点击化学法构建多生长因子序贯控释型ECM及骨组织工程化研究

Bone regeneration is regulated by multi-growth factors cooperatively, in which both controlled sequential delivery system of multi-growth factors and functionalized Extracellular Matrix (ECM) are critical challenges for bone tissue engineering applications. In this project, new four-arm block copolymers will be synthesized, and the growth factor loaded hydrogel will be prepared via “click” chemistry. After that, in-situ forming microspheres-hydrogel composites will be fabricated by “click” reaction. Based on the growth factor loaded on microspheres or hydrogel by different loading force, different growth factors will be loaded in microspheres and hydrogels respectively with different formulations, thus the sequential delivery system of multi-growth factors will be fabricated, at the same time, so does with multi-growth factors controlled delivery models. Lastly, cell-laden hydrogels will be formed through “click” chemistry, and new type of ECM with multi-growth factors functionalization will also be constructed. Herein, the release behavior of growth factors in hydrogels will be studied, on the other hand, it will be researched on the mechanism of controlled sequential release system of multi-growth factors fabricated by microspheres-hydrogel composites. Furthermore, this project will explore the principle of growth and differentiation of cells regulated by multi-growth factors release, in which leading to form new tissue-engineered ECM. The above result will lay the foundation of achieving a new generation of bone tissue engineering technology.

骨组织修复是多生长因子协同调控过程，而多生长因子序贯控释系统及功能型细胞外基质（ECM）构建是目前研究的难点之一。本项目拟合成新型可“点击化”四臂嵌段共聚物，点击凝胶化并装载生长因子。其次，原位构建微球-凝胶复合控释体系，对微球/凝胶两相中生长因子装载类别和装载量设计，利用生长因子在两相中的释放速率差异及迁移释放互补特点，实现多生长因子序贯释放，针对骨修复对生长因子的需求特点设计多生长因子序贯控释模型。最后，点击化学法制备细胞装载凝胶，构建多生长因子序贯控释型ECM。本研究将掌握新型凝胶对生长因子的装载与释放调控机理，微球-凝胶复合体系序贯释放多生长因子的内在机制，探讨功能型ECM多生长因子和细胞对骨组织工程化的协同调控作用，为新一代骨组织工程技术提供科学依据。

骨组织修复是多生长因子协同调控过程，而多生长因子序贯控释系统及功能型细胞外基质（ECM）构建是前几年组织工程领域研究的热点和难点之一。本项目拟合成新型可“点击化”四臂嵌段共聚物，以及四臂炔基和四臂环炔基小分子，通过叠氮炔基点击化学方法制备新型水凝胶。项目中制备三种类型的点击化学化水凝胶，获得了发明专利授权三项。其次，在点击化学凝胶化装载生长因子，同时，制备高分子微球，作为生长因子装载载体，通过微球结构及高分子分子量调控生长因子的释放速率，本项目成功构建了VEGF、MCP-1和TGF-β1装载微球。在以上研究结果基础伤，采用点击化学法原位构建微球-凝胶复合控释体系，对微球/凝胶两相中生长因子装载类别和装载量设计，利用生长因子在两相中的释放速率差异及迁移释放互补特点，针对骨修复对生长因子的需求特点成功构建了3种多生长因子序贯释放模型。最后，利用制备的新型水凝胶，通过点击化学法制备细胞装载凝胶，并再次引入生长因子，构建多生长因子序贯控释型ECM。本项目掌握新型凝胶对生长因子的装载与释放调控机理，掌握了微球-凝胶复合体系序贯释放多生长因子的调控行为。在本项目的支持下，获得了中国发明专利6项，在国际期刊上发表SCI论文15篇，发表书稿1章。本项目的研究成果为同行探讨功能型ECM多生长因子和细胞对骨组织工程的协同调控作用，以及构建新一代骨组织工程技术提供了科学依据。