Adhesion and Bactericidal Properties of a Wettability-Controlled Artificial Nanostructure

The adhesion behavior and bactericidal properties of the nanostructured surface of Si nanopillar array, which mimicked a cicada wing surface, were evaluated using Escherichia coli. Wettability of the nanostructured surface was controlled by using self-assembled monolayer (SAM). The adhesion behavior was strongly dependent on the wettability of the surface and whether it was a nanostructured or a flat surface. The number of adhered cells on the nanostructured surface was higher than that on the flat Au surface. In addition, the cell membrane was more strongly damaged at a higher contact angle than at a lower contact angle on the nanostructured surface. Time-lapse imaging was used to analyze the changes in fluorescence intensity caused by the effusion of an intercellular fluid, including fluorescent protein (mCherry), at the single cell level on the cicada wing surface and the artificial nanostructured surface. We found that there were three stages of changes in the fluorescence intensity gradient.