3D Bioplotter Research Papers

Tissue engineering based on bioprinting technology has broad prospects in the treatment of critical-sized bone defect. Nevertheless, it is challenging to construct composite tissues or organs with structural integrity. Periosteum and stem cells are important in bone regeneration, and it has been shown that co-culture engineering system could successfully repair bone defects. Here, a strategy of co-culture bioprinting was proposed, and a tissue-engineered bone-periosteum biphasic complex was designed. Poly-L-lactic acid/hydroxyapatite (PLLA/HA) was used to construct the supporting scaffold of bone phase. Gelatin methacryl (GelMA) loaded with rabbit bone mesenchymal stem cells (BMSCs) and periosteum-derived stem cells (PDSCs) were used to…

3D printed bioceramics derived from preceramic polymers are of great interest in bone tissue engineering due to their simplified fabrication processes. In this study, three-dimensional (3D) porous β-Ca2SiO4 scaffolds incorporated with ZrO2 were fabricated from silicone resin loaded with active CaCO3 and inert ZrO2 fillers by 3D printing. The fabricated scaffolds possessed uniform interconnected macropores with a high porosity (> 67%). The results showed that the increase of ZrO2 incorporation significantly enhanced the compressive strength, and stimulated cell proliferation and differentiation of osteoblasts. Importantly, the in vivo results indicated that the ZrO2-incorporated β-Ca2SiO4 scaffolds improved osteogenic capacity compared to pure…

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,…

Contaminated or infected bone defects remain serious challenges in clinical trauma and orthopaedics, and a bone substitute with both osteoconductivity and antibacterial properties represents an improvement for treatment strategy. In this study, quaternized chitosan (hydroxypropyltrimethyl ammonium chloride chitosan, HACC) was grafted to 3D-printed scaffolds composed of polylactide-co-glycolide (PLGA) and hydroxyapatite (HA), in order to design bone engineering scaffolds endowed with antibacterial and osteoconductive properties. We found that both the PLGA/HA/HACC and PLGA/HACC composite scaffolds decreased bacterial adhesion and biofilm formation under in vitro and in vivo conditions. Additionally, ATP leakage assay indicated that immobilizing HACC on the scaffolds could effectively…

Synthetic polymeric scaffolds are commonly used in bone tissue engineering (BTE) due to their biocompatibility and adequate mechanical properties. However, their hydrophobicity and the lack of specific cell recognition sites confined their practical application. In this study, to improve the cell seeding efficiency and osteoinductivity, an injectable thermo-sensitive chitosan hydrogel (CSG) was incorporated into a 3D-printed poly(ε-caprolactone) (PCL) scaffold to form a hybrid scaffold. To demonstrate the feasibility of this hybrid system for BTE application, rabbit bone marrow mesenchymal stem cells (BMMSCs) and bone morphogenetic protein-2 (BMP-2) were encapsulated in CSG. Pure PCL scaffolds were used as controls. Cell proliferation…

Natural fracture healing is most efficient when the fine-tuned mechanical force and proper micromotion are applied. To mimick this micromotion at the fracture gap, a near-infrared-II (NIR–II)–activated hydrogel was fabricated by integrating two-dimensional (2D) monolayer Nb2C nanosheets into a thermally responsive poly(N-isopropylacrylamide) (NIPAM) hydrogel system. NIR–II–triggered deformation of the NIPAM/Nb2C hydrogel was designed to generate precise micromotion for co-culturing cells. It was validated that micromotion at 1/300 Hz, triggering a 2.37-fold change in the cell length/diameter ratio, is the most favorable condition for the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). Moreover, mRNA sequencing and verification revealed that…

Although several bioactive 3D-printed bone scaffolds loaded with multiple kinds of biomolecules for enhanced bone regeneration have been recently developed, the manipulation of on-demand release profiles of different biomolecules during bone regeneration remains challenging. Herein, a 3D-printed dual-drug-loaded biomimetic scaffold to regulate the host stem cell recruitment and osteogenic differentiation in a two-stage process for bone regeneration was successfully fabricated. First, a chemotactic small-molecule drug, namely, simvastatin (SIM) was directly incorporated into the hydroxyapatite/collagen bioink for printing and could be rapidly released during the early stage of bone regeneration. Further, near-infrared (NIR)-light-responsive polydopamine-coated hydroxyapatite nanoparticles were designed to deliver the…

Rapid bone regeneration in implants is important for successful transplantation. In this regard, we report the development of calcium silicate/zinc silicate (CS/ZS) dual-compound-incorporated calcium phosphate cement (CPC) scaffolds with a three-dimensional poly (lactic-co-glycolic acid) network that synergistically promote bone regeneration. In vitro results demonstrated that the incorporation of CS/ZS dual compounds into the CPC significantly promoted the osteogenic differentiation of stem cells compared to the addition of CS or ZS alone. Moreover, the bone-regeneration efficacy of the composite scaffolds was validated by filling in femur condyle defects in rabbits, which showed that the scaffolds with CS and ZS possessed a…

Creating interconnected macropores in calcium phosphate cement (CPC) is an effective strategy to promote its degradation and osteogenesis. However, little attention has been given to the osteogenic effect of the CPC scaffolds with pre-forming and in-situ forming interconnected macropores. Herein, two types of CPC scaffolds were prepared by infiltrating CPC pastes into 3D-printed polycaprolactone (PCL) and poly(lactic-co-glycolic acid) (PLGA) networks. Meanwhile, the sacrificial PCL network within CPC was dissolved to obtain the CPC scaffold with approximately 300 μm macropores, whereas the PLGA network was retained within the CPC to obtain the PLGA/CPC scaffold. The results indicated that the PLGA/CPC scaffold…

The application of hydroxyapatite (HA)-based templates is quite often seen in bone tissue engineering since that HA is an osteoconductive bioceramic material, which mimics the inorganic component of mineralized tissues. However, the reported osteoconductivity varies in vitro and in vivo, and the levels of calcium (Ca) release most favorable to osteoconduction have yet to be determined. In this study, HA-based templates were fabricated by melt-extrusion 3D-printing and characterized in order to determine a possible correlation between Ca release and osteoconduction. The HA-based templates were blended with poly(lactide-co-trimethylene carbonate) (PLATMC) at three different HA ratios: 10, 30, and 50%. The printability…

