Biofabrication最新文献

Stem cells can respond to mechanical stimuli such as stiffness, viscoelasticity, fluid shear stress, micropatterned geometry and hydraulic pressure. However, viscosity as an important cue is often overlooked. Thus, in this study, the influence of viscosity on trilineage differentiation (adipogenesis, chondrogenesis and osteogenesis) of human bone marrow-derived mesenchymal stem cells (hMSCs) was disclosed by three-dimensionally (3D) culturing hMSCs in viscous media. The viscosity was modulated using bioinert polyethylene glycol (PEG) at a range of 88.8-645.5 cP. A cuboid agarose hydrogel container was used to encapsulate the cells and viscous media to prevent cell leakage and PEG diffusion during cell culture. Viscosity showed inhibitory effects on trilineage differentiation of hMSCs during 3D culture in viscous media containing PEG. The inhibitory effect on adipogenic and chondrogenic differentiation was stronger than that on osteogenic differentiation. Viscosity also affected cell proliferation. Viscosity strongly promoted cell proliferation during chondrogenesis, and weakly promoted cell proliferation during osteogenesis, while inhibited cell proliferation during adipogenesis. The influences of viscosity on proliferation and trilineage differentiation of hMSCs were related to the formation of cell aggregates and spheroids during 3D culture in the viscous media. The results revealed the importance of viscosity on stem cell differentiation and could provide some information for tissue engineering applications.

Vessel forming assays are a valuable technology to evaluate the vasculogenic and angiogenic potential of different cell types, matrix proteins, and soluble factors. Recent advances in high-content microscopy allow for vascular morphogenesis assays to be captured in real-time and in high-throughput formats. Unfortunately, existing microvascular network (MVN) quantification algorithms are either inaccurate, not user-friendly, or manually analyse one image at a time, unfavourable to high-throughput screening. This manuscript introduces the Batch-Resourcing Angiogenesis Tool (BRAT), an open-source computer software which efficiently segments, skeletonizes, and analyses large batches of vascular network images with high accuracy. Benchmarked across diverse clinical and cultured MVN images, BRAT is the most sensitive vascular network image analysis tool (94.5%), exhibiting leading accuracy (93.3%). BRAT's multi-threaded processing automatically analyses 886 microscopy images at a speed of 0.17 s/image on a performance computer (2:29 min) or 2.31 s/image on a laptop (34:04). This is 10-to-100 fold more time-efficient than existing software, which require 12-16 s of direct user input per image. BRAT successfully compares diverse microvascular cell types cultured in 2D and 3D biomaterials. BRAT represents a powerful approach for the accurate and high-throughput screening of vessel forming assays for disease models, regenerative medicines, and therapeutic testing. BRAT is avaliable to download at:https://github.com/BMSE-UQ/BRAT-Vascular-Image-Tool.

Towards achieving biomimetic complexity in biofabricated systems, an all-granular bioprinting system might use particle-based hydrogel inks to establish structures within a particle-based support matrix. In such a system, the granular support matrix can be designed to persist in the final construct and include cells incorporated prior to printing. To biofabricate complexity, bioprinting can introduce high-resolution heterogeneous structures that guide cell behaviors. The designs of the granular ink and support hydrogels are crucial to achieving complexity. High resolution structures and channels depend on small particles that flow and can be stabilized, and that can be printed and then removed, respectively. Herein, an all-granular system is described that used a granular formulation of an established, tunable hyaluronic acid-based hydrogel as the basis for a support matrix and a small particle gelatin hydrogel as an ink. Towards facilitating stabilization of the printed structure and flow during printing, the support and ink materials included soluble, interstitial components, and all exhibited yield stress behaviors characteristic of granular hydrogel systems. The support matrix's viscoelastic properties were dependent on intraparticle hydrogel network design, and it could be stabilized against flow by photoinitiated crosslinking. The gelatin ink could form fine filaments, as small as 100µm in testing here, and melted to leave channels within crosslinked support matrices. Channels could support flows introduced by hydrostatic pressure and could be used to rapidly transport soluble factors into the construct, which could be used to establish soluble gradients by diffusion and support cell viability. The all-granular system supported printing of complex, multimaterial structures, with feature resolution on the order of 100µm and spatial positioning on the order of 10 sµm. The process and materials exhibited biocompatibility with respect to cells included within the support matrix during printing or introduced into channels to begin establishing endothelialized bioprinted vessels.

