Control of cell detachment on poly(N-isopropylacrylamide) grafted glass surfaces

IPAAm grafted glass coverslips was prepared (PIPAAm-CS) using electron beam and coverslips modified with MPTMS. XPS analysis of the PIPAAm-CS surfaces revealed that PIPAAm was successfully grafted onto the coverslips. Initial monomer concentration significantly influenced thickness and amount of the grafted PIPAAm. Surface wettability of PIPAAm-CSs increased with an increase in thickness and amount of the grafted PIPAAm. PIPAAm-CS with the grafted PIPAAm = 0.84 mug/cm² (0.84PIPAAm-CS) showed cell attachment and detachment properties in response to temperature, while PIPAAm-CS having the grafted PIPAAm more than 1.28 mu/cm² exhibited cell repellent surfaces. Wettability of PIPAAm-CSs supports this cell adhesion behavior. AFM measurements of the PIPAAm grafted coverslips, which are subjected to locally limited UV laser ablation, demonstrate that the grafted PIPAAm is ultra thin layer. Thickness of 0.84PIPAAm-CS and 1.28PIPAAm-CS are 3.6 nm and 8.8 nm, respectively. We further discuss thickness-dependent cell adhesion properties in terms of different molecular motion of the grafted PIPAAm chains between PIPAAm-CSs with thinner and thicker PIPAAm layer, referring our previous report