Immobilization of galactose ligands on thermoresponsive culture surface and its influence on cell adhesion/detachment

A novel bio-functionalized thermoresponsive surface was prepared by UV-induced copolymerization of N-isopropylacrylamide (NIPAAm) and acrylic acid (AAc) and grafting onto tissue culture polystyrene (TCPS) dishes, followed by immobilization of galactose ligands. The results indicated that the roughness of surfaces was increased after copolymerization with NIPAAm and immobilization of galactose ligands. The amount of monomers grafted on TCPS was increased with increasing photografting time. The temperature sensitivity of surface was improved with increasing amount of NIPAAm grafted on TCPS, and surface hydrophilicity was enhanced by the introduction of carboxyl groups and galactose ligands, which accelerated cell detachment. Adhesion, proliferation, detachment and transshipment of human hepatoma cell line (HepG2) on the modified surfaces were examined. The immobilization of galactose ligands facilitated the cell adhesion and proliferation. HepG2 cells growing on the modified surfaces could be recovered spontaneously by only reducing culture temperature. The activity of cells obtained by temperature induction was higher than that obtained by enzymatic digestion.