THERMORESPONSIVE POLYMER BRUSHES PREPARED BY POST-POLYMERIZATION MODIFICATION OF POLY(PENTAFLUOROPHENYL ACRYLATE) FOR CELL SHEET PREPARATION

Abstract

Here in this research, polymer brushes of poly(pentafluorophenyl acrylate-co-N-isopropylacrylamide) or P(PFPA-co-NIPAM) were fabricated on glass substrates by either “grafting from” or “grafting onto” methods. For the “grafting from approach”, the surface-grafted PPFPA were first prepared by surface-initiated reversible addition−fragmentation chain transfer (RAFT) polymerization followed by post-polymerization modification with isopropylamine (IPA). Alternatively, PPFPA synthesized by RAFT polymerization in solution underwent post polymerization modification with IPA prior to being grafted onto the aminated glass substrates. Characterization by Fourier transform-infrared spectroscopy (FTIR), x-ray photoelectron spectroscopy (XPS) and water contact angle measurements proved the successful formation of the copolymer brushes, of which composition can be controlled by IPA concentration and reaction time. Tandem modification of the remaining PFPA units in the surface-grafted copolymer brushes with collagen type I, a cell adhesion promoter, was found to enhance adhesion of Keratinocyte cell upon cell culturing. Hydrolysis of P(PFPA-co-NIPAM) brushes were also performed to yield P(AA-co-NIPAM) brushes. Both copolymer brushes were then evaluated as substrates for cell sheet preparation. This study has suggested that this multifunctional and thermoresponsive platform can be used for cell sheet fabrication which is beneficial for tissue engineering applications.