This study aimed to improve the efficiency of decellularization and enhance the functional properties of vascular grafts to optimize their application in vascular repair. Rabbit abdominal aortas were used as the decellularization target, and ultrasound-assisted decellularization was performed using intermittent ultrasound at 100 W power, 20 kHz frequency, and 4 °C. Rabbit abdominal aortas were subjected to three different decellularization techniques. Based on comparative evaluation, ultrasound-assisted decellularization was implemented to enhance cell removal efficiency. In addition, dual-factor surface modification was performed using sodium heparin (HEP) and vascular endothelial growth factor 165 (VEGF165) to investigate anticoagulant and endothelialization potential. Ultrasound optimization enhanced decellularization efficiency by 1.5 times, increased matrix integrity to 85%, and decreased chemical residues by 30%. Dual-factor functionalization with HEP and VEGF165 improved anticoagulant properties by 40%, prolonged thrombus formation time by 45%, and enhanced endothelialization by 68%.In vivoanimal studies demonstrated a 93% blood flow patency rate post-implantation, with superior tissue repair compared to the control group. This study presents an innovative approach that integrates ultrasound optimization and functional modification, addressing the limitations of traditional decellularization methods. It offers a high-performance, low-toxicity strategy for developing vascular grafts with significant clinical potential, particularly for small-diameter vascular applications.

Skeletal diseases pose a significant threat to both physical and mental health, emerging as a critical global issue. A thorough understanding of bone physiology and the development of effective clinical interventions necessitate robust research methodologies. Recently, organoids have gained widespread attention as three-dimensionalin vitromodels capable of recapitulating complexin vivoenvironments, addressing key limitations of traditional two-dimensional cell cultures and animal models. As an innovative frontier in bone tissue engineering, bone organoids have shown great promise in applications such as disease modeling, drug screening, and regenerative medicine. Despite notable advances, bone organoids research is still in its early stages, with many challenges yet to be addressed. This review explores the structural characteristics of natural bone, outlines the methodologies for constructing different types of bone organoids, and discusses their potential applications. Additionally, we summarize the current challenges and propose future directions for improving bone organoids technology. By offering theoretical insights and technical guidance, this review aims to facilitate the development of bone organoids with enhanced functionality and biomimetic properties.

Psoriasis is a chronic inflammatory skin disease involving complex genetic, immune, and environmental interactions. Currentin vitromodels fail to fully replicate the human psoriatic microenvironment, while animal models are limited by species differences and ethical concerns, restricting their applicability in pathogenesis studies and drug screening. Here, we present a human-derivedin vitropsoriasis model constructed via 3D bioprinting. By optimizing the bioink composition, we fabricated a full-thickness skin model with a vascularized dermal layer and a dense stratified epidermis. Cell viability in the bioprinted skin exceeded 90% after 7 d. The full-thickness skin exhibited a TEER value of ∼383 kΩ, reflecting native-like barrier integrity. Psoriatic features, including epidermal hyperplasia and upregulated inflammatory cytokines, were successfully induced through TNF-αand IL-22 stimulation. Structural and functional analyses confirmed that the model closely mimics the pathological hallmarks of psoriasis. Furthermore, drug testing showed that both tofacitinib and Danshensu effectively reduced IL-22 and TNF-αexpression by more than 60%, while concurrently enhancing LOR expression by nearly 2-fold, reflecting improved epidermal differentiation. This study highlights the potential of 3D bioprinting in developing physiologically relevant skin disease models, providing a robust platform for psoriasis research and preclinical drug testing.

