ABMES

This paper describes the development of a visible-light-crosslinkable thermoresponsive polymer for fabricating cell culture substrates that enable temperature-dependent alteration of cell attachment and detachment. Poly(N-isopropylacrylamide) (PNIPAAm) copolymer with camphorquinone (CQ) side chains (PNIPAAm-CQ) was synthesized to enable covalent immobilization onto polystyrene surfaces via visible-light-induced radical reactions. Two coating strategies—spin-coating and adsorption—were used to fabricate thermoresponsive surfaces. Both coating methods achieved comparable polymer grafting densities; however, they exhibited distinct surface properties. Spin-coated surfaces exhibited pronounced temperature-dependent changes in receding contact angles and fibronectin adsorption, resulting in efficient endothelial cell attachment at 37 °C and rapid detachment upon lowering the temperature to 20 °C. In contrast, surfaces prepared by the adsorption method showed reduced molecular reorientation of grafted PNIPAAm chains, lower protein adsorption, and slower cell detachment kinetics. Confluent endothelial cell sheets could be harvested from both surface types by reducing the temperature from 37 °C to 20 °C while preserving cell–cell junctions. Notably, spin-coated surfaces enabled efficient cell sheet detachment, whereas adsorption-based coating has the potential to be applied for non-planar substrates. Eventually, this study demonstrates a facile and flexible coating approach for fabricating thermoresponsive culture substrates using visible-light-reactive CQ, highlighting the influence of coating methodology on surface behavior and cell interactions. These findings advance cell sheet engineering for regenerative medicine applications.