The galactosylated chitosan (GC) was synthesized by the reaction of the amino group of chitosan and carboxyl group of lactobionic acid under the activation of 1ethyl3-(3dimethyllaminopropyl)carbodiimide hydrochloride (EDC) and N-hydroxysulfosuccinimide sodium salt (NHS).Subsequently

thermo-sensitive galactosylated chitosan-graft-poly(N-isopropylacrylamide) (Gal-CS-g-PNIPAm) hydrogels were prepared via free radical polymerization method.The chemical composition and structure of the novel copolymer obtained were characterized by Fourier transform infrared spectroscopy (FTIR)

X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM)

respectively.Thermo-sensitive feature of the hydrogel was studied by measuring its swelling ratio and contact angle.The results showed that Gal-CS-g-PNIPAm hydrogels exhibited good temperature response.HL-7702 cell behaviors such as proliferation

detachment and cell transfer were carefully investigated via cell culture on the surface of Gal-CS-g-PNIPAAm hydrogels in vitro. The results indicated that Gal-CS-g-PNIPAAm hydrogel exhibited a good biocompatibility.HL-7702 cells cultured on this hydrogel surface proliferated better than on the PNIPAAm hydrogel.Besides

HL-7702 cells could spontaneously detach from the surface of the Gal-CS-g-PNIPAAm hydrogel by lowering the temperature below the LCST (32.5℃)

and the detached cells showed less damage than those detached by enzymes from TCPS.Meanwhile

cells detached from Gal-CS-g-PNIPAAm hydrogel showed higher viability than those from the PNIPAAm hydrogel

suggesting that introduction of GC monomer to PNIPAAm hydrogel evidently improved the activity of the detached cells.