World's Most Sensitive Nanomechanical Sensor Can Detect the Mass of One Proton - Researchers at ICN's Quantum NanoElectronics Group have fabricated and tested the world's most sensitive nanomechanical sensor. The sensor is capable of detecting changes in mass of 1.7 yoctograms (1.7 x 10^-24 g), which is about the mass of one proton. Reference: 'A nanomechanical mass sensor with yoctogram resolution', J. Chaste et al, Nature Nanotechnology (2012) doi:10.1038/nnano.2012.42