PASADENA, Calif.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 l'Energie Atomique et aux Energies Alternatives, Laboratoire d'lectronique 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 devicewhich is only a couple millionths of a meter in sizeconsists 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.
"As each particle comes in, we can measure its mass," says Michael Roukes, the Robert M. Abbey Professor of Physics, Applied Physics, and Bioengineering at Caltech. "Nobody's ever done this before."
The new instrument is based on a technique Roukes and his colleagues developed over the last 12 years. In work published in 2009, they showed that a bridge-like devicecalled a nanoelectromechanical system (NEMS) resonatorcould indeed measure the masses of individual particles, which were sprayed onto the apparatus. The difficulty, however, was that the measured shifts in frequencies depended not only on the particle's actual mass, but also on where the particle landed. Without knowing the particle's landing site, the researchers had to analyze measurements of about 500 identical particles in order to pinpoi
|Contact: Lawren Markle|
California Institute of Technology