These days, chemical analysts are expected to track down even single molecules. To do this highly sensitive detective work, nano researchers have developed minute strings that resonate in characteristic fashion. If a molecule docks onto one of the strings, then it becomes heavier, and its oscillations become measurably slower. Until recently, however, such “nano-electromechanical systems”, or NEMS, have been short of practical applications. Physicists at LMU Munich have now made a breakthrough in this field: They have constructed a system of nanostrings made of non-conducting material, where each string can be electrically excited separately. Thousands of these strings can be produced on a small chip. One of the devices that could be created with this system is a highly sensitive “artificial nose” that detects various molecules – pollutants for example – individually. These new NEMS could also be used in a multitude of other applications – acting as tiny pulse generators in mobile phone clocks, for example. (Nature, 22nd April 2009)

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