Subcutaneous delivery of cell therapy is an appealing minimally-invasive strategy for the treatment of various diseases. However, the subdermal site is poorly vascularized making it inadequate for supporting engraftment, viability, and function of exogenous cells. In this study, we developed a 3D bioprinted scaffold composed of alginate/gelatin (Alg/Gel) embedded with mesenchymal stem cells (MSCs) to enhance vascularization and tissue ingrowth in a subcutaneous microenvironment. We identified bio-ink crosslinking conditions that optimally recapitulated the mechanical properties of subcutaneous tissue. We achieved controlled degradation of the Alg/Gel scaffold synchronous with host tissue ingrowth and remodeling. Further, in a rat model, the Alg/Gel…

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…

In this study, inspired by the components of cartilage matrix, a photo-cross-linked extracellular matrix (ECM) bioink composed of modified proteins and polysaccharides was presented, including gelatin methacrylate, hyaluronic acid methacrylate, and chondroitin sulfate methacrylate. The systematic experiments were performed, including morphology, swelling, degradation, mechanical and rheological tests, printability analysis, biocompatibility and chondrogenic differentiation characterization, and RNA sequencing (RNA-seq). The results indicated that the photo-cross-linked ECM hydrogels possessed suitable degradation rate and excellent mechanical properties, and the three-dimensional (3D) bioprinted ECM scaffolds obtained favorable shape fidelity and improved the basic properties, biological properties, and chondrogenesis of synovium-derived MSCs (SMSCs). The strong…

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…

Three-dimensional (3D) bioprinting is a promising technique to construct heterogeneous architectures that mimic cell microenvironment. However, the current bioinks for 3D bioprinting usually show some limitations, such as low printing accuracy, unsatisfactory mechanical properties and compromised cytocompatibility. Herein, a novel bioink comprising hydroxyphenyl propionic acid-conjugated gelatin and tyramine-modified alginate is developed for printing 3D constructs. The bioink takes advantage of an ionic/covalent intertwined network that combines covalent bonds formed by photo-mediated redox reaction and ionic bonds formed by chelate effect. Benefiting from the thermosensitivity of gelatin and the double-crosslinking mechanism, the developed bioink shows controllable rheological behaviors, enhanced mechanical behavior,…

The emergence and innovation of three-dimensional (3D) bioprinting provide new development opportunities for tissue engineering and regenerative medicine. However, how to obtain bioinks with both biomimicry and manufacturability remains a great issue in 3D bioprinting. Developing intelligent responsive biomaterials is conducive to break through the current dilemma. Herein, a stepwise multi-cross-linking strategy concerning thermosensitive thiolated Pluronic F127 (PF127-SH) and hyaluronic acid methacrylate (HAMA) is proposed to achieve temperature-controlled 3D embedded bioprinting, specifically pre-cross-linking (Michael addition reaction) at low temperatures (4–20 °C) and subsequently self-assembly (hydrophobic interaction) in a high-temperature (30–37 °C) suspension bath as well as final photo-cross-linking (mainly thiol-ene…

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…

Meniscus is a complex and crucial fibrocartilaginous tissue within the knee joint. Meniscal regeneration remains to be a scientific and translational challenge. We clarified that mesenchymal stem cells (MSCs) participated in meniscal maturation and regeneration using MSC-tracing transgenic mice model. Here, inspired by meniscal natural maturational and regenerative process, we developed an effective and translational strategy to facilitate meniscal regeneration by three-dimensionally printing biomimetic meniscal scaffold combining autologous synovium transplant, which contained abundant intrinsic MSCs. We verified that this facilitated anisotropic meniscus–like tissue regeneration and protected cartilage from degeneration in large animal model. Mechanistically, the biomechanics and matrix stiffness up-regulated…

Metabolic energy to steer osteoblastic differentiation of bone marrow mesenchymal stem cells (BMSCs) could be a promising therapeutic target for bone tissue engineering (BTE), but prior knowledge of this issue is limited. To address bone defects with BTE, we customized a three-dimensional (3D)-printed composite scaffold (Cur@MS) to allow the controlled release of curcumin, which could facilitate the “switch-on” mode of Glucose transporter 1 (GLUT1) in BMSCs. Consequently, bioenergetic channels, i.e. glucose uptake, were “switched on” to activate GLUT1-RUNX2 crosstalk, which was closely orchestrated with bone regeneration. Furthermore, curcumin-induced cholesterol/lipid raft (Cho/LR) was a “sensor” to trigger the “switch” (GLUT1) by…

Large size bone defects affect human health and remain a worldwide health problem that needs to be solved immediately. 3D printing technology has attracted substantial attention for preparing penetrable multifunctional scaffolds to promote bone reconditioning and regeneration. Inspired by the spongy structure of natural bone, novel porous degradable scaffolds have been printed using polymerization of lactide and caprolactone (PLCL) and bioactive glass 45S5 (BG), and polydopamine (PDA) was used to decorate the PLCL/BG scaffolds. The physicochemical properties of the PLCL/BG and PLCL/BG/PDA scaffolds were measured, and their osteogenic and angiogenic effects were characterized through a series of experiments both in…

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…

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…

Polyelectrolyte complex (PEC) hydrogels are advantageous as therapeutic agent and cell carriers. However, due to the weak nature of physical crosslinking, PEC swelling and cargo burst release are easily initiated. Also, most current cell-laden PEC hydrogels are limited to fibers and microcapsules with unfavorable dimensions and structures for practical implantations. To overcome these drawbacks, alginate (Alg)/poly-L-ornithine (PLO) PEC hydrogels are fabricated into microcapsules, fibers, and bulk scaffolds to explore their feasibility as drug and cell carriers. Stable Alg/PLO microcapsules with controllable shapes are obtained through aqueous electrospraying technique, which avoids osmotic shock and prolongs the release time. Model enzyme and…

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…

The inevitable gap between in vitro and in vivo degradation rate of biomaterials has been a challenging factor in the optimal designing of scaffold’s degradation to be balanced with new tissue formation. To enable non-/minimum-invasive tracking of in vivo scaffold degradation, chemical modifications have been applied to label polymers with fluorescent dyes. However, the previous approaches may have limited expandability due to complicated synthesis processes. Here, we introduce a simple and efficient method to fluorescence labeling of polymeric scaffolds via blending with near-infrared (NIR) quantum dots (QDs), semiconductor nanocrystals with superior optical properties. QDs-labeled, 3D-printed PCL scaffolds showed promising efficiency…

