Molecular water accumulation on silica measured by land-contrast interferometry with picometer height resolution

We observed water film accumulation on silica surfaces in the air to 2 picometer resolution using optical land-contrast (LC) interferometry. The land-contrast approach is non-destructive and allows real-time measurement of thickness variation of small molecular films on a surface. Water accumulation rates are observed to be different on bare or protein monolayer coated silica surfaces. This suggests that water contributes false signals to mass-sensitive biosensors for protein microarray.