双缓释多功能复合原位凝胶敷料的构建及创伤修复机制研究

Hydrogels, three-dimensional cross-linked hydrophilic polymers have been chosen as good candidate for wound dressing materials because of their flexibility, permeability to air, and high intrinsic content of water, which can provide a moist or wetted environment to the wound area and absorb the exudates. Till now, significant progress has been made in the antibacterial activity of hydrogel dressing. However, it is still difficult to solve the low adherence to the wound site and the restriction in promoting the healing process at the same time. Therefore, designing a hydrogel would dressing with antibacterial activity, good adherence to the wound site and promoting the healing process is very important. In this project, a dual-release hydrogel dressing system would be prepared from a platelet lysate (PL)-loaded 6-aminoethylamino-6-deoxy chitosan (CS-en) based hydrogel (PL-CS-en-HG), in combination with the vancomycin (VCM)-loaded alginate-coated chitosan nanoparticles (VCM-CS-Alg-NPs). The modes and mechanisms of intermolecular reaction would be investigated to build a new efficient dual-release in situ hydrogel system. The drug release behavior, biological safety, antibacterial property, cell proliferation would be studied in vitro, and a rat dorsal wound model would be used to evaluate this bioactive hydrogel dressing in vivo. The project has important scientific significance on clarifying the formation and stability mechanism of the dual-release in situ hydrogel system, and providing theoretical support for the development of new would dressing.

具有3D网络结构的水凝胶柔韧性和透气性好，能保持创面湿润、吸收大量创面渗出液，因而在创伤敷料研究领域倍受关注。目前对水凝胶敷料的抗菌性研究已取得很大进展，但仍难以同时解决水凝胶敷料与创面贴合度不高、促愈合作用不强等难题。因此，设计同时具有高创面贴合度、促愈、抗菌功能的水凝胶敷料意义重大。本项目拟以水溶性的6-氨乙胺基-6-脱氧壳聚糖为原料制备荷载血小板裂解液(PL)的温敏型原位水凝胶作为相变基质，复合荷载万古霉素(VCM)的壳聚糖-海藻酸盐双层纳米粒，研究分子间作用方式和稳定机制，构建PL和VCM的双缓释原位凝胶敷料；对敷料的药物缓释行为、生物安全性、抗菌性、促细胞增殖能力、创面贴合度、促伤口愈合能力进行分析，探究敷料对创面的作用机制，初步揭示皮肤修复过程中的生物学和医学问题。本项目的研究对阐明生物材料复合体系的形成和稳定机制具有重要科学意义，并为新型多功能原位凝胶敷料的构建提供理论支持。

具有3D网络结构的水凝胶在创伤敷料研究领域备受关注，但难以同时解决其与创面贴合度不高、促愈作用不强、抗感染效果不好等难题。因此，设计同时具有高创面贴合度、促愈、抗菌功能的水凝胶敷料意义重大。本项目首先制备了壳聚糖（CS）的衍生物6-氨乙胺基-6-脱氧壳聚糖（CS-en），然后以CS-en为原料制备了温敏型原位凝胶（CS-en-HG）作为相变基质；合成了同时含有游离羧基和氨基的CS衍生物PICMCS，并成功构建了平均粒径为144 nm、具有核-壳结构的电负性纳米粒PICMCS-NPs。PICMCS-NPs对VCM具有良好的药物装载和缓释效果，缓释时间长达48 h。将VCM-PICMCS-NPs均匀的分散在CS-en-HG溶胶中成功构建了复合原位凝胶敷料（CS-en-HG/VCM-PICMCS-NPs），该敷料凝胶温度可控，可通过调整制备参数和条件使其凝胶温度在25℃-50℃之间变化；在低温下表现为液态的溶胶，温度升高到凝胶温度后相变为半固态的凝胶；具有良好细胞相容性、生物可降解性和抑菌活性；支持L929的3D培养与分裂增殖；与VCM-PICMCS-NPs相比具有更理想的药物缓释效果。CS-en-HG/VCM-PICMCS-NPs可通过滴加或涂抹的方式给药，与大鼠创伤皮肤具有良好的贴合能力，可通过促进血管新生、胶原沉积和纤维细胞分裂增殖来促进伤口的愈合，使伤口的愈合期提前4-5 d。本项目同时制备了CS-en/MTX-CS-MSs复合原位凝胶敷料，虽然该敷料的药物缓释效果不如CS-en-HG/VCM-PICMCS-NPs理想，但该敷料同样具有凝胶温度可控，凝胶温度下发生相变的特性，并具有良好细胞相容性和生物可降解性，可与皮肤有效贴合并促进伤口的愈合。