표면전하를 함유한 고분자 나노 입자의 제조와 응용

Abstract

Pluronic F127, poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide), amphiphilic triblock copolymer can form nanosized micelle in aqueous environment above its critical micelle temperature (CMT) and critical micelle concentration (CMC). Here, we present a method to control the density of charges on surface of stabilized F127 micelle via semi-interpenetrating network(sIPN) formation. We prepared F127 nanoparticles (NPs) covered with 0 - 100 % positive and negative charges in every 10% interval and characterized the NPs by dynamic light scattering, zeta potential and gel electrophoresis. Then using the charged fluorescent NPs passive cellular uptake in fourteen cell lines was investigated by fluorescence microscopy. We found out that, three cell lines exhibit specific charge-dependent uptake. These findings may contribute to understand fundamental role of charges on polymeric NPs for biological applications through passive targeting. In addition, a defined number of polymer is required to form a spherical micelle, which represents aggregation number (Naggre). While there are several methods to determine Naggre such as fluorescence quenching, fluorescence correlation spectroscopy and light scattering, in this study, we adopted electrophoresis to determine the Naggre of F127. Micelles consisting of pristine F127 and phosphorylated F127 (PP-F127), where the hydroxyl end-groups of F127 were converted into phosphate, were blended in different volume ratio to control the number of surface charges per micelle. Furthermore, the core of micelle was stabilized to prevent exchange of individual polymer among micelles. To assess the role of surface charge coverage on electrophoretic mobility, agarose gel electrophoresis of the blends was performed. By analyzing discrete gel bands, we determined Naggre of F127.