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…

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…

The lack of an effective printable ink preparation method and the usual mechanically weak performance obstruct the functional 3D printing hydrogel exploitation and application. Herein, we propose a gentle pre-cross-linking strategy to enable a loosely cross-linked cellulose network for simultaneously achieving favorable printability and a strong hydrogel network via mediating the cellulose self-assembly. A small amount of epichlorohydrin is applied to (i) slightly pre-cross-link the cellulose chains for forming the percolating network to regulate the rheological properties and (ii) form the loosely cross-linked points to mediate the cellulose chains’ self-assembly for achieving superior mechanical properties. The fabrication of the complex…

Critical bone defects with a sluggish rate of auto-osteoconduction and imperfect reconstruction are motivators for the development of an alternate innovative approach for the regeneration of bone. Tissue engineering for bone regeneration signifies an advanced way to overcome this problem by creating an additional bone tissue substitute. Among different fabrication techniques, the 3D printing technique is obviously the most efficient and advanced way to fabricate an osteoconductive scaffold with a controlled porous structure. In the current article, the polycarbonate and polyester diol based polyurethane–urea (P12) was synthesized and 3D porous nanohybrid scaffolds (P12/TP-nHA) were fabricated using the 3D printing technique…

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…

In the field of orthopedics, an infected bone defect is a refractory disease accompanied by bone infection and defects as well as aggravated circulation. There are currently no personalized scaffolds that can treat bone infections using local stable and sustained-release antibiotics while providing mechanical support and bone induction to promote bone repair in the process of absorption in vivo. In our previous study, rifampicin/moxifloxacin-poly lactic-co-glycolic acid (PLGA) microspheres were prepared and tested for sustained release and antibacterial activity. The composite scaffold of poly-L-lactic acid (PLLA)/Pearl had a positive effect on mechanics supports and promoted osteogenesis. Therefore, in this study, the…

Epigenetic approaches using the histone deacetylase 2 and 3 inhibitor-MI192 have been reported to accelerate stem cells to form mineralised tissues. Gelatine methacryloyl (GelMA) hydrogels provide a favourable microenvironment to facilitate cell delivery and support tissue formation. However, their application for bone repair is limited due to their low mechanical strength. This study aimed to investigate a GelMA hydrogel reinforced with a 3D printed scaffold to support MI192-induced human bone marrow stromal cells (hBMSCs) for bone formation. Cell culture: The GelMA (5 wt%) hydrogel supported the proliferation of MI192-pre-treated hBMSCs. MI192-pre-treated hBMSCs within the GelMA in osteogenic culture significantly increased…

Protein delivery and release from synthetic scaffold materials are major challenges within the field of bone tissue engineering. In this study, 13-93B1.5 borosilicate bioactive glass (BSG) base paste was 3D printed to produce BSG-based scaffolds with high porosity (59.85 ± 6.04%) and large pore sizes (350–400 μm) for functionalization with a sodium alginate (SA)/calcitonin gene-related peptide (CGRP) hydrogel mixture. SA/CGRP hydrogel was uniformly filled into the interconnected pores of 3D printed BSG constructs to produce BSG-SA/CGRP scaffolds which were subject to bioactivity and biocompatibility analysis. BSG scaffolds filled with SA hydrogel underwent dissolution in simulated body fluid (SBF), resulting in…

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…

Background To support bone regeneration, 3D-printed templates function as temporary guides. The preferred materials are synthetic polymers, due to their ease of processing and biological inertness. Poly(lactide-co-trimethylene carbonate) (PLATMC) has good biological compatibility and currently used in soft tissue regeneration. The aim of this study was to evaluate the osteoconductivity of 3D-printed PLATMC templates for bone tissue engineering, in comparison with the widely used 3D-printed polycaprolactone (PCL) templates. Methods The printability and physical properties of 3D-printed templates were assessed, including wettability, tensile properties and the degradation profile. Human bone marrow-derived mesenchymal stem cells (hBMSCs) were used to evaluate osteoconductivity and…

Three-dimensional printing (3D printing) is a promising technique for producing scaffolds for bone tissue engineering applications. Porous scaffolds can be printed directly, and the design, shape and porosity can be controlled. 3D synthetic biodegradable polymeric scaffolds intended for in situ bone regeneration must meet stringent criteria, primarily appropriate mechanical properties, good 3D design, adequate biocompatibility and the ability to enhance bone formation. In this study, healing of critical-sized (5 ​mm) femur defects of rats was enhanced by implanting two different designs of 3D printed poly(l-lactide-co-ε-caprolactone) (poly(LA-co-CL)) scaffolds seeded with rat bone marrow mesenchymal stem cells (rBMSC), which had been pre-differentiated…

Human bone marrow stromal cells (hBMSCs) have been extensively utilised for bone tissue engineering applications. However, they are associated with limitations that hinder their clinical utility for bone regeneration. Cell fate can be modulated via altering their epigenetic functionality. Inhibiting histone deacetylase (HDAC) enzymes have been reported to promote osteogenic differentiation, with HDAC3 activity shown to be causatively associated with osteogenesis. Therefore, this study aimed to investigate the potential of using an HDAC2 & 3 selective inhibitor – MI192 to induce epigenetic reprogramming of hBMSCs and enhance its therapeutic efficacy for bone formation. Treatment with MI192 caused a time-dose dependant…

Intensively studied 3D printing technology is frequently hindered by the effective printable ink preparation method. Herein, we propose an elegant and gentle solvent consumption strategy to slowly disrupt the thermodynamic stability of the biopolymer (polysaccharide: cellulose, chitin, and chitosan) solution to slightly induce the molecule chains to in situ self-assemble into nanostructures for regulating the rheological properties, eventually achieving the acceptable printability. The polysaccharides are dissolved in the alkali/urea solvent. The weak Lewis acid fumed silica (as solvent mediator) is used to (i) slowly and partially consume the alkali/urea solvent to induce the polysaccharide chains to self-assemble into nanofibers to…

