3D Bioplotter Research Papers

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

Three Dimensional (3D) bioprinting is one of the most recent additive manufacturing technologies and enables the direct incorporation of cells within a highly porous 3D-bioprinted construct. While the field has mainly focused on developing methods for enhancing printing resolution and shape fidelity, little is understood about the biological impact of bioprinting on cells. To address this shortcoming, this study investigated the in vitro and in vivo response of human osteoblasts subsequent to bioprinting using gelatin methacryloyl (GelMA) as the hydrogel precursor. First, bioprinted and two-dimensional (2D) cultured osteoblasts were compared, demonstrating that the 3D microenvironment from bioprinting enhanced bone-related gene…

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

Three-dimensional (3D) bioprinting has brought new promising strategies for the regeneration of cartilage with specific shapes. In cartilage bioprinting, chondrocyte-laden hydrogels are the most commonly used bioinks. However, the dispersion of cells and the dense texture of the hydrogel in the conventional bioink may limit cell–cell/ cell–extracellular matrix (ECM) interactions, counting against cartilage regeneration and maturation. To address this issue, in this study, we developed a functional bioink for cartilage bioprinting based on chondrocyte spheroids (CSs) and microporous hydrogels, in which CSs as multicellular aggregates can provide extensive cell– cell/cell–ECM interactions to mimic the natural cartilage microenvironment, and microporous hydrogels…

Recent studies on osteosarcoma and matrix stiffness are still mostly performed in a 2D setting, which is distinct from in vivo conditions. Therefore, the results from the 2D models may not reflect the real effect of matrix stiffness on cell phenotype. Here, we employed a 3D bioprinted osteosarcoma model, to study the effect of matrix stiffness on osteosarcoma cells. Through density adjustment of GelMA, we constructed three osteosarcoma models with distinct matrix stiffnesses of 50, 80, and 130 kPa. In this study, we found that osteosarcoma cells proliferated faster, migrated more actively, had a more stretched morphology, and a lower…

The healing of meniscus injuries poses a significant challenge, as prolonged failure to heal can lead to osteoarthritis, which presents a therapeutic dilemma in the field of sports medicine. Decellularized extracellular matrix (MdECM) derived from natural meniscus, and the incorporated growth factors have been used for potential fibrochondrocyte induction and meniscus regeneration. However, homogeneous MdECM is difficult to achieve region-specific biomimetic microenvironment for tissue regeneration. In this study, we successfully prepared a region-specific MdECM, which were then mixed with an ultraviolet responsible Gelatin Methacryloyl (GelMA)/hyaluronic acid Methacryloy (HAMA) hydrogel incorporated with bioactive factors, faciliatated a functional region-specific bioink. The 3D…

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

Tissue-engineered ear cartilage scaffold based on three-dimensional (3D) bioprinting technology presents a new strategy for ear reconstruction in individuals with microtia. Natural hydrogel is a promising material due to its excellent biocompatibility and low immunogenicity. However, insufficient mechanical property required for cartilage is one of the major issues pending to be solved. In this study, the gelatin methacryloyl (GelMA) hydrogel reinforced with bacterial nanocellulose (BNC) was developed to enhance the biomechanical properties and printability of the hydrogel. The results revealed that the addition of 0.375% BNC significantly increased the mechanical properties of the hydrogel and promoted cell migration in the…

Poor fiber orientation and mismatched bone–ligament interface fusion have plagued the regeneration of periodontal defects by cell-based scaffolds. A 3D bioprinted biomimetic periodontal module is designed with high architectural integrity using a methacrylate gelatin/decellularized extracellular matrix (GelMA/dECM) cell-laden bioink. The module presents favorable mechanical properties and orientation guidance by high-precision topographical cues and provides a biochemical environment conducive to regulating encapsulated cell behavior. The dECM features robust immunomodulatory activity, reducing the release of proinflammatory factors by M1 macrophages and decreasing local inflammation in Sprague Dawley rats. In a clinically relevant critical-size periodontal defect model, the bioprinted module significantly enhances the…

