The Preparation Of Specific Bioactive Poly(Lactic Acid)

A method for covalently grafting polyethylene glycol (PEG) onto MPLA with maleic anhydride grafted PLA (MPLA) and polypropylene glycol as raw material. The product was PPLA. The modifying time and temperature were optimaized. Then with biotin as raw material, by covalently grafting PPLA, a bioactive materials (BPLA) was obtained. The infra-red (FTIR), magnetic resonance imaging (NMR) and differential scanning calorimetry (DSC) were used to characterize PPLA. The anti-non-specific protein absorption property of material was tested using FITC labeled BSA. The bioactive of biotin on BPLA was tested using FITC labeled avidin. The hydrophilicity and degradation of MPLA and PPLA were investigated.The main works and conclusions are included as follows:(1)With maleic anhydride grafted PLA (MPLA) as raw material, two methods for covalently grafting polyethylene glycol (N-PEG) onto MPLA, which were linkage by DCC and direct reaction of PEG with anhydride groups on MPLA were used, aiming at developing a new drug delivery material with hydrophility and the property of decreasing the non-specific protein absorption. Because there were many reactive groups(-COOH and -NH2) in PPLA bulk, which provided reactivity for farther grafting reaction by protein or peptide to produce bioactive PLA. The analysis results of FTIR, ~1H-NMR and DSC indicated that N-PEG was successfully grafted onto MPLA and PPLA, and had the property of decreasing the non-specific protein absorption, only 37.3% of PLA. The unique Tg of PPLA is 50.4℃, compared with 53.5℃of MPLA.(2)The reaction time and temperature of PPLA were optimized according to the grafted amino group in PPLA tested by indenone reaction. The results of optimization is T=50℃, t=2h.(3)The bulk-modification of PLA was carried out from biotin and PPLA with Dicyclohexylcarbodiimide(DCC) as a condenser, the product was BPLA. Examine the capacity of PPLA, which keep the specific bioactive of bioactive molecule. 1H-NMR, DSC, FITC-BSA and FITC-avidin was used to characterize BPLA. The results indicated that biotin was successfully grafted onto PPLA, and BPLA had the property of decreasing the non-specific protein absorption, only 45.99% of PLA.(4) The hydrophilicity of MPLA and PPLA was characterized by water uptake. The change of pH and weight loss(0.1M PBS as medium, pH=7.4, T=37.0±0.5℃) of...