to promote cell attachment and migration has precluded the non-modified starch hydrogel from direct applications in the biomedical field. Herein, a novel 3D printable nanocomposite starch hydrogel is developed with highly enhanced biocompatibility for promoting 3D cell growth, by formulating with gelatin nanoparticles and collagen. The rheological evaluation reveals the shear-thinning and thixotropic properties of the starch-based hydrogel, as well as the combinatorial effect of collagen and gelatin nanoparticles on maintaining printability and 3D shape fidelity. The homogeneous microporous structure with abundant…

Massive oral and maxillofacial bone defect regeneration remains a major clinical challenge due to the absence of functionalized bone grafts with ideal mechanical and proregeneration properties. In the present study, Laponite (LAP), a synthetic nanosilicate, is incorporated into polycaprolactone (PCL) to develop a biomaterial for bone regeneration. It is explored whether LAP-embedded PCL would accelerate bone regeneration by orchestrating osteoblasts to directly and indirectly induce bone regeneration processes. The results confirmed the presence of LAP in PCL, and LAP is distributed in the exfoliated structure without aggregates. Incorporation of LAP in PCL slightly improved the compressive properties. LAP-embedded PCL is…

This article reports tunable crosslinking, reversible phase transition, and three-dimensional printing (3DP) of hyaluronic acid (HyA) hydrogels via dynamic coordination of Fe3+ ions with their innate carboxyl groups for the first time. The concentrations of Fe3+ and H+ ions and the reaction time determine the tunable ratios of mono-, bi-, and tridentate coordination, leading to the low-to-high crosslinking densities and reversible solid–liquid phase transition of HyA hydrogels. At the monodentate-dominant coordination, the liquid hydrogels have low crosslinking densities (HyA_L). At the mixed coordination of mono-, bi-, and tridentate bonding, the solid hydrogels have medium crosslinking densities (HyA_M). At the tridentate-dominant…

Pressure-assisted coating (PAC) is introduced to coat 3D-printed polymeric scaffolds with β-tricalcium phosphate (β-TCP) for tissue engineering applications. The method consists of four steps: infiltration of ceramic particles into the porous structure of the polymeric scaffold, dehydration of the slurry, compaction of ceramic particles around the scaffold, and heat treatment. The optimal coating is obtained at an infiltration speed of 400 mm/min followed by complete dehydration, compaction under ca. 8 MPa pressure, and subsequent heat treatment at 65 °C. The outcome is a uniformly coated scaffold with no deformation or structural defects, as confirmed by micro-CT analysis and laser and…

The field of 3D cell cultures is currently emerging, and material development is essential in striving toward mimicking the microenvironment of a native tissue. By using the response of reporter cells to a 3D environment, a comparison between materials can be assessed, allowing optimization of material composition and microenvironment. Of particular interest, the response can be different in a normoxic and hypoxic culturing conditions, which in turn may alter the conclusion regarding a successful recreation of the microenvironment. This study aimed at determining the role of such environments to the conclusion of a better resembling cell culture model to native…

The development of 3D printing techniques has provided a promising platform to study tissue engineering and mechanobiology; however, the pursuit of printability limits the possibility of tailoring scaffolds’ mechanical properties. The brittleness of those scaffolds also hinders potential clinical application. To overcome these drawbacks, a double-network ink composed of only natural biomaterials is developed. A shear-thinning hydrogel made of silk fibroin (SF) and methacrylated hyaluronic acid (MAHA) presents a high mechanical modulus with a low concentration of macromers. The physical cross-linking due to protein folding further increases the strength of the scaffolds. The proposed SF/MAHA scaffold exhibits a storage modulus…

In the past decade, cartilage tissue engineering has arisen as a promising therapeutic option for degenerative joint diseases, such as osteoarthritis, in the hope of restoring the structure and physiological functions. Hydrogels are promising biomaterials for developing engineered scaffolds for cartilage regeneration. However, hydrogel-delivered mesenchymal stem cells or chondrocytes could be exposed to elevated levels of reactive oxygen species (ROS) in the inflammatory microenvironment after being implanted into injured joints, which may affect their phenotype and normal functions and thereby hinder the regeneration efficacy. To attenuate ROS induced side effects, a multifunctional hydrogel with an innate anti-oxidative ability was produced…

The use of porous 3D scaffolds for the repair of bone nonunion and osteoporotic bone is currently an area of great interest. Using a combination of thermally-induced phase separation (TIPS) and 3D-plotting (3DP), we have generated hierarchical 3DP/TIPS scaffolds made of poly(lactic-co-glycolic acid) (PLGA) and nanohydroxyapatite (nHA). A full factorial design of experiments was conducted, in which the PLGA and nHA compositions were varied between 6‒12% w/v and 10‒40% w/w, respectively, totaling 16 scaffold formulations with an overall porosity ranging between 87%‒93%. These formulations included an optimal scaffold design identified in our previous study. The internal structures of the scaffolds…

Advances in 3D bioprinting allows not only controlled deposition of cells or cell-laden hydrogels but also flexibility in creating constructs that match the anatomical features of the patient. This is especially the case for reconstructing the pinna (ear), which is a large feature of the face and made from elastic cartilage that primarily relies on diffusion for nutrient transfer. The selection of cell lines for reconstructing this cartilage becomes a crucial step in clinical translation. Chondrocytes and mesenchymal stem cells are both studied extensively in the area of cartilage regeneration as they are capable of producing cartilage in vitro. However,…

Micropores are essential for tissue engineering to ensure adequate mass transportation for embedded cells. Despite the considerable progress made by advanced 3D bioprinting technologies, it remains challenging to engineer micropores of 100 µm or smaller in cell-laden constructs. Here, a microgel-templated porogel (MTP) bioink platform is reported to introduce controlled microporosity in 3D bioprinted hydrogels in the presence of living cells. Templated gelatin microgels are fabricated with varied sizes (≈10, ≈45, and ≈100 µm) and mixed with photo-crosslinkable formulations to make composite MTP bioinks. The addition of microgels significantly enhances the shear-thinning and self-healing viscoelastic properties and thus the printability of bioinks…

The three-dimensional (3D)-printing processes reach increasing recognition as important fabrication techniques to meet the growing demands in tissue engineering. However, it is imperative to fabricate 3D tissue units, which contain cells that have the property to be regeneratively active. In most bio-inks, a metabolic energy-providing component is missing. Here a formulation of a bio-ink is described, which is enriched with polyphosphate (polyP), a metabolic energy providing physiological polymer. The bio-ink composed of a scaffold (N,O-carboxymethyl chitosan), a hydrogel (alginate) and a cell adhesion matrix (gelatin) as well as polyP substantially increases the viability and the migration propensity of mesenchymal stem…

Controlled release of drugs from medical implants is an effective approach to reducing foreign body reactions and infections. We report here on a one-step 3D printing strategy to create drug-eluting polymer devices with a drug-loaded bulk and a drug-free coating. The spontaneously formed drug-free coating dramatically reduces the surface roughness of the implantable devices and serves as a protective layer to suppress the burst release of drugs. A high viscosity liquid silicone that can be extruded based on its shear-thinning property and quickly vulcanize upon exposure to ambient moisture is used as the ink for 3D printing. S-Nitrosothiol type nitric…

Gelatin has emerged as a biocompatible polymer with high printability in scaffold-based tissue engineering. The aim of the current study was to investigate the potential of genipin-crosslinked 3D printed gelatin scaffolds for temporomandibular joint (TMJ) cartilage regeneration. Crosslinking with genipin increased the stability and mechanical properties, without any cytotoxic effects. Chondrogenic differentiation of human bone marrow-derived mesenchymal stem cells (hBMSC) on the scaffolds were compared to cell pellets and spheres. Although hBMSC seeded scaffolds showed a lower expression of chondrogenesis-related genes compared to cell pellets and spheres, they demonstrated a significantly reduced expression of collagen (COL) 10, suggesting a decreased…

The 3D printability of poly(l-lysine-ran–l-alanine) and four-arm poly(ethylene glycol) (P(KA)/4-PEG) hydrogels as 3D biomaterial inks was investigated using two approaches to develop P(KA)/4-PEG into 3D biomaterial inks. Only the “composite microgel” inks were 3D printable. In this approach, P(KA)/4-PEG hydrogels were processed into microparticles and incorporated into a polymer solution to produce a composite microgel paste. Polymer solutions composed of either 4-arm PEG-acrylate (4-PEG-Ac), chitosan (CS), or poly(vinyl alcohol) (PVA) were used as the matrix material for the composite paste. The three respective composite microgel inks displayed good 3D printability in terms of extrudability, layer-stacking ability, solidification mechanism, and 3D…

Tailor-made polymers are needed to fully exploit the possibilities of additive manufacturing, constructing complex, and functional devices in areas such as bioelectronics. In this paper, the synthesis of a conducting and biocompatible graft copolymer which can be 3D printed using direct melting extrusion methods is shown. For this purpose, graft copolymers composed by conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) and a biocompatible polymer polylactide (PLA) are designed. The PEDOT-g-PLA copolymers are synthesized by chemical oxidative polymerization between 3,4-ethylenedioxythiophene and PLA macromonomers. PEDOT-g-PLA copolymers with different compositions are obtained and fully characterized. The rheological characterization indicates that copolymers containing below 20 wt% of…

Fabrication of scaffolds using polymers and then cell seeding is a routine protocol of tissue engineering applications. Synthetic polymers have adequate mechanical properties to substitute for some bone tissue, but they are generally hydrophobic and have no specific cell recognition sites, which leads to poor cell affinity and adhesion. Some natural polymers, have high cell affinity but are mechanically weak and do not have the strength required as a bone supporting material. In the present study, 3D printed hybrid scaffolds were fabricated using PCL and GelMA carrying dental pulp stem cells (DPSCs), which is printed in the gaps between the…

Objective Alveolar bone defects can be highly variable in their morphology and, as the defect size increases, they become more challenging to treat with currently available therapeutics and biomaterials. This investigation sought to devise a protocol for fabricating customized clinical scale and patient-specific, bioceramic scaffolds for reconstruction of large alveolar bone defects. Methods Two types of calcium phosphate (CaP)-based bioceramic scaffolds (alginate/β-TCP and hydroxyapatite/α-TCP, hereafter referred to as hybrid CaP and Osteoink™, respectively) were designed, 3D printed, and their biocompatibility with alveolar bone marrow stem cells and mechanical properties were determined. Following scaffold optimization, a workflow was developed to use…

Although bioinks with both high printability and shape fidelity while maintaining high cell viability are developed, the biofunctionality of the resulting bioprinted construct is often overlooked. To address this, a methacrylated gelatin (GelMA)-based bioink biofunctionalized with bone particles (BPs) is developed as a personalized treatment strategy for bone regeneration. The bioink consists of incorporating BPs of various sizes (0–500 µm) in GelMA at various concentrations (ranging from 5 to 15% w/v). The printability of the bioink is systematically investigated and it is demonstrated that a 15% w/v BP-loading results in high print quality for 10% and 12.5% GelMA concentrations. Rheological…

3D printing of soft-tissue like cytocompatible single material constructs with appropriate mechanical properties remains a challenge. Hybrid printing technology provides an attractive alternative as it combines a cell-free ink for providing mechanical support with a bioink for housing embedded cells. Several hybrid printed structures have been developed, utilizing thermoplastic polymers such as polycaprolactone as structural support. These thermoplastics demonstrated limited structural integration with the cell-laden components, and this may compromise the overall performance. In this work, a hybrid printing platform is presented using two distinct hydrogel inks that share the same photo-crosslinking chemistry to enable simple fabrication and seamless structural…

The current study introduces two novel, smart polymer three-dimensional (3D)-printable interpenetrating polymer network (IPN) hydrogel biomaterials with favorable chemical, mechanical, and morphological properties for potential applications in traumatic brain injury (TBI) such as potentially assisting in the restoration of neurological function through closure of the wound deficit and neural tissue regeneration. Additionally, removal of injury matter to allow for the appropriate scaffold grafting may assist in providing a TBI treatment. Furthermore, due to the 3D printability of the IPN biomaterials, complex structures can be designed and fabricated to mimic the native shape and structure of the injury sight, which can…

Although allogeneic islet transplantation has been proposed as a therapy for type 1 diabetes, its success rate remains low. Disruption of both extracellular matrix (ECM) and dense vascular network during islets isolation are referred to as some of the main causes of their poor engraftment. Therefore, the recapitulation of the native pancreatic microenvironment and its prompt revascularization should be beneficial for long-term islet survival. In this study, we developed novel bioinks suitable for the microfluidic-assisted multi-material biofabrication of 3D porous pancreatic and vascular structures. The tissue-specific bioactivity was introduced by blending alginate either with pancreatic decellularized extracellular matrix powder (A_ECM)…

Beta-tricalcium phosphate (β-TCP)-based bioinks were developed to support direct-ink 3D printing-based manufacturing of macroporous scaffolds. Binding of the gelatin:β-TCP ink compositions was optimized by adding carboxymethylcellulose (CMC) to maximize the β-TCP content while maintaining printability. Post-sintering, the gelatin:β-TCP:CMC inks resulted in uniform grain size, uniform shrinkage of the printed structure, and included microporosity within the ceramic. The mechanical properties of the inks improved with increasing β-TCP content. The gelatin:β-TCP:CMC ink (25:75 gelatin:β-TCP and 3% CMC) optimized for mechanical strength was used to 3D print several architectures of macroporous scaffolds by varying the print nozzle tip diameter and pore spacing during…

Three-dimensional (3D) bioprinting is an emerging fabrication technique to create 3D constructs with living cells. Notably, bioprinting bioinks are limited due to the mechanical weakness of natural biomaterials and the low bioactivity of synthetic peers. This paper presents the development of a natural bioink from chicken eggwhite and sodium alginate for bioprinting cell-laden patches to be used in endothelialized tissue engineering applications. Eggwhite was utilized for enhanced biological properties, while sodium alginate was used to improve bioink printability. The rheological properties of bioinks with varying amounts of sodium alginate were examined with the results illustrating that 2.0–3.0% (w/v) sodium alginate…

Piezoelectric ceramics, such as BaTiO3, have gained considerable attention in bone tissue engineering applications thanks to their biocompatibility, ability to sustain a charged surface as well as improve bone cells’ adhesion and proliferation. However, the poor processability and brittleness of these materials hinder the fabrication of three-dimensional scaffolds for load bearing tissue engineering applications. For the first time, this study focused on the fabrication and characterisation of BaTiO3 composite scaffolds by using a multi-material 3D printing technology. Polycaprolactone (PCL) was selected and used as dispersion phase for its low melting point, easy processability and wide adoption in bone tissue engineering.…

Researchers have looked to cartilage tissue engineering to address the lack of cartilage regenerative capability related to cartilage disease/trauma. For this, a promising approach is extrusion-based three-dimensional (3D) printing technique to deliver cells, biomaterials, and growth factors within a scaffold to the injured site. This paper evaluates the printability of chitosan scaffolds for a cartilage tissue engineering, with a focus on identifying the influence of drying technique implemented before crosslinking on the improvement of chitosan printability. First, the printability of chitosan with concentrations of 8%, 10%, and 12% (w/v) was evaluated and 10% chitosan was selected for further studies. Then,…

Liquid deposition modeling (LDM) is an evolving three-dimensional (3D) printing approach that mainly utilizes polymer solutions to enable the fabrication of biomedical scaffolds under mild conditions. A deep understanding of the rheological properties of polymer printing inks and the features of yielded scaffolds are critical for a successful LDM based fabrication of biomedical scaffolds. In this work, polymer printing inks comprised of Poly(epsilon-caprolactone) (PCL), sodium chloride (NaCl), and trichloromethane (CHCl3) were prepared. The rheological properties, including extrudability (shear stress, viscosity, and shear-thinning) and self-supporting ability (viscosity) of all printing inks were analyzed. Then printing performance was evaluated by measuring the…

3D printing of cell laden bioinks has the potential to recapitulate the hierarchical and spatial complexity of native tissues. However, the addition of cells can alter physical properties of printable resins, which in turn may impede or induce cellular sedimentation or affect the printability and shape fidelity of the final construct. In this study we investigated these considerations by bioprinting gelatin methacrylate (GelMA) bioinks, loaded with various concentrations of mouse fibroblast cells (L929), using extrusion-based direct-write 3D printing (EDP). The impact of various cellular concentrations on viscosity, and temperature-driven gelation of GelMA was examined with a rheometer. The effect of…

