基于醛-胺席夫碱反应的葡聚糖荧光水凝胶及其结构、性质研究

Fluorescent dextran hydrogel based on the aldehyde-amine Schiff base reaction: Synthesis and characterizations

摘要:

以葡聚糖为原料，首先采用高碘酸钠氧化对其进行醛基化改性，再通过与胱胺二盐酸盐发生醛-胺席夫碱反应进行交联，制备了一系列具有经典三维多孔结构及良好荧光性质的葡聚糖水凝胶。进一步探究了交联密度（-CHO/-NH2摩尔比）、葡聚糖分子量和聚合物浓度对所获得的水凝胶的交联时间、微观结构、溶胀性能及流变性能的影响行为，结果表明：以分子量为40 000、氧化葡聚糖浓度为75 mg/mL、及-CHO/-NH2摩尔比为1.49条件下获得的水凝胶具有更优良的三维网状结构、粘弹性能及溶胀性能。此外，该荧光水凝胶由于含有酸敏感席夫碱键及还原敏感裂解二硫键，其降解行为具有明显的pH/还原双敏感性，可作为环境敏感局部给药平台应用于生物医学领域。

Abstract:

A series of fluorescent dextran hydrogels with typical three-dimensional sponge-like structure were prepared by the oxidation of dextran with sodium periodate and followed cross-linking with cystamine dihydrochloride via the aldehyde-amine Schiff base reaction. The effects of crosslinking density (-CHO/-NH2 molar ratio), dextran molecular weight and polymer concentration on the crosslinking time, microstructure, swelling properties and rheological properties of the obtained hydrogels were investigated, the results indicated that dextran hydrogel prepared with dextran T40, an oxidized dextran concentration of 75 mg/mL, and a -CHO/-NH2 molar ratio of 1.49 had the better three-dimensional network structure, viscoelastic properties and swelling properties. Furthermore, due to the presence of acid-sensitive Schiff base bonds and reduction-sensitive disulfide cleavage bonds, the resulted hydrogel exhibits pH/reduction dual sensitive degradation behavior, making it suitable for the application as an environmentally sensitive platform for local drug delivery.