Weighing Molecules One at a Time

This scanning electron micrograph shows one of the molecule-weighing devices. The bridge-like section at the center vibrates sideways. The scale bar at the bottom is two microns (millionths of a meter).

[Credit: Caltech / Scott Kelberg and Michael Roukes]

A team led by scientists at the California Institute of Technology (Caltech) have made the first-ever mechanical device that can measure the mass of individual molecules one at a time.

This new technology, the researchers say, will eventually help doctors diagnose diseases, enable biologists to study viruses and probe the molecular machinery of cells, and even allow scientists to better measure nanoparticles and air pollution.

The team includes researchers from the Kavli Nanoscience Institute at Caltech and Commissariat à l’Energie Atomique et aux Energies Alternatives, Laboratoire d'électronique des technologies de l'information (CEA-LETI) in Grenoble, France. A description of this technology, which includes nanodevices prototyped in CEA-LETI's facilities, appears in the online version of the journal Nature Nanotechnology on August 26.
The device—which is only a couple millionths of a meter in size—consists of a tiny, vibrating bridge-like structure. When a particle or molecule lands on the bridge, its mass changes the oscillating frequency in a way that reveals how much the particle weighs.

Read more...
  http://media.caltech.edu/press_releases/13546
 http://www.sciencedaily.com/releases/2012/08/120826143528.htm