Self-assembled nanostructures of red fluorescent amphiphilic block copolymers as both imaging probes and drug carriers

• Main Authors: Huang, Shuo, Wei, Xin, Wang, Mingfeng
• Other Authors: School of Chemical and Biomedical Engineering
• Format: Article
• Language: English
• Published: 2019
• Subjects: Fluorescence; Polymer; DRNTU::Engineering::Chemical engineering::Biochemical engineering
• Online Access: https://hdl.handle.net/10356/106605; http://hdl.handle.net/10220/47423
• Institution: Nanyang Technological University

We report a red-fluorescent drug delivery system formed by biodegradable and biocompatible amphiphilic A-B-A block copolymers. Each polymer consists of a red fluorescent dye covalently bonded in the middle of hydrophobic block (B) of polylactone, tethered at both ends with poly[(oligo ethylene glycol) methyl ether methacrylate] (POEGMA) as the hydrophilic block. Two types of polylactones, i.e., semicrystalline poly(ε-caprolactone) (PCL) and amorphous poly(δ-decalactone) (PDL), respectively, were incorporated as the hydrophobic segment in the block copolymers. Using transmission electron microscopy, we characterized the self-assembled nanostructures formed by these amphiphilic block copolymers in mixtures of water/tetrahydrofuran or water/dimethylformamide. All of these polymers remained highly fluorescent in water, although some extent of aggregation-induced fluorescence quenching was still observed. Among the three types of polymers presented here, the polymer (RPO-3) containing an amorphous block of PDL showed the highest drug-loading capacity and the largest extent of drug release in acidic media. RPO-3 micelles loaded with doxorubicin as a model of anticancer drug showed sustainable intracellular release and cytotoxicity against HeLa cells.