Novel water-soluble thermosensitive chitosan copolymers were prepared by graft polymerization of N-isopropylacrylamide (NIPAAm) onto chitosan using cerium ammonium nitrate (CAN) as an initiator. Sol-gel transition behavior was investigated by the cloud point measurement of the chitosan-g-NIPAAm aqueous solution. The gelling temperature was examined by vial inversion method. The percentage of grafting (%) and efficiency of grafting (%) were investigated according to concentrations of monomer and initiator.
Water-soluble chitosan-g-NIPAAm copolymers were prepared successfully and they formed thermally reversible hydrogel, which exhibits a lower critical solution temperature (LCST) around 32℃ in aqueous solutions. Preliminary in-vitro cell study showed nontoxic and biocompatible properties. These results suggest that chitosan-g-NIPAAm copolymer would be very useful in biomedical and pharmaceutical applications as an injectable material for cell and drug delivery.