Nanoscale sensors 1,000 times more sensitive than those available today could be available in a couple of years as researchers at ORNL are approaching detection of single molecules under ambient conditions. Already, Panos Datskos and Nickolay Lavrik have set a world record by detecting 5.5 femtograms—or about 5/1,000ths of a millionth of a millionth of a gram—using tiny gold-coated silicon cantilevers (2 microns long and 50 nanometers thick) that they activate using a diode laser. The laser causes the cantilevers to vibrate—in this case at about 2 megahertz—and, depending on the coating, absorb particles of DNA, proteins, cells or trace amounts of various chemical contaminants. Datskos expects the sensors to be able to detect a single molecule by increasing the resonance frequency to 50 megahertz. The higher the frequency, the smaller the amount of mass that can be detected; however, the cantilevers must also be made smaller and stiffer. The research was published in the April 21 issue of Applied Physics Letters.