Repair of large bone defects represents a major challenge for orthopedic surgeons. The newly formed microvessels inside grafts play a crucial role in successful bone tissue engineering. Previously, an active role for mesenchymal stem cell (MSC)-derived exosomes in blood vessel development and progression was suggested in the repair of multiple tissues. However, the reports on the application of MSC-derived exosomes in the repair of large bone defects are sparse. In this study, we encapsulated umbilical MSC-derived exosomes (uMSCEXOs) in hyaluronic acid hydrogel (HA-Gel) and combined them with customized nanohydroxyapatite/poly-ε-caprolactone (nHP) scaffolds to repair cranial defects in rats. Imaging and histological…

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…

Critical oral-maxillofacial bone defects, damaged by trauma and tumors, not only affect the physiological functions and mental health of patients but are also highly challenging to reconstruct. Personalized biomaterials customized by 3D printing technology have the potential to match oral-maxillofacial bone repair and regeneration requirements. Laponite (LAP) nanosilicates have been added to biomaterials to achieve biofunctional modification owing to their excellent biocompatibility and bioactivity. Herein, porous nanosilicate-functionalized polycaprolactone (PCL/LAP) was fabricated by 3D printing technology, and its bioactivities in bone regeneration were investigated in vitro and in vivo. In vitro experiments demonstrated that PCL/LAP exhibited good cytocompatibility and enhanced the…

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…

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,…

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…

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…

Articular cartilage has unique load-bearing properties but has minimal capacity for intrinsic repair. Here, we used three-dimensional weaving, additive manufacturing, and autologous mesenchymal stem cells to create a tissue-engineered, bicomponent implant to restore hip function in a canine hip osteoarthritis model. This resorbable implant was specifically designed to function mechanically from the time of repair and to biologically integrate with native tissues for long-term restoration. A massive osteochondral lesion was created in the hip of skeletally mature hounds and repaired with the implant or left empty (control). Longitudinal outcome measures over 6 months demonstrated that the implant dogs returned to…

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…

The current standard for cell encapsulation platforms is enveloping cells in semipermeable membranes that physically isolate transplanted cells from the host while allowing for oxygen and nutrient diffusion. However, long-term viability and function of encapsulated cells are compromised by insufficient oxygen and nutrient supply to the graft. To address this need, a strategy to achieve enhanced vascularization of a 3D-printed, polymeric cell encapsulation platform using platelet-rich plasma (PRP) and mesenchymal stem cells (MSCs) is investigated. The study is conducted in rats and, for clinical translation relevance, in nonhuman primates (NHP). Devices filled with PRP, MSCs, or vehicle hydrogel are subcutaneously…

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)…

The potential translation of bio-inert polymer scaffolds as bone substitutes is limited by the lack of neovascularization upon implantation and subsequently diminished ingrowth of host bone, most likely resulted from the inability to replicate appropriate endogenous crosstalk between cells. Human umbilical vein endothelial cell-derived decellularized extracellular matrix (HdECM), which contains a collection of angiocrine biomolecules, has recently been demonstrated to mediate endothelial cells(ECs) – osteoprogenitors(OPs) crosstalk. We employed the HdECM to create a PCL (polycaprolactone)/fibrin/HdECM (PFE) hybrid scaffold. We hypothesized PFE scaffold could reconstitute a bio-instructive microenvironment that reintroduces the crosstalk, resulting in vascularized bone regeneration. Following implantation in a…

Background: Traditionally, the iliac crest has been the most common harvesting site for autologous bone grafts; however, it has some limitations, including poor bone availability and donor-site morbidity. This study sought to explore the effect of enhanced bone marrow (eBM) in conjunction with three-dimensional (3D)-printed polylactide–hydroxyapatite (PLA-HA) scaffolds in the repair of critical-sized bone defects in a rabbit model. Methods: First, 3D-printed PLA-HA scaffolds were fabricated and evaluated using micro-computed tomography (µCT) and scanning electron microscopy (SEM). Twenty-seven New Zealand white rabbits were randomly divided into 3 groups (n=9 per group), and the defects were treated using 3D-printed PLA-HA scaffolds…

Bone defects remain a major threat to human health and bone tissue regeneration has become a prominent clinical demand worldwide. The combination of microRNA (miRNA) therapy with 3D printed scaffolds has always posed a challenge. It can mimic physiological bone healing processes, in which a biodegradable scaffold is gradually replaced by neo-tissue, and the sustained release of miRNA plays a vital role in creating an optimal osteogenic microenvironment, thus achieving promising bone repair outcomes. However, the balance between two key factors – scaffold degradation behavior and miRNA release profile – on osteogenesis and bone formation is still poorly understood. Herein,…

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…

The repair of large bone defects has always been a challenge, especially with respect to regeneration capacity and autogenous bone availability. To address this problem, we fabricated a 3D-printed polylactic acid (PLA) and hydroxyapatite (HA) scaffold (3D-printed PLA-HA, providing scaffold) loaded with enhanced bone marrow (eBM, providing seed cells) combined with induced membrane (IM, providing grow factors) to repair large radial defects in rabbits. in vitro assays, we demonstrated that 3D-printed PLA-HA had excellent biocompatibility, as shown by co-culturing with mesenchymal stem cells (MSCs); eBM-derived MSCs exhibited considerable differentiation potential, as shown in trilineage differentiation assays. To investigate bone formation…

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…

A self-hardening three-dimensional (3D)-porous composite bone graft consisting of 65 wt% hydroxyapatite (HA) and 35 wt% aragonite was fabricated using a 3D-Bioplotter®. New tetracalcium phosphate and dicalcium phosphate anhydrous/aragonite/gelatine paste formulae were developed to overcome the phase separation of the liquid and solid components. The mechanical properties, porosity, height and width stability of the end products were optimised through a systematic analysis of the fabrication processing parameters including printing pressure, printing speed and distance between strands. The resulting 3D-printed bone graft was confirmed to be a mixture of HA and aragonite by X-ray diffraction, Fourier transform infrared spectroscopy and energy…

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…

The development of viable tissue surrogates requires a vascular network that sustains cell metabolism and tissue development. The coculture of endothelial cells (ECs) and mesenchymal stem cells (MSCs), the two key players involved in blood vessel formation, has been heralded in tissue engineering (TE) as one of the most promising approaches for scaffold vascularization. However, MSCs may exert both proangiogenic as well antiangiogenic role. Furthermore, it is unclear which cell type is responsible for the upregulation of angiogenic pathways observed in EC:MSC cocultures. There is disagreement on the proangiogenic action of MSCs, as they have also been shown to negatively…