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

Osteoarthritis is a highly prevalent rheumatic musculoskeletal disorder that commonly affects many joints. Repetitive joint overloading perpetuates the damage to the affected cartilage, which undermines the structural integrity of the osteochondral unit. Various tissue engineering strategies have been employed to design multiphasic osteochondral scaffolds that recapitulate layer-specific biomechanical properties, but the inability to fully satisfy mechanical demands within the joint has limited their success. Through computational modeling and extrusion-based bioprinting, we attempted to fabricate a biphasic osteochondral scaffold with improved shear properties and a mechanically strong interface. A 3D stationary solid mechanics model was developed to simulate the effect of…

Current in vitro models for osteosarcoma investigation and drug screening, including two-dimensional (2D) cell culture and tumour spheroids (i.e. cancer stem-like cells), lack extracellular matrix (ECM). Therefore, results from traditional models may not reflect real pathological processes in genuine osteosarcoma histological structures. Here, we report a three-dimensional (3D) bioprinted osteosarcoma model (3DBPO) that contains osteosarcoma cells and shrouding ECM analogue in a 3D frame. Photo-crosslinkable bioinks composed of gelatine methacrylamide and hyaluronic acid methacrylate mimicked tumour ECM. We performed multi-omics analysis, including transcriptomics and DNA methylomics, to determine differences between the 3DBPO model and traditional models. Compared with 2D models…

Tissue engineering provides a promising strategy for auricular reconstruction. Although the first international clinical breakthrough of tissue-engineered auricular reconstruction has been realized based on polymer scaffolds, this approach has not been recognized as a clinically available treatment because of its unsatisfactory clinical efficacy. This is mainly since reconstruction constructs easily cause inflammation and deformation. In this study, we present a novel strategy for the development of biological auricle equivalents with precise shapes, low immunogenicity, and excellent mechanics using auricular chondrocytes and a bioactive bioink based on biomimetic microporous methacrylate-modified acellular cartilage matrix (ACMMA) with the assistance of gelatin methacrylate (GelMA),…

Extrusion-based bioprinting is an emerging and most frequently used technique for the fabrication of cell-laden constructs. A suitable hydrogel-based bioink for cell encapsulation and protection is critical for printability, structural stability, and post-printing cell viability. The thiol–ene chemistry-based gelatin-norbornene (GelNB) hydrogels have drawn much attention as a promising substitution of gelatin methacryloyl (GelMA), owing to the fast and controllable step-growth polymerization mechanism, as well as a significant reduction in reactive oxygen species (ROS) accumulation. Herein, thiolated heparin (HepSH) was synthesized and used as a macromolecular crosslinker for GelNB-based bioprinting, so that GelNB gelation became less sensitive to the thiol/ene ratio.…

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,…

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

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

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

Engineering hierarchical vasculatures is critical for creating implantable functional thick tissues. Current approaches focus on fabricating mesoscale vessels for implantation or hierarchical microvascular in vitro models, but a combined approach is yet to be achieved to create engineered tissue flaps. Here, millimetric vessel-like scaffolds and 3D bioprinted vascularized tissues interconnect, creating fully engineered hierarchical vascular constructs for implantation. Endothelial and support cells spontaneously form microvascular networks in bioprinted tissues using a human collagen bioink. Sacrificial molds are used to create polymeric vessel-like scaffolds and endothelial cells seeded in their lumen form native-like endothelia. Assembling endothelialized scaffolds within vascularizing hydrogels incites…

Wounds impact millions of patients every year and represent a serious cause of morbidity and mortality worldwide, yet current treatment outcomes are far from ideal. Therapies based on delivery of multiple growth factors offer a promising approach for optimal wound management; however, their high production cost, low stability, and lack of effective delivery system limits their application in the clinic. Platelet lysate is a suitable, abundant and cost-effective source of growth factors that play an important role in the healing cascade. The aim of this current work is to develop an extrusion-based bioink consisting of platelet lysate (PL) and gelatin…

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

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

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

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