Rapid Cell Sheet Recovery by Successive Grafting of PHEMA and PIPAAm onto TCPS Dish Surfaces

Abstract

Rapid recovery of cell sheets is considered important to maintain the biological function and viability of recovered cell sheets. To accelerate required culture substrate hydrophilic/ hydrophobic structural changes in response to culture temperature alteration, poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(N-isopropylacrylamide) (PIPAAm) were grafted successively onto tissue culture polystyrene (TCPS) dishes by electron beam irradiation. Analysis by attenuated total reflection-Fourier transform infrared revealed that PHEMA and PIPAAm were successfully grafted to surfaces of TCPS dish. PIPAAm-PHEMA-grafted TCPS (PIPAAm-PHEMA-TCPS) dishes were compared with PIPAAm-grafted TCPS dishes for cell sheet detachment experiments. Approximately 75 min was required to completely detach cell sheets from PIPAAm-TCPS dish, compared to only 13 min to detach cell sheets from PIPAAm-PHEMA-TCPS dish, which is successively grafted with PHEMA and PIPAAm. PHEMA is a well-known as a high hygroscopic polymer. In the case of PIPAAm-PHEMA-TCPS dish, PHEMA layer acted as a water pool to accelerate the hydration of PIPAAm layer due to the effective and simultaneous water supply to PIPAAm layer, resulting in rapid hydration of grafted PIPAAm molecules and detachment of cell sheet compare to PIPAAm-TCPS dish without PHEMA layer.