巨噬细胞分型时序可控的CoFe2O4@BaTiO3/P(VDF-TrFE)生物复合涂层构建及其评价

When the surface of the bone implant induces an inflammatory response, the M1 and M2 phenotypes generated by macrophage polarization can promote osseointegration in the early and middle stages of inflammation, respectively. Therefore, the temporally controlling macrophage phenotypes become a key scientific issue. Based on the research that macrophage polarization is controlled by the interaction between adsorbed protein and integrin, and surface potential can effectively regulate the interaction between adsorbed protein and integrin, this project innovatively proposes a research strategy that manipulating the controllable variation of surface potential of the coating, temporally modulating the phenotypes generated by macrophage polarization, in order to match the needs of different inflammatory stages, accelerate the formation of osseointegration. From a perspective of improving actionable dipole, the CoFe2O4@BaTiO3 core-shell structure was designed to enhance the local effective dipole of CoFe2O4, and the CoFe2O4@BaTiO3/P(VDF-TrFE) high magnetoelectric performance composite coating with dynamic controllable surface potential was constructed. The magnetic field manipulates the dynamic controllable variation of the surface potential of the coating, regulates the protein adsorption conformation, and modulates the protein-integrin interaction to achieve the temporal controllability of macrophage phenotype. It is proposed to study the coating construction and the relationship between controllable variation of surface potential and cell phenotype, and reveal the mechanism of surface potential temporally controlling macrophage phenotype.

骨植入体表面引发炎症反应时，巨噬细胞极化所产生的M1和M2分型可分别在炎症早期和中晚期对骨整合产生重要促进作用，因此，巨噬细胞分型的时序可控成为了关键科学问题。基于巨噬细胞极化受控于吸附蛋白与整合素相互作用、表面电势可有效调控吸附蛋白与整合素相互作用的研究基础，本项目创新性地提出“操纵涂层表面电势可控变化，时序调控巨噬细胞极化所得分型，以期匹配不同炎症时期分型需求，加速骨整合形成”的研究策略。从提高可作用偶极视角，设计CoFe2O4@BaTiO3核壳结构增强CoFe2O4表面局域有效偶极，构建表面电势动态可控的CoFe2O4@BaTiO3/P(VDF-TrFE)高磁电性能复合涂层。通过磁场操纵涂层表面电势动态可控变化，调节蛋白吸附构象，调制蛋白-整合素相互作用，实现巨噬细胞分型的时序可控。拟开展涂层构建、表面电势可控变化与细胞分型间的关系等研究，揭示表面电势对巨噬细胞分型时序可控作用机制。

在骨生物材料植入到体内后，巨噬细胞极化所得的M1和M2分型可发挥重要的成骨调控作用。因此，如何通过骨植入材料表面性能调控巨噬细胞分型是获得快速骨整合的关键。前期研究中，我们已经证实材料表面电势对成骨细胞具有重要调控作用。在本项目中，通过溶胶凝胶法合成了核壳结构CoFe2O4@BaTiO3（CFO@BTO）纳米粒子，构建了CFO@BTO/P(VDF-TrFE)磁电生物复合涂层，并研究了核壳纳米粒子对复合涂层磁电性能的影响；采用不同强度的磁场诱导复合涂层表面产生的不同的表面电势，研究了表面电势对巨噬细胞生长行为与极化分型的影响；通过PCR等分子生物学方法，研究了表面电势与功能蛋白活性位点暴露程度、功能蛋白活性位点暴露程度与整合素介导的巨噬细胞极化信号通路之间的相互关系。研究表明，较低的表面电势有利于纤维蛋白原上活性位点的暴露，可激活整合素αMβ2介导的M1极化信号通路；而较高的表面电势则有利于纤连蛋白上活性位点的暴露，可激活整合素α5β1介导的M2极化信号通路。通过细胞培养实验，评价了表面电势对巨噬细胞极化分型及成骨分化的影响。结果表明，相比静态培养，表面电势动态时序调控可引导巨噬细胞分型之间的转化，从而提升ALP、Col-Ⅰ、OCN、Runx2等成骨因子的表达水平。该研究成果为发展了一类可时序调控的生物活性材料，可加快实现植入体的骨整合，为设计刺激响应型的新型骨植入体提供了理论依据和方向。在本项目的支持下，发表了SCI论文五篇，授权国家发明专利一项。