Biofabrication最新文献

Large bone defects are usually treated with autografts, allografts, synthetic materials, or bioactive ceramics. Each of these options has limitations, including donor site issues, limited availability, and poor fit for individual patient needs. Bioactive glasses have the potential to promote bone growth but often lack sufficient strength for clinical use. This study investigated the possibility of using 3D-printed bone grafts made from polylactic acid (PLA), polycaprolactone (PCL), and borate bioactive glass (BBG, 13-93B3) to create customized and strong grafts. We created composite filaments (PLA/BBg and PCL/BBg; 50 wt% polymer and 50 wt% BBg) as well as pure PLA and PCL filaments. We then tested for the compatibility of these materials with cells and living tissue, their mechanical properties, and the ease of printing. Tests with mesenchymal stem cells revealed increased metabolic activity of approximately 15.4% for PCL/BBg and 20.7% for PLA/BBg and higher alkaline phosphatase activity of approximately 20.8% and 35.4%, respectively, on day 7, which indicates better early bone formation. The constructs made from PCL/BBg had mineral contents similar to those of natural bone and were easy to print via fused deposition modeling. They produced porous structures with a compressive strength of approximately 9 MPa and a modulus of 168 MPa that matched human mandibular trabecular bone.In vivotests on a rabbit model with premaxillary defects over 14 weeks revealed better bone healing in the PCL/BBg-treated areas, with no signs of inflammation or toxicity. These results indicate that PCL/BBg composite filaments could be effective for making patient-specific, biodegradable bone grafts that have precise structures and strong mechanical properties. More studies involving larger animals are needed to push this research toward clinical use.

Large bone defects present a major clinical challenge, exceeding the body's natural regenerative capacity. In this study, we investigated the physicochemical and biological properties of a novel cross-linked collagen-hydroxyapatite (Coll-HA-XL) biomaterial ink designed for additive manufacturing of scaffolds for bone tissue engineering. The biomaterial ink was developed through three stages: initially as a hydrogel, then molded and freeze-dried into disk-shaped forms, and finally tailored into three-dimensional (3D)-printed scaffolds subjected to subsequent freeze-drying. To optimize the ink, we systematically varied the HA proportions and the sequence of HA incorporation and cross-linking. The composite materials were then 3D-printed into scaffolds by a direct ink writing method, and were seeded with primary human osteoblasts (hOBs). The introduction of HA and subsequent collagen cross-linking induced a significantly increased storage modulus and thermal stability of the material, when compared with the non-crosslinked, HA-containing controls. Biocompatibility of the materials was assessed by hOB cultures, and Coll-HA-XL induced higher alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) activity when compared to the non-crosslinked control. After four weeks of culture on 3D-printed Coll-HA-XL scaffolds, high ALP and LDH activities and osteocalcin staining of hOB indicated robust osteoblastic differentiation. Our findings show that a crosslinked, collagen-based biomaterial ink supplemented with HA is suitable for direct ink writing of scaffolds tailored for bone tissue engineering.

A central hurdle in spinal cord injury (SCI) therapy involves not only reconstructing neural pathways but also overcoming the detrimental inflammatory milieu. Inspired by olfactory microenvironmental niches, we implemented a niche-targeted strategy. Our investigation defines the biological properties of ectodermal olfactory mesenchymal stem cells (OMSCs) and further elucidates their niche-targeted paracrine effectin vivoandin vitro. The findings demonstrate that OMSC-conditioned medium (OMSC-CM) delivered in fibrin hydrogel mediates potent SCI repair by concurrently protecting neurons, enhancing axonal regeneration, and suppressing destructive inflammation via IL-10 signaling. Critically, persistence of IL-10 signalingin vivois sustained both by direct supply from OMSC-CM and by OMSC-CM-induced activation of CD206⁺macrophages^IL-10. Successful neural circuit reconstruction with OMSC-CM depends on maximizing neuronal involvement in neural pathway formation. These findings may establish a special conceptual framework for developing regenerative medicine strategies in the future.

