The world鈥檚 most sensitive scales can now measure a mass of just one zeptogram (10-21 grams) 鈥� roughly the mass of a single protein molecule.
Researchers can measure masses of one attogram (10-18 grams), which is equivalent to a cluster of gold atoms, by placing an object on a vibrating silicon blade and noting how the frequency of vibrations changes.
By making a shorter blade out of much stiffer silicon carbide