Self‐crosslinked poly‐L‐ornithine and poly‐L‐arginine networks: Synthesis, characterization, pH‐responsibility, biocompatibility, and AIE‐functionality

Abstract

AbstractA pH‐responsive hydrogel consists of polypeptides only is a promising biomaterial with the advantages of good biocompatibility and non‐toxicity. This work reports the synthesis of poly‐L‐ornithine(poc) (polyLOpoc) serving as the precursor for hydrogels of poly‐L‐ornithine (polyOrn) and poly(L‐arginine‐r‐L‐ornithine) (poly(Arg‐r‐Orn)). Their controllable degree of crosslinking, good mechanical properties, good biocompatibility, and pH‐responsibility are detailedly investigated. The swelling ratio of polyOrn hydrogel in acidic aqueous solution is 5.7 times higher than that in a basic environment. In the deprotection of phenoxycarbonyl group, polyLOpoc releases amino pendant groups, which attack the remaining poc‐protected amino groups to fulfill self‐crosslinking without any crosslinking agent. In addition, the pH‐responsive behavior of hydrogels is visualized by aggregation‐induced emission phenomena with polyOrn and poly(Arg‐r‐Orn) containing tetrakis(4‐aminophenyl)ethene moisture.