Calcium silicate (CS) composite bone tissue engineering scaffolds were three-dimensionally printed using titanium metallic powders as the second strengthening phase for overcoming the inherent brittleness and fast degradability. In order to promote the sintering process of all composite scaffolds, mesoporous structure was further introduced into sol-gel-derived CS powders obtaining mesoporous CS (MCS) with larger surface area. The influences of mesoporous structure, sintering temperature and Ti content have been investigated through comparisons of the final scaffold composition, microstructure, compressive strength and in vitro stability. Results showed that CS matrix materials reacted with Ti could form less degradable CaTiO3 and TiC ceramic…

Osteochondral repair remains a significant clinical challenge due to the multiple tissue phenotypes and complex biochemical milieu in the osteochondral unit. To repair osteochondral defects, it is necessary to mimic the gradation between bone and cartilage, which requires spatial patterning of multiple tissue-specific cues. To address this need, we have developed a facile system for the conjugation and patterning of tissue-specific peptides by melt extrusion of peptide-functionalized poly(ε-caprolactone) (PCL). In this study, alkyne-terminated PCL was conjugated to tissue-specific peptides via a mild, aqueous, and Ru(II)-catalyzed click reaction. The PCL-peptide composites were then 3D printed by multimaterial segmented printing to generate…

Injuries affecting load bearing tendon tissues are a significant clinical burden and efficient treatments are still unmet. Tackling tendon regeneration, tissue engineering strategies aim to develop functional substitutes that recreate native tendon milieu. Tendon mimetic scaffolds capable of remote magnetic responsiveness and functionalized magnetic nanoparticles (MNPs) targeting cellular mechanosensitive receptors are potential instructive tools to mediate mechanotransduction in guiding tenogenic responses. In this work, we combine magnetically responsive scaffolds and targeted Activin A type II receptor in human adipose stem cells (hASCs), under alternating magnetic field (AMF), to synergistically facilitate external control over signal transduction. The combination of remote triggering…

The integration of multiscale micro- and macroenvironment has been demonstrated as a critical role in designing biomimetic scaffolds for peripheral nerve tissue regeneration. While it remains a remarkable challenge for developing a biomimetic multiscale scaffold for enhancing 3D neuronal maturation and outgrowth. Herein, we present a 3D bioprinted multiscale scaffold based on a modular bioink for integrating the 3D micro- and macroenvironment of native nerve tissue. Gelatin methacryloyl (GelMA)/Chitosan Microspheres (GC-MSs) were prepared by a microfluidic approach, and the effect of these microspheres on enhancing neurite outgrowth and elongation of PC12 cells was demonstrated. The 3D multiscale composite scaffolds were…

Biofabrication techniques such as microlithography and 3-D bioprinting have emerged in recent years as technologies capable of rendering complex, biocompatible constructs for biosensors, tissue and regenerative engineering and bioelectronics. While instruments and processes have been the subject of immense advancement, multifunctional bioinks have received less attention. A novel photocrosslinkable, hybrid bioactive and inherently conductive bioink formed from poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) nanomaterials within poly(2-hydroxyethyl methacrylate-co-polyethyleneglycol methacrylate) p(HEMA-co-EGMA) was used to render complex hydrogel constructs through microlithographic fabrication and 3-D printing. Constructs were directly compared through established metrics of acuity and fidelity, using side-by-side comparison of microarray grids, triangles incorporating angles 15–90°,…

Bone tissue plays an important role in supporting and protecting the structure and function of the human body. Bone defects are a common source of injury and there are many reconstruction challenges in clinical practice. However, 3D bioprinting of scaffolds provides a promising solution. Hydrogels have emerged as biomaterials with good biocompatibility and are now widely used as cell-loaded materials for bioprinting. This study involved three steps: First, sodium alginate (SA), gelatin (Gel), and nano-hydroxyapatite (na-HA) were mixed into a hydrogel and its rheological properties assessed to identify the optimum slurry for printing. Second, SA/Gel/na-HA bioscaffolds were printed using 3D…

Embedded bio-printing has fostered significant advances toward the fabrication of soft complex tissue-like constructs, by providing a physical support that allows the freeform shape maintenance within the prescribed spatial arrangement, even under gravity force. Current supporting materials still present major drawbacks for up-scaling embedded 3D bio-printing technology towards tissue-like constructs with clinically relevant dimensions. Herein, we report a a cost-effective and widely available supporting material for embedded bio-printing consisting on a continuous pseudo-plastic matrix of xanthan-gum (XG). This natural polisaccharide exhibits peculiar rheological properties that have enabled the rapid generation of complex volumetric 3D constructs with out-of-plane features. The freedom…

Improving the printability of pure, decellularized extracellular matrix (dECM) bio-ink without altering its physiological components has been a challenge in three-dimensional (3D) cell printing. To improve the printability of the bio-ink, we first investigated the digestion process of the powdered dECM material obtained from porcine tendons. We manifested the digestion process of tendon derived dECM powders, which includes dissolution, gelatinization and solubilization. After a short dissolution period (around 10 min), we observed a ‘High viscosity slurry’ status (3 h) of the dECM precursors, i.e. the gelatinization process, followed by the solubilization processes, i.e. a ‘Medium viscosity slurry’ period (12 h)…

A promising alternative to current treatment options for degenerative conditions of the temporomandibular joint (TMJ) is cartilage tissue engineering, using 3D printed scaffolds and mesenchymal stem cells. Gelatin, with its inherent biocompatibility and printability has been proposed as a scaffold biomaterial, but because of its thermoreversible properties, rapid degradation and inadequate strength it must be crosslinked to be stable in physiological conditions. The aim of this study was to identify non-toxic and effective crosslinking methods intended to improve the physical properties of 3D printed gelatin scaffolds for cartilage regeneration. Dehydrothermal (DHT), ribose glycation and dual crosslinking with both DHT and…

Three-dimensional (3D) bioprinting technologies have great attention in different researching areas such as tissue engineering, medicine, etc. due to its maximum mimetic property of natural biomaterials by providing cell combination, growth factors, and other biomaterials. Bioprinting of tissues, organs, or drug delivery systems emerged layer-by-layer deposition of bioinks. 3D bioprinting technique has some complexity such as choice of bioink combination, cell type, growth, and differentiation. In this study, a composite material in 3D bioprinting studies has been developed for biofabrication of the cell carrying scaffolds namely cryogenic scaffolds. Cryogenic scaffolds are highly elastic and have a continuous interconnected macroporous structure…

In tissue engineering, biomaterials have been used to steer the host response. This determines the outcome of tissue regeneration, which is modulated by multiple growth factors (GFs). Hence, a sustainable delivery system for GFs is necessary to control tissue regeneration actively. A delivery technique of single and multiple GF combinations, using a layer‐by‐layer (LBL) procedure to improve tissue remodeling, is developed. TGF‐β1, PDGF‐ββ, and IGF‐1 are incorporated on tailor‐made polymeric rods, which could be used as a tool for potential tissue engineering applications, such as templates to induce the formation of in situ tissue engineered blood vessels (TEBVs). Cell response…

Myocardial infarction (MI) or heart attack occurs when the bloodstream to the heart is blocked, which may destroy a part of the heart muscle (or myocardium) and form perdurable scarred tissue. The infarcted myocardial muscle nowadays has no revival treatments, and also transplantation is limited as an option. Tissue engineering has the potential to restore myocardial function after an MI by fabricating tailored tissues for treatment. For tissue engineering, three-dimensional (3D) bioprinting is a fabrication method to create 3D constructs with living cells, which would be impossible by other traditional methods. Although various biomaterials, biologically-derived or synthetic, are available, only…

Bone related diseases and disorders increasingly impact human health. Electrical stimulation (ES) has been shown to promote osteogenesis and healing of bone defects. Graphene, is an electrically conductive and biocompatible material with good mechanical properties (strength with flexibility), and therefore shows significant promise as a cell-compatible electrode for ES. Graphene-based scaffolds may therefore be used for 3D cell and tissue support, including 3D osteoinduction. We have fabricated 3D graphene electrode structures to provide ES to human adipose stem cells (ADSCs). The assemblies support ADSC growth and differentiation, with ES augmenting proliferation and osteogenesis. Our findings expand our previous work on…

3D bioprinting has been increasingly employed in skin tissue engineering for manufacturing living constructs with three-dimensional spatial precision and controlled architecture. There is however, a bottleneck in the tunability of bioinks to address specific biocompatibility challenges, functional traits and printability. Here we report on a traditional gelatin methacryloyl (GelMA) based bioink, tuned by addition of an ulvan type polysaccharide, isolated from a cultivated source of a specific Australian Ulvacean macroalgae (Ul84). Ul84 is a sulfate- and rhamnose-rich polysaccharide, resembling mammalian glycosaminoglycans that are involved in wound healing and tissue matrix structure and function. Printable bioinks were developed by addition of…

Herein, the cytotoxicity of a novel zwitterionic sulfobetaine hydrogel system with a nano-clay crosslinker has been investigated. We demonstrate that careful selection of the composition of the system (monomer to Laponite content) allows the material to be formed into controlled shapes using an extrusion based additive manufacturing technique with the ability to tune the mechanical properties of the product. Moreover, the printed structures can support their own weight without requiring curing during printing which enables the use of a printing-then-curing approach. Cell culture experiments were conducted to evaluate the neural cytotoxicity of the developed hydrogel system. Cytotoxicity evaluations were conducted…

High molecular weight polyhydroxymethylene (PHM) has a repeat unit identical to that of low molecular weight sugar alcohols and exhibits carbohydrate‐like properties. Herein, cryogenic extrusion‐based 3D printing is combined with a phase separation in water to fabricate hierarchically porous PHM scaffolds containing interconnected macro‐, micro‐, and nanopores. As PHM is infusible and insoluble in common solvents, its precursor polyvinylene carbonate (PVCA) dissolved in dimethylsulfoxide (DMSO) is used to 3D print hierarchically porous PVCA scaffolds that are converted into PHM by hydrolysis without impairing the pore architectures. Similar to low‐temperature deposition manufacturing, the PVCA/DMSO freezes on a build platform at −78…

Designing bone scaffolds containing both organic and inorganic composites simulating the architecture of the bone is the most important principle in bone tissue engineering. The objective of this study was to fabricate a composite scaffold containing poly (D, l)-lactide (PDLLA) and β-tricalcium phosphate (β-TCP) as a platform for osteogenic differentiation of adipose-derived mesenchymal stem cells. In this study, PDLLA/β-TCP scaffolds were fabricated using three-dimensional printing (3D) technology through melt excursion technique. The physicomechanical characteristics, including microstructure, mechanical properties, of the customized scaffolds were investigated. Further, the in vitro biological characteristics of manufactured scaffolds were evaluated in conjugation with buccal fat…

Breast cancer is a heterogeneous disease where the tumor microenvironment, including extracellular components, plays a crucial role in tumor progression, potentially modulating treatment response. Different approaches have been used to develop three‐dimensional models able to recapitulate the complexity of the extracellular matrix. Here, we use cell‐free patient‐derived scaffolds (PDSs) generated from breast cancer samples that were recellularized with cancer cell lines as an in vivo‐like culture system for drug testing. We show that PDS cultured MCF7 cancer cells increased their resistance against the front‐line chemotherapy drugs 5‐fluorouracil, doxorubicin and paclitaxel in comparison to traditional two‐dimensional cell cultures. The gene expression…

The ability to produce constructs with a high control over the bulk geometry and internal architecture has situated 3D printing as an attractive fabrication technique for scaffolds. Various designs and inks are actively investigated to prepare scaffolds for different tissues. In this work, we prepared 3D printed composite scaffolds comprising polycaprolactone (PCL) and various amounts of reduced graphene oxide (rGO) at 0.5, 1, and 3 wt.%. We employed a two-step fabrication process to ensure an even mixture and distribution of the rGO sheets within the PCL matrix. The inks were prepared by creating composite PCL-rGO films through solvent evaporation casting…

Here, we report a newly designed knee plug to be used in the 3rd generation of Autologous Chondrocyte Implantation (ACI) in order to heal the damaged knee cartilage. It is composed of three components: The first component (Bone Portion) is a 3D printed hard scaffold with large pores (~ 850 µm), made by hydroxyapatite and β-tricalcium phosphate to accommodate the bony parts underneath the knee cartilage. It is a cylinder with a diameter of 20 mm and height of 7.5 mm, with a slight dome shape on top. The plug also comprises a Cartilage Portion (component 2) which is a 3D…

In this study, porous bioglass/gelatin/alginate bone tissue engineering scaffolds were fabricated by three-dimensional printing. The compressive strength and in vitro biomineralization properties of the bioglass–gelatin–alginate scaffolds (BG/Gel/SA scaffolds) were significantly improved with the increase of bioglass content until 30% weight percentage followed by a rapid decline in strength. In addition, the cells attach and spread on the BG/Gel/SA scaffolds surfaces represents good adhesion and biocompatibility. Furthermore, the cells (rat bone marrow mesenchymal stem cells, mBMSCs) proliferation and osteogenic differentiation on the BG/Gel/SA scaffolds were also promoted with the increase of bioglass content. Overall, the adding of bioglass in Gel/SA scaffolds…

Regenerative repair of craniomaxillofacial bone injuries is challenging due to both the large size and irregular shape of many defects. Mineralized collagen scaffolds have previously been shown to be a promising biomaterial implant to accelerate craniofacial bone regeneration in vivo. Here we describe inclusion of a 3D-printed polymer or ceramic-based mesh into a mineralized collagen scaffold to improve mechanical and biological activity. Mineralized collagen scaffolds were reinforced with 3D-printed Fluffy-PLG (ultraporous polylactide-co-glycolide co-polymer) or Hyperelastic Bone (90wt% calcium phosphate in PLG) meshes. We show degradation byproducts and acidic release from the printed structures have limited negative impact on the viability…

This work reports the versatility of polydopamine (PD) when applied as a particle coating in a composite of polylactide (PLA). Polydopamine was observed to increase the particle–matrix interface strength and facilitate the adsorption of drugs to the material surface. Here, barium sulfate radiopaque particles were functionalized with polydopamine and integrated into a polylactide matrix, leading to the formulation of a biodegradable and X-ray opaque material with enhanced mechanical properties. Polydopamine functionalized barium sulfate particles also facilitated the adsorption and release of the antibiotic levofloxacin. Analysis of the antibacterial capacity of these composites and the metabolic activity and proliferation of human…

We present a solution to regenerate adipose tissue using degradable, soft, pliable 3D-printed scaffolds made of a medical-grade copolymer coated with polydopamine. The problem today is that while printing, the medical grade copolyesters degrade and the scaffolds become very stiff and brittle, being not optimal for adipose tissue defects. Herein, we have used high molar mass poly(L-lactide-co-trimethylene carbonate) (PLATMC) to engineer scaffolds using a direct extrusion-based 3D printer, the 3D Bioplotter®. Our approach was first focused on how the printing influences the polymer and scaffold’s mechanical properties, then on exploring different printing designs and, in the end, on assessing surface…

A major challenge in three-dimensional (3D) bioprinting is the limited number of bioinks that fulfill the physicochemical requirements of printing while also providing a desirable environment for encapsulated cells. Here, we address this limitation by temporarily stabilizing bioinks with a complementary thermo-reversible gelatin network. This strategy enables the effective printing of biomaterials that would typically not meet printing requirements, with instrument parameters and structural output largely independent of the base biomaterial. This approach is demonstrated across a library of photocrosslinkable bioinks derived from natural and synthetic polymers, including gelatin, hyaluronic acid, chondroitin sulfate, dextran, alginate, chitosan, heparin, and poly(ethylene glycol).…

Reduced periodontal support, deriving from chronic inflammatory conditions, such as periodontitis, is one of the main causes of tooth loss. The use of dental implants for the replacement of missing teeth has attracted growing interest as a standard procedure in clinical practice. However, adequate bone volume and soft tissue augmentation at the site of the implant are important prerequisites for successful implant positioning as well as proper functional and aesthetic reconstruction of patients. Three-dimensional (3D) scaffolds have greatly contributed to solve most of the challenges that traditional solutions (i.e., autografts, allografts and xenografts) posed. Nevertheless, mimicking the complex architecture and…

Osteocytes, essential regulators of bone homeostasis, are embedded in the mineralized bone matrix. Given the spatial arrangement of osteocytes, bioprinting represents an ideal method to biofabricate a 3D osteocyte network with a suitable surrounding matrix similar to native bone tissue. Here, we reported a 3D bioprinted osteocyte-laden hydrogel for biomimetic mineralization in vitro with exceptional shape fidelity, a high cell density (107 cells per ml) and high cell viability (85–90%). The bioinks were composed of biomimetic modified biopolymers, namely, gelatine methacrylamide (GelMA) and hyaluronic acid methacrylate (HAMA), with or without type I collagen. The osteocyte-laden constructs were printed and cultured…

