"MEMS: sensor detects single virus particle in real-time"
Detection of a single virus particle was recently demonstrated for the first time in a sensor based on microelectromechanical systems (MEMS). The tiny cantilever, measuring just 1 x 4 microns x 20 nanometers thick, vibrates at a fixed frequency until a virus particle lands on it, which changes its resonance enough to be detected. A single particle of vaccinia-a virus that forms the basis for the smallpox vaccine-weighs only 9 femtograms, or quadrillionths of a gram.
Audio Interviews / Text: http://www.eetimes.com/story/OEG20040213S0009