具有免疫逃逸仿生功能的自组装多肽血管支架涂层构建及其抗再狭窄和抗血栓的研究

Macrophages and their inflammatory responses profoundly effect on the occurrence and development of atherosclerosis, as well as restenosis and late thrombosis caused by vascular stenting. This project proposes to construct a self-assembling peptide nanofiber hydrogel matrix coating for stent，functionalized with CD47-derived immune escaping peptide，to achieve the regulation of macrophage adhesion and activation on the stent surface. The self-assembling peptide (RADA)4 has excellent biocompatibility and editorial ability，that to realize the nanofibers with the bionic function of CD47-derived peptides through sequence extension. Nanofiber hydrogel matrix coating can exponentially increase the graft amount of active peptide on surface. By mixing with unmodified (RADA)4, the dosage of CD47-derived peptide on fiber surface can be controlled. In addition to direct coating, this project proposes the use of plasma polymerized allylamine (PPAam) and polydopamine as transition coatings to enhance the binding of the hydrogel matrix to the stent. The relevance of CD47-derived peptide dosage to inflammation, neointimal hyperplasia, endothelial regeneration, and thrombosis was established by evaluating the combined effect of the biomimetic coating on macrophages, endothelial cells, smooth muscle cells, and platelets. The further understanding of the comprehensive effect of CD47-derived peptide biomimetic coating on restenosis and late thrombosis, provide theoretical guidance and lay the technical foundation for the application of CD47 derivative peptide biomimetic coating for vascular stents.

巨噬细胞及其介导的炎症反应深刻影响动脉粥样硬化的发生和发展，以及支架植入所引起的再狭窄和晚期血栓形成。本项目提出在支架表面构建具有CD47免疫逃逸仿生功能的自组装多肽涂层，实现对支架表面巨噬细胞活性的调控。自组装多肽(RADA)4具有优异的生物相容性和可编辑性，通过序列延伸可实现纳米纤维的CD47衍生多肽功能化。纳米纤维水凝胶基质涂层可成倍提升材料表面活性多肽的接枝量，与未改性(RADA)4混合，可实现表面CD47衍生多肽剂量的可控。除直接涂覆外，拟采取等离子体聚烯丙胺和聚合多巴胺作为过渡涂层，增强水凝胶与支架的结合力。通过评价仿生涂层对巨噬细胞、平滑肌细胞、内皮细胞以及血小板的综合影响，建立CD47衍生多肽剂量与炎症反应、内膜增生、内皮再生和血栓形成的相关性。探究CD47衍生多肽仿生涂层对再狭窄和晚期血栓的综合作用行为，为CD47衍生多肽仿生涂层在血管支架的应用提供理论指导和技术基础。

巨噬细胞及其介导的炎症反应是目前血管支架为代表的医疗器械植入后失败的重要因素。近年来，随着对肿瘤免疫环境认识的不断加深，以“别吃我”蛋白CD47为代表的肿瘤免疫逃逸机制引起了广泛的关注。本项目提出在血管支架等心血管植入器械表面构建具有CD47免疫逃逸仿生功能的自组装多肽涂层，实现对支架表面巨噬细胞活性的调控。研究发现，仿生水凝胶涂层不仅可以降低单核/巨噬细胞的黏附，还具有较好的内皮细胞相容性，以及降低血栓的形成。此外，本项目的衍生研究探索出了以一系列功能化涂层，实现了抗再狭窄和晚期血栓的形成。例如在探索过渡涂层的过程中，我们开发了通过沉积多层正负电荷交替的等离子体聚合薄膜的技术，成功并稳定的固定了大量肝素分子，取得了优异的抗凝效果。并且，对多酚聚合物过渡层的开发中，我们偶然间首次发现了绿茶中天然多酚EGCG的自荧光，经过研究我们判断这是一种独特的聚集诱导发光（AIE）现象，为此开发了可以实现活细胞成像的AIE纳米探针。本项目还对炎症反应调控、心血管材料表面改性技术等进行了摸索，取得了一定的成果。本项目为炎症反应调控生物材料的应用提供了理论指导和技术基础。