Microengineering vascularized and innervated bone-like scaffolds as an alternative to autologous bone grafts

项目摘要 广泛的骨骼状况需要辅助骨修复，包括创伤、癌症切除和骨 用于口腔种植治疗的隆乳。目前治疗这些疾病的方法依赖于收获的程序 以及植入骨自体移植物，这是昂贵的、侵入性的并且难以扩大规模。其他的选择是 合成骨替代材料，其显示出高失效率并且不能模仿天然骨结构， 组成和成骨特性。长期以来，基于干细胞的组织工程一直被认为是一种 骨缺损修复的有前途的替代品。然而，治疗大的骨结构仍然是有问题的。 通常认为，与天然骨的特征非常接近的支架材料 代表用于骨再生的改进材料。然而，体外支架的发展模仿 高度血管化、神经支配和矿化的富含细胞的骨基质一直保持到纳米级 至今仍难以捉摸在这里，我们将开发一种新的骨支架生物制造工艺， 被三维地嵌入受控的纳米矿化的、预血管化的和神经支配的骨样 可注射微凝胶，从而模拟矿化纳米结构、细胞和细胞外微环境 原生骨(aim 1）我们将确定使hMSC分化的机制特征， 成骨表型的影响，骨样微环境，工程细胞负载矿化 可注射的微凝胶，其近似自体骨移植物的再生潜力。然后我们会适应 这一策略工程（目标2）周细胞支持的血管毛细血管和（目标3）神经元网络，这是 嵌入纳米级矿化水凝胶中，以确定使脉管系统和 神经支配增强体外成骨和体内再生。我们认为这种多管齐下的 该战略将使高度创新的骨支架材料和体外骨模型系统的工程 与天然骨骼在纳米结构和物理结构上有很大的相似性。最终，这将导致 生物材料，非常接近临床自体骨的再生潜力。

PROJECT SUMMARY A wide range of skeletal conditions require assisted bone repair, including trauma, cancer resections, and bone augmentation for oral implant therapy. Current methods to treat these conditions rely on procedures to harvest and implant bone autografts, which are costly, invasive and difficult to scale up. The other alternatives are synthetic bone replacement materials, which show high failure rates and fail to mimic the native bone structure, composition and osteogenic properties. Stem cell-based tissue engineering has long been proposed as a promising alternative for the repair of bone defects. However, treating large bony structures remains problematic. It is generally believed that scaffold materials that closely approximate the characteristics of native bone represent improved materials for bone regeneration. However, the development of in-vitro scaffolds mimicking the highly vascularized, innervated, and mineralized cell-rich bone matrix down to the nanoscale has remained elusive to date. Here, we will develop a new bone scaffold biomanufacturing process where osteoprogenitor cells are three-dimensionally embedded in controlled nano-mineralized, pre-vascularized and innervated bone-like injectable microgels, thus mimicking the mineralized nanostructure, cellular and extracellular microenvironment of native bone. (aim 1) We will determine the mechanistic characteristics enabling the differentiation of hMSCs into osteogenic phenotypes as influenced by bone-like microenvironments, and engineer cell-laden mineralized injectable microgels that approximate the regenerative potential of autologous bone grafts. We will then adapt this strategy to engineer (aim 2) pericyte-supported vascular capillaries and (aim 3) neuronal networks, that are embedded in nanoscale mineralized hydrogels, to determine the mechanisms that enable vasculature and innervation enhancement of osteogenesis in-vitro and regeneration in-vivo. We argue that this multi-pronged strategy will enable the engineering of highly innovative bone scaffold materials and in-vitro bone model systems that will share great nanostructural and physical similarities to native bone. Ultimately, this will lead to biomaterials that closely approximate the regenerative potential of autologous bone in the clinic.