Cell-laden cardiac patches have recently been emerging to renew cellular sources for myocardial infarction (MI, commonly know as a heart attack) repair. However, the fabrication of cell-laden patches with porous structure remains challenging due to the limitations of currently available hydrogels and existing processing techniques. The present study utilized a bioprinting technique to fabricate hydrogel patches and characterize them in terms of printability, mechanical and biological properties. Cell-laden hydrogel (or bio-ink) was formulated from alginate dialdehyde (ADA) and gelatin (GEL) to improve the printability, degradability as well as bioactivity. Five groups of hydrogel compositions were designed to investigate the influence…

Despite their outstanding potential and the success that has already been achieved with three-dimensional (3D) printed hydrogel scaffolds, there has been little investigation into their application in the regeneration of damaged or missing adipose tissue (AT). Due to their macroscopic shape, microarchitecture, extracellular matrix-mimicking structure, degradability and soft tissue biomimetic mechanical properties, 3D printed hydrogel scaffolds have great potential for use in aesthetic, structural and functional restoration of AT. Here, we propose a simple and cost-effective 3D printing strategy using gelatin-based ink to fabricate scaffolds suitable for AT engineering. The ink, successfully printed here for the first time, was prepared…

Patients with aortic heart valve disease are limited to valve replacements that lack the ability to grow and remodel. This presents a major challenge for pediatric patients who require a valve capable of somatic growth and at a smaller size. A patient-specific heart valve capable of growth and remodeling while maintaining proper valve function would address this major issue. Here, we recreate the native valve leaflet structure composed of poly-ε-caprolactone (PCL) and cell-laden gelatin-methacrylate/poly (ethylene glycol) diacrylate (GelMA/PEGDA) hydrogels using 3D printing and molding, and then evaluate the ability of the multilayered scaffold to produce collagen matrix under physiological shear…

The use of composite materials, processed as 3D tissue-like scaffolds, has been widely investigated as a promising strategy for bone tissue engineering applications. Also, additive manufacturing technologies such as fused deposition modelling (FDM) have greatly contributed to the manufacture of patient-specific scaffolds with predefined pore structures and intricate geometries. However, conventional FDM techniques require the use of materials exclusively in the form of filaments, which in order to produce composite scaffolds lead to additional costs for the fabrication of precursor filaments as well as multi-step production methods. In this study, we propose the use of an advantageous extrusion-based printing technology,…

Bone defects are common and, in many cases, challenging to treat. Tissue engineering is an interdisciplinary approach with promising potential for treating bone defects. Within tissue engineering, three-dimensional (3D) printing strategies have emerged as potent tools for scaffold fabrication. However, reproducibility and quality control are critical aspects limiting the translation of 3D printed scaffolds to clinical use, which remain to be addressed. To elucidate the factors that yield to the generation of defects in bioprinting and to achieve reproducible biomaterial printing, the objective of this article is to frame a systematic approach for optimizing and validating 3D printing of poly(caprolactone)…

In this work, we describe a new 3D printing methodology for the fabrication of multimaterial scaffolds involving the combination of thermoplastic extrusion and low temperature extrusion of bioinks. A fiber engraving technique was used to create a groove on the surface of a thermoplastic printed fiber using a commercial 3D printer and a low viscosity bioink was deposited into this groove. In contrast to traditional extrusion bioinks that rely on increased viscosity to prevent lateral spreading, this groove creates a defined space for bioink deposition. By physically constraining bioink spreading, a broader range of viscosities can be used. As proof-of-concept,…

As scaffolds approach dimensions that are of clinical relevance, mechanical integrity and distribution becomes an important factor to the overall success of the implant. Hydrogels often lack the structural integrity and mechanical properties for use in vivo or handling. The inclusion of a structural support during the printing process, referred to as hybrid printing, allows the implant to retain structure and protect cells during maturation without needing to compromise its biological performance. In this study, scaffolds for the purpose of auricular cartilage reconstruction were evaluated via a hybrid printing approach using methacrylated Gelatin (GelMA) and Hyaluronic acid (HAMA) as the…

As 3D printing becomes more common and the technique is used to build culture platforms, it is imperative to develop surface treatments for specific responses. The advantages of aminating and oxidizing polystyrene (PS) for human mesenchymal stem cell (hMSC) proliferation and osteogenic differentiation are investigated. We find that ammonia (NH3) plasma incorporates amines while oxygen plasma adds carbonyl and carboxylate groups. Across 2D, 3D, and 3D dynamic culture, we find that the NH3- treated surfaces encouraged cell proliferation. Our results show that the NH3-treated scaffold was the only treatment allowing dynamic proliferation of hMSCs with little evidence of osteogenic differentiation.…

In this study of three-dimensional (3D) printed composite β-tricalcium phosphate (β-TCP)-/hydroxyapatite/poly(ɛ-caprolactone)-based constructs, the effects of vertical compositional ceramic gradients and architectural porosity gradients on the osteogenic differentiation of rabbit bone marrow-derived mesenchymal stem cells (MSCs) were investigated. Specifically, three different concentrations of β-TCP (0, 10, and 20 wt%) and three different porosities (33% ± 4%, 50% ± 4%, and 65% ± 3%) were examined to elucidate the contributions of chemical and physical gradients on the biochemical behavior of MSCs and the mineralized matrix production within a 3D culture system. By delaminating the constructs at the gradient transition point, the spatial separation of cellular phenotypes could be specifically…

Synthetic polycaprolactone (PCL) was modified with various concentrations of gelatin (GL) to enhance its physical properties and biological activity for bone regeneration. A novel trisolvent mixture has been used to mix PCL and GL that were fabricated as scaffolds using 3D plotting. The scaffolds were characterized for their mechanical properties, hydrophilicity and swelling ability. In addition, the structure and morphology of the printed scaffolds were analyzed by Fourier-Transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and microcomputed tomography (μCT). Attachment, proliferation and osteogenic differentiation of rat bone marrow stromal cells (BMSC) cultured on the printed scaffolds were…

Conventional tough hydrogels offer enhanced mechanical properties and high toughness. Their application scope however is limited by their lack of processability. Here, a new porous tough hydrogel system is introduced which is processable via gel fiber spinning and 3D printing. The tough hydrogels are produced by rehydrating processable organogels developed by induced phase separation between two linear polymer chains capable of intermolecular hydrogen bonding. Through a slow sol–gel phase separation, highly porous gel networks made of hydrogen bonded polymer chains is formed. These organogels can be easily transformed to 3D printed multimaterial constructs or gel fibers, and after rehydration produce…

Scaffolds based on bioconjugated hydrogels are attractive for tissue engineering because they can partly mimic human tissue characteristics. For example, they can further increase their bioactivity with cells. However, most of the hydrogels present problems related to their processability, consequently limiting their use in 3D printing to produce tailor-made scaffolds. The goal of this work is to develop bioconjugated hydrogel nanocomposite inks for 3D printed scaffold fabrication through a micro-extrusion process having improved both biocompatibility and processability. The hydrogel is based on a photocrosslinkable alginate bioconjugated with both gelatin and chondroitin sulfate in order to mimic the cartilage extracellular matrix,…

Osteoarthritis is a degenerative joint disease that limits mobility of the affected joint due to the degradation of articular cartilage and subchondral bone. The limited regenerative capacity of cartilage presents significant challenges when attempting to repair or reverse the effects of cartilage degradation. Tissue engineered medical products are a promising alternative to treat osteochondral degeneration due to their potential to integrate into the patient’s existing tissue. The goal of this study was to create a scaffold that would induce site‐specific osteogenic and chondrogenic differentiation of human adipose‐derived stem cells (hASC) to generate a full osteochondral implant. Scaffolds were fabricated using…

There is a growing interest in developing 3D porous scaffolds with tunable architectures for bone tissue engineering. Surface topography has been shown to control stem cell behavior including differentiation. In this study, we printed 3D porous scaffolds with wavy or linear patterns to investigate the effect of wavy scaffold architecture on human mesenchymal stem cell (hMSC) osteogenesis. Five distinct wavy scaffolds were designed using sinusoidal waveforms with varying wavelengths and amplitudes, and orthogonal scaffolds were designed using linear patterns. We found that hMSCs attached to wavy patterns, spread by taking the shape of the curvatures presented by the wavy patterns,…

3D printing/bioprinting are promising techniques to fabricate scaffolds with well controlled and patient-specific structures and architectures for bone tissue engineering. In this study, we developed a composite bioink consisting of silk fibroin (SF), gelatin (GEL), hyaluronic acid (HA), and tricalcium phosphate (TCP) and 3D bioprinted the silk fibroin-based hybrid scaffolds. The 3D bioprinted scaffolds with dual crosslinking were further treated with human platelet-rich plasma (PRP) to generate PRP coated scaffolds. Live/Dead and MTT assays demonstrated that PRP treatment could obviously promote the cell growth and proliferation of human adipose derived mesenchymal stem cells (HADMSC). In addition, the treatment of PRP…

This paper introduces a kit of parts as a novel three‐dimensional (3D)–printed joint plug, in which each of the parts function cooperatively to treat cartilage damage in joints of the human body (e.g., hips, wrists, elbow, knee, and ankle). Three required and one optional parts are involved in this plug. The first part is a 3D‐printed hard scaffold (bone portion) to accommodate bone cells, and the second is a 3D‐printed soft scaffold (cartilage portion) overlying the bone portion to accommodate chondrocytes. The third part of joint plug is a permeable membrane, termed film, to cover the entire plug to provide…

Hyaluronic acid (HA)-based hydrogels are widely used in biomedical applications due to their excellent biocompatibility. HA can be Ultraviolet (UV)-crosslinked by modification with methacrylic anhydride (HA-MA) and crosslinked by modification with 3,3′-dithiobis(propionylhydrazide) (DTP) (HA-SH) via click reaction. In the study presented in this paper, a 3D-bioprinted, double-crosslinked, hyaluronic-acid-based hydrogel for wound dressing was proposed. The hydrogel was produced by mixing HA-MA and HA-SH at different weight ratios. The rheological test showed that the storage modulus (G’) of the HA-SH/HA-MA hydrogel increased with the increase in the HA-MA content. The hydrogel had a high swelling ratio and a high controlled degradation…

The field of 3D bioprinting has rapidly grown, yet the fundamental ability to manipulate material properties has been challenging with current bioink methods. Here, we change bioink properties using our PEG cross-linking (PEGX) bioink method with the objective of optimizing cell viability while retaining control of mechanical properties of the final bioprinted construct. First, we investigate cytocompatible, covalent cross-linking chemistries for bioink synthesis (e.g. Thiol Michael type addition and bioorthogonal inverse electron demand Diels-Alder reaction). We demonstrate these reactions are compatible with the bioink method, which results in high cell viability. The PEGX method is then exploited to optimize extruded…

Scaffolds with controlled drug release are valuable for bone tissue engineering, but constructing the scaffolds with controllable dual-drug release behaviors is still a challenge. In this study, layered mesoporous bioactive glass/sodium alginate-sodium alginate (MBG/SA–SA) scaffolds with controllable dual-drug release behaviors were fabricated by 3D printing. The porosity and compressive strength of three-dimensional (3D) printed MBG/SA–SA scaffolds by cross-linking are about 78% and 4.2 MPa, respectively. As two model drugs, bovine serum albumin (BSA) and ibuprofen (IBU) were separately loaded in SA layer and MBG/SA layer, resulting in a relatively fast release of BSA and a sustained release of IBU. Furthermore,…

Supplying oxygen to inner areas of cell constructs to support cell proliferation and metabolism is a major challenge in tissue engineering involving stem cells. Developing devices that incorporate oxygen release materials to increase the availability of the localized oxygen supply is therefore key to addressing this limitation. Herein, we designed and developed a 3D-printed oxygen-releasing device composed of an alginate hydrogel scaffold combined with an oxygen-generating biomaterial (calcium peroxide) to improve the oxygen supply of the microenvironment for culturing adipose tissue-derived stem cells. The results demonstrated that the 3D-printed oxygen-releasing device alleviated hypoxia, maintained oxygen availability, and ensured proliferation of…

3D bioprinting techniques have been attracting attention for tissue scaffold fabrication in nerve tissue engineering applications. However, due to the inherent complexity of nerve tissues, bioprinting scaffolds that can appropriately promote the regeneration of damaged tissues is still challenging. This paper presents our study on bioprinting Schwann cell-laden scaffolds from low-viscosity hydrogel compositions including RGD modified alginate, hyaluronic acid and fibrin, with a focus on investigating the printability of hydrogel compositions and characterizing the functions of printed scaffolds for potential use in nerve tissue regeneration. We assessed the rheological properties of hydrogel precursors via temperature, time and shear rate sweeps,…

Silk, with highly crystalline structure and well-documented biocompatibility, is promising to be used as reinforcing material and build functionalized composite scaffolds. In the present study, we developed chitosan/silk composite scaffolds using silk particles, silk microfibres and nanofibres via 3D printing method. The three forms of silk fillers with varied shapes and dimensions were obtained via different processing methods and evaluated of their morphology, crystalline structure and thermal property. All silk fillers showed different degrees of improvement on printability in terms of ink rheology and printing shape fidelity. Different silk fillers led to different scaffold surface morphology and different roughness, while…

This work investigated a new 3D-printing methodology to prepare porous scaffolds containing horizontal pore and composition gradients. To achieve that, a multimaterial printing technology developed in our laboratory was adapted to incorporate pore gradients. Fibers were printed by welding segments with unique material compositions and fiber diameters. Particularly, we focused on the preparation of model composite poly(ε-caprolactone)-based scaffolds with radial gradients of particulate hydroxyapatite (HA) content (higher concentrations in the outer region of the scaffold) and porosity (higher in the inner region). The morphology of the scaffolds revealed that the methodology allowed the fabrication of discrete regions with compressive mechanical…

Abrasive flow machining (AFM) is a nontraditional surface finishing method that finishes complex surface by pushing the abrasive media flow through the workpiece surface. The entrance effect that the material removal increases at the entrance of changing the cross-sectional flow channel is a difficult problem for AFM. In this paper, the effects of media rheological properties on the entrance effect are discussed. To explore the effects of the media’s viscoelasticity on the entrance effect, two sets of media with different viscoelasticity properties are adopted to study their rheological and machining performances in the designed flow channel with a contraction area.…

Three-dimensional (3D) bioprinting is a promising technique used to fabricate scaffolds from hydrogels with living cells. However, the printability of hydrogels in bioprinting has not been adequately studied. The aim of this study was to quantitatively characterize the printability and cell viability of alginate dialdehyde (ADA)-gelatin (Gel) hydrogels for bioprinting. ADA-Gel hydrogels of various concentrations were synthesized and characterized using Fourier transform infrared spectroscopy, along with rheological tests for measuring storage and loss moduli. Scaffolds (with an area of 11 × 11 mm) of 1, 2, and 13 layers were fabricated from ADA-Gel hydrogels using a 3D-bioplotter under printing conditions…

In the present work we have revisited the application of quantitative ultrasound imaging (QUI) to cellular hydrogels, by using the reference phantom method (RPM) in combination with a local attenuation compensation algorithm. The investigated biological samples consisted of cell-laden collagen hydrogels with PC12 neural cells. These cell-laden hydrogels were used to calibrate the integrated backscattering coefficient (IBC) as a function of cell density, which was then used to generate parametric images of local cell density. The image resolution used for QUI and its impact on the relative IBC error was also investigated. Another important contribution of our work was the…

Lower back pain (LBP), which is strongly associated with intervertebral disc (IVD) degeneration, is one of the most frequently reported age- and work-related disorder in actual society, leading to a huge socio-economic impact worldwide. The current treatments have poor clinical outcomes and do not consider each patient needs. Thus, there is a growing interest in the potential of personalized cell-based tissue engineering (TE) approaches aimed to regenerate the damaged IVD and efficiently restore full disc function. In this work, a bioink composed by silk fibroin (SF) hydrogel combined with elastin was used to bioprint patient-specific substitutes mimicking IVD ultrastructure, in…

Simple ternary SiO2CaOP2O5 bioglasses proved sufficient osteogenesis capacity. In this study, the bioglasses were 3D printed into porous scaffolds and SiO2/CaO molar ratio was altered (from 90/5 to 60/35) to achieve tunable glass-ceramic compositions after thermal treatment. Scaffolds possessed interconnected porous structure with controllable porosities via 3D printing technique. In addition, microstructure and properties of mechanical strength, degradation, ion dissolution and apatite formation were investigated. Characterization results showed that higher content of SiO2 produced more homogeneous crystalline particles and sintering compactness, thus led to higher strength. For scaffolds with higher CaO content, more glasses were maintained and faster degradation rate…

