Thermoresponsive Surface Prepared by Atom Transfer Radical Polymerization Directly from Poly(vinylidene fluoride) for Control of Cell Adhesion and Detachment

摘要

Thermoresponsive surface was preparedfrom commercial poly(vinylidene fluoride) (PVDF) filmsvia surface-initiated atom transfer radical polymerization.The direct initiation of the secondary fluorinated site ofPVDF facilitated grafting of the N-isopropylacrylamide(NIPAAm) monomer. The PVDF surfaces grafted withpoly(N-isopropylacrylamide) [P(NIPAAm)] were charac-terized by X-ray photoelectron spectroscopy. Kineticsstudy revealed that the P(NIPAAm) chain growth fromthe PVDF surface was consistent with a "controlled" pro-cess. The temperature-dependent swelling behavior of thesurfaces in aqueous solution was studied by atomic force microscope. At 37°C [above the lower critical solution tem-perature (LCST, about 32°C) of NIPAAm], the seeded cellsadhered and spread on the NIPAAm grafted PVDF sur-face. Below the LCST, the cells detached from theP(NIPAAm)-grafted PVDF surface spontaneously. Thethermoresponsive surfaces are potentially useful as stim-uli-responsive adhesion modifiers in the biomedical fields.