Biofabrication of New Composite Scaffolds for Bone Tissue Engineering Applications

最近的综述强调了电纺纳米纤维在各种组织工程应用中的主要潜力。这项拟议的研究计划旨在利用静电纺丝技术和水凝胶制造用于骨组织工程应用的新型可生物降解复合支架。物理特性(成分、结构、孔径等)熔融电纺聚(e-己内酯)(PCL)网将首先进行优化，以促进骨祖细胞的附着和分化。然后，使用纤维蛋白-海藻酸盐水凝胶以受控方式输送的内皮细胞和生长因子将被整合到PCL网状物(先前种植有骨祖细胞)中，以促进血管形成。事实上，骨修复的一个主要挑战是提供一个不仅促进骨矿化，而且促进血管形成的环境。研究内容如下：目标1：利用熔融电纺、表面修饰和成骨细胞制备具有特定物理特性的矿化聚己内酯(PCL)网状物。将具有不同孔径的PCL网熔融电纺，包覆一层磷酸钙(CAP)，并用扫描电子显微镜和能量色散X射线能谱对其进行表征。目的：在灌流条件下，测定矿化的PCL网(在目标1中开发)与血管内皮生长因子165纤维蛋白-海藻酸盐水凝胶和内皮细胞复合的生物学和力学性能。将通过扫描电子显微镜、碱性磷酸酶定量、共聚焦显微镜、免疫细胞化学、组织学/免疫组织化学和力学测试来评估构建物的生物学和力学性能。自体骨移植通常用于修复临界大小的骨缺损，但骨替代物的使用为这种侵入性技术提供了一种替代方法。然而，目前的骨替代材料仍然面临着严重的局限性，包括供应不足、成本高以及替代材料无法与周围宿主组织结合。因此，拟议的研究将为加拿大的医疗保健系统提供切实的好处。此外，它可能会导致最终可转让商业化的新的、可申请专利的产品和/或工艺。最后，只有招募高素质的团队成员，他们才有可能进行这项研究，他们将接触到最先进的技术，并将有独特的机会在基础研究和应用研究之间获得多学科培训。

Recent reviews have highlighted the major potential of electrospun nanofibers for various tissue engineering applications. The proposed research program aims to fabricate new biodegradable composite scaffolds for bone tissue engineering applications using electrospinning technologies and hydrogels. The physical characteristics (composition, architecture, pore size, etc.) of melt electrospun poly(e-caprolactone) (PCL) meshes will first be optimized to promote osteoprogenitor cell attachment and differentiation. Endothelial cells and growth factors, delivered in a controlled manner using fibrin-alginate hydrogels, will then be incorporated into the PCL meshes (previously seeded with osteoprogenitor cells) to promote vascularization. Indeed, a major challenge for bone repair is to provide an environment that promotes not only bone mineralization, but also vascularization. Research will be segmented as follows: Objective 1: Fabricate mineralized poly(e-caprolactone) (PCL) meshes with specific physical characteristics by using melt electrospinning, surface modification, and osteoprogenitor cells. PCL meshes with different pore sizes will be melt electrospun, coated with calcium phosphate (CaP) and characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy. Osteoprogenitor cells will then be cultured on the mesh surface for mineralization.Objective 2: Determine the biological and mechanical properties of the mineralized PCL meshes (developed in Objective 1) combined with fibrin-alginate hydrogels loaded with vascular endothelial growth factor (VEGF)-165 and endothelial cells, under perfused conditions. SEM, quantification of alkaline phosphatase, confocal microscopy, immunocytochemistry, histology/immunohistochemistry, and mechanical testing will be performed to evaluate the biological and mechanical properties of the constructs.The proposed research uses cutting-edge technology to fabricate new mineralized and vascularized bone substitutes. Autologous bone grafts are often used to heal critical-size bone defects, but the use of bone substitutes presents an alternative to this invasive technique. However, current bone substitutes are still facing significant limitations including insufficient supply, high cost and the inability of the substitutes to integrate with the surrounding host tissue. The proposed research will therefore provide tangible benefits to the Canadian health-care system. In addition, it will potentially lead to new and patentable products and/or processes eventually transferable for commercialization. Finally, this research will only be possible by recruiting highly qualified team members, who will be exposed to state-of-the-art technologies and will have a unique opportunity to acquire multidisciplinary training at the interface between fundamental and applied research.