Stiffening of the extracellular matrix underlying the epithelial cells of the large intestine is associated with aging as well as many diseases. Yet the impact of the stiffened matrix on epithelial physiology remains poorly understood. A 2D and 3D microphysiological model of the large intestine was developed using a collagen scaffold with a physiologic or excessive stiffness (Young's moduli of 2.84 ± 0.85 kPa and 15.9 ± 0.73 kPa) by altering the collagen concentration within the substrate. Diffusion of a 10 and 40 kDa fluorescent dextran was significantly different between the physiologic and stiff scaffold (97.8 vs 79.8µm²s^-1[10 kDa] and 68.2 vs 56.8µm²s^-1[40 kDa], respectively). When primary human epithelial cells of the large intestine were grown as a 2D monolayer, cultures on the physiologic scaffold grew to a significantly higher density with more proliferative and fewer differentiated cells than cultures on the stiffened scaffold. Three-dimensional crypt arrays were also fabricated with the physiologic and stiff substrates, populated with cells, and a growth factor gradient applied. The cell density, proliferation, and height-to-width ratio was significantly greater for cells on the physiologic scaffold relative to that of cells on the stiffened scaffolds. Placement of a layer of intestinal fibroblasts below the epithelium on the crypt arrays did not mitigate the impact of the stiffened substrate. Bulk-RNA sequencing revealed 378 genes that were significantly upregulated and 385 genes significantly downregulated in the stiffened vs physiologic scaffolds. This work demonstrates that a molded collagen hydrogel can be used to mimic the biophysical characteristics of a stiffened intestinal stroma, recapitulating physiology observedin vivo. Thisin vitromodel of polarized crypts with a tunable underlying substrate will enable an improved understanding of intestinal epithelial cell morphology, stem cell maintenance and lineage allocation within a stiffened environment.

Replicating the complex mechanical and biological properties of native tissues remains a key challenge in three-dimensional bioprinting due to the limitations of single-nozzle systems. Here we present a multi-nozzle alternating bioprinting platform that addresses these problems by enabling precise control of mechanical and bioactive components' composition and distribution. By alternating cell-laden bioinks with mechanically reinforcing inks, our method enables precise spatial control for fabricating complex, anisotropic tissue architectures. A tri-layer printing strategy, using heart valve leaflets as a demonstrative model, was developed. In detail, gelatin methacryloyl bioinks, incorporating with porcine aortic valve interstitial cells and bioactive substances (e.g. basic fibroblast growth factor, polyaspartic acid, or chondroitin sulfate) to support cell function, are alternated with pluronic F-127 diacrylate mechanical reinforcement inks. This approach enhanced mechanical integrity of the constructs while supporting collagen, proteoglycan, and elastin production. Crucially, the constructs' mechanical robustness allowed direct cyclic mechanical stimulation during culture, further promoting tissue functional maturation and extracellular matrix remodeling.In vivo, the constructs showed excellent biocompatibility, with minimal calcification and favorable immune responses. This multi-material bioprinting platform enables the fabrication of tissue models that meet both structural and functional requirements, and can be adapted for a wide range of heterogeneous tissue and organ engineering applications, with the potential to significantly advance regenerative medicine.

A comprehensive understanding of the female reproductive system is essential for safeguarding fertility and preventing diseases related to women's health. Organoid/organ-on-a-chip (OOC), as a promising platform, could simulate complex physiological and pathological conditions, has revolutionized our understanding and management of female reproductive health. This technology is anticipated to advance the development of more effective assisted reproductive techniques, treatments and drug screening methods. This review focuses on various organoid/ OOC models designed to mimic the ovary, uterus, mammary gland, and vagina. Then, we introduce the current state of organoid/ OOC in female reproductive health and highlight how these models contribute to the study of female reproductive diseases. Additionally, we discuss the limitations of organoid/ OOC technology as well as its challenges and perspectives. Collectively, we believe that as organoid/ OOC technology continues to evolve, it holds great potential for transforming the diagnosis and treatment of female reproductive disorders, thereby enhancing women's overall health and well-being worldwide.

