中文摘要：

制备了香菇多糖羧甲基衍生物,再通过化学接枝方法利用共价键将羧甲基香菇多糖固定在氨基化聚乳酸基材表面,得到羧甲基香菇多糖化学接枝修饰的聚乳酸材料.此外,通过在氨基化聚乳酸基材表面进行羧甲基香菇多糖与壳聚糖的层层自组装,得到生物多糖层层自组装修饰的聚乳酸材料.采用扫描电子显微镜、水接触角测量仪、抗菌活性测试、溶血试验和血栓试验等方法对被修饰聚乳酸材料的表面性能和生物性能进行了分析和比较.结果表明采用2种表面修饰方法得到的羧甲基香菇多糖修饰的聚乳酸材料的亲水性、血液相容性以及对大肠杆菌抗菌活性得到改善.与化学接枝方法相比,经过羧甲基香菇多糖与壳聚糖层层自组装修饰的聚乳酸材料具有更好的亲水性、血液相容性和抗菌活性.

英文摘要：

Lentinan,a mushroom polysaccharide,isolated from Lentinus edodes（Shiitake mushroom） was carboxymethylated in NaOH and isopropanol solution to obtain a water-soluble derivative.Then,carboxymethylated lentinan was covalently immobilized onto the surface of aminated poly（lactic acid）（PLA） substrates via chemical grafting method.In addition,carboxymethylated lentinan and chitosan were alternatively deposited on the aminated PLA substrates via layer-by-layer（LbL） assembly method,in order to construct a polysaccharide-based multilayer on the substrates.The carboxymethylated lentinan was proved by infrared spectroscopy.The degree of substitution and molecular weight（Mw） of carboxymethylated lentinan were determined by UV spectrophotometry and gel permeation chromatography（GPC）,respectively.The modified and unmodified PLA surfaces were investigated by scanning electron microscope（SEM） and water contact angle measurements.The hemolysis test,thrombus test,and the antibacterial activity against Escherichia coli of modified and unmodified PLA were tested in vitro,respectively.Then,the surface properties of PLA modified by different modification methods were evaluated and compared.The results showed that the hydrophilicity,blood compatibility,and antibacterial activity against Escherichia coli of PLA modified by LbL assembly and chemical grafting were both improved.In addition,PLA modified by carboxymethylated lentinan and chitosan through LbL assembly method showed better hydrophilicity,blood compatibility,and antibacterial activity against Escherichia coli,in comparison with that modified by chemical grafting method.