Thermosensitive gel formation of novel polypeptides containing a collagen-derived Pro-Hyp-Gly sequence and an elastin-derived Val-Pro-Gly-Val-Gly sequence

A triple-helix-forming collagen model peptide, (prolyl-trans-4-hydroxyprolyl-glycyl)₁₀ [(Pro-Hyp-Gly)₁₀], and a thermosensitive elastin-derived pentapeptide, valyl-prolyl-glycyl-valyl-glycyl (Val-Pro-Gly-Val-Gly), were copolymerized in various mole ratios using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride and 1-hydroxy-benzotriazole in dimethyl sulfoxide at 20 °C. All of the obtained polypeptides have molecular weight higher than 10 ³ and contain a triple-helical structure, and showed an inverse phase transition from transparent solution to turbid suspension in response to a rise in temperature. The lower critical solution temperature of the polypeptide solution decreased upon increasing the content of Val-Pro-Gly-Val-Gly. Furthermore, polypeptides containing 82-86 mol % of Val-Pro-Gly-Val-Gly in composition showed reversible gel formation, suggesting that (Pro-Hyp-Gly)₁₀ acts as a hydrated unit and Val-Pro-Gly-Val-Gly acts as a thermosensitive crosslinking point. These biodegradable thermosensitive polypeptides may be useful for biomedical applications, including, as a scaffold for tissue regeneration.