Papers by Keyword: Ceramic Semiconductor

Abstract: Several techniques have been employed to attach/detach cells to/from a substrate. Cells cultured on a substrate are generally detached from the substrate into a sheet by the destruction of protein between the cells and the substrate using enzymes such as trypsin. However, the enzymes also damage the adhesion molecules among the cells. TiO₂ is an n-type semiconductor with an energy band gap of 3.0-3.2 eV, which displays a photocatalytic activity under ultraviolet (UV) light. The purpose of this work was to fabricate photo-responsive cell culture vessel using TiO₂ film and to investigate adhesion behaviour of cells on it. TiO₂ films were prepared on SiO₂ plates by a sol-gel method using titanium tetraisopropoxide. Primary osteoblasts were seeded on the vessels and then incubated at 37 °C. During the incubation, UV irradiation was performed continuously from back-side of the vessels. Basically the number of cells monotonically increased with incubation periods under darkness. Previous light irradiation promoted the cell adhesion on the surface. The formation of Ti-OH groups on the TiO₂ seems to be facilitated by the UV irradiation. In contrast, the cells decreased under continuous light irradiation. The cells were not exposed to UV in the vessels since it was completely absorbed by the TiO₂ layer. It might be due to generated photocurrent or hydroxyl radicals on the TiO₂ surface. These results imply that the adhesion/proliferation/detachment behaviours of cells can be controlled by the photocatalytic reaction of TiO₂ and the irradiation patterns.