新型聚乙烯醇微囊的制备及其结构性能研究

采用低温物理交联法制备新型聚乙烯醇微囊,所得微囊机械强度好,克服了目前普遍采用的海藻酸钠-聚赖氨酸-海藻酸钠(APA)微囊易碎的缺点,在APA微囊已完全破碎的机械强度下,聚乙烯醇微囊的破碎率仅为3%.在体外模拟肠胃生理极限条件下可保持稳定的物理化学性质,对尿素、尿酸和肌酐等小分子具有良好的通透性,能在10min内完全通透.将高效分解尿素的脲酶基因工程菌E.coliDH5包埋于聚乙烯醇微囊之中,其工程菌仍具有很高的分解尿素能力,其活力约为自由菌的80%.

Preparation, Structure Characterization and Properties of New Poly(vinyl alcohol) Microcapsules

Uremia is a very severe and wide spread disease, oral administration of microcapsulated genetically engineered E. coli is a better method for treating uremia than renal hemodialysis in terms of its high efficiency and low cost. In this paper, a new type of polyvinyl alcohol(PVA) microcapsules was prepared by using low temperature physical crosslinking method, which showed a strong mechanical strength, high chemical stability and low toxicity. Comparing with APA microcapsules that is currently used, PVA microcapsules has much higher mechanical strength. Moreover, the PVA microcapsules had a good permeability to small molecules such as urea, uric acid and creatitine, all of which can permeate through PVA microcapsules within 10 min. When the genetically engineered E. coli DH5 was entrapped to PVA microcapsules, the bacteria showed a high capacity for removal of urea, which was believed to be a key factor in the pathogenesis of uremia. Therefore, PVA microcapsules prepared by low temperature physical crosslinking method had a high potential for oral administration in the treatment of uremia patients.