In situ BMSC Seeding of 3D Printed Scaffolds Using Cell-releasing Hydrogels

使用细胞释放水凝胶原位接种3D打印支架的BMSC 在目前的提议中，我们将研究3D打印的聚HIPE移植物的原位BMSC接种对细胞增殖的影响。 骨形成细胞释放水凝胶载体与先进的3D制造相结合 技术有可能生成具有患者特定几何形状和增强骨的移植物 再生为此，我们最近开发了一种多模式打印系统， 模拟骨骼天然结构的支架。在这一编制中，以丙烯酸酯为基础的乳化油墨具有层次性 多孔性（聚HIPE）用聚（乳酸）壳增强，以同时改善 渗透性和压缩性能。除了设计支架的性能外， 这取决于骨髓基质细胞（BMSC）的输送或募集，BMSC通过细胞增殖来帮助再生。 多种机制，包括作为新的骨形成中心和营养因子的分泌， 调节炎症、刺激血管生成和限制纤维化。我们研制出了一种可生物降解的细胞- 释放水凝胶载体，原位固化，在手术时用BMSC接种我们的3D打印骨移植物 随后在初始炎症期后细胞释放到支架上。原位BMSC接种 支架有可能最大限度地减少成本，治疗延迟，以及延长预处理的监管障碍。 文化时期。在资助期结束时，我们将确定目标细胞释放概况， 异位骨模型中的细胞滞留和BMSC启动的骨生成。这将提供强有力的证据， 细胞种植骨移植物的骨诱导特性，并支持在大型动物中进行进一步研究 正交各向异性模型（R 01）。除了改进骨移植手术，这些研究将验证一种方法， BMSC的交付，可用于广泛的应用。

IN SITU BMSC SEEDING OF 3D PRINTED SCAFFOLDS USING CELL-RELEASING HYDROGELS In the current proposal, we will investigate the effect of in situ BMSC seeding of 3D printed polyHIPE grafts on bone formation. The combination of the cell-releasing hydrogel carrier with advanced 3D manufacturing technologies has the potential to generate a graft with patient-specific geometries and enhanced bone regeneration. To this end, we recently developed a multi-modal printing system to generate tissue engineered scaffolds that mimic the native structure of bone. In this system, fumarate-based emulsion inks with hierarchical porosity (polyHIPE) were reinforced with a poly(lactic acid) shell to achieve simultaneous improvements in permeability and compressive properties. In addition to the design of scaffold properties, success as a bone graft depends on the delivery or recruitment of bone marrow stromal cells (BMSC) that aid regeneration through a variety of mechanisms including serving as new centers of bone formation and secretion of trophic factors that modulate inflammation, stimulate angiogenesis, and limit fibrosis. We have developed a biodegradable cell- releasing hydrogel carrier that cures in situ to seed our 3D printed bone graft with BMSC at the time of surgery with subsequent cell release onto the scaffold after the initial inflammatory period. In situ BMSC seeding of scaffolds has the potential to minimize the costs, treatment delays, and regulatory hurdles of extended pre- culture periods. At the end of the grant period, we will have identified the target cell-release profile that improves cell retention and BMSC-initiated osteogenesis in an ectopic bone model. This will provide strong evidence of the osteoinductive character of the cell-seeded bone graft and support future investigation in a large animal orthotropic model (R01). In addition to improving bone grafting procedure, these studies will validate a method of BMSC delivery that can be used in a broad range of applications.