There is a growing interest in 3D printing to fabricate culture substrates; however, the surface properties of the scaffold remain pertinent to elicit targeted and expected cell responses. Traditional 2D polystyrene (PS) culture systems typically require surface functionalization (oxidation) to facilitate and encourage cell adhesion. Determining the surface properties which enhance protein adhesion from media and cellular extracellular matrix (ECM) production remains the first step to translating 2D PS systems to a 3D culture surface. Here we show that the presence of carbonyl groups to PS surfaces correlated well with successful adhesion of ECM proteins and sustaining ECM production of…

There is an urgent need of biosynthetic bone grafts with enhanced osteogenic capacity. In this study, we describe the design of hierarchical meso-macroporous 3D-scaffolds based on mesoporous bioactive glasses (MBGs), enriched with the peptide osteostatin and Zn2+ ions, and their osteogenic effect on human mesenchymal stem cells (hMSCs) as a preclinical strategy in bone regeneration. The MBG compositions investigated were 80%SiO2–15%CaO–5%P2O5 (in mol-%) Blank (BL), and two analogous glasses containing 4% ZnO (4ZN) and 5% ZnO (5ZN). By using additive fabrication techniques, scaffolds exhibiting hierarchical porosity: mesopores (around 4 nm), macropores (1–600 μm) and big channels (∼1000 μm), were prepared. These MBG scaffolds…

Information from the brain travels back and forth along peripheral nerves in the form of electrical impulses generated by neurons and these impulses have repetitive patterns. Schwann cells in peripheral nerves receive molecular signals from axons to coordinate the process of myelination. There is evidence, however, that non-molecular signals play an important role in myelination in the form of patterned electrical impulses generated by neuronal activity. The role of patterned electrical impulses has been investigated in the literature using co-cultures of neurons and myelinating cells. The co-culturing method, however, prevents the uncoupling of the direct effect of patterned electrical impulses…

3D printing provides a novel approach to repair bone defects using customized biomimetic tissue scaffolds. To make a bone substitute closest to natural bone structure and composition, two different types of hydroxyapatite, Nano hydroxyapatite (nHA) and deproteinized bovine bone (DBB), were dispersed into collagen (CoL) to prepare the bio-ink for 3D printing. In doing so, a porous architecture was manufactured with 3D printing technology. The physical and chemical properties of the materials were evaluated, including biocompatibility and effect on the osteogenic differentiation of the human bone marrow-derived mesenchyme stem cells (hBMSCs). The XPS, XRD, FTIR, and the mechanical analysis of…

Porous scaffolds were 3D-printed using poly lactic-co-glycolic acid (PLGA)/TiO2 composite (10:1 weight ratio) for bone tissue engineering applications. Addition of TiO2 nanoparticles improved the compressive modulus of scaffolds. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) revealed an increase in both glass transition temperature and thermal decomposition onset of the composite compared to pure PLGA. Furthermore, addition of TiO2 was found to enhance the wettability of the surface evidenced by reducing the contact angle from 90.5 ± 3.2 to 79.8 ± 2.4 which is in favor of cellular attachment and activity. The obtained results revealed that PLGA/TiO2 scaffolds significantly improved osteoblast proliferation compared to…

In an attempt to fabricate biomimetic bone repair scaffolds and improve bone regeneration point of view, we have three dimensionally printed porous scaffolds with biomineralized hydroxyapatite/silk fibroin nanocomposites. SF/HA composite particles were firstly produced via an in-situ mineral precipitation process when SF molecules were served as templates.. Microscopy observations of SF/HA showed homogeneous morphology and narrowly distributed size. By using sodium alginate (SA) as paste binder, scaffolds with different contents of SF/HA were subsequently 3D-printed under proper conditions. All the scaffolds were porous with 3D interconnected large pores (size ～400 μm) and an overall porosity about 70%, combined with a relative…

In this work, we synthesized a novel polymeric biomaterial platform with tunable functionalizability for extrusion-based 3D printing. Biodegradable polymers were synthesized using 4-hydroxyphenethyl 2-(4-hydroxyphenyl)acetate (HTy), which is derived from Tyrosol and 2-(4-hydroxyphenyl)acetic acid. p-Phenylenediacetic acid (PDA) was introduced to enhance crystallinity. To enable functionalizability without deteriorating printability, glutamic acid derivatives were introduced into the polymer design, forming copolymers including poly(HTy-co-45%PDA-co-5%Gluhexenamide ester) (HP5GH), poly(HTy-co-45%PDA-co-5%Glupentynamide ester) (HP5GP), and poly(HTy-co-45%PDA-co-5%BocGlu ester) (HP5BG). The resulting polymers have: two melting temperatures (125–131 °C and 141–147 °C), Young’s moduli of 1.9–2.4 GPa, and print temperatures of 170–190 °C. The molecular weight (Mw) loss due to hydrolytic…

Gelatin methacryloyl is a promising material in tissue engineering and has been widely studied in three-dimensional bioprinting. Although gelatin methacryloyl possesses excellent biocompatibility and tunable mechanical properties, its poor printability/processability has hindered its further applications. In this study, we report a reversible physical crosslinking strategy for precise deposition of human chondrocyte-laden gelatin methacryloyl bioink at low concentration without any sacrificial material by using extrusive three-dimensional bioprinting. The precise printing temperature was determined by the rheological properties of gelatin methacryloyl with temperature. Ten percent (w/v) gelatin methacryloyl was chosen as the printing formula due to highest biocompatibility in three-dimensional cell cultures…

3D printed polycaprolactone (PCL) has potential as a scaffold for bone tissue engineering, but the hydrophobic surface may hinder optimal cell responses. The surface properties can be improved by coating the scaffold with cellulose nanofibrils material (CNF), a multiscale hydrophilic biocompatible biomaterial derived from wood. In this study, human bone marrow-derived mesenchymal stem cells were cultured on tissue culture plates (TCP) and 3D printed PCL scaffolds coated with CNF. Cellular responses to the surfaces (viability, attachment, proliferation, and osteogenic differentiation) were documented. CNF significantly enhanced the hydrophilic properties of PCL scaffolds and promoted protein adsorption. Live/dead staining and lactate dehydrogenase…

Lignin is a low-cost, natural polymer with abundant polar sites on its backbone that can be utilized for physical cross-linking of polymers. Here, we use lignin for additional cross-linking of hydrophilic polyether-based polyurethane (HPU) hydrogels, aiming to improve their mechanical properties and processability. Without reducing the swelling, simple addition of 2.5 wt % lignin increases the fracture energy and Young’s modulus of HPU hydrogels from, respectively, 1540 ± 40 to 2050 ± 50 J m–2 and 1.29 ± 0.06 to 2.62 ± 0.84 MPa. Lignin also increases the lap shear adhesiveness of hydrogels and induces an immediate load recovery of…

Trophoblast invasion and remodeling of the maternal spiral arteries are required for pregnancy success. Aberrant endothelium–trophoblast crosstalk may lead to preeclampsia, a pregnancy complication that has serious effects on both the mother and the baby. However, our understanding of the mechanisms involved in this pathology remains elementary because the current in vitro models cannot describe trophoblast–endothelium interactions under dynamic culture. In this study, we developed a dynamic three‐dimensional (3D) placenta model by bioprinting trophoblasts and an endothelialized lumen in a perfusion bioreactor. We found the 3D printed perfusion bioreactor system significantly augmented responses of endothelial cells by encouraging network formations…

Present bioprinting techniques lack the methodology to print with bioactive materials that retain their biological functionalities. This constraint is due to the fact that extrusion-based printing of synthetic polymers is commonly performed at very high temperatures in order to achieve desired mechanical properties and printing resolutions. Consequently, current methodology prevents printing scaffolds embedded with bioactive molecules, such as growth factors. With the wide use of mesenchymal stem cells (MSCs) in regenerative medicine research, the integration of growth factors into 3D printed scaffolds is critical because it can allow for inducible MSC differentiation. We have successfully incorporated growth factors into extrusion…

Soft tissue fixation of implant and bioelectrodes relies on mechanical means (e.g., sutures, staples, and screws), with associated complications of tissue perforation, scarring, and interfacial stress concentrations. Adhesive bioelectrodes address these shortcomings with voltage cured carbene‐based bioadhesives, locally energized through graphene interdigitated electrodes. Electrorheometry and adhesion structure activity relationships are explored with respect to voltage and electrolyte on bioelectrodes synthesized from graphene 3D‐printed onto resorbable polyester substrates. Adhesive leachates effects on in vitro metabolism and human‐derived platelet‐rich plasma response serves to qualitatively assess biological response. The voltage activated bioadhesives are found to have gelation times of 60 s or less…

Hydrogel bioprinting is a major area of focus in the field of tissue engineering. However, 3D printed hydrogel scaffolds often suffer from low printing accuracy and poor mechanical properties because of their soft nature and tendency to shrink. This makes it challenging to process them into structural materials. In this study, natural chitosan hydrogel scaffolds were, for the first time, reinforced with milled silk particles and fabricated by 3D printing. Compared with pure chitosan scaffolds, the addition of silk particles resulted in up to a 5-fold increase in compressive modulus as well as significantly better printing accuracy and improved scaffold…

Bioengineered adipose tissues have gained increased interest as a promising alternative to autologous tissue flaps and synthetic adipose fillers for soft tissue augmentation and defect reconstruction in clinic. Although many scaffolding materials and biofabrication methods have been investigated for adipose tissue engineering in the last decades, there are still challenges to recapitulate the appropriate adipose tissue microenvironment, maintain volume stability, and induce vascularization to achieve long-term function and integration. In the present research, we fabricated cryogels consisting of methacrylated gelatin, methacrylated hyaluronic acid, and 4arm poly(ethylene glycol) acrylate (PEG-4A) by using cryopolymerization. The cryogels were repeatedly injectable and stretchable, and…

Three‑dimensional printed (3DP) scaffolds have become an excellent resource in alveolar bone regeneration. However, selecting suitable printable materials remains a challenge. In the present study, 3DP scaffolds were fabricated using three different ratios of poly (ε‑caprolactone) (PCL) and poly‑lactic‑co‑glycolic acid (PLGA), which were 0.1PCL/0.9PLGA, 0.5PCL/0.5PLGA and 0.9PCL/0.1PLGA. The surface characteristics and degradative properties of the scaffolds, and the response of human periodontal ligament stem cells (hPDLSCs) on the scaffolds, were assessed to examine the preferable ratio of PCL and PLGA for alveolar bone regeneration. The results demonstrated that the increased proportion of PLGA markedly accelerated the degradation, smoothed the surface…

Three-dimensional (3D) porous scaffolds with sustained drug delivery are pursued for osteoarticular tuberculosis therapy after surgery. In this study, mesoporous bioactive glass/metal-organic framework (MBG/MOF) scaffolds with sustained antitubercular drug release have been fabricated by 3D printing. The results showed that the MBG/MOF scaffolds possess macropores of ca. 400 μm and enhanced compressive strength of 3–7 MPa, also exhibited good biocompatibility and apatite forming ability in vitro. Furthermore, the drug release rate and pH microenvironment of the MBG/MOF scaffolds could be controlled due to the MOF degradation. These results indicated that the 3D printed MBG/MOF scaffolds are promising for treating osteoarticular tuberculosis.

Three-dimensional bioprinting of biomaterials shows great potential for producing cell-encapsulated scaffolds to repair nerves after injury or disease. For this, preparation of biomaterials and bioprinting itself are critical to create scaffolds with both biological and mechanical properties appropriate for nerve regeneration, yet remain unachievable. This paper presents our study on bioprinting Schwann cell-encapsulated scaffolds using composite hydrogels of alginate, fibrin, hyaluronic acid, and/or RGD peptide, for nerve tissue engineering applications. For the preparation of composite hydrogels, suitable hydrogel combinations were identified and prepared by adjusting the concentration of fibrin based on the morphological spreading of Schwann cells. In bioprinting, the…

Biofabrication processes can affect biological quality attributes of encapsulated cells within constructs. Currently, assessment of the fabricated constructs is performed offline by subjecting the constructs to destructive assays that require staining and sectioning. This drawback limits the translation of biofabrication processes to industrial practice. In this work, we investigate the dielectric response of viable cells encapsulated in bioprinted 3D hydrogel constructs to an applied alternating electric field as a label-free non-destructive monitoring approach. The relationship between β-dispersion parameters (permittivity change—Δε, Cole–Cole slope factor—α, critical polarization frequency—f c ) over the frequency spectrum and critical cellular quality attributes are investigated. Results…

The external auditory canal (EAC) is an osseocartilaginous structure extending from the auricle to the eardrum, which can be affected by congenital, inflammatory, and neoplastic diseases, thus reconstructive materials are needed. Current biomaterial-based approaches for the surgical reconstruction of EAC posterior wall still suffer from resorption (biological) and extrusion (synthetic). In this study, 3D fiber deposited scaffolds based on poly(ethylene oxide terephthalate)/poly(butylene terephthalate) were designed and fabricated to replace the EAC wall. Fiber diameter and scaffold porosity were optimized, leading to 200 ± 33 µm and 55% ± 5%, respectively. The mechanical properties were evaluated, resulting in a Young’s modulus of 25.1 ± 7.0 MPa. Finally, the EAC…

Vascularization of engineered bone tissue is critical for ensuring its survival after implantation. In vitro pre-vascularization of bone grafts with endothelial cells is a promising strategy to improve implant survival. In this study, we pre-cultured human smooth muscle cells (hSMCs) on bone scaffolds for 3 weeks followed by seeding of human umbilical vein endothelial cells (HUVECs), which produced a desirable environment for microvasculature formation. The sequential cell-seeding protocol was successfully applied to both natural (decellularized native bone, or DB) and synthetic (3D-printed Hyperelastic “Bone” scaffolds, or HB) scaffolds, demonstrating a comprehensive platform for developing natural and synthetic-based in vitro vascularized…

Bioactive scaffolds with interconnected porous structures are essential for guiding cell growth and new bone formation. In this work, we successfully fabricated three-dimensional (3D) porous β-tricalcium phosphate (β-TCP)/calcium silicate (CS) composite scaffolds with different ratios by 3D printing technique and further investigated the physiochemical properties, in vitro apatite mineralization properties and degradability of porous β-TCP/CS scaffolds. Moreover, a series of in vitro cell experiments including the attachment, proliferation and osteogenic differentiation of mouse bone marrow stromal cells were conducted to testify their biological performances. The results showed that 3D printed β-TCP/CS scaffolds possessed of controllable internal porous structures and external…

Three dimensional (3D) printing is highly amenable to the fabrication of tissue-engineered organs of a repetitive microstructure such as the liver. The creation of uniform and geometrically repetitive tissue scaffolds can also allow for the control over cellular aggregation and nutrient diffusion. However, the effect of differing geometries, while controlling for pore size, has yet to be investigated in the context of hepatocyte function. In this study, we show the ability to precisely control pore geometry of 3D-printed gelatin scaffolds. An undifferentiated hepatocyte cell line (HUH7) demonstrated high viability and proliferation when seeded on 3D-printed scaffolds of two different geometries.…

Adipose-derived mesenchymal stem/stromal cells (ADMSC) are one of the major stromal cells in the breast cancer microenvironment that promote cancer progression. Previous studies on the effects of ADMSC on breast cancer metastasis and drug resistance, using two-dimensional (2D) cultures, remained inconclusive. In the present study, we compared cocultured ADMSC and human epidermal receptor 2 positive breast primary breast cancer cells (21PT) in 2D and three-dimensional (3D) cultures and then examined their response to doxorubicin (DOX). We examined 3D bioprinted constructs with breast cancer cells in the middle and ADMSC in the edge region, which were made by using dual hydrogel-based…

Advancements in additive manufacturing have made it possible to fabricate biologically relevant architectures from a wide variety of materials. Hydrogels have garnered increased attention for the fabrication of muscle tissue engineering constructs due to their resemblance to living tissue and ability to function as cell carriers. However, there is a lack of systematic approaches to screen bioinks based on their inherent properties, such as rheology, printability and cell viability. Furthermore, this study takes the critical first-step for connecting in-process sensor data with construct quality by studying the influence of printing parameters. Alginate-chitosan hydrogels were synthesized and subjected to a systematic…

The pursuit for the “perfect” biomimetic and personalized implant for musculoskeletal tissue regeneration remains a big challenge. 3D printing technology that makes use of a novel and promising biomaterials can be part of the solution. In this study, a fast setting enzymatic-crosslinked silk fibroin (SF) bioink for 3D bioprinting is developed. Their properties are fine-tuned and different structures with good resolution, reproducibility, and reliability can be fabricated. Many potential applications exist for the SF bioinks including 3D bioprinted scaffolds and patient-specific implants exhibiting unique characteristics such as good mechanical properties, memory-shape feature, suitable degradation, and tunable pore architecture and morphology.

