Surface Modification On Biopolymer Materials By Poria Cocos Polysaccharide Derivatives

Biopolymer materials have extensive applications in many fields. When conventional biopolymer materials are in contact with blood and tissues, they will induce rejections, such as thrombosis, protein fouling and the potential inflammatory reactions. The surface modifications of biopolymer materials become important when biopolymer materials are contacting with the physiological component such as blood and living tissues. It is generally accepted that surface modification by bioactive biomacromolecules is one of the most effective methods to improve the biocompatibility of biopolymer materials. After immobilized bioactive biomacromolecules such as polysaccharides, lipids and peptides, the biomaterial surface can be accepted by tissues, and the notorious rejections are restrained.In this paper, a water-insolubleβ-D-glucan (PCSG) isolated from Poria cocos was sulfated and carboxymethylated to afford two water-soluble polysaccharides coded as SP and CP, respectively. After the derivatives were immobilized to the biopolymer materials (PU and PLA) surface, the surface properties of the modified biopolymer material were investigated.In the part of the PU surface modification, SP and CP were respectively immobilized onto the PU surface, after free amino groups had been introduced onto the surface of PU membranes. Sessile drop water contact angles show the increased hydrophilicity of the PU surfaces after modification. The protein adsorption and in vitro blood compatibility results suggest that the blood compatibility of PU membranes is improved by CP and SP immobilization. The results demonstrate that the immobilization is a promising method to improve the biocompatibility of PU materials. In addition, the PU-CP membranes have shown the antibacterial bioactivity of inhibition the growth of Pseudomonas aeruginosa.In the part of the PLA surface modification, free amino groups were introduced onto the PLA surface by aminolyzed, and then CP was immobilized to the aminolyzed PLA membranes. The aminolysis reaction temperature, time and concentration of PLA membranes were studied. The suitable aminolyzed condition of PLA membranes is 45℃, 4min, in 0.09g/ml ethylenediamine, or 60℃, 6min, in 0.09g/ml 1,6-hexanediamine. Sessile drop water contact angles show the hydrophilicity of the PLA surfaces increased after modified by CP.The results of this foundation research have scientific significance and application value. It can provide theory and application data for preparing biocompatible materials with special bioactivity and multi-function. It is hoped that our idea will benefit to the researchers who are working in the field of multi-function biomaterials.