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‐hydroxybenzotriazole in dimethyl sulfoxide at 20 °C. All of the obtained polypeptides have molecular weight higher than 10³ 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. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6048–6056, 2005