17. Environmental pH-Responsive Fluorescent PEG-Polyurethane for Potential Optical Imaging
writer：Hong Yu Yang, Xiu Mei Zhang, Li Jie Duan, Ming Yao Zhang, Guang Hui Gao, Hui Xuan Zhang
keywords：nanostructured polymers, polyurethanes, biomedical applications
source：期刊
specific source：J. APPL. POLYM. SCI
Issue time：2013年
A series of environmental pH-responsive block copolymers PEG-polyurethane with tertiary amine groups in the main chain and free carboxyl groups in the side chain were synthesized, including poly(ethylene glycol) (PEG), 1,4-bis (hydroxyethyl) piperazine, 1,6-diisocyanato hexamethylene, and 2,2-dimethylolpropionic acid. The chemical structure, molecular weight, and pH-dependent capacity of pH-responsive PEG-polyurethane were examined by 1H-NMR, FTIR, gel permeation chromatography (GPC), and an acid-base titration. Moreover, the fluorescent dye fluorescein isothiocyanate was conjugated with PEG-polyurethane by the similar polymerization method and the obtained polymer was measured by ultraviolet visible spectroscopy (UV-vis) and fluorescent spectroscopy. The results indicated that the pH-responsive PEG-polyurethane showed a pH-buffering phenomenon and fluorescent imaging in a range of pH values. As a result, we demonstrated its potential application for optical imaging; however, it is believed that more applications in the areas of biomedicine will be possible owing to its free carboxyl acid terminal residues in the stimuli-responsive polymer.