The high surface area ratio and special structure of mesoporous bioactive glass (MBG) endow it with excellent physical adsorption of various drugs without destroying the chemical activity. Silicate 1393 bioactive glass (1393) is famous for its fantastic biodegradability and osteogenesis. Herein, we have built a novel vehicle-like drug delivery 3D printing scaffold with multiplexed drug delivery capacity by coating MBG on the surface of 1393 (1393@MBG). Furthermore, we have applied DEX and BMP-2 on the 1393@MBG scaffold to endow it with antibacterial and osteogenic properties. Results indicated that this 1393@MBG scaffold could effectively load and controlled release BMP-2, DNA and…

Injury of corpus cavernosa results in erectile dysfunction, but its treatment has been very difficult. Here we construct heparin-coated 3D-printed hydrogel scaffolds seeded with hypoxia inducible factor-1α (HIF-1α)-mutated muscle-derived stem cells (MDSCs) to develop bioengineered vascularized corpora. HIF-1α-mutated MDSCs significantly secrete various angiogenic factors in MDSCs regardless of hypoxia or normoxia. The biodegradable scaffolds, along with MDSCs, are implanted into corpus cavernosa defects in a rabbit model to show good histocompatibility with no immunological rejection, support vascularized tissue ingrowth, and promote neovascularisation to repair the defects. Evaluation of morphology, intracavernosal pressure, elasticity and shrinkage of repaired cavernous tissue prove that…

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…

Meniscus deficiency, the most common and refractory disease in human knee joints, often progresses to osteoarthritis (OA) due to abnormal biomechanical distribution and articular cartilage abrasion. However, due to its anisotropic spatial architecture, complex biomechanical microenvironment, and limited vascularity, meniscus repair remains a challenge for clinicians and researchers worldwide. In this study, we developed a 3D printing-based biomimetic and composite tissue-engineered meniscus scaffold consisting of polycaprolactone (PCL)/silk fibroin (SF) with extraordinary biomechanical properties and biocompatibility. We hypothesized that the meticulously tailored composite scaffold could enhance meniscus regeneration and cartilage protection. Methods: The physical property of the scaffold was characterized by…

Repairing massive rotator cuff tendon defects remains a challenge due to the high retear rate after surgical intervention. 3D printing has emerged as a promising technique that enables the fabrication of engineered tissues with heterogeneous structures and mechanical properties, as well as controllable microenvironments for tendon regeneration. In this study, we developed a new strategy for rotator cuff tendon repair by combining a 3D printed scaffold of polylactic-co-glycolic acid (PLGA) with cell-laden collagen-fibrin hydrogels. We designed and fabricated two types of scaffolds: one featuring a separate layer-by-layer structure and another with a tri-layered structure as a whole. Uniaxial tensile tests…

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)…

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…

Background The anatomical properties of the enthesis of the rotator cuff are hardly regained during the process of healing. The tendon-to-bone interface is normally replaced by fibrovascular tissue instead of interposition fibrocartilage, which impairs biomechanics in the shoulder and causes dysfunction. Tissue engineering offers a promising strategy to regenerate a biomimetic interface. Here, we report heterogeneous tendon-to-bone interface engineering based on a 3D-printed multiphasic scaffold. Methods A multiphasic poly(ε-caprolactone) (PCL)–PCL/tricalcium phosphate–PCL/tricalcium phosphate porous scaffold was manufactured using 3D printing technology. The three phases of the scaffold were designed to mimic the graded tissue regions in the tendon-to-bone interface—tendon, fibrocartilage, and…

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…

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,…

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,…

The residual of malignant tumor cells and lack of bone‐tissue integration are the two critical concerns of bone‐tumor recurrence and surgical failure. In this work, the rational integration of 2D Ti3C2 MXene is reported with 3D‐printing bioactive glass (BG) scaffolds for achieving concurrent bone‐tumor killing by photonic hyperthermia and bone‐tissue regeneration by bioactive scaffolds. The designed composite scaffolds take the unique feature of high photothermal conversion of integrated 2D Ti3C2 MXene for inducing bone‐tumor ablation by near infrared‐triggered photothermal hyperthermia, which has achieved the complete tumor eradication on in vivo bone‐tumor xenografts. Importantly, the rational integration of 2D Ti3C2 MXene…

Tissue engineered heart valves (TEHV) provide several advantages over currently available aortic heart valve replacements. Bioprinting provides a patient-specific means of developing a TEHV scaffold from imaging data, and the capability to embed the patient’s own cells within the scaffold. In this work we investigated the remodeling capacity of a collagen-based bio-ink by implanting bioprinted disks in a rat subcutaneous model for 2, 4 and 12 weeks and evaluating the mechanical response using biaxial testing and subsequent finite element (FE) modeling. Samples explanted after 2 and 4 weeks showed inferior mechanical properties compared to native tissues while 12 week explants…

Tissue survival in regenerative tissue engineering requires rapid vascularization, which is influenced by scaffold material and seeded cell selection. Poly-l-lactide-co-glycolide (PLGA) and beta-tricalcium phosphate (β-TCP) are well-established biomaterials with angiogenic effects because of their material properties. Given the importance of the seeded cell type as a co-factor for vascularization, mesenchymal stem cells (MSCs) are known to have high angiogenic potential. We hypothesized that PLGA and β-TCP scaffolds seeded with MSCs would effectively induce a potent angiogenic response. Therefore, we studied the angiogenic effects after implanting PLGA and β-TCP scaffolds seeded with isogeneic MSCs in vivo. Fifty-six BALB/c mice were equally…

The classic cell culture involves the use of support in two dimensions, such as a well plate or a Petri dish, that allows the culture of different types of cells. However, this technique does not mimic the natural microenvironment where the cells are exposed to. To solve that, three-dimensional bioprinting techniques were implemented, which involves the use of biopolymers and/or synthetic materials and cells. Because of a lack of information between data sources, the objective of this review paper is, to sum up, all the available information on the topic of bioprinting and to help researchers with the problematics with…

