壳聚糖脱乙酰度对海藻酸钠/壳聚糖微胶囊的表面性质及蛋白吸附的影响

Effect of chitosan deacetylation degree on surface properties and fibrinogen adsorption of alginate/chitosan microcapsules

采用流动电势技术、接触角技术及表面轮廓技术分别考察了由不同脱乙酰度壳聚糖制备的海藻酸钠/壳聚糖（ACA）膜的表面电荷分布、表面亲疏水性、表面粗糙度,并以纤维蛋白原为模型,采用静态吸附实验技术考察了表面性质对蛋白在ACA微胶囊表面的吸附量及吸附构象的影响。结果表明,ACA微胶囊表面净电荷为负,表面正电荷随脱乙酰度的降低而减少。由脱乙酰度60%-90%壳聚糖制备的ACA膜的表面接触角均为70°左右,且无显著性差异。ACA微胶囊表面呈颗粒状结构,表面粗糙度随壳聚糖脱乙酰度的降低而减小。蛋白吸附分析表明,＂棒状＂的纤维蛋白原分子以＂侧向＂和＂直立＂2种形式吸附于ACA微胶囊表面。当壳聚糖脱乙酰度较低时,蛋白吸附量较小,且此时蛋白多以＂直立＂形式吸附。以上结果表明,由壳聚糖脱乙酰度带来的ACA微胶囊表面性质差异不仅影响了蛋白吸附量,而且影响了蛋白吸附方式。

The surface charge,wettability and roughness of ACA microcapsule membranes were firstly analyzed by streaming potential,contact angle and surface profile measurement.The effect of surface properties on the amount and conformation of fibrinogen adsorbed onto ACA microcapsules was then studied.The results show that there are a negative Zeta potential of ACA microcapsules which decrease with decreasing in chitosan deacetylation degree,indicating less positively charged groups on the surface.The surface wettability of ACA membranes made of chitosans with degree of deacetylation range from 60% to 90% has no statistical difference.ACA membranes have a granular structure surface.The surface roughness decreases with decreasing in chitosan deacetylation degree.Fibrinogen molecules are arranged on the surface of ACA microcapsules in a mixture of side-on and end-on configurations.With the decreasing in deacetylation degree of chitosan,the amount of protein adsorbed decreases,and more fibrinogen molecules adsorbed are in end-on configuration in this case.The results indicate that the surface properties of ACA microcapsules made of chitosans with different deacetylation degree have great effect on the amount and configuration of fibrinogen adsorbed.