基于银离子交联改善壳聚糖水凝胶的力学性能

Mechanical properties of chitosan hydrogel based on silver ion crosslinking

目的壳聚糖(chitosan,CTS)分子在碱性氛围(NH_(3))中通过分子链缠结和非共价键作用以及分子间的低能键(如氢键、配位键等)的相互作用,可以逐步形成网状结构的壳聚糖水凝胶(CTS/NH_(3))。但在实际应用中,由于纯壳聚糖水凝胶的力学性能比较差,通常需要与刚性的保护性凝胶复合形成双层物理交联后,才能应用于生物材料领域。本文拟通过加入金属银离子以改善其相关性能。方法首先在100 mL的2%(体积分数)的乙酸水溶液中加入2.5 g的壳聚糖,配制浓度为2.5%(质量分数)的壳聚糖溶液;在壳聚糖溶液中加入一定量的硝酸银形成壳聚糖-AgNO_(3)溶液,将30 mL壳聚糖-AgNO_(3)溶液倒入培养皿,将培养皿放在0.2 m^(3)的含有100 mL氨水的密闭环境内,放置12 h至水凝胶形成。将水凝胶从培养皿中取出,用蒸馏水洗涤至洗涤液呈中性,制备不同银离子浓度的壳聚糖-银离子水凝胶;然后通过溶胀性能、表面形态、流变学和拉伸特性,检测其力学性能。结果银离子赋予壳聚糖水凝胶良好的溶胀性能和稳定的流变学性能,从而使其力学性能明显改善,且随着银离子浓度的增加,力学性能更加优异。相比于纯壳聚糖水凝胶,适当加入银离子,能使其力学强度增大至少10倍。结论金属银离子可以有效改善壳聚糖水凝胶的力学性能。

Objective Chitosan(CTS)molecules in alkaline atmosphere(NH_(3))through molecular chain entanglement,non-covalent bond interaction and intermolecular low energy bond(such as hydrogen bond,coordination bond,etc.)interaction,can gradually form a network structure of chitosan hydrogel(CTS/NH_(3)).But in practice,due to the poor mechanical properties of pure chitosan hydrogel,it can be used in the field of biomaterials only after it is combined with a rigid protective gel to form a bilayer physical cross-linking.This article aims to improve its related properties by adding metal silver ions.Methods First,2.5 g chitosan was added to 100 mL 2%acetic acid solution to prepare 2.5%chitosan solution.A certain amount of silver nitrate was added to the chitosan solution to form chitosan-AgNO_(3) solution,and 30 mL of chitosan-AgNO_(3) solution was poured into the Petri dish.The Petri dish was placed in a closed environment of 0.2 m^(3) containing 100 mL of ammonia water for 12 hours until the hydrogel was formed.The hydrogel was removed from the Petri dish and washed with distilled water until the washing solution was neutral to prepare chitosan-silver ion hydrogels with different silver ion concentrations.The mechanical properties were then examined by swelling properties,surface morphology,rheology and tensile properties.Results Silver ion enhanced the swelling and rheological properties of chitosan hydrogel,which significantly improved its mechanical properties.With the increase of silver ion concentration,the mechanical properties became better.Compared with pure chitosan hydrogel,the mechanical strength of chitosan hydrogel can be increased by at least 10 times with the proper addition of silver ions.Conclusions Metal silver ions can effectively improve the mechanical properties of chitosan hydrogel.