Surface Modification Of Polyurethane By Bioactive Lentinan Derivatives

Biomedical polymer material is one of advanced hi-tech materials which have special functions on repairation, replacement and regeneration of organic tissues. It has not only highly economic values but also has great applications to human health and society development.Biocompatibility is one of the most important characteristic of biomedical polymer material. Surface modification is an important and useful method to improve the surface properties but not damage the bulk properties of the material. In this study, lentinan extracted from shiitake mushroom was sulfated and carboxymethylated to afford two water-soluble polysaccharides, respectively. Then, the lentinan derivatives were immobilized onto the surface of polyurethane by different methods.Positively charged amino groups were introduced to the surface of polyurethane. Then, positively charged chitosan and negatively charged lentinan sulfate were alternatively deposited onto polyurethane surface through layer-by-layer self-assembly technique. The results showed that the water contact angle decreased gradually during the progressive buildup of the polyelectrolyte multilayers, and reached a steady value after five bilayers were assembled. At the same time, the fibrinogen adsorption decreased 80% and reached a steady value after five bilayers. In addition, the modified PU possessed antibacterial activity against Pseudomonas aeruginosa, the number of viable bacteria on the modified surface decreased by 57%.PEI-AgNO3 and lentinan sulfate were alternatively deposited onto polyurethane surface through layer-by-layer self-assembly technique. Then, a composite film containing Ag nanoparticals was obtained through the reducion reaction between Ag ions and NaBH4. The adsorption of fibrinogen decreased 41%, compared with unmodified polyurethane. In addition, the modified PU possessed antibacterial activity against Escherichia coli.The results of this foundation research have scientific significance and application value. These works have scientific significance and application value for preparing biocompatible materials with specific bioactivity, such as antibacterial, antitumor, or antiviral bioactivity.