Preparation of triblock copolymer containing grant pendant group and hifu-induced response behaviors of micelles

mPEG-Cys(trt)-Cys(trt)-PCL-Cys(trt)-Cys(trt)-mPEG thiol-protected triblock copolymer was prepared using dicyclohexylcarbodiimide (DCC) as coupling agent and 4-dimethylaminopyridine (DMAP) as catalyst. mPEG was used as hydrophilic block and PCL as hydrophobic block. Thiol-protected amino acid Cys(trt) was also introduced into the block copolymer (between mPEG and PCL blocks) using esterification reaction. 1H-NMR was used to characterize structures of the products. Block copolymer micelle was prepared through the selective solvents induction method. The size and size distribution of the copolymer micelles were characterized by dynamic light scattering (DLS). The results show that the triblock copolymer in aqueous solution could self-assemble into spherical micelles with the diameter of ~50 nm and the diameter of the micelles increases to ~85 nm after ultrasound irradiation. The release behavior was investigated by the fluorescence spectrometer. Ultrasound irradiation benefits the solubilization of pyrene in micelles, and the fluorescence intensity of micelles can increase with power and time of ultrasound irradiation. ©, 2015, Chengdu University of Science and Technology. All right reserved.