Mechanical effects of attaching protein layers on nanoscale-thick cantilever beams for resonant detection of virus particles

The purpose of this paper is to present experimental results on the alteration of mechanical properties and stiffness constant of nanoscale thick cantilever beams upon attachment of protein layers to the top and bottom surfaces of silicon cantilever beams. Depending on the initial unloaded spring constant value of the cantilever beams, the resonant frequencies were observed to either increase or decrease upon attachment of the protein layers. This depends on whether the increase in spring constant outweighs the increase in the added mass or vice-versa. The spring constant demarcation value at which the resonant frequency will either increase or decrease is estimated to be around 0.01 N/m for the present study.