仿生矿化水凝胶调控骨再生的机制研究

Traditional approaches to bone regeneration focus on the use of bone autografts, allografts, and xenografts. However, complications such as donor-site morbidity, host immune rejection, and disease transmission restrict the application of these tissue grafts. To circumvent the aforementioned limitations, synthetic biomatrials including ceramics, polymers, and composites have been developed as potential bone grafting materials. Self-healing hydrogels based on constitutional dynamic chemistry have received a lot of attentions recently. Hydrogel as a soft matter have long been vastly used in biomedical applications due to their superior biocompatibility and resemblance to biological tissues as mainly components of hydrogel are water. They are playing a more and more important role in biomedical applications such as drug delivery systems, cell culture, tissue engineering and manmade biomimetic materials. Developing multifunctional smart soft matter with self-healing property as self-healing hydrogels would be quite helpful to this emerging field with unexpected more biomedical materials. In this study, we aim to develope a facile approach to prepare a self-healing hydrogel using cheap chitosan and add osteoinductive factors to facilite osteogenesis. We aim to use this osteogenetic self-healing hydrogels as a 3D cell carrier to repair large bone defects in vivo.

目前的骨组织工程支架材料往往不能兼备良好的生物相容性、骨引导性、可降解性等特点，导致支架材料的临床应用应用较为受限。自愈性水凝胶是近年来热门的组织工程新材料。目前的研究表明，利用价廉易得的原料，采用简单的制备方法，可以获得具有良好生物相容性的自愈性水凝胶，并能将其作为细胞的三维培养载体，通过模拟真实的体内微环境，引导细胞进行三维增殖、分泌、矿化，充分发挥潜能细胞的再生能力，获得优异的骨再生效果。本研究计划以成本低廉的壳聚糖为主要原料，制备自愈性水凝胶，在其基础上添加矿化诱导因子和具有分化潜能的种子细胞，获得仿生矿化的水凝胶体系。并通过体外试验对该体系的生物相容性与成骨诱导特性进行检验；利用大鼠、比格犬骨缺损模型，探究生物矿化水凝胶应用于位点保存、骨再生的效果及其相关机制，旨在开发一种操作便捷、易于推广、成骨效果优异的仿生材料。

目前的骨组织工程支架材料往往不能兼备良好的生物相容性、骨引导性、可降解性等特点，导致支架材料的临床应用应用较为受限。本课题旨在模仿天然骨组织细胞外基质微纳结构的多孔矿化胶原基质，探讨其对骨髓间充质干细胞（BMSCs）迁移及骨缺损的修复效果。研究中采用仿生矿化法合成多孔胶原基质支架材料，使用micro-CT、扫描电子显微镜、透射电子显微镜、原子力显微镜检测多孔矿化胶原基质微纳结构、机械性能，体外细胞共培养检测胶原基质对BMSCs细胞增殖、迁移的影响，大鼠下颌骨临界骨缺损植入支架材料后比较各组支架材料引导骨再生的能力。结果表明，本研究提供的仿生矿化法可制备矿化均匀的胶原基质，可以模仿天然骨基质的理化特征，并能制备成为疏松多孔、含纤维内纳米磷灰石的胶原基质支架材料（MIA）；与传统含纤维外磷灰石的胶原基质材料（MEA）相比，MIA具5倍以上的杨氏模量；体外接种2、14 d可观察到MIA组BMSCs细胞MTT染色和细胞渗透深度明显高于对照组，体内植入10周后MIA组缺损区域明显减小，Runt相关转录因子2（Runx2）和Osterix阳性细胞增多。本课题的研究结果表明，仿生多孔纤维内矿化胶原基质具有良好的生物学性能，可促进骨髓间充质干细胞增殖和迁移，促进新骨形成，是具备临床应用前景的骨再生支架材料。