Abstract

Biopolymer-based hydrogels are important cell scaffolding materials for drug delivery and regenerative medicine. In this study, we report a covalently cross-linked composite chitosan-alginate hydrogel possessing pH sensitivity to degradation for drug delivery. To enhance mechanical strength of hydrogel, polyvinyl alcohol (PVA) was also added to form hydrogen bonds with polysaccharides under physiological condition. The gelation mechanism is attributed to the Schiff-base reaction occurring between amino groups in carboxymethyl chitosan (CMCS) and aldehyde groups in oxidized sodium alginate (OAlg). Synchronously, to enhance antibacterial properties of biomaterials, 5-fluorouracil (5-Flu) was mechanically mixed in the PVA solution, followed by incorporation into the CMCS-OAlg hydrogel to form a composite gel scaffold. Molecular weight and concentration of PVA would affect the gelation morphology, mechanical properties, swelling ratio, in vitro degradation and pH sensitivity of the gel scaffold. The composite gel scaffold has good drug release and antibacterial properties through drug release calculation and antibacterial performance evaluation. These results indicate that the composite gel scaffold has great potential for pH-sensitive drug delivery and wound healing applications.

摘要

基于生物聚合物的水凝胶是用于药物递送和再生医学的重要细胞支架材料。在这项研究中，我们报告了一种共价交联的复合壳聚糖 - 海藻酸盐水凝胶，其具有对药物递送降解的 pH 敏感性。为了提高水凝胶的机械强度，还加入了聚乙烯醇（PVA），在生理条件下与多糖形成氢键。凝胶化机制归因于羧甲基壳聚糖 (CMCS) 中的氨基与氧化海藻酸钠 (OAlg) 中的醛基之间发生的席夫碱反应。同时，为了增强生物材料的抗菌性能，将 5-氟尿嘧啶 (5-Flu) 机械混合在 PVA 溶液中，然后掺入 CMCS-OAlg 水凝胶中以形成复合凝胶支架。凝胶支架的体外降解和 pH 敏感性。通过药物释放计算和抗菌性能评价，该复合凝胶支架具有良好的药物释放和抗菌性能。这些结果表明复合凝胶支架在 pH 敏感的药物递送和伤口愈合应用中具有巨大的潜力。