Biodegradable star-shaped PEG-PLLA block copolymer-cholesterol conjugate exhibiting sol-gel transition as an injectable scaffold for tissue engineering

POLY 540

Yuichi Ohya, yohya@ipcku.kansai-u.ac.jp, Koji Nagahama, and Tatsuro Ouchi, touchi@ipcku.kansai-u.ac.jp. Department of Applied Chemistry, Faculty of Engineering, Kansai University, 3-3-35 Yamate, Suita, Osaka, 564-8680, Japan
Sol-gel transition systems of biodegradable polymers aq. solution in response to a change in temperature has been widely investigated, because such system has a possibility for an injectable drug delivery system for sustained drug release and in situ cell delivery with scaffold for tissue regeneration. In this study, to obtain temperature-responsive gelling polymer exhibiting high mechanical strength in gel state, the conjugate of star-shaped 8-arms PEG-b-PLLA with cholesterol moiety was synthesized. The obtained conjugate showed sol-gel transition at 36°C and the mechanical strength of the hydrogel formed was higher than the previously reported biodegradable temperature-responsive gelling polymers. The possibility of the conjugate as a novel injectable scaffold for tissue regeneration was investigated through the temperature-responsive behavior of the conjugate, mechanical and degradation properties of the hydorgel, and cell proliferation inside of the hydrogel. The good cell proliferation inside of the hydrogel was observed.