Diabetes, including all forms, remains a critical global health issue, affecting over 589 million adults and causing approximately 3.4 million deaths annually. Developing more relevantin vitromodels for pancreatic islet functions is crucial for advancing diabetes research and therapy. Microfluidic platforms enable precise control over experimental conditions, notably the mechanical cues within the tissue microenvironment, thereby offering a powerful tool for studying cell behavior under physiologically relevant conditions. In this study, we introduce an automated stimulation platform for single-islet glucose-stimulated insulin secretion, while insulin quantification remains off-chip. This platform incorporates an integrated micro-pump and automated fluid handling, obviating the need for external injection devices. Using both EndoC-βH5® spheroids and human donor islets, we demonstrate that the platform ensures high islet viability and functionality. This scalable and reproducible system represents a significant advancement in-depth studies of islet function, with broad applications for diabetes research and personalized treatment strategies.

Three-dimensional (3D) bioprinting enables the fabrication of tissues with controlled architecture and cell composition, yet the formation of mature and functional vascular networks remains a major bottleneck for clinical translation. Constructs thicker than 100-200 µm require stable and perfusable vasculature to sustain viability. This review compares vascularisation strategies in two contrasting contexts: regenerative tissue engineering, which requires hierarchical, mechanically stable networks capable of long-term perfusion and host integration, and tumour microenvironment modelling, which demands heterogeneous, leaky, and dynamically remodelling vasculature. Vascularisation approaches are examined across the complementary, technological and biological axes. The technological axis encompasses extrusion-, inkjet-, laser-, and microfluidic-assisted bioprinting methods, each with distinct trade-offs in resolution, cell viability, and scalability. Additionally, lumen-forming strategies, sacrificial, embedded, and coaxial printing, enable controlled formation of perfusable channels, while modular microgel-based bioinks enhance porosity, nutrient diffusion, and matrix remodelling. The biological axis comprises prevascularisation strategies and cellular mechanisms that drive functional vessel formation. Growth factor delivery (VEGF, FGF, PDGF) and hypoxia-driven angiogenesis provide biochemical stimuli, while co-culture systems combining endothelial cells with stromal partners (fibroblasts, pericytes, mesenchymal stem cells) promote endothelialisation, vessel stabilisation, and functional network formation. Mechanical and biochemical cues, including controlled flow, shear stress, and angiogenic factor gradients, are presented as key regulators of vascular maturation and perfusion stability. Validation metrics such as perfusion stability, oxygenation profiles, barrier integrity, and drug transport are emphasised as essential for assessing physiological relevance. Emerging technologies, including smart stimuli-responsive bioinks, 4D bioprinting enabling temporal tissue transformation, and AI-assisted adaptive volumetric fabrication, offer promising solutions for context-aware and dynamically regulated vascular systems. Together, this comparative framework guides strategy selection for either long-term regenerative perfusion or the pathophysiological complexity of tumour vascularisation, and provides practical design principles for translating vascularised tissue models toward clinical application and industrial-scale biofabrication.

3D bioprinting enables rapid fabrication of complex biological structures for tissue engineering applications. However, optimizing bioink formulation remains challenging due to complex relationships among material properties, printability, and cell viability. While the perimeter ratio (Pr) is commonly used to evaluate printability, it cannot adequately capture the full geometric fidelity required for comprehensive printability assessments, thereby limiting robust bioink design. To address this limitation, a novel Hausdorff distance (HD) metric is employed to quantify printability, directly measuring the maximum deviation between the designed and printed structures. Furthermore, multiple machine-learning approaches were applied to alginate-hyaluronic acid composite inks and rat pheochromocytoma-derived PC12 cells to assess printability and cell viability. Rheological parameters were characterized using support vector regression (SVR) withR²⩾ 0.974. Multi-layer perceptron (MLP) regressors achievedR²values of 0.932 and 0.945 when predicting HD values of printed grid structures and cell viability, respectively. A regression-based convolutional neural network (CNN) was developed to predict HD values directly from grid structure images, achieving anR²of 0.986. Through optimization, optimal as-extruded cell viability (⩾95%) was achieved while maintaining high printability (HD ⩽ 0.20). The optimal ink composition was further demonstrated with good long-term cell viability and proliferation potential. This proposed AI-integrated approach can dramatically reduce ink optimization time by rapidly predicting rheological properties, printability, and cell viability from minimal experimental data.