Angiopep-2修饰的脑靶向多肽胶束的制备及体外评价

Preparation and in vitro evaluation of angiopep-2-modified brain-targeting polypeptide micelles

目的构建angiopep-2修饰的硫辛酸-聚精氨酸组氨酸(LHRss)多肽纳米胶束并包载抗肿瘤药物多柔比星(DOX)的脑胶质瘤靶向纳米给药系统(LHRss-An/DOX)。方法采用超声乳化法制备包载化疗药物DOX的多肽胶束LHRss-An/DOX,检测复合物的粒径、zeta电位和外观形态;测定载药量和包封率,并对其体外释放特性进行考察;通过体外血脑屏障(BBB)模型考察载药胶束的跨膜转运效率,使用激光扫描共聚焦显微镜观察DOX胞内的分布情况及对脑胶质瘤的靶向性。结果胶束LHRss-An/DOX呈球形,平均粒径为(100.9±8.7)nm,聚合物分散性指数为0.232,电位为(28.8±3.3)m V,最佳药载比为40%,载药量为15.8%,包封率为55.3%,在pH 7.4、pH 5.5和pH 5.5+10 mmol/L DL-二硫苏糖醇(DTT)环境下72 h内的累积释放率分别为(60.3±2.6)%、(84.1±3.9)%和(96.6±2.7)%;LHRss-An/DOX的跨BBB效率分别是LHRss/DOX和游离DOX的2.04和4.27倍,差异有统计学意义(P<0.05);脑胶质瘤细胞U251摄取LHRss-An/DOX的荧光强度强于LHRss/DOX和游离DOX的荧光强度。结论经过angiopep-2修饰的载药纳米胶束的跨BBB能力及脑胶质瘤的靶向性显著增强,是一种潜在高效的靶向胶质瘤给药系统。

Objective To prepare an angiopep-2 modified disulfide cross-linked lipoic acid-polyarginine polypeptide and histidine nanomicelle loading anticancer agent doxorubicin(DOX)brain-targeting drug delivery system for glioma(LHRss-An/DOX).Methods LHRss-An/DOX was prepared by ultrasonic emulsification method,and the particle size,zeta potential and appearance were detected.The loading content(LC)and encapsulation efficiency(EE)of DOX in the polymeric micelles and the in vitro release profiles were determined.Transmembrane transport efficiency of LHRss-An/DOX was evaluated using in vitro blood-brain barrier(BBB)model.The intracellular distribution of DOX and glioma targeting ability were observed by laser scanning confocal microscopy.Results Spherical micelles LHRss-An/DOX were successfully obtained.The mean particle size of the LHRss-An/DOX was(100.9±8.7)nm,polymer dispersity index was 0.232,zeta potential was(28.8±3.3)mV,optimal drug loading ratio was 40%,LC was 15.8%and EE was 55.3%.Cumulative DOX release within 72 h reached(60.3±2.6)%,(84.1±3.9)%and(96.6±2.7)%in the solutions of pH 7.4,pH 5.5 and pH 5.5 with 10 mmol/L DL-dithiothreitol(DTT),respectively.The transporting BBB efficiency of LHRss-An/DOX was 2.04 and 4.27 times of that of LHRss/DOX and free DOX,respectively(both P<0.05).The fluorescence intensity of LHRss-An/DOX uptake by of glioma cells U251 was stronger than that of LHRss/DOX and free DOX.Conclusion Angiopep-2-modified loading drug nanomicelles have good penertrating capacity of BBB and gliomatargeting,and it can be a potential drug delivery system for brain-targeting.