Three-dimensional (3D) printing is an emerging technology for the fabrication of scaffolds to repair/replace damaged tissue/organs in tissue engineering. This paper presents our study on 3D printed alginate scaffolds treated with phosphate buffered saline (PBS) and polyethyleneimine (PEI) coating and their impacts on the surface morphology and cellular response of the printed scaffolds. In our study, sterile alginate was prepared by means of the freeze-drying method and then, used to prepare the hydrogel for 3D printing into calcium chloride, forming 3D scaffolds. Scaffolds were treated with PBS for a time period of two days and seven days, respectively, and PEI…

Here we describe the formulation of a morphogenetically active bio-ink consisting of amorphous microparticles (MP) prepared from Ca2+ and the physiological inorganic polymer, polyphosphate (polyP). Those MP had been fortified by mixing with poly-ε-caprolactone (PCL) to allow 3D-bioprinting. The resulting granular PCL/Ca-polyP-MP hybrid material, liquefied by short-time heating to 100 °C, was used for the 3D-printing of tissue-like scaffolds formed by strands with a thickness of 400 µm and a stacked architecture leaving ≈0.5 mm2-sized open holes enabling cell migration. The printed composite scaffold turned out to combine suitable biomechanical properties (Young’s modulus of 1.60 ± 0.1 GPa; Martens hardness of 153 ± 28 MPa), matching those of cortical…

Regenerative medicine has emerged as an important discipline that aims to repair injury or replace damaged tissues or organs by introducing living cells or functioning tissues. Successful regenerative medicine strategies will likely depend upon a simultaneous optimization strategy for the design of biomaterials, cell-seeding methods, cell-biomaterial interactions and molecular signaling within the engineered tissues. It remains a challenge to image three-dimensional (3-D) structures and functions of the cell-seeded scaffold in mesoscopic scale (>2∼3 mm). In this study, we utilized angled fluorescence laminar optical tomography (aFLOT), which allows depth-resolved molecular characterization of engineered tissues in 3-D to investigate cell viability, migration and…

Biofabrication of cell supportive cardiac patches that can be directly implanted on myocardial infarct is a potential solution for myocardial infarction repair. Ideally, cardiac patches should be able to mimic myocardium extracellular matrix for rapid integration with the host tissue, raising the need to develop cardiac constructs with complex features. In particular, cardiac patches should be electrically conductive, mechanically robust and elastic, biologically active and pre-vascularized.. In this study, we aim to biofabricate a nano-reinforced hybrid cardiac patch laden with human coronary artery endothelial cells (HCAECs) with improved electrical, mechanical and biological behavior. A safe UV exposure time with insignificant…

The functionalization of biomaterials substrates used for cell culture is gearing towards an increasing control over cell activity. Although a number of biomaterials have been successfully modified by different strategies to display tailored physical and chemical surface properties, it is still challenging to step from 2D substrates to 3D scaffolds with instructive surface properties for cell culture and tissue regeneration. In this study, additive manufacturing and thermally induced phase separation are combined to create 3D scaffolds with tunable surface morphology from polymer gels. Surface features vary depending on the gel concentration, the exchanging temperature, and the nonsolvent used. When preosteoblasts…

OBJECTIVE: To evaluate the cytotoxicity of gelatin/alginate hydrogel scaffolds prepared by 3D bioprinting in human dental pulp cells (HDPCs) and compare the cell adhesion and proliferation of the cells seeded in the biomaterial using two different methods. METHODS: HDPCs isolated by tissue block culture and enzyme digestion were cultured and passaged. Gelatin/alginate hydrogel scaffolds were printed using a bioplotter, and the cytotoxicity of the aqueous extracts of the scaffold material was tested in the third passage of HDPCs using cell counting kit-8. Scanning electron microscopy and trypan blue were used to assess the adhesion and proliferation of the cells seeded…

The ability to create 3D tissues from induced pluripotent stem cells (iPSCs) is poised to revolutionize stem cell research and regenerative medicine, including individualized, patient-specific stem cell-based treatments. There are, however, few examples of tissue engineering using iPSCs. Their culture and differentiation is predominantly planar for monolayer cell support or induction of self-organizing embryoids (EBs) and organoids. Bioprinting iPSCs with advanced biomaterials promises to augment efforts to develop 3D tissues, ideally comprising direct-write printing of cells for encapsulation, proliferation, and differentiation. Here, such a method, employing a clinically amenable polysaccharide-based bioink, is described as the first example of bioprinting human…

Electrospun scaffolds provide a dense framework of nanofibers with pore sizes and fiber diameters that closely resemble the architecture of native extracellular matrix. However, it generates limited three-dimensional structures of relevant physiological thicknesses. 3D printing allows digitally controlled fabrication of three-dimensional single/multimaterial constructs with precisely ordered fiber and pore architecture in a single build. However, this approach generally lacks the ability to achieve submicron resolution features to mimic native tissue. The goal of this study was to fabricate and evaluate 3D printed, electrospun, and combination of 3D printed/electrospun scaffolds to mimic the native architecture of heterogeneous tissue. We assessed their…

Collagen is the most abundant protein found in mammals and it exhibits a low immunogenicity, high biocompatibility and biodegradability when compared with others natural polymers. For this reason, it has been explored for the development of biologically instructive biomaterials with applications for tissue substitution and regeneration. Marine origin collagen has been pursued as an alternative to the more common bovine and porcine origins. This study focused on squid (Teuthoidea: Cephalopoda), particularly the Antarctic squid Kondakovia longimana and the Sub-Antarctic squid Illex argentinus as potential collagen sources. In this study, collagen has been isolated from the skins of the squids using…

3D printing technology is driving innovation in a wide variety of disciplines, and is beginning to make inroads into the fields of medicine and biology. In particular, 3D printing is being increasingly utilized for the design and fabrication of three-dimensional cell culture scaffolds. This technology allows for scaffolds to be produced rapidly while maintaining a great deal of control over the matrix architecture. This paper presents an effective technique for rapidly designing and fabricating scaffolds from silicone rubber and polycaprolactone (PCL), appropriate for primary human cardiomyocyte cell cultures. Additionally, a stimulation device is developed and presented which can provide 6…

One of the critical challenges that scaffolding faces in the organ and tissue regeneration field lies in mimicking the structure, and the chemical and biological properties of natural tissue. A high-level control over the architecture, mechanical properties and composition of the materials in contact with cells is essential to overcome such challenge. Therefore, definition of the method, materials and parameters for the production of scaffolds during the fabrication stage is critical. With the recent emergence of rapid prototyping (RP), it is now possible to create three-dimensional (3D) scaffolds with the essential characteristics for the proliferation and regeneration of tissues, such…

In this work, we combined three-dimensional (3D) scaffolds with flow perfusion bioreactors to evaluate the gradient effects of scaffold architecture and mechanical stimulation, respectively, on tumor cell phenotype. As cancer biologists elucidate the relevance of 3D in vitro tumor models within the drug discovery pipeline, it has become more compelling to model the tumor microenvironment and its impact on tumor cells. In particular, permeability gradients within solid tumors are inherently complex and difficult to accurately model in vitro. However, 3D printing can be used to design scaffolds with complex architecture, and flow perfusion can simulate mechanical stimulation within the tumor…

β-TCP-Zirconia scaffolds with different architectures were fabricated by means of 3D-Bioplotting in order to enhance the mechanical and in-vitro ability of the scaffold to heal large size bone defects. In the present study scaffold architecture with different strand orientations (0o-90o, 0o-45o-135o-180o, 0o-108o-216o and 0o-72o-144o-36o-108o) were fabricated, characterized and evaluated for mechanical strength and cell proliferation ability. β-TCP powder (25µm) and PVA (Polyvinyl Alcohol) was acquired from Fisher Scientific, India. Zirconia (18 to 32 µm) was procured from Lobachemie, India. In brief 7.5%, PVA in distilled water was used as a binder and was mixed with 10 grams of (70/30) TCP-Zirconia…

Preeclampsia (PE) is a leading cause of maternal and perinatal morbidity and mortality. Current research suggests that the impaired trophoblastic invasion of maternal spiral arteries contributes significantly to the development of PE. However, the pathobiology of PE remains poorly understood, and there is a lack of treatment options largely due to ineffective experimental models. Utilizing the capability of bioprinting and shear wave elastography, we developed a 3D, bioengineered placenta model (BPM) to study and quantify cell migration. Through BPM, we evaluated the effect of epidermal growth factor (EGF) on the migratory behavior of trophoblast and human mesenchymal stem cells. Our…

In the study, we developed hierarchical composite scaffolds by 3D printing technique with mesoporous CaSiO3 containing controlled amounts of Ce substitution in Ca–Si system. The scaffolds were porous with 3D interconnected large pores (size ~400 μm) and an overall porosity above 70 %, combined with a relative high compressive strength (~7 MPa). These properties are essential for enhancing bone ingrowth in tissue engineering. The in vitro biological properties of apatite formation, cell proliferation, and differentiation were characterized on CeO2-MCS scaffolds and MCS scaffolds. Results indicated that CeO2-MCS scaffolds induced similar apatite deposition and cell attachment of human bone marrow stromal…

The blood clotting protein fibrin contains cell-binding domains, providing potential advantage for the fabrication of tissue repair scaffolds and for live cell encapsulation. However, fabrication of fibrin scaffolds with encapsulated cells using three dimensional (3D) printing has proven challenging due to the mechanical difficulties of fabricating protein hydrogel scaffolds with defined microstructure. For example, extrusion based 3D printing of fibrin is generally unfeasible because of the low viscosity of precursor fibrinogen solution. Here we describe a novel technique for bioprinting of fibrin scaffolds by extruding fibrinogen solution into thrombin solution, utilizing hyaluronic acid (HA) and polyvinyl alcohol (PVA) to increase…

In this work we demonstrate how to print 3D biomimetic hydrogel scaffolds for cartilage tissue engineering with high cell density (>107 cells ml−1), high cell viability (85 ÷ 90%) and high printing resolution (≈100 μm) through a two coaxial-needles system. The scaffolds were composed of modified biopolymers present in the extracellular matrix (ECM) of cartilage, namely gelatin methacrylamide (GelMA), chondroitin sulfate amino ethyl methacrylate (CS-AEMA) and hyaluronic acid methacrylate (HAMA). The polymers were used to prepare three photocurable bioinks with increasing degree of biomimicry: (i) GelMA, (ii) GelMA + CS-AEMA and (iii) GelMA + CS-AEMA + HAMA. Alginate was added…

Hydrogels are particularly attractive as scaffolding materials for cartilage tissue engineering because their high water content closely mimics the native extracellular matrix (ECM). Hydrogels can also provide a three-dimensional (3D) microenvironment for homogeneously suspended cells that retains their rounded morphology and thus facilitates chondrogenesis in cartilage tissue engineering. However, fabricating hydrogel scaffolds or cell-laden hydrogel constructs with a predesigned external shape and internal structure that does not collapse remains challenging because of the low viscosity and high water content of hydrogel precursors. Here, we present a study on the fabrication of (cell-laden) alginate hydrogel constructs using a 3D bioplotting system…

Synchrotron radiation inline phase-contrast imaging combined with computed tomography (SR-inline-PCI-CT) offers great potential for non-invasive characterization and three-dimensional visualization of fine features in weakly absorbing materials and tissues. For cartilage tissue engineering, the biomaterials and any associated cartilage extracellular matrix (ECM) that is secreted over time are difficult to image using conventional absorption-based imaging techniques. For example, three-dimensional printed polycaprolactone (PCL)/alginate/cell hybrid constructs have low, but different, refractive indices and thicknesses. This paper presents a study on the optimization and utilization of inline-PCI-CT for visualizing the components of three-dimensional printed PCL/alginate/cell hybrid constructs for cartilage tissue engineering. First, histological analysis…

Continuous composite fibres composed of polypyrrole (PPy) nanoparticles and reduced graphene oxide (rGO) at different mass ratios were fabricated using a single step wet-spinning approach. The electrical conductivity of the composite fibres increased significantly with the addition of rGO. The mechanical properties of the composite fibres also improved by the addition of rGO sheets compared to fibres containing only PPy. The ultimate tensile strength of the fibres increased with the proportion of rGO mass present. The elongation at break was greatest for the composite fibre containing equal mass ratios of PPy nanoparticles and rGO sheets. L929 fibroblasts seeded onto fibres…

The application of magnetic nanoparticles (MNPs) in tissue engineering (TE) approaches opens several new research possibilities in this field, enabling a new generation of multifunctional constructs for tissue regeneration. This study describes the development of sophisticated magnetic polymer scaffolds with aligned structural features aimed at applications in tendon tissue engineering (TTE). Tissue engineering magnetic scaffolds are prepared by incorporating iron oxide MNPs into a 3D structure of aligned SPCL (starch and polycaprolactone) fibers fabricated by rapid prototyping (RP) technology. The 3D architecture, composition, and magnetic properties are characterized. Furthermore, the effect of an externally applied magnetic field is investigated on…

An ideal behavior of a tissue engineering scaffold is that it degrades and reshapes at a rate that matches the formation of new tissues. However, this ideal situation may not occur as the scaffold often undergoes too slow or too fast degradation. To test the promise of the active control of scaffold degradation, in this work, a photo/water dual-degradable porous scaffold was designed and fabricated using a 3D fiber deposition (3DF) system from a linear biopolymer (named PLANB) that combined the o-nitrobenzyl linkages and hydrolysable ester bone in the polymer chains. The chemical structure, molecular weight and polydispersity of PLANB…

Development of 3D porous scaffolds with proper mechanical strength is crucial in bone tissue engineering. In this study, calcium sulfate hemihydrate (CSH) cement was functionally incorporated into mesoporous calcium silicate (MCS) through a 3D printing technique in order to improve the scaffold strength. Compared to printed MCS scaffolds, the characterizations revealed that 20% CSH incorporation had enhanced their compressive strength by 2 times via 4 weeks’ hydration. Furthermore, CSH incorporation prevented the fast pH value rise and achieved a balanced degradation rate. SEM observations showed a good apatite formation on the surfaces of both MCS and MCS/CSH scaffolds. Cellular experiments…

Bone infection is a feared complication following surgery or trauma that remains as an extremely difficult disease to deal with. So far, the outcome of therapy could be improved with the design of 3D implants, which combine the merits of osseous regeneration and local multidrug therapy so as to avoid bacterial growth, drug resistance and the feared side effects. Herein, hierarchical 3D multidrug scaffolds based on nanocomposite bioceramic and polyvinyl alcohol (PVA) prepared by rapid prototyping with an external coating of gelatin-glutaraldehyde (Gel-Glu) have been fabricated. These 3D scaffolds contain three antimicrobial agents (rifampin, levofloxacin and vancomycin), which have been…

The current study reports on the manufacturing by rapid prototyping technique of three-dimensional (3D) scaffolds based on silicon substituted hydroxyapatite with Elastin-like Recombinamers (ELRs) functionalized surfaces. Silicon doped hydroxyapatite (Si-HA), with Ca10(PO4)5.7(SiO4)0.3(OH)1.7h0.3 nominal formula, was surface functionalized with two different types of polymers designed by genetic engineering: ELR-RGD that contain cell attachment specific sequences and ELR-SNA15/RGD with both hydroxyapatite and cells domains that interact with the inorganic phase and with the cells, respectively. These hybrid materials were subjected to in vitro assays in order to clarify if the ELRs coating improved the well-known biocompatible and bone regeneration properties of calcium…

The aim of this study was to synthesize and characterize self-crosslinked bioactive glass/alginate composite scaffolds, as a kind of potential biomaterial for bone regeneration. The scaffolds were fabricated through a self-crosslinking process of alginate by bioactive glass microspheres provided Ca2+ completely, without any organic solvent, crosslinking agent or binder. The microstructure, mechanical properties, apatite-forming ability, ionic release, adhesion, proliferation and ALP activity of human bone marrow-derived mesenchymal stem cells (hBMSCs) of the scaffolds were evaluated. The results showed that uniform films could be obtained on the surface as well as abundant of crosslinking bridges in the interior of scaffolds. The…

Mesoporous bioactive glass-polycaprolactone (MBG-PCL) scaffolds have been prepared by robocasting, a layer by layer rapid prototyping method, by stacking of individual strati. Each stratus was independently analyzed during the cell culture tests with MC3T3-E1 preosteblast-like cells. The presence of MBG stimulates the colonization of the scaffolds by increasing the cell proliferation and differentiation. MBG-PCL composites not only enhanced pre-osteoblast functions but also allowed cell movement along its surface, reaching the upper stratus faster than in pure PCL scaffolds. The cells behavior on each individual stratus revealed that the scaffolds colonization depends on the chemical stimuli supplied by the MBG dissolution…

