Molecular design of poly (amino acid) microspheres byemulsion polymerization to apply as a biomaterial

我们投资the emulsion polymerization of r-benzyl-L-glutamete N-carboxyanhydride，r-methyl-l-glutamete n-carboxyanhydride,and leucine N-carboxyanhydride in mixtures of organic solvents and various surface surfactants undervarious reaction conditions in order to establish the approbate condition to obtain high molecular重量ploy (α-amino acid) microspheres quantatively. Copolymer microspheres obtained by usingpolyethylene glycol (MW 200) as surface surfactant and their diameter was within the range of 50-60micrometers confirmed by electron microscope. As a result of the further examinations changing thecomposition of monomers and surfactants in the reaction mixture我们succeeded in obtaining the microspheres whose diameter was within the order of 100-200 nmconstantly.Lipase was immobilized onto These microspheres by water-soluble carbodiimid method and tocheck their capacity to enhance the thermal and storage stabilities of the enzyme after theincubation in water under different PH condition. While the free enzyme lost its activity afterseveral hours under acidic PH，immobilized enzyme retained 80% of the initial activity under the same condition. theimmobilized enzyme also displayed considerable thermal stability retaining 20 % of the initialactivity even under 80 - C. Any activity loss was not observed at extremely high PH. These resultssuggested that the change of the conformation of the enzyme by storage, heatingand change of pH could be inhibited by immobilization and that the microsphere may function as abarrier against the deterioration by microorganisms and other factors。

We investigated the emulsion polymerization of r-benzyl-L-glutamete N-carboxyanhydride, r-methyl-L-glutamete N-carboxyanhydride, and leucine N-carboxyanhydride in mixtures of organic solvents and various surface surfactants under various reaction conditions in order to establish the approbate condition to obtain high molecular weight ploy (α-amino acid) microspheres quantatively. Copolymer microspheres obtained by using polyethylene glycol (MW 200) as surface surfactant and their diameter was within the range of 50-60 micrometers confirmed by electron microscope. As a result of the further examinations changing the composition of monomers and surfactants in the reaction mixture, we succeeded in obtaining the microspheres whose diameter was within the order of 100-200 nm constantly.Lipase was immobilized onto These microspheres by water-soluble carbodiimid method and to check their capacity to enhance the thermal and storage stabilities of the enzyme after the incubation in water under different PH condition. While the free enzyme lost its activity after several hours under acidic PH, the immobilized enzyme retained 80 % of the initial activity under the same condition. The immobilized enzyme also displayed considerable thermal stability retaining 20 % of the initial activity even under 80ーC. Any activity loss was not observed at extremely high PH. These results suggested that the change of the conformation of the enzyme by storage, heating, and change of pH could be inhibited by immobilization and that the microsphere may function as a barrier against the deterioration by microorganisms and other factors.