Improving Cell Detachment from Temperature-Responsive Poly(<i>N</i>-isopropylacrylamide-<i>co</i>-acrylamide)-Grafted Culture Surfaces by Spin Coating

Abstract

Poly(N-isopropylacrylamide-co-acrylamide) (PNIAM-co-AM)-grafted surfaces have been reported to promote cell adhesion and detachment by a hydrophobic-to-hydrophilic transition triggered by temperature change. However, the surface uniformity and cell detachment consistency are still an issue. In this study, PNIAM-co-AM is prepared with spin coating to control the grafting density and the thickness and to achieve better cell detachment. The atomic force microscopy results indicate that the surface becomes smoother as the spin speed increases. The attenuated total reflection Fourier transform infrared results show a grafting density from 1.68 to 2.03 μg/cm2. Ellipsometry suggests that the thickness of the spin-coated PNIAM-co-AM layer is 11–21 nm. The grafted surfaces were tested with mouse preosteoblast MC3T3-E1 cells, which grew successfully. The detachment reached 100 percent with the samples prepared with 1.5 and 2 h ultraviolet exposure times without the use of a poly(vinylidene difluoride) membrane. The detached sheet was in good condition, as indicated by Live/Dead stains.