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…

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…

Vascularization is a crucial process during the growth and development of bone 1, yet it remains one of the main challenges in the reconstruction of large bone defects. The use of in vitro coculture of human umbilical vein endothelial cells (HUVECs) and human mesenchymal stem cells (hMSCs) has been one of the most explored options. Both cell types secrete specific growth factors that are mutually beneficial, and studies suggested that cell-cell communication and paracrine secretion could be affected by a number of factors. However, little is known about the effect of cell patterning and the distance between cell populations on…

Objective To evaluate the recellularization potential of a bioprinted aortic heart valve scaffold printed with highly concentrated Type I collagen hydrogel (Lifeink® 200) and MSCs. Materials and methods A suspension of rat mesenchymal stem cells (MSCs) was mixed with Lifeink® 200 and was 3D-printed into gelatin support gel to produce disk scaffolds which were subsequently implanted subcutaneously in Sprague-Dawley rats for 2, 4, 8, and 12 weeks. The biomechanical properties of the scaffolds were evaluated by uniaxial tensile testing and cell infiltration and inflammation assessed via immunohistochemistry (IHC) and histological staining. Results There was an average decrease in both UTS…

This study investigates if the application of bone marrow-derived mesenchymal stem cells (BM-MSCs) loaded 3D-printed scaffolds could improve rotator cuff repair. The polylactic-co-glycolic acid (PLGA) scaffolds were fabricated by 3D print technology. Rabbit BM-MSCs were transfected with a recombinant adenovirus encoding bone morphogenic protein 12 (BMP-12). The effect of BM-MSCs loaded PLGA scaffolds on tendon-bone healing was assessed by biomechanical testing and histological analysis in a rabbit rotator cuff repair model. We found that the PLGA scaffolds had good biocompatible and biodegradable property. Overexpression of BMP-12 increased the mRNA and protein expression of tenogenic genes in BM-MSCs cultured with DMEM…

Super-paramagnetic iron oxide nanoparticles (SPIONs) have multiple theranostics applications such as T2 contrast agent in magnetic resonance imaging (MRI) and electromagnetic manipulations in biomedical devices, sensors, and regenerative medicines. However, SPIONs suffer from the limitation of free radical generation, and this has a certain limitation in its applicability in tissue imaging and regeneration applications. In the current study, we developed a simple hydrothermal method to prepare carbon quantum dots (CD) doped SPIONs (FeCD) from easily available precursors. The nanoparticles are observed to be cytocompatible, hemocompatible, and capable of scavenging free radicals in vitro. They also have been observed to be…

The fabrication of bone tissue engineering scaffolds with high osteogenic ability and favorable mechanical properties is of huge interest. In this study, a silk fibroin (SF) solution of 30 wt% was extracted from cocoons and combined with mesoporous bioactive glass (MBG) to fabricate MBG/SF composite scaffolds by 3D printing. The porosity, compressive strength, degradation and apatite forming ability were evaluated. The results illustrated that MBG/SF scaffolds had superior compressive strength (ca. 20 MPa) and good biocompatibility, and stimulated bone formation ability compared to mesoporous bioactive glass/polycaprolactone (MBG/PCL) scaffolds. We subcutaneously transplanted hBMSCs-loaded MBG/SF and MBG/PCL scaffolds into the back of nude mice…

Inefficient bone regeneration of self‐hardening calcium phosphate cement (CPC) increases the demand for interconnected macropores and osteogenesis‐stimulated substances. It remains a challenge to fabricate porous CPC with interconnected macropores while maintaining its advantages, such as plasticity. Herein, pastes containing CPC and wollastonite (WS) are infiltrated into a 3D plotted poly(lactic‐co‐glycolic acid) (PLGA) network to fabricate plastic CPC‐based composite cement (PLGA/WS/CPC). The PLGA/WS/CPC recovers the plasticity of CPC after being heated above the glass transition temperature of PLGA. The presence of the 3D PLGA network significantly increases the flexibility of CPC in prophase and generates 3D interconnected macropores in situ upon…

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…

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…

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…

Calcium phosphate (CaPs)-based nanostructures are mostly known to induce osteogenic differentiation of mesenchymal stem cells (MSCs). However, in the current study, doping of carbon quantum dots into calcium phosphate nanorods (C-CaPs) has been observed to affect the differentiation pathway and enhanced the expression of chondrogenic genes instead of osteogenic ones. Here, we report a microwave-assisted single-step synthesis and doping of carbon dot into calcium phosphate nanorods and their ectopic chondrogenicity in a rodent subcutaneous model. High-resolution transmission electron microscopy, X-ray powder diffraction, and X-ray photoelectron spectroscopy studies show that the doping of carbon dots results in p-type semiconductor-like structure formation…

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…

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…

While articular cartilage defects affect millions of people worldwide from adolescents to adults, the repair of articular cartilage defects still remains challenging due to the limited endogenous regeneration of the tissue and poor integration with implants. In this study, we developed a 3D-printed scaffold functionalized with aggrecan that supports the cellular fraction of bone marrow released from microfracture, a widely used clinical procedure, and demonstrated tremendous improvement of regenerated cartilage tissue quality and joint function in a lapine model. Optical coherence tomography (OCT) revealed doubled thickness of the regenerated cartilage tissue in the group treated with our aggrecan functionalized 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 (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.

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…

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…

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…

Vascularization is a fundamental prerequisite for large bone construct development and remains one of the main challenges of bone tissue engineering. Our current study presents the combination of 3D printing technique with a hydrogel-based prevascularization strategy to generate prevascularized bone constructs. Human adipose derived mesenchymal stem cells (ADMSC) and human umbilical vein endothelial cells (HUVEC) were encapsulated within our bioactive hydrogels, and the effects of culture conditions on in vitro vascularization were determined. We further generated composite constructs by forming 3D printed polycaprolactone/hydroxyapatite scaffolds coated with cell-laden hydrogels and determined how the co-culture affected vascularization and osteogenesis. It was demonstrated…

Articular cartilage injuries experienced at an early age can lead to the development of osteoarthritis later in life. In situ 3D printing is an exciting and innovative bio-fabrication technology that enables the surgeon to deliver tissue- engineering techniques at the time and location of need. We have created a hand- held 3D printing device (Biopen) that allows the simultaneous co-axial extrusion of bioscaffold and cultured cells directly into the cartilage defect in vivo in a single session surgery. This pilot study assesses the ability of the Biopen to repair a full thickness chondral defect and the early outcomes in cartilage…

