摘要
探讨表面结合聚（２－乙基丙烯酸）后脂质小囊的体外ｐＨ敏感性。方法将巯基化的聚（２－乙基丙烯酸）连接在含有二肉豆蔻酰－Ｎ－［（４－马来酰亚胺甲基）环己羰基］磷脂酰乙醇胺的类脂双分子层表面，制备ｐＨ－敏感型脂质小囊。以内容物钙黄绿素酸化前后体外释放百分率的变化作为指标，考察不同相对分子质量的聚（２－乙基丙烯酸）和不同离子强度磷酸盐缓冲液对脂质小囊ｐＨ敏感性的影响。结果高相对分子质量聚（２－乙基丙烯酸）表面结合脂质小囊对ｐＨ最敏感；以１００ｍｍｏｌ／Ｌ磷酸盐缓冲液为介质制备的脂质小囊ｐＨ敏感性最好。
Purpose To determine the pH-sensitivity of the PEAA-bound vesicles with a reactive maleimide handle imcorporated into the lipid membrane in the form of dimyristoly-N-{[4-(maleimidomethyl)cyclohexyl]carbonyl} phosphatidylethanolamine(MAL-PE). Methods A semisynthetic vesicular membrane was constructed by immobilization of a synthetic polyelectrolyte [poly(2-ethylacrylic acid)](PEAA) on the surface of a phosphatidylcholine bilayer conaining MAL-PE.Semisynthetic membranes prepared in this way were sensitive to hydrogen ion concentration.Calcein was used as a model drug to determine the pH-sensitivity of the vesicles.Release of calcein can be achieved by mild acidification within the physiological pH range.The influence of molecular weight of PEAA and the ion strength of the vesicle suspension were studied on the pH-sensitivity of the polymer-bound vesicles. Results Vesicles prepared in this way was sensitive to the mild change of pH.PEAA with the highest molecule(S H)was most sensitive to the change of pH.Within our experimental conditions,100mmol/L PBS was found to be the best to the pH-sensitivity of polymer-bound vesicles. Conclusions [WT10.BZ〗The results support that vesicles bearing PEAA were sensitive to hydrogen ion concentration.
出处
《上海医科大学学报》
CSCD
1999年第1期26-28,共3页
Journal of Fudan University(Medical Science)
基金
国家自然科学基金
关键词
敏感型
脂质体
pH-脂质体
脂质小囊
体外释放
pH-sensitive vesicles
surface conjunction
calcein
molecular weight of PEAA
ion strength
