Preparation Of The Polylactide And Chitosan Composite Membrane And Detect Method Of NTF

A kind of composite membrane based on polylactide (PDLLA) and chitosan, which can carry Nerve Growth Factor, was investigated to repair nerve defect. Polylactide and .chitosan were both superordinary polymer materials that have good biocompatibility and no poisonousness can be degraded by organisms. But the polylactide was high molecular compound with acidity, and it cannot be dissolved by polar solvent;on the other side, the chitosan, a kind of high molecular compound with alkalinity, can be dissolved by nonpolar solven but not polar solvent such as H2O. In this paper, a preparative method, by that polylactide and chitosan can be compounded uniformly to a composit membrance whose pH value was close to neutral field was focused on.The solvent evaporation method was adopted based on summarizing a deal of methods to prepare PDLLA/chitosan composite membrane. According to membrane-formed mechanism and influential factor, the design of experiment aimed directly at choice of the solvent,the molecular weight of PDLLA and chitosan, the chitosan's mass percentage in whole membrance, and there was a pH-detection experiment in vitro based on uniform membrance was preparation. Experimental result was: It can prepare the better character membrane by solvent evaporation method by those condition: the solute were PDLLA whose molecular weight is 200,000 and chitosan with 3,8000 molecular weight;the as solvent was acetic ether;chitosan's mass percentage in whole membrance was 30%.There was a test for cytotoxicity in vitro in this paper. The content of this test were: cellular damage evaluation in morphologic method , cell counting and MTT reduction assay. Experimental result: all the material adopted had the same cytotoxicity degree—0 level. This result showed that the composite membrane had great biocompatibility and accorded with health safety control.The PDLLA/chitosan composite membrane can promote reparation of nerve defect. There were many methods to detect the neurotrophic factors(NTF) that were released from composite membrane, but many of them worked in hard experiment condition or had a series of sophisticated operations. A part of this paper involved in how to detect the NTF conveniently by instrumentations of Biomaterial center such as High Performance Liquid Chromatogram(HPLC) system(Waters Alliance series) ^ ultraviolet spectrophotometer(Shimadzu, UV-2550). The experimental result showed that the separating property of Waters Alliance worked well, but the detection limit of the detector—PDA 996 can not meet requirement.