In the clinic, bone defects resulting from infections, trauma, surgical resection and genetic malformations remain a significant challenge. In the field of bone tissue engineering, three-dimensional (3D) scaffolds are promising for the treatment of bone defects. In this study, calcium sulfate hydrate (CSH)/mesoporous bioactive glass (MBG) scaffolds were successfully fabricated using a 3D printing technique, which had a regular and uniform square macroporous structure, high porosity and excellent apatite mineralization ability. Human bone marrow-derived mesenchymal stem cells (hBMSCs) were cultured on scaffolds to evaluate hBMSC attachment, proliferation and osteogenesis-related gene expression. Critical-sized rat calvarial defects were applied to investigate the…

The development of biomaterials with high osteogenic ability for fast osteointegration with a host bone is of great interest. In this study, pearl/CaSO4 composite scaffolds were fabricated using three-dimensional (3D) printing, followed by a hydration process. The pearl/CaSO4 scaffolds showed uniform interconnected macropores (∼400 μm), high porosity (∼60%), and enhanced compressive strength. With CaSO4 scaffolds as a control, the biological properties of the pearl/CaSO4 scaffolds were evaluated in vitro and in vivo. The results showed that the pearl/CaSO4 scaffolds possessed a good apatite-forming ability and stimulated the proliferation and differentiation of rat bone mesenchymal stem cells (rBMSCs), as well as…

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…

Despite substantial attention given to the development of osteoregenerative biomaterials, severe deficiencies remain in current products. These limitations include an inability to adequately, rapidly, and reproducibly regenerate new bone; high costs and limited manufacturing capacity; and lack of surgical ease of handling. To address these shortcomings, we generated a new, synthetic osteoregenerative biomaterial, hyperelastic “bone” (HB). HB, which is composed of 90 weight % (wt %) hydroxyapatite and 10 wt % polycaprolactone or poly(lactic-co-glycolic acid), could be rapidly three-dimensionally (3D) printed (up to 275 cm3/hour) from room temperature extruded liquid inks. The resulting 3D-printed HB exhibited elastic mechanical properties (~32…

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…

Bone defects, particularly large bone defects resulting from infections, trauma, surgical resection or genetic malformations, maintain a significant challenge for clinicians. In this study, the tricalcium silicate/mesoporous bioactive glass (C3S/MBG) cement scaffolds were successfully fabricated for the first time by 3D printing with a curing process, which combined the hydraulicity of C3S with the excellent biological property of MBG together. The C3S/MBG scaffolds exhibited 3D interconnected macropores (~400μm), high porosity (~70%), enhanced mechanical strength (>12MPa) and excellent apatite mineralization ability. Human bone marrow-derived mesenchymal stem cells (hBMSCs) were cultured on the scaffolds to evaluate their cell responses, and the results…

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…

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…

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…

The exceptional properties of graphene enable applications in electronics, optoelectronics, energy storage, and structural composites. Here we demonstrate a 3D printable graphene (3DG) composite consisting of majority graphene and minority polylactide-co-glycolide, a biocompatible elastomer, 3D-printed from a liquid ink. This ink can be utilized under ambient conditions via extrusion-based 3D printing to create graphene structures with features as small as 100 μm composed of as few as two layers (10 cm thick object). The resulting 3DG material is mechanically robust and flexible while retaining electrical conductivities greater than 800 S/m, an order of magnitude increase over previously reported 3D-printed carbon…

After surgical treatment of osteoarticular tuberculosis (TB), it is necessary to fill the surgical defect with an implant, which combines the merits of osseous regeneration and local multi-drug therapy so as to avoid drug resistance and side effects. In this study, a 3D-printed macro/meso-porous composite scaffold is fabricated. High dosages of isoniazid (INH)/rifampin (RFP) anti-TB drugs are loaded into chemically modified mesoporous bioactive ceramics in advance, which are then bound with poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) through a 3D printing procedure. The composite scaffolds show greatly prolonged drug release time compared to commercial calcium phosphate scaffolds either in vitro or in vivo.…

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.…

Aims Rapid blood vessel ingrowth in transplanted tissue engineering constructs is the key factor for successful incorporation, but many potential patients who may use engineered tissues suffer from widespread diseases that limit the capacity of neovascularization (e.g. diabetes). Thus, in vivo vascularization analyses of tissue-engineered constructs in angiogenically affected organisms are required. Methods We therefore investigated the in vivo incorporation of collagen-coated and cell-seeded poly-L-lactide-co-glycolide scaffolds in diabetic B6.BKS(D)-Leprdb/J mice using repetitive intravital fluorescence microscopy over a time period of two weeks. For this purpose, scaffolds were seeded with osteoblast-like or bone marrow mesenchymal stem cells and implanted into the…

Angiogenesis–osteogenesis coupling processes are vital in bone tissue engineering. Normal biomaterials implanted in bone defects have issues in the sufficient formation of blood vessels, especially in the central part. Single delivery of vascular endothelial growth factors (VEGF) to foci in previous studies did not show satisfactory results due to low loading doses, a short protein half-life and low efficiency. Development of a hypoxia-mimicking microenvironment for cells by local prolyl-4-hydroxylase inhibitor release, which can stabilize hypoxia-inducible factor 1α (HIF-1α) expression, is an alternative method. The aim of this study was to design a dimethyloxallyl glycine (DMOG) delivering scaffold composed of mesoporous…

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…

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…

In tissue engineering research, generating constructs with an adequate extent of clinical applications remains a major challenge. In this context, rapid blood vessel ingrowth in the transplanted tissue engineering constructs is the key factor for successful incorporation. To accelerate the microvascular development in engineered tissues, we preincubated osteoblast-like cells as well as mesenchymal stem cells or a combination of both cell types in Matrigel-filled PLGA scaffolds before transplantation into the dorsal skinfold chambers of balb/c mice. By the use of preincubated mesenchymal stem cells, a significantly accelerated angiogenesis was achieved. Compared with previous studies that showed a decisive increase of…