Purpose/Aim: Cementogenesis is a critical step in periodontal tissue regeneration given the essential role of cementum in anchoring teeth to the alveolar bone. This study is designed to achieve integrated cementum formation on the root surfaces of human teeth using growth factor–releasing scaffolds with periodontal ligament stem/progenitor cells (PDLSCs). Materials and methods: Human PDLSCs were sorted by CD146 expression, and characterized using CFU-F assay and induced multi-lineage differentiation. Polycaprolactone scaffolds were fabricated using 3D printing, embedded with poly(lactic-co-glycolic acids) (PLGA) microspheres encapsulating connective tissue growth factor (CTGF), bone morphogenetic protein-2 (BMP-2), or bone morphogenetic protein-7 (BMP-7). After removing cementum on…

Bioinks play a central role in 3D-bioprinting by providing the supporting environment within which encapsulated cells can endure the stresses encountered during the digitally-driven fabrication process, and continue to mature, proliferate, and eventually form extracellular matrix (ECM). In order to be most effective, it is important that bioprinted constructs recapitulate the native tissue milieu as closely as possible. As such, musculoskeletal soft tissue constructs can benefit from bioinks that mimic their nanofibrous matrix constitution, which is also critical to their function. This study focuses on the development and proof-of-concept assessment of a fibrous bioink composed of alginate hydrogel, polylactic acid…

Direct-write printing of stem cells within biomaterials presents an opportunity to engineer tissue for in vitro modeling and regenerative medicine. Here, a first example of constructing neural tissue by printing human neural stem cells that are differentiated in situ to functional neurons and supporting neuroglia is reported. The supporting biomaterial incorporates a novel clinically relevant polysaccharide-based bioink comprising alginate, carboxymethyl-chitosan, and agarose. The printed bioink rapidly gels by stable cross-linking to form a porous 3D scaffold encapsulating stem cells for in situ expansion and differentiation. Differentiated neurons form synaptic contacts, establish networks, are spontaneously active, show a bicuculline-induced increased calcium…

Gelatin/Alginate hydrogels were engineered for bioplotting in tissue engineering. One major drawback of hydrogel scaffolds is the lack of adequate mechanical properties. In this study, using a bioplotter, we constructed the scaffolds with different pore architectures by deposition of gelatin/alginate hydrogels layer-by-layer. The scaffolds with different crosslinking degree were obtained by post-crosslinking methods. Their physicochemical properties, as well as cell viability, were assessed. Different crosslinking methods had little influence on scaffold architecture, porosity, pore size and distribution. By contrast, the water absorption ability, degradation rate and mechanical properties of the scaffolds were dramatically affected by treatment with various concentrations of…

With the emergence of 3D-printing (3DP) as a vital tool in tissue engineering and medicine, there is an ever growing need to develop new biomaterials that can be 3D-printed and also emulate the compositional, structural, and functional complexities of human tissues and organs. In this work, we probe the 3D-printable biomaterials spectrum by combining two recently established functional 3D-printable particle-laden biomaterial inks: one that contains hydroxyapatite microspheres (Hyperelastic Bone, HB) and another that contains graphene nanoflakes (3D-Graphene, 3DG). We demonstrate that not only can these distinct, osteogenic and neurogenic inks be co-3D-printed to create complex, multi-material constructs, but that composite…

Three-dimensional (3D) bioprinting of hybrid constructs is a promising biofabrication method for cartilage tissue engineering because a synthetic polymer framework and cell-impregnated hydrogel provide structural and biological features of cartilage, respectively. During bioprinting, impregnated cells may be subjected to high temperatures (caused by the adjacent melted polymer) and process-induced mechanical forces, potentially compromising cell function. This study addresses these biofabrication issues, evaluating the heat distribution of printed polycaprolactone (PCL) strands and the rheological property and structural stability of alginate hydrogels at various temperatures and concentrations. The biocompatibility of parameters from these studies was tested by culturing 3D hybrid constructs bioprinted…

Magnetic nanocomposite scaffolds based on poly(ε-caprolactone) and poly(ethylene glycol) were fabricated by 3D fibre deposition modelling (FDM) and stereolithography techniques. In addition, hybrid coaxial and bilayer magnetic scaffolds were produced by combining such techniques. The aim of the current research was to analyse some structural and functional features of 3D magnetic scaffolds obtained by the 3D fibre deposition technique and by stereolithography as well as features of multimaterial scaffolds in the form of coaxial and bilayer structures obtained by the proper integration of such methods. The compressive mechanical behaviour of these scaffolds was investigated in a wet environment at 37…

Cells and tissues are intrinsically adapted to molecular gradients and use them to maintain or change their activity. The effect of such gradients is particularly important for cell populations that have an intrinsic capacity to differentiate into multiple cell lineages, such as bone marrow derived mesenchymal stromal cells (MSCs). Our results showed that nutrient gradients prompt the spatiotemporal organization of MSCs in 3D culture. Cells adapted to their 3D environment without significant cell death or cell differentiation. Kinetics data and whole-genome gene expression analysis suggest that a low proliferation activity phenotype predominates in stromal cells cultured in 3D, likely due…

In the surgical treatment of tuberculosis of the bones, excision of the lesion site leaves defects in the bone structure. Recent research has shown benefits for bone tissue support, such as tricalcium phosphate, as regrowth materials. These biocompatible engineering materials have good bone inductivity and biologic mechanical performance. The goal of this study was to evaluate the use of 3D printing, a new technology, to design and build 3-dimensional support structures for use in grafting at lesion sites and for use in embedding the sustained release anti-tuberculosis drugs Rifampin and Isoniazid and determine the in vivo performance of these structures.…

3D scaffolds based in mesoporous bioactive glasses (MBGs) are being widely investigated to use in bone tissue engineering (TE) applications. These scaffolds are often obtained by rapid prototyping (RP) and exhibit an array of interconnected pores in a hierarchy of sizes. The ordered mesopore network (around 4 nm in diameter) is optimal for the adsorption and release of bone inductor biomolecules, and the arrangement of macropores over 100 μm facilitates the bone cell ingrowths and angiogenesis. Nevertheless MBG composition can be varied almost infinitely at the atomic scale by including in the glass network oxides of inorganic elements with a…

Recently alginate-based tissue repair scaffolds fabricated using 3D printing techniques have been extensively examined for use in tissue engineering applications. However, their physical and mechanical properties are unfavorable for many tissue engineering applications because these properties are poorly controlled during the fabrication process. Some improvement of alginate gel properties can be realized by addition of hyaluronic acid (HA), and this may also improve the ability of cells to interact with the gel. Here, we report improvement of the physical properties of alginate–HA gel scaffolds by the addition of the polycation polyethyleneimine (PEI) during the fabrication process in order to stabilize…

A multimaterial bio-ink method using polyethylene glycol crosslinking is presented for expanding the biomaterial palette required for 3D bioprinting of more mimetic and customizable tissue and organ constructs. Lightly crosslinked, soft hydrogels are produced from precursor solutions of various materials and 3D printed. Rheological and biological characterizations are presented, and the promise of this new bio-ink synthesis strategy is discussed.

Graphene-based polymer composites are a very promising class of compounds for tissue engineering scaffolds. However, in general the methods of synthesis are environmentally hazardous and residual toxic materials can affect the biocompatibility significantly. In this paper a simple, scalable, environmentally-friendly, microwave-assisted synthesis is described that results in conducting graphene/polycaprolactone composites that retain the processability and biocompatibility of the pristine polymer without introducing possibly hazardous reducing agents. Composites of polycaprolactone and graphene oxide were synthesised in a single step by the ring-opening polymerisation of ε-caprolactone in the presence of dispersed graphene oxide nanosheets under microwave irradiation. The graphene oxide provides a…

Porous 3-D scaffolds consisting of gelatine and Si-doped hydroxyapatite were fabricated at room temperature by rapid prototyping. Microscopic characterization revealed a highly homogeneous structure, showing the pre-designed porosity (macroporosity) and a lesser in-rod porosity (microporosity). The mechanical properties of such scaffolds are close to those of trabecular bone of the same density. The biological behavior of these hybrid scaffolds is greater than that of pure ceramic scaffolds without gelatine, increasing pre-osteoblastic MC3T3-E1 cell differentiation (matrix mineralization and gene expression). Since the fabrication process of these structures was carried out at mild conditions, an antibiotic (vancomycin) was incorporated in the slurry…

The tympanic membrane (TM) is a thin tissue able to efficiently collect and transmit sound vibrations across the middle ear thanks to the particular orientation of its collagen fibers, radiate on one side and circular on the opposite side. Through the combination of advanced scaffolds and autologous cells, tissue engineering (TE) could offer valuable alternatives to autografting in major TM lesions. In this study, a multiscale approach based on electrospinning (ES) and additive manufacturing (AM) was investigated to fabricate scaffolds, based on FDA approved copolymers, resembling the anatomic features and collagen fiber arrangement of the human TM. A single scale…

The long-term in vitro culture and differentiation of human pancreatic islets is still hindered by the inability to emulate a suitable microenvironment mimicking physiological extracellular matrix (ECM) support and nutrient/oxygen perfusion. This is further amplified by the current lack of a non-invasive and rapid monitoring system to readily evaluate cellular processes. In this study, we realized a viable method for non-invasively monitoring isolated human pancreatic islets in vitro. Islets are induced to dedifferentiate into proliferative duct-like structures (DLS) in preparation for potential and subsequent re-differentiation into functional islet-like structures (ILS) in a process reminiscent of islet regeneration strategies. This long-term…

Nanocellulose has a variety of advantages, which make the material most suitable for use in biomedical devices such as wound dressings. The material is strong, allows for production of transparent films, provides a moist wound healing environment, and can form elastic gels with bioresponsive characteristics. In this study, we explore the application of nanocellulose as a bioink for modifying film surfaces by a bioprinting process. Two different nanocelluloses were used, prepared with TEMPO mediated oxidation and a combination of carboxymethylation and periodate oxidation. The combination of carboxymethylation and periodate oxidation produced a homogeneous material with short nanofibrils, having widths

Scaffolds play an important role in tissue engineering by providing structural framework and a surface for cells to attach, proliferate, and secrete extracellular matrix (ECM). In order to enable efficient tissue formation, delivering sufficient cells into the scaffold three-dimensional (3D) matrix using traditional static and dynamic seeding methods continues to be a critical challenge. In this study, we investigate a new cell delivery approach utilizing deposition of hydrogel-cell encapsulated microspheroids into polycaprolactone (PCL) scaffolds to improve the seeding efficiency. Three-dimensional-bioplotted PCL constructs (0 deg/90 deg lay down, 284 ± 6 μm strand width, and 555 ± 8 μm strand separation) inoculated with MG-63 model bone cells encapsulated within…

Bioplotting is an emerging freeform scaffold fabrication technique useful for creating artificial tissue scaffolds containing living cells. Simultaneous maintenance of scaffold structural integrity and cell viability is a challenging task. In this article, we present strategies developed to bioplot alginate-based three-dimensional tissue scaffolds containing hyaluronic acid and living Schwann cells for potential use in peripheral nerve tissue engineering. The fabrication platform, upon which the scaffold is created, was coated with the polycation polyethylenimine to immobilize the first layer of the scaffold on the platform. Each layer was then dispensed into a bath containing calcium chloride to cross-link the alginate, polyvinyl…

In this study, three-dimensional (3D) magnetic Fe3O4 nanoparticles containing mesoporous bioactive glass/polycaprolactone (Fe3O4/MBG/PCL) composite scaffolds have been fabricated by the 3D-printing technique. The physiochemical properties, in vitro bioactivity, anticancer drug delivery, mechanical strength, magnetic heating ability and cell response of Fe3O4/MBG/PCL scaffolds were systematically investigated. The results showed that Fe3O4/MBG/PCL scaffolds had uniform macropores of 400 μm, high porosity of 60% and excellent compressive strength of 13–16 MPa. The incorporation of magnetic Fe3O4 nanoparticles into MBG/PCL scaffolds did not influence their apatite mineralization ability but endowed excellent magnetic heating ability and significantly stimulated proliferation, alkaline phosphatase (ALP) activity, osteogenesis-related gene…

Calcium carbonate is the material that builds up the spicules of the calcareous sponges. Recent results revealed that the calcium carbonate/biocalcite-based spicular skeleton of these animals is formed through an enzymatic mechanism, such as the skeleton of the siliceous sponges, evolutionarily the oldest animals that consist of biosilica. The enzyme that mediates the calcium carbonate deposition has been identified as a carbonic anhydrase (CA) and has been cloned from the calcareous sponge species Sycon raphanus. Calcium carbonate deposits are also found in vertebrate bones besides the main constituent, calcium phosphate/hydroxyapatite (HA). Evidence has been presented that during the initial phase…

We investigated the effect of bioglass (bioactive glass) on growth and mineralization of bone-related SaOS-2 cells, encapsulated into a printable and biodegradable alginate/gelatine hydrogel. The hydrogel was supplemented either with polyphosphate (polyP), administered as polyP•Ca2+-complex, or silica, or as biosilica that had been enzymatically prepared from ortho-silicate by silicatein. These hydrogels, together with SaOS-2 cells, were bioprinted to computer-designed scaffolds. The results revealed that bioglass (nano)particles, with a size of 55 nm and a molar ratio of SiO2∶CaO∶P2O5 of 55∶40∶5, did not affect the growth of the encapsulated cells. If silica, biosilica, or polyP•Ca2+-complex is co-added to the cell-containing alginate/gelatin…

In this study, we fabricated strontium-containing mesoporous bioactive glass (Sr-MBG) scaffolds with controlled architecture and enhanced mechanical strength using a three-dimensional (3-D) printing technique. The study showed that Sr-MBG scaffolds had uniform interconnected macropores and high porosity, and their compressive strength was ∼170 times that of polyurethane foam templated MBG scaffolds. The physicochemical and biological properties of Sr-MBG scaffolds were evaluated by ion dissolution, apatite-forming ability and proliferation, alkaline phosphatase activity, osteogenic expression and extracelluar matrix mineralization of osteoblast-like cells MC3T3-E1. The results showed that Sr-MBG scaffolds exhibited a slower ion dissolution rate and more significant potential to stabilize the…

Sodium alginate hydrogel, stabilized with gelatin, is a suitable, biologically inert matrix that can be used for encapsulating and 3D bioprinting of bone-related SaOS-2 cells. However, the cells, embedded in this matrix, remain in a non-proliferating state. Here we show that addition of an overlay onto the bioprinted alginate/gelatine/SaOS-2 cell scaffold, consisting of agarose and the calcium salt of polyphosphate [polyP·Ca2+-complex], resulted in a marked increase in cell proliferation. In the presence of 100 μm polyP·Ca2+-complex, the cells proliferate with a generation time of approximately 47–55 h. In addition, the hardness of the alginate/gelatin hydrogel substantially increases in the presence…

Despite various studies to minimize host reaction following a biomaterial implantation, an appealing strategy in regenerative medicine is to actively use such an immune response to trigger and control tissue regeneration. We have developed an in vitro model to modulate the host response by tuning biomaterials’ surface properties through surface modifications techniques as a new strategy for tissue regeneration applications. Results showed tunable surface topography, roughness, wettability, and chemistry by varying treatment type and exposure, allowing for the first time to correlate the effect of these surface properties on cell attachment, morphology, strength and proliferation, as well as proinflammatory (IL-1β,…

In the present study, we report on the combined efforts of material chemistry, engineering and biology as a systemic approach for the fabrication of high viability 3D printed macroporous gelatin methacrylamide constructs. First, we propose the use and optimization of VA-086 as a photo-initiator with enhanced biocompatibility compared to the conventional Irgacure 2959. Second, a parametric study on the printing of gelatins was performed in order to characterize and compare construct architectures. Hereby, the influence of the hydrogel building block concentration, the printing temperature, the printing pressure, the printing speed, and the cell density were analyzed in depth. As a…

Artificial tissue engineering scaffolds can potentially provide support and guidance for the regrowth of severed axons following nerve injury. In this study, a hybrid biomaterial composed of alginate and hyaluronic acid (HA) was synthesized and characterized in terms of its suitability for covalent modification, biocompatibility for living Schwann cells and feasibility to construct three dimensional (3D) scaffolds. Carbodiimide mediated amide formation for the purpose of covalent crosslinking of the HA was carried out in the presence of calciumions that ionically crosslink alginate. Amide formation was found to be dependent on the concentrations of carbodiimide and calcium chloride. The double-crosslinked composite…

