Dual-stimuli responsive polymeric micelles: preparation, characterization, and controlled drug release

摘要

The preparation of stimuli-responsive polymeric micelles sensitive to both temperature and UV irradiation is achieved through the self-assembly from a series of amphiphilic block copolymers, poly(triethylene glycol methacrylate)- b-poly(2-nitrobenzyl methacrylate) (PTEGMA-b-PNBMA). The block ratios of the hydrophilic and thermoresponsive PTEGMA block to the hydrophobic and photoclevable PNBMA block are manipulated in the range of 4: 1 to 1:1. The nanostructure and stimuli-responsive properties of the micelles are well-correlated with the chemical structures of the copolymers. The thermal transition temperature of micelles is reduced to 38-41 degrees C and close to body temperature as compared to that of PTEGMA homopolymer around 52 degrees C. After UV irradiation, the enhanced hydrophilicity of micelle core causes swelling and increased size of micelles. The capabilities of these micelles for drug encapsulation are demonstrated by using doxorubicin as the model drug and the subsequent drug release could be triggered by elevated temperature and/or UV irradiation. Furthermore, the potential application of these micelles in controlled drug release is explored by studying the in vitro cytotoxicity of drugloaded micelles as triggered by external stimuli.