Melt electro-writing (MEW) is an advanced 3D printing technique with significant potential in tissue engineering due to its ability to create highly precise microscale structures using biocompatible materials. This review provides a comprehensive guide to the principles, process parameters, and recent advancements in MEW technology, with a specific focus on its applications in tissue engineering. We explore the core mechanisms behind MEW, including the influence of material selection, nozzle temperature, voltage, and feed rate on scaffold architecture. The review examines both computational and experimental modelling of process parameters and their impact on resolution capabilities, including pore size, thickness, and achievable diameters, alongside their effects on cellular behaviour such as adhesion, proliferation, and differentiation. We also discuss the fabrication of custom MEW devices, the integration of machine learning, and the use of automated design tools to enhance scaffold precision and customization. Furthermore, we address key challenges limiting the widespread adoption of MEW, such as the high cost of commercially available devices and the complexity of building custom machines, while offering strategies to overcome these barriers. Recentin vitroandin vivostudies are discussed, demonstrating the promising potential of MEW in tissue regeneration, particularly in bone, cartilage, and soft tissue engineering. This review aims to serve as a valuable resource for researchers and practitioners working in the field of tissue engineering, offering insights into the capabilities, challenges, and future directions of MEW in advancing regenerative medicine.

2D Ti₃C₂T_x(MXene) is attracting significant attention in tissue engineering. The incorporation of these promising materials into conventional scaffolds remains challenging, particularly with physicochemical properties compatible with biological systems. Melt electrowriting (MEW) has emerged as a powerful additive manufacturing technique for biofabrication of customized three-dimensional (3D) scaffolds composed of bioactive materials. This study introduces MEW of 2D MXene and polycaprolactone (PCL) nanocomposite scaffolds for tissue engineering applications. First, Ti₃C₂T_xwas functionalized using (3-aminopropyl) triethoxysilane (referred to asf-MXene) to obtain a blended nanocomposite in PCL matrix (referred to as MX/PCL). Fourier transform infrared spectroscopy revealed the nanocomposite composition. X-ray diffraction analysis showed the reduced crystallinity in PCL after incorporation off-MXene. Differential scanning calorimetry helped to establish the optimal MEW parameters. Thermogravimetric analysis conducted on nanocomposites containing 0.1, 0.5, and 1% (w/w)f-MXene showed the thermal stability of MXene during the MEW process. The extrudability and printability of the nanocomposites with varying concentrations was demonstrated using MEW in 0-90-degree mesh scaffolds with fine filament dimensions. Scanning electron microscopy and Energy-dispersive x-ray spectroscopy mapping showed the shape fidelity, printing accuracy, and structural integrity of 3D MEW scaffolds with uniform distribution off-MXene, respectively. Further characterization showed the concentration-dependent enhancement in hydrophilicity and compressive modulus and yield strength of scaffolds upon integration off-MXene. Atomic force microscopy analysis demonstrated that the topography of the 3D MEW MX/PCL scaffolds changed compared to the pristine PCL and the roughness of the surfaces increased as the concentration of thef-MXene increased. Accelerated degradation tests demonstrated that increasing filler concentration in the reinforced scaffolds progressively delayed degradation compared to the control. Thein vitrocharacterization showed the adherence of MC3T3-E1 preosteoblast cells on MX/PCL scaffolds and their enhanced osteogenic differentiation. The findings indicate that 3D printed MX/PCL nanocomposite scaffolds have significant potential as mechanically robust scaffolds with controlled degradation rate and cytocompatibility for tissue regeneration, with properties tunable for specific applications.

The intricate three dimensional architecture at different spatial length scales affects the functionality and growth performance of immobilized photosynthesizing cells in biofilms and bioprinted constructs. Despite the tremendous potential of 3D bioprinting in precisely defining sample heterogeneity and composition in spatial context, cell metabolism is mostly measured in media surrounding the constructs or by destructive sample analyzes. The exploration and application of non-invasive techniques for monitoring physico-chemical microenvironments, growth and metabolic activity of cells in 3D printed constructs is thus in strong demand. Here, we present a pipeline for the fabrication of 3D bioprinted microalgal constructs with a functionalized gelatin methacryloyl-based bioink for imaging O₂dynamics within bioprinted constructs, as well as their characterization using various, non-invasive functional imaging techniques in concert with numerical simulation of their photophysiological performance. This fabrication, imaging and simulation pipeline now enables investigation of the effect of structure and composition on photosynthetic efficiency of bioprinted constructs with microalgae or cyanobacteria. It can facilitate designing efficient construct geometries for enhanced light penetration and improved mass transfer of nutrients, CO₂or O₂between the 3D printed construct and the surrounding medium, thereby providing a mechanistic basis for the design of more efficient artificial photosynthetic systems.