功能化多层一体化组织工程骨软骨复合支架的研究

This project is aimed at solving the problems of the integration between bone and cartilage in osteochondral tissue engineering scaffolds as well as the integration between these scaffolds and the surrounding host osteochondral tissues, which will carry out the study on integrated multi-layer scaffolds for osteochondral tissue engineering. This study will use degradable PCL nanofibers and degradable nonstoichiometric micro or nami hydroxyapatite crystals to compose with RGD-grafted heparin sulfate-grafted sodium alginate to produce a composite, so as to improve the mechanical property of the material and cell compatibility, and meanwhile use the controlled release technology of gene to achieve combined and sequential delivery of growth factors for osteochondral tissue engineering, so as to effectively guide the formation and reconstruction of bone and cartilage via in vitro and in vivo tissue engineering. The effect of material factors on cell adhesion, growth, proliferation and differentiation will be determined; the mechanisms and laws in material degradation, growth factor release as well as the in vitro and in vivo formation of osteochondral tissue in scaffolds will be explored, based on the study on the preparation of materials, cell adhesion on modified materials, degradation of materials, growth factor release and the in vitro and in vivo study and so on. These will provide certain theory basis for the preparation of materials, which match osteochondral tissue better and are closer to the physiological metabolism, for osteochondral reconstruction and repair.

本项目针对组织工程骨软骨支架材料种植体构建的骨和软骨界面结合较差而且种植体与周围宿主软骨整合性能不佳等问题，开展组织工程骨软骨多层一体化支架的研究。本研究将用微纳米羟基磷灰石晶体和可降解的非化学计量的PCL纳米纤维以及接枝了RGD的硫酸肝素与海藻酸钠进行复合，以改善材料的力学性能和细胞相容性。同时将基因控释技术引入组织工程，以实现生长因子的联合和序贯使用。通过体内外组织工程有效地引导软骨和骨的形成和实现骨软骨的重建。通过材料的制备、材料改性对细胞粘附、材料的降解、生长因子的控释等研究, 确定材料因素对细胞粘附生长、增殖及分化的影响；探明材料的降解、生长因子控释以及支架在体内的骨软骨的形成机制和规律,为制备与骨软骨的重建更匹配、更接近生理代谢特征的骨软骨修复材料提供一定的理论依据。

本项目针对制约软骨组织工程的种子细胞来源有限、增殖传代能力及诱导的软骨细胞表型稳定性差以及目前方法制备得到的3D天然高分子基质材料的力学性能和细胞相容性差、降解速度快等问题，开展了不借助外源细胞的类天然软骨结构的3D仿生软骨基质支架材料的研究。本研究用可降解的非化学计量的纳米羟基磷灰石晶体和PCL纳米纤维以及接枝了RGD的硫酸肝素与海藻酸钠进行复合对其进行修饰，以改善材料的力学性能和细胞相容性。同时将基因控释技术引入组织工程，以实现生长因子的联合和序贯使用。结果证明一体化多次功能支架材料与新形成的软骨下骨和软骨实现良好的键合。此外，我们提出的生长因子的联合和顺序释放策略有效地引导了血管、骨和软骨的形成，加速了骨和软骨的重建。实验结果还表明，我们设计的水凝胶支架材料的降解能够较好地匹配骨和软骨重建的要求。本研究通过材料的制备、材料改性对细胞粘附、材料的降解、生长因子的控释和软骨诱导等研究, 确定了材料因素对细胞粘附生长、增殖及分化的影响；探明了材料的降解、生长因子控释以及支架在体内的软骨诱导的机制和规律,为制备与软骨的重建更匹配、更接近生理代谢特征的软骨修复材料提供一定的理论依据。