Bioactive, in situ forming materials have the potential to complement minimally invasive surgical procedures and enhance tissue healing. For such biomaterials to be adopted in the clinic, they must be cost-effective, easily handled by the surgeon and have a history of biocompatibility. To this end, we report a novel and facile self-assembling strategy to create membranes and encapsulating structures using collagen and hyaluronic acid (HA). Unlike membranes built by layer-by-layer deposition of oppositely charged biomolecules, the collagen–HA membranes described here form a diffusion barrier upon electrostatic interaction of the oppositely charged biomolecules, which is further driven by osmotic pressure imbalances.…

Combining technologies to engineer scaffolds that can offer physical and chemical cues to cells is an attractive approach in tissue engineering and regenerative medicine. In this study, we have fabricated polymer-ceramic hybrid scaffolds for bone regeneration by combining rapid prototyping (RP), electrospinning (ESP) and a biomimetic coating method in order to provide mechanical support and a physico-chemical environment mimicking both the organic and inorganic phases of bone extracellular matrix (ECM). Poly(ethylene oxide terephthalate)-poly(buthylene terephthalate) (PEOT/PBT) block copolymer was used to produce three dimensional scaffolds by combining 3D fiber (3DF) deposition, and ESP, and these constructs were then coated with a…

The bioactivity of sol–gel synthesized poly(ε-caprolactone) (PCL)/TiO2 or poly(ε-caprolactone)/ZrO2 particles was already known. In designing innovative 2D composite substrates for hard-tissue engineering, the possibility to embed PCL/TiO2 or PCL/ZrO2 hybrid fillers into a PCL matrix was previously proposed. In the present study, the potential of 3D fiber-deposition technique to design morphologically controlled scaffolds consisting of PCL reinforced with PCL/TiO2 or PCL/ZrO2 hybrid fillers was demonstrated. Finite element analysis was initially carried out on 2D substrates to find a correlation between the previously obtained results from the small punch test and the Young’s modulus of the materials, whilst mechanical and biological…

The rationale for the use of polymer–ceramic composites for bone regeneration stems from the natural composition of bone, with collagen type I and biological apatite as the main organic and inorganic constituents, respectively. In the present study composite materials of PolyActive™ (PA), a poly(ethylene oxide terephthalate)/poly(butylene terephtalate) co-polymer, and hydroxyapatite (HA) at a weight ratio of 85:15 were prepared by rapid prototyping (RP) using two routes. In the first approach pre-extruded composite filaments of PA–HA were processed using three-dimensional fibre deposition (3DF) (conventional composite scaffolds). In the second approach PA scaffolds were fabricated using 3DF and combined with HA pillars…

Fabricating three-dimensional (3D) porous scaffolds with controlled structure and geometry is crucial for tissue regeneration. To date, exploration in printing 3D natural protein scaffolds is limited. In this study, soy protein slurry was successfully printed using the 3D Bioplotter to form scaffolds. A method to verify the structural integrity of resulting scaffolds during printing was developed. This process involved measuring the mass extrusion flow rate of the slurry from the instrument, which was directly affected by the extrusion pressure and the soy protein slurry properties. The optimal mass flow rate for printing soy slurry at 27°C was 0.0072±0.0002 g/s. The addition…

The present study aimed to investigate the effect of structure (design and porosity) on the matrix stiffness and osteogenic activity of stem cells cultured on poly(ester-urethane) (PEU) scaffolds. Different three-dimensional (3D) forms of scaffold were prepared from lysine-based PEU using traditional salt-leaching and advanced bioplotting techniques. The resulting scaffolds were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), mercury porosimetry and mechanical testing. The scaffolds had various pore sizes with different designs, and all were thermally stable up to 300 °C. In vitro tests, carried out using rat bone marrow stem cells (BMSCs) for bone tissue…

Optimal cell interaction with biomaterial scaffolds is one of the important requirements for the development of successful in vitro tissue-engineered tissues. Fast, efficient and spatially uniform cell adhesion can improve the clinical potential of engineered tissue. Three-dimensional (3-D) solid free form fabrication is one widely used scaffold fabrication technique today. By means of deposition of polymer fibers, scaffolds with various porosity, 3-D architecture and mechanical properties can be prepared. These scaffolds consist mostly of solid round fibers. In this study, it was hypothesized that a corrugated fiber morphology enhances cell adhesion and proliferation and therefore leads to the development of…

In a versatile modular scaffold system, gradient nonwovens of in situ crosslinked gelatin nanofibers (CGN), fabricated by reactive electrospinning, are laminated with perforated layers and nonwovens of thermoplastic non-crosslinked biodegradable polyesters. The addition of glyoxal to a gelatin solution in a non-toxic solvent mixture consisting of acetic acid, ethyl acetate, and water (5:3:2 w/w/w) enables the in situ crosslinking of gelatin nanofibers during electrospinning. The use of this fluorine-free crosslinking system eliminates the need of post-treatment crosslinking and purification steps typical for conventional CGN scaffolds. The slowly progressing crosslinking of the dissolved gelatin in the presence of glyoxal increases the…

A new application of layer-by-layer assembly is presented, able to create nano/micro fibrils or nanocoatings inside 3D scaffolds using non-fibrillar polyelectrolytes for tissue-engineering applications. This approach shows promise for developing advanced scaffolds with controlled nano/micro environments, and nature and architectures similar to the natural extracellular matrix, leading to improved biological performance.

The costs associated with the treatment of medical device and surgical site infections are a major cause of concern in the global healthcare system. To prevent transmission of such infections, a prophylactic surface system that provides protracted release of antibacterial silver ions using low intensity direct electric current (LIDC; 28 μA system current at 6 V) activation has been recently developed. To ensure the safety for future in vivo studies and potential clinical applications, this study assessed the biocompatibility of the LIDC-activated interdigitated silver electrodes-based surface system; in vitro toxicity to human epidermal keratinocytes, human dermal fibroblasts, and normal human…

This study reports the design and preparation of zwitterionic nanocrystalline hydroxyapatite (HA) capable of inhibiting bacterial adhesion while allowing osteoblast cell colonization. The surface functionalization of HA powders was carried out by post-synthesis grafting of 3-aminopropyltriethoxysilane (APTES) and carboxyethylsilanetriol sodium salt (CES) as amine and carboxylate precursors, respectively. The successful functionalization of HA surfaces was assessed by elemental chemical analysis, FTIR, 29Si, 31P and 13C solid state CP/MAS NMR and ζ-potential measurements, and the zwitterionic nature of the synthesized HA was proved through the presence of –NH3+/–COO− pairs on the material surfaces. With the aim of evaluating the feasibility of…

Nerve conduits for peripheral nerve repair have progressed from simple silicon tubes to complex engineered scaffolds. Recent advances in scaffold fabrication have enabled the incorporation of neurotrophins, extracellular matrix components and various cells into scaffolds for enhanced biologic properties. Bioplotting is one of the emerging methods, where the scaffold material, in form of a solution, is dispensed from a needle, layer by layer forming a three-dimensional structure. It enables the use of a wide range of materials, ranging from synthetic polymers (like polycaprolactone, polyglycolic acid, etc.) to naturally occurring polymers like alginate, chitosan, etc. Notably, the use of hydrogels gives…

Spinal cord injuries (SCI) present a major challenge to therapeutic development due to its complexity. Combinatorial approaches using biodegradable polymers that can simultaneously provide a tissue scaffold, a cell vehicle, and a reservoir for sustained drug delivery have shown very promising results. In our previous studies we have developed a novel hybrid system consisting of starch/poly-e-caprolactone (SPCL) semi-rigid tubular porous structure, based on a rapid prototyping technology, filled by a gellan gum hydrogel concentric core for the regeneration within spinal-cord injury sites. In the present work we intend to promote enhanced osteointegration on these systems by pre-mineralizing specifically the external…

The mechanical properties of amorphous, degradable, and highly porous poly(lactide-co-caprolactone) structures have been improved by using a 3D fiber deposition (3DF) method. Two designs of 3DF scaffolds, with 45° and 90° layer rotation, were printed and compared with scaffolds produced by a salt-leaching method. The scaffolds had a porosity range from 64% to 82% and a high interconnectivity, measured by micro-computer tomography. The 3DF scaffolds had 8–9 times higher compressive stiffness and 3–5 times higher tensile stiffness than the salt-leached scaffolds. There was a distinct decrease in the molecular weight during printing as a consequence of the high temperature. The…

Spinal cord injury (SCI) represents a major world health problem. Therefore it is urgent to develop novel strategies that can specifically target it. We have previously shown that the implantation of starch-based scaffolds (SPCL) aimed for spine stabilization on SCI animals leads to motor skills improvements. Therefore, we hypothesize that the combination of these scaffolds with relevant cell populations for SCI repair will, most likely, lead to further improvements. Therefore, in this work, the ability of SPCL scaffolds to support the 3D culture of olfactory ensheathing cells (OECs) and Schwann cells (SCs) was studied and characterized. The results demonstrate for…

The requirement of a multifunctional scaffold for tissue engineering capable to offer at the same time tunable structural properties and bioactive interface is still unpaired. Here we present three-dimensional (3D) biodegradable polymeric (PCL) scaffolds with controlled morphology, macro-, micro-, and nano-mechanical performances endowed with bioactive moieties (RGD peptides) at the surface. Such result was obtained by a combination of rapid prototyping (e.g., 3D fiber deposition) and surface treatment approach (aminolysis followed by peptide coupling). By properly designing process conditions, a control over the mechanical and biological performances of the structure was achieved with a capability to tune the value of…

In this study, we introduce a cellular differentiation cellular model based on dielectric spectroscopy that characterizes epithelial differentiation processes. Non-invasive cellular monitoring was achieved within a three-dimensional microenvironment consisting of a cell-containing collagen I gel seeded onto microfabricated scaffolds. In this proof-of-concept investigation, Madin-Darby canine kidney cells were cultured within microfabricated, geometrically controlled scaffolds and allowed us to differentiate to hollow cyst-like structures. This transformation within the three-dimensional environment is monitored and characterized through dielectric spectroscopy while maintaining cell culture in vitro.

A basic approach toward the design of three-dimensional (3D) rapid prototyped magnetic scaffolds for hard-tissue regeneration has been proposed. In particular, 3D scaffolds consisting of a poly(ε-caprolactone) (PCL) matrix and iron oxide (Fe3O4) or iron-doped hydroxyapatite (FeHA) nanoparticles were fabricated through a 3D fibre deposition technique. As a first approach, a polymer to nanoparticle weight ratio of 90/10 (wt/wt) was used. The effect of the inclusion of both kinds of nanoparticles on the mechanical, magnetic, and biological performances of the scaffolds was studied. The inclusion of Fe3O4 and FeHA nanoparticles generally improves the modulus and the yield stress of the…

Magnetic scaffolds for bone tissue engineering based on a poly(ε-caprolactone) (PCL) matrix and iron oxide (Fe3O4) magnetic nanoparticles were designed and developed through a three-dimensional (3D) fiber-deposition technique. PCL/Fe3O4 scaffolds were characterized by a 90/10 w/w composition. Tensile and magnetic measurements were carried out, and nondestructive 3D imaging was performed through microcomputed tomography (Micro-CT). Furthermore, confocal analysis was undertaken to investigate human mesenchymal stem cell adhesion and spreading on the PCL/Fe3O4 nanocomposite fibers. The results suggest that nanoparticles mechanically reinforced the PCL matrix; the elastic modulus and the maximum stress increased about 10 and 30%, respectively. However, the maximum strain…

In this study we examined the release kinetics of valproate from polycaprolactone (PCL) implants constructed for local antiepileptic therapy. The PCL implants were produced with a novel 3D-Bioplotting technology. Release kinetics were determined by superfusion of these implants. Valproate was measured in the superfusate fractions with high pressure liquid chromatography (HPLC). The HPLC measurements were linear over a concentration range of 10-500 g/mL for valproate and the limit of quantification was found to be 9 g/mL. The HPLC method used is simple, accurate and sensitive. Within the first day, valproate (10%w/w)-PCL implants released already 77% of the maximum possible liberated…

Scaffolds produced by rapid prototyping (RP) techniques have proved their value for tissue engineering applications, due to their ability to produce predetermined forms and structures featuring fully interconnected pore architectures. Nevertheless, low cell seeding efficiency and non-uniform distribution of cells remain major limitations when using such types of scaffold. This can be mainly attributed to the inadequate pore architecture of scaffolds produced by RP and the limited efficiency of cell seeding techniques normally adopted. In this study we aimed at producing scaffolds with pore size gradients to enhance cell seeding efficiency and control the spatial organization of cells within the…

Parathyroid hormone-related protein (107-111) (osteostatin) induces osteogenic effects in osteoblasts in vitro and in regenerating bone in mice and rabbits. In this study we used osteoblastic MC3T3-E1 cell cultures to evaluate and compare the bioactivity of this peptide either adsorbed or covalently bound (by its C-terminus) to Si-doped hydroxyapatite (Si-HA) scaffolds after organic (-NH2) functionalization. By these means osteostatin can be locally released or kept anchored to the scaffold surface. This was confirmed by chemical analysis and by testing the efficiency of osteostatin-loaded Si-HA scaffolds (placed in Transwell chambers) in healing a scratch wound in mouse pluripotent mesenchymal C3H10T1/2 cells.…

Sufficient nutrient and oxygen transport is a potent modulator of cell proliferation in in vitro tissue-engineered constructs. The lack of oxygen and culture medium can create a potentially lethal environment and limit cellular metabolic activity and growth. Diffusion through scaffold and multi-cellular tissue typically limits transport in vitro, leading to potential hypoxic regions and reduction in the viable tissue thickness. For the in vitro generation of clinically relevant tissue-engineered grafts, current nutrient diffusion limitations should be addressed. Major approaches to overcoming these include culture with bioreactors, scaffolds with artificial microvasculature, oxygen carriers and pre-vascularization of the engineered tissues. This study…

Scaffolds used in the field of tissue engineering should facilitate the adherence, spreading, and ingrowth of cells as well as prevent microbial adherence. For the first time, this study simultaneously deals with microbial and tissue cell adhesion to rapid prototyping-produced 3D-scaffolds. The cell growth of human osteosarcoma cells (CAL-72) over a time period of 3-11 days were examined on three scaffolds (PLGA, PLLA, PLLA-TCP) and compared to the adhesion of salivary microorganisms and representative germs of the oral flora (Porphyromonas gingivalis, Prevotella nigrescens, Candida albicans, Enterococcus faecalis, Streptococcus mutans, and Streptococcus sanguinis). Scanning electron microscopy (SEM), cell proliferation measurements, and…

Fibroblast growth factors (FGFs) are polypeptides that control the proliferation and differentiation of various cell types including osteoblasts. FGFs are also strong inducers of angiogenesis, necessary to obtain oxygen and nutrients during tissue repair. With the aim to incorporate these desirable FGF biological properties into bioceramics for bone repair, silicon substituted hydroxyapatites (Si-HA) were used as materials to immobilize bioactive FGF-1 and FGF-2. Thus, the binding of these growth factors to powdered Si-HA and Si-HA scaffolds was carried out efficiently in the present study and both FGFs maintained its biological activity on osteoblasts after its immobilization. The improvement of cell…

A practical method of photocrosslinking high molecular weight poly(trimethylene carbonate)(PTMC) is presented. Flexible, elastomeric and biodegradable networks could be readily prepared by UV irradiating PTMC films containing pentaerythritol triacrylate (PETA) and a photoinitiator. The network characteristics, mechanical properties, wettability, and in vitro enzymatic erosion of the photocrosslinked PTMC films were investigated. Densely crosslinked networks with gel contents up to 98% could be obtained in this manner. Upon photocrosslinking, flexible and tough networks with excellent elastomeric properties were obtained. To illustrate the ease with which the properties of the networks can be tailored, blends of PTMC with mPEG-PTMC or with PTMC-PCL-PTMC…

Scaffolds should possess suitable properties to play their specific role. In this work, the potential of 3D fiber deposition technique to develop multifunctional and well‐defined magnetic poly(ε‐caprolactone)/iron oxide scaffolds has been highlighted, and the effect of iron oxide nanoparticles on the biological and mechanical performances has been assessed.

