Human embryonic kidney 293T (HEK293T) cells are used in various biological experiments and researches. In this study, we investigated the effect of cell culture environments on morphological and functional properties of HEK293T cells. We used several kinds of dishes made of polystyrene or glass for cell culture, including three types of polystyrene dishes provided from different manufacturers for suspension and adherent cell culture. In addition, we also investigated the effect of culturing on gelatin-coated surfaces on the cell morphology. We found that HEK293T cells aggregated and formed into three-dimensional (3-D) multicellular spheroids (MCS) when non-coated polystyrene dishes were used for suspension culture. In particular, the non-coated polystyrene dish from Sumitomo bakelite is the most remarkable characteristic for 3-D MCS among the polystyrene dishes. On the other hand, HEK293T cells hardly aggregated and formed 3-D MCS on gelatin-coated polystyrene dishes for suspension culture. HEK293T cells adhered on the non-or gelatin-coated polystyrene dish for adherent culture, but they did not form 3-D MCS. HEK293T cells also adhered to non-or gelatin-coated glass dishes and did not form 3-D MCS in serum-free medium. These results suggest that HEK293T cells cultured on non-coated polystyrene dish may be useful for the tool to analyze the characteristics of 3D-MCS.

No abstract

No abstract

Polydimethylsiloxane (PDMS) is used as a flexible cell culture substrate in medical and biological research fields. It has been demonstrated that surface modification by oxygen plasma irradiation was performed to improve cell adhesion, because PDMS has poor cell adhesiveness. However, the surface modification effect was not sufficient due to the flexibility of PDMS. In this study, active oxygen and UV lights were exposed to PDMS surface to improve the cell adhesion. The active oxygen was generated by a UV lamp emitting at wavelengths of 185 nm and 254 nm. The surface modification effect of PDMS before and after exposure of active oxygen and UV lights were evaluated. As a result, although the surface roughness did not change before and after exposure of active oxygen and UV lights, the wettability was improved. In addition, temporal change of PDMS surface after exposure of active oxygen and UV lights was smaller than that after plasma irradiation. Because the formation of silicon oxide layer on the surface was confirmed, it was considered that this layer prevented the penetration of polar groups getting into the PDMS substrate. Furthermore, osteoblast-like cells on the PDMS after exposure of active oxygen and UV lights were adhered and extend well. Therefore, it was demonstrated that a stable surface modification of PDMS surface was achieved by exposure of active oxygen and UV lights.