Synthesis and characterization of active functional copolymers of N-isopropylacrylamide

Abstract

Well-defined random and block copolymers consisting of active ester-containing monomer (N-acryloxysuccinimide, NAS and pentafluorophenyl acrylate, PFPA) and N- sopropylacrylmide (NIPAAm) were synthesized by reversible addition-fragmentation chain transfer polymerization. Light responsive moieties of O-nitrobenzyl (ONB) were introduced to the copolymers via post polymerization modification. The ONB-containing copolymers could be successfully self-assembled or fabricated into micelles or electrospun fibers, respectively. Under UV irradiation, the ONB groups can be released, which subsequently induced an in situ crosslinking by spontaneous reaction with the remaining active esters and yielded stable cross-linked micelles or fibers. The cross-linked micelles are alternative cargo for incorporating active compounds that may be useful for biomedical applications. Furthermore, results from in vitro cytocompatibility studies demonstrated that the GRGDS- immobilized cross-linked fibers may be applicable as thermoresponsive 3D scaffold suitable for cell culture and tissue engineering applications.