Figure 1
Phys. Rev. B 83 245421 (2011)

Lighter than a feather. A proposed mass detection system consists of a nanoscale vibrating bar containing an embedded quantum dot and a metal nanoparticle (sphere). The extra mass of a strand of DNA dropped onto the bar (not shown) would shift the bar’s vibration frequency–and therefore the electron excitations in the dot and nanoparticle, which could be measured with lasers. The system would achieve high sensitivity by avoiding any electrical connections to the bar.