Nano-vibration effect on cell adhesion and its shape.

Extracellular physical features of underlying the adhesive substrate affect cell adhesion to it substrate. In this study, the effects of vibration, a type of artificial physical stimulation, on the adhesion of mouse L929 cells, mouse embryonic fibroblasts (MEFs), HeLa cells and human umbilical vein endothelial cells (HUVECs) are reported. A nano-vibration system was designed to produce nanometer-scale vibration. When L929 cells, HeLa cells, and HUVECs were subjected to vibration at 100 Hz and 1 kHz, they were not affected. On the other hand, in MEFs, the adherent cells were increased and changed their shape remarkably in response to 1 kHz vibration. To investigate the MEFs' sensitivity to vibration in detail, the cells shape was classified into four types; round, stellate, filopodia-formed and lamellipodia-formed. In serum addition culture, 1 kHz vibration increased the number of filopodia-formed cells but decreased lamellipodia cells. Furthermore, the preliminary cDNA microarray experiments showed that expression of genes which regulate cytoskeleton were changed by vibration stimulation. These results suggest that vibration could affect cell adhesion and the determination cell shape.