The aim of this study was to develop 3-D tissue engineered constructs that mimic the in vivo conditions through a self-contained growth factor delivery system. A set of nanoparticles providing the release of BMP-2 initially followed by the release of BMP-7 were incorporated in poly(ε-caprolactone) scaffolds with different 3-D architectures produced by 3-D plotting and wet spinning. The release patterns were: each growth factor alone, simultaneous, and sequential. The orientation of the fibers did not have a significant effect on the kinetics of release of the model protein BSA; but affected proliferation of bone marrow mesenchymal stem cells. Cell proliferation…

To study cell responses, polymeric scaffolds with a controllable pore size and porosity have been fabricated using rapid-prototyping methods. However, the scaffolds fabricated by rapid prototyping have very smooth surfaces, which tend to discourage initial cell attachment. Initial cell attachment, migration, differentiation and proliferation are strongly dependent on the chemical and physical characteristics of the scaffold surface. In this study, we propose a three-dimensional (3D) plotting method supplemented with a chemical blowing agent to produce a surface-modified 3D scaffold in which the surface is inscribed with nano- and micro-sized pores. The chemically-blown 3D polymeric scaffold exhibited positive qualities, including the…

In this paper, we design and fabricate a 3D scaffold using rapid prototyping (RP) technology for tissue engineering. The scaffold should have a three-dimensional interconnected pore network. We fabricate a polycaprolactone (PCL) scaffold with interconnecting pores and uniform porosity for cell ingrowth using a 3D plotting system. In order to keep the three dimensional shape under mechanical loading while implanted, we design an oscillating nozzle system to increase elastic modulus and yield strength of PCL strand. We characterize the influence of pore geometry, compressive modulus of the scaffold, elastic modulus and yield strength of the strand using SEM, dynamical mechanical…

Designing a three-dimensional (3-D) ideal scaffold has been one of the main goals in biomaterials and tissue engineering, and various mechanical techniques have been applied to fabricate biomedical scaffolds used for soft and hard tissue regeneration. Scaffolds should be biodegradable and biocompatible, provide temporary support for cell growth to allow cell adhesion, and consist of a defined structure that can be formed into customized shapes by a computer-aided design system. This versatility in preparing scaffolds gives us the opportunity to use rapid prototyping devices to fabricate polymeric scaffolds. In this study, we fabricated polycaprolactone scaffolds with interconnecting pores using a…

Various mechanical techniques have been used to fabricate biomedical scaffolds, including rapid prototyping (RP) devices that operate from CAD files of the target feature information. The three-dimensional (3-D) bio-plotter is one RP system that can produce design-based scaffolds with good mechanical properties for mimicking cartilage and bones. However, the scaffolds fabricated by RP have very smooth surfaces, which tend to discourage initial cell attachment. Initial cell attachment, migration, differentiation and proliferation are strongly dependent on the chemical and physical characteristics of the scaffold surface. In this study, we propose a new 3-D plotting method supplemented with a piezoelectric system for…

Purpose Hydrogels with low viscosities tend to be difficult to use in constructing tissue engineering (TE) scaffolds used to replace or restore damaged tissue, due to the length of time it takes for final gelation to take place resulting in the scaffolds collapsing due to their mechanical instability. However, recent advances in rapid prototyping have allowed for a new technology called bioplotting to be developed, which aims to circumvent these inherent problems. This paper aims to present details of the process. Design/methodology/approach The paper demonstrates how by using the bioplotting technique complex 3D geometrical scaffolds with accurate feature sizes and…

Engineered scaffolds for tissue-engineering should be designed to match the stiffness and strength of healthy tissues while maintaining an interconnected pore network and a reasonable porosity. In this work, we have used 3D-ploting technique to produce poly-LLactide (PLLA) macroporous scaffolds with two different pore sizes. The ability of these macroporous scaffolds to support chondrocyte attachment and viability were compared under static and dynamic loading in vitro. Moreover, the 3D-plotting technique was combined with porogen-leaching, leading to micro/macroporous scaffolds, so as to examine the effect of microporosity on the level of cell attachment and viability under similar loading condition. Canine chondrocytes…

Articular cartilage has a limited regenerative capacity. Tissue engineering strategies adopting seeding and differentiation of individual chondrocytes on porous 3D scaffolds of clinically relevant size remains a considerable challenge. A well documented method to produce small samples of differentiated cartilage tissue in vitro is via micro-mass (pellet) culture, whereby, high concentrations of chondrocytes coalesce to form. a spherical tissue pellet. However, pellet culture techniques are not applied clinically as it is only possible to produce small amounts of tissue (1–2mm). The aims of this study were to develop a method for mass-production of pellets, and investigate whether an alternative “pellet…

In this study we tested the possibility of seeding chondrocytes into poly (ethylene glycol)-terephthalate-poly (butylene terephthalate) PEOT/PBT scaffold through an intra-scaffold medium flow and the impact of this continuous medium flow on subsequent chondrocyte-scaffold culture. Eight cubic PEOT/PBT co-polymers (1 cm3) were assigned into two groups. In the semi-dynamic seeding group a continuous medium flow was created inside the scaffolds by a pump system. Around six million chondrocytes were harvested each day, suspended in 1 ml medium and delivered onto the scaffold through the perfusion for a sequential five days. Traditional chondrocytes directly seeding and static culture method was performed…

Apatite layers were grown on the surface of newly developed starch/polycaprolactone (SPCL)-based scaffolds by a 3D plotting technology. To produce the biomimetic coatings, a sodium silicate gel was used as nucleating agent, followed by immersion in a simulated body fluid (SBF) solution. After growing a stable apatite layer for 7 days, the scaffolds were placed in SBF under static, agitated (80 strokes min−1) and circulating flow perfusion (Q = 4 ml min−1; tR = 15 s) for up to 14 days. The materials were characterized by scanning electron microscopy/energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and thin-film X-ray diffraction.…

Fibrous structures mimicking the morphology of the natural extracellular matrix are considered promising scaffolds for tissue engineering. This work aims to develop a novel hierarchical starch-based scaffold. Such scaffolds were obtained by a combination of starch-polycaprolactone micro- and polycaprolactone nano-motifs, respectively produced by rapid prototyping (RP) and electrospinning techniques. Scanning electron microscopy (SEM) and micro-computed tomography analysis showed the successful fabrication of a multilayer scaffold composed of parallel aligned microfibres in a grid-like arrangement, intercalated by a mesh-like structure with randomly distributed nanofibres (NFM). Human osteoblast-like cells were dynamically seeded on the scaffolds, using spinner flasks, and cultured for 7…

Application of hydrogels in tissue engineering and innovative strategies such as organ printing, which is based on layered 3D deposition of cell-laden hydrogels, requires design of novel hydrogel matrices. Hydrogel demands for 3D printing include: 1) preservation of the printed shape after the deposition; 2) maintaining cell viability and cell function and 3) easy handling of the printed construct. In this study we analyze the applicability of a novel, photosensitive hydrogel (Lutrol) for printing of 3D structured bone grafts. We benefit from the fast temperature-responsive gelation ability of thermosensitive Lutrol-F127, ensuring organized 3D extrusion, and the additional stability provided by…

The construction of biomaterial scaffolds for cell seeding is now seen as the most common approach for producing artificial tissue as compared with cell self-assembly and Acellular matrix techniques. This paper describes the use of synthetic and natural polymeric material shaped into 3D biological matrices by using Rapid Prototyping (RP) technology. Recent advances in RP technology have greatly enhanced the range of biomaterials that can now be constructed into scaffolds, also allowing for maximized control of the pore size and architecture. Bioplotting is one such method which allows the dispensing of various biomaterials into a media bath which has similar…

An ideal scaffold should have good mechanical properties and provide a biologically functional implant site. A rapid prototyping system has been introduced as a good method of fabricating 3D scaffolds that mimic the structure in the human body. However, the scaffolds have strands that are too smooth and a pore size that is too large relative to the seeded cells and present unfavorable conditions for initial cell attachment. To overcome these problems, we propose a hybrid technology combining a 3D rapid prototyping system and an electrospinning process to produce a hierarchical 3D biomedical scaffold. The resulting structure consists of alternating…

Organ or tissue printing, a novel approach in tissue engineering, creates layered, cell-laden hydrogel scaffolds with a defined three-dimensional (3D) structure and organized cell placement. In applying the concept of tissue printing for the development of vascularized bone grafts, the primary focus lies on combining endothelial progenitors and bone marrow stromal cells (BMSCs). Here we characterize the applicability of 3D fiber deposition with a plotting device, Bioplotter, for the fabrication of spatially organized, cell-laden hydrogel constructs. The viability of printed BMSCs was studied in time, in several hydrogels, and extruded from different needle diameters. Our findings indicate that cells survive…

The ability to control the architecture and strength of a bone tissue engineering scaffold is critical to achieve a harmony between the scaffold and the host tissue. Rapid prototyping (RP) technique is applied to tissue engineering to satisfy this need and to create a scaffold directly from the scanned and digitized image of the defect site. Design and construction of complex structures with different shapes and sizes, at micro and macro scale, with fully interconnected pore structure and appropriate mechanical properties are possible by using RP techniques. In this study, RP was used for the production of poly(ε-caprolactone) (PCL) scaffolds.…

Tissue engineered scaffolds must have an organized and repeatable microstructure which enables cells to assemble in an ordered matrix that allows adequate nutriental perfusion. In this work, to evaluate the reciprocal cell interactions of endothelial and osteoblast-like cells, human osteoblast-like cells (MG63) and Human Umbilical Vein Endothelial Cells (HUVEC) were co-seeded onto 3D geometrically controlled porous poly(ε-caprolactone) (PCL) and cultured by means of a rotary cell culture system (RCCS-4DQ). In our dynamic co-culture system, the lack of significant enhancement of osteoblast ALP activity and ECM production indicated that the microgravity conditions of the rotary system affected the cells by favoring…

Despite the periodical and completely interconnected pore network that characterizes rapid prototyped scaffolds, cell seeding efficiency remains still a critical factor for optimal tissue regeneration. This can be mainly attributed to the current resolution limits in pore size. We present here novel three-dimensional (3D) scaffolds fabricated by combining 3D fiber deposition (3DF) and electrospinning (ESP). Scaffolds consisted of integrated 3DF periodical macrofiber and random ESP microfiber networks (3DFESP). The 3DF scaffold provides structural integrity and mechanical properties, while the ESP network works as a “sieving” and cell entrapment system and offers?at the same time?cues at the extracellular matrix (ECM) scale.…

Embryonic stem (ES) cells are a potential source for cartilage tissue engineering because they provide an unlimited supply of cells that can be differentiated into chondrocytes. So far, chondrogenic differentiation of both mouse and human ES cells has only been demonstrated in two-dimensional cultures, in pellet cultures, in a hydrogel, or on thin biomaterials. The next challenge will be to form cartilage on a load-bearing, clinically relevant-sized scaffold in vitro and in vivo, to regenerate defects in patients suffering from articular cartilage disorders. For a successful implant, cells have to be seeded efficiently and homogenously throughout the scaffold. Parameters investigated…

Rapid prototyping (RP)-produced scaffolds aregaining increasing importance in scaffold-guided tissueengineering. Microbial adhesion on the surface of replacement materials has a strong influence on healing and long-term outcome. Consequently, it is important to examine the adherence of microorganisms on RP-produced scaffolds. This research focussed on manufacturing of scaffolds by 3D-bioplotting and examination of their microbial adhesion characteristics. Tricalciumphosphate (TCP), calcium/sodium alginate, and poly(lactide-co-glycolic acid) (PLGA) constructs were produced and used to study the adhesion of dental pathogens. Six oral bacterial strains, one Candida strain and human saliva were used for the adhesion studies. The number of colony forming units (CFU) were…

Biomaterials capable of efficient gene delivery by embedded cells provide a fundamental tool for the treatment of acquired or hereditary diseases. A major obstacle is maintaining adequate nutrient and oxygen diffusion to cells within the biomaterial. In this study, we combined the solid free-form fabrication and porogen leaching techniques to fabricate three-dimensional scaffolds, with bimodal pore size distribution, for cell-based gene delivery. The objective of this study was to design micro-/macroporous scaffolds to improve cell viability and drug delivery. Murine bone marrow-derived mesenchymal stromal cells (MSCs) genetically engineered to secrete erythropoietin (EPO) were seeded onto poly-l-lactide (PLLA) scaffolds with different…

Reconstruction of bone defects in the field of craniomaxillofacial surgery is a relevant problem. In regenerative medicine, autologous bone is not available sufficiently. The full replacement of autologous bone grafts is required. A promising research field is the bone engineering. Especially the application of rapid prototyping (RP) enables new perspectives concerning the scaffold design. The aim of the study was to compare scaffolds produced by RP-technology (native and plasma-coated PLGA-scaffolds) with conventionally produced scaffolds (agar plates with hydroxyapatite and hyaluronic acid coated agar plates with hydroxyapatite) relating to proliferation, adhesion, and morphology of osteoblasts to get knowledge about the application…

The advantage of using anatomically shaped scaffolds as compared to modeled designs was investigated and assessed in terms of cartilage formation in an artificial tracheal construct. Scaffolds were rapid prototyped with a technique named three-dimensional fiber deposition (3DF). Anatomical scaffolds were fabricated from a patient-derived computerized tomography dataset, and compared to cylindrical and toroidal tubular scaffolds. Lewis rat tracheal chondrocytes were seeded on 3DF scaffolds and cultured for 21 days. The 3-(4,5-dimethylthiazol-2yl)-2,5-dyphenyltetrazolium bromide (MTT) and sulfated glycosaminoglycan (GAG) assays were performed to measure the relative number of cells and the extracellular matrix (ECM) formed. After 3 weeks of culture, the…

Three-dimensional (3D) fiber deposition (3DF), a rapid prototyping technology, was successfully directly applied to produce novel 3D porous Ti6Al4V scaffolds with fully interconnected porous networks and highly controllable porosity and pore size. A key feature of this technology is the 3D computer-controlled fiber depositing of Ti6Al4V slurry at room temperature to produce a scaffold, consisting of layers of directionally aligned Ti6Al4V fibers. In this study, the Ti6Al4V slurry was developed for the 3D fiber depositing process, and the parameters of 3D fiber depositing were optimized. The experimental results show how the parameters influence the structure of porous scaffold. The potential…

Hollow fibers find useful applications in different disciplines like fluid transport and purification, optical guidance, and composite reinforcement. In tissue engineering, they can be used to direct tissue in-growth or to serve as drug delivery depots. The fabrication techniques currently available, however, do not allow to simultaneously organize them into three-dimensional (3D) matrices, thus adding further functionality to approach more complicated or hierarchical structures. We report here the development of a novel technology to fabricate hollow fibers with controllable hollow cavity diameter and shell thickness. By exploiting viscous encapsulation, a rheological phenomenon often undesired in molten polymeric blends flowing through…

In Tissue Engineering and bone reconstruction, alongside the choice of materials, the scaffold design is of great importance. Three dimensional structures not only permit the tuning of chemical and mechanical properties, but they can also copy the outer form of the required bone or cartilaginous structures. While new processes that create such 3D scaffolds by means of Rapid Prototyping have been developed, they are still restricted to a limited type of materials. At the Freiburger Materialforschungszentrum, our group has developed a new process called 3D BioplottingTM. Most kinds of polymers and biopolymers can be used for the fabrication of 3D…

Two important rapid-prototyping technologies (3D Printing and 3D Bioplotting) were compared with respect to the computer-aided design and free-form fabrication of biodegradable polyurethane scaffolds meeting the demands of tissue-engineering applications. Aliphatic polyurethanes were based on lysine ethyl ester diisocyanate and isophorone diisocyanate. Layer-by-layer construction of the scaffolds was performed by 3D Printing, that is, bonding together starch particles followed by infiltration and partial crosslinking of starch with lysine ethyl ester diisocyanate. Alternatively, the 3D Bioplotting process permitted three-dimensional dispensing and reactive processing of oligoetherurethanes derived from isophorone diisocyanate, oligoethylene oxide, and glycerol. The scaffolds were characterized with X-ray microtomography, scanning…

Scaffolds are of great importance for tissue engineering because they enable the production of functional living implants out of cells obtained from cell culture. These scaffolds require individual external shape and well defined internal structure with interconnected porosity. The problem of the fabrication of prototypes from computer assisted design (CAD) data is well known in automotive industry. Rapid prototyping (RP) techniques are able to produce such parts. Some RP techniques exist for hard tissue implants. Soft tissue scaffolds need a hydrogel material. No biofunctional and cell compatible processing for hydrogels exists in the area of RP. Therefore, a new rapid…

In the year 2000 a new rapid prototyping (RP) technology was developed at the Freiburg Materials Research Center to meet the demands for desktop fabrication of scaffolds useful in tissue engineering. A key feature of this RP technology is the three-dimensional (3D) dispensing of liquids and pastes in liquid media. In contrast to conventional RP systems, mainly focused on melt processing, the 3D dispensing RP process (3D plotting) can apply a much larger variety of synthetic as well as natural materials, including aqueous solutions and pastes, to fabricate scaffolds for application in tissue engineering. For the first time, hydrogel scaffolds…