Polypeptide-PEG Conjugates via Ring Opening Polymerization of L-Alanine N-Carboxyanhydride

Ucak, Ö. et al., Macromolecular Chemistry and Physics, 2022, 2200344,


The synthesis of well-defined homo- and co-polypeptides of L-alanine (L-Ala) by ring-opening polymerization (ROP) of its N-carboxyanhydride (NCAs), either via suspension/interfacial- or solution phase-polymerization using 10-undecene-1-amine and α,ω-diamino poly(ethylene glycol) (8 or 1.5 kDa) as primary amine initiators is reported. Subsequently, the folding of the homo- and triblock amphiphilic co-polypeptides under a variety of parameters such as temperature, chain length, and backbone composition and the further transitions of these secondary structures are investigated in HFIP and HFIP-H2O mixtures via circular dichroism (CD) spectroscopy. A solvent induced helical switch from a 310-helix to a α-helix when changing from HFIP to HFIP–water mixtures is observed, with water inducing helicity stronger in both, homo-polyalanine and poly(alanine)-PEG-poly(alanine) triblock copolymers. © 2022 The Authors. Macromolecular Chemistry and Physics published by Wiley‐VCH GmbH.