原位交联马铃薯淀粉膜的酶解性能

Properties of In Situ Cross-Linked Potato Starch Films under Enzymatic Degradability

摘要: 淀粉基材料因其无毒、生物相容性好、可生物降解而在生物医用领域具有广泛应用价值，但其体内服役时易酶解，从而影响其性能并制约其应用。本文研究了三偏磷酸钠(STMP)原位交联淀粉膜在酶解环境下的结构与性能。以pH为7.4的含有α-淀粉酶的磷酸盐缓冲溶液模拟人体环境，研究了不同交联程度的淀粉膜的酶解性能。采用3,5-二硝基水杨酸法测定降解液中的多糖含量，以定量反映交联膜材料的降解率，测定酶水解曲线，并表征了交联淀粉膜在溶胀和酶解过程中形态的变化及膜湿强的变化。结果表明，交联剂STMP的含量介于0~15 wt%时，随着其含量的增加，交联膜的平衡溶胀率不断下降，即交联程度不断提高。随着交联程度的增大，交联膜的湿强逐渐提高，耐酶解能力不断增强，7 d内纯淀粉膜降解率达到55.0%，而15%交联剂淀粉膜的降解率仅为1.6%。由SEM、TG分析可知，淀粉膜的降解是由表及里的，从较为疏松的部分开始。交联后的淀粉膜是一种应用于诱导组织再生薄膜的潜在材料。

Abstract: As a non-toxic, good biocompatibility, biodegradable natural polymer, starch was widely used in biomedical fields. However, starch-based materials are easy to be degraded by enzyme system, which limits its application. In the present work, the structure and performance of cross-linked potato starch film were investigated. In the paper, human body environment was simulated by the pH of 7.4 phosphate buffer solution containing alpha amylase and the degradability of the different crosslinking degree of starch film was studied. The content of polysaccharides in degradation liquid was determined by 3,5-dinitrosalicylic acid colorimetry, which could quantitatively reflect the degradation rate of cross-linked starch film. Besides, the dynamic changes in the morphology and mechanical strength were characterized. Results showed that the equilibrium swelling ratio (ESR) of starch film decreased with the increasing of STMP content. The degradation rate of starch film decreased as the degree of crosslinking increased when the crosslinking agent content was below 15 wt%. The degradation rate of pure starch film reached 55.0% within 7 days, while the degradation rate of crosslinked starch film was only 1.6%. The SEM and TG results indicated: starch film began to degrade from the surface of the more loose part. No poisonous substance was imported during the crosslinking process. It shows a promis-ing prospect as materials of guided tissue regeneration.