Regeneration of complex tissues, such as kidney, liver, and cartilage, continues to be a scientific and translational challenge. Survival of ex vivo cultured, transplanted cells in tissue grafts is among one of the key barriers. Meniscus is a complex tissue consisting of collagen fibers and proteoglycans with gradient phenotypes of fibrocartilage and functions to provide congruence of the knee joint, without which the patient is likely to develop arthritis. Endogenous stem/progenitor cells regenerated the knee meniscus upon spatially released human connective tissue growth factor (CTGF) and transforming growth factor–β3 (TGFβ3) from a three-dimensional (3D)–printed biomaterial, enabling functional knee recovery. Sequentially…

Three-dimensional printing has come into the spotlight in the realm of tissue engineering. We intended to evaluate the plausibility of 3D-printed (3DP) scaffold coated with mesenchymal stem cells (MSCs) seeded in fibrin for the repair of partial tracheal defects. MSCs from rabbit bone marrow were expanded and cultured. A half-pipe-shaped 3DP polycaprolactone scaffold was coated with the MSCs seeded in fibrin. The half-pipe tracheal graft was implanted on a 10 × 10-mm artificial tracheal defect in four rabbits. Four and eight weeks after the operation, the reconstructed sites were evaluated bronchoscopically, radiologically, histologically, and functionally. None of the four rabbits showed any…

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.…

Animal experiments help to progress and ensure safety of an increasing number of novel therapies, drug development and chemicals. Unfortunately, these also lead to major ethical concerns, costs and limited experimental capacity. We foresee a coercion of all these issues by implantation of well systems directly into vertebrate animals. Here, we used rapid prototyping to create wells with biomaterials to create a three-dimensional (3D) well-system that can be used in vitro and in vivo. First, the well sizes and numbers were adjusted for 3D cell culture and in vitro screening of molecules. Then, the functionality of the wells was evaluated…

Bone marrow derived mesenchymal stem cells (bmMSCs) are widely used for the generation of tissue engineering constructs, since they can differentiate into different cell types occurring in bone tissues. Until now their use for the generation of tissue engineering constructs is limited. All cells inside a tissue engineering construct die within a short period of time after implantation of the construct because vascularization and establishment of connections to the recipient circulatory system is a time consuming process. We therefore compared the influences of bmMSC, VEGF and a combination of both on the early processes of vascularization, utilizing the mice skinfold…

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…

Background To address the challenge of treating critical sized intercalary defects, we hypothesized that under physiologic cyclic loading, autografts, allografts, and scaffolds loaded with and without human mesenchymal stem cells (hMSCs) would have different biomechanical characteristics. Methods Using a rat femoral defect model, 46 rats were assigned to four groups, ie, autograft (n = 12), allograft (n = 10), scaffold (n = 13), and scaffold with hMSCs (n = 11). The scaffold groups used a 5 mm segment of scaffold composed of 80% poly-ε-caprolactone and 20% hydroxyapatite. Rats were sacrificed 4 months postoperatively, and the repairs were assessed radiographically and…

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…

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…

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…

The demanding need for tissue replacement resulted in manifold approaches for the construction of different tissues. One common problem which hampers the clinical usage of tissue engineering constructs is a limited vascularization. In an attempt to accelerate the vascularization of tissue engineering constructs we compared the usage of bone marrow mesenchymal stem cells (bmMSCs) and fragments derived from the aorta in vivo. Tissue engineering constructs composed of PLGA scaffolds containing Matrigel (n = 8), aortic fragments embedded in Matrigel (n = 8), bmMSCs embedded in Matrigel (n = 8), and aortic fragments embedded in Matrigel combined with bmMSCs (n =…

Gene therapy for hemophilia B and other hereditary plasma protein deficiencies showed great promise in pre-clinical and early clinical trials. However, safety concerns about in vivo delivery of viral vectors and poor post-transplant survival of ex vivo modified cells remain key hurdles for clinical translation of gene therapy. We here describe a 3D scaffold system based on porous hydroxyapatite-PLGA composites coated with biomineralized collagen 1. When combined with autologous gene-engineered factor IX (hFIX) positive mesenchymal stem cells (MSCs) and implanted in hemophilic mice, these scaffolds supported long-term engraftment and systemic protein delivery by MSCs in vivo. Optimization of the scaffolds…

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…

Scale-up of bioengineered grafts toward clinical applications is a challenge in regenerative medicine. Here, we report tissue formation and vascularization of anatomically shaped human tibial condyles ectopically with a dimension of 20 × 15 × 15 mm3. A composite of poly-ɛ-caprolactone and hydroxyapatite was fabricated using layer deposition of three-dimensional interlaid strands with interconnecting microchannels (400 μm) and seeded with human bone marrow stem cells (hMSCs) with or without osteogenic differentiation. An overlaying layer (1 mm deep) of poly(ethylene glycol)-based hydrogel encapsulating hMSCs or hMSC-derived chondrocytes was molded into anatomic shape and anchored into microchannels by gel infusion. After 6 weeks of subcutaneous implantation in athymic rats,…

Implantation of tissue engineering constructs is a promising technique to reconstruct injured tissue. However, after implantation the nutrition of the constructs is predominantly restricted to vascularization. Since cells possess distinct angiogenic potency, we herein assessed whether scaffold vitalization with different cell types improves scaffold vascularization. 32 male balb/c mice received a dorsal skinfold chamber. Angiogenesis, microhemodynamics, leukocyte–endothelial cell interaction and microvascular permeability induced in the host tissue after implantation of either collagen coated poly (l-lactide-co-glycolide) (PLGA) scaffolds (group 4), additionally seeded with osteoblast-like cells (OLCs, group 1), bone marrow mesenchymal stem cells (bmMSCs, group 2) or a combination of OLCs…

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…

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.…

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…

In this study, porous 3D fiber deposition titanium (3DFT) and 3DFT combined with porous biphasic calcium phosphate ceramic (3DFT+BCP) implants, both bare and 1 week cultured with autologous bone marrow stromal cells (BMSCs), were implanted intramuscularly and orthotopically in 10 goats. To assess the dynamics of bone formation over time, fluorochrome markers were administered at 3, 6 and 9 weeks and the animals were sacrificed at 12 weeks after implantation. New bone in the implants was investigated by histology and histomorphometry of non-decalcified sections. Intramuscularly, no bone formation was found in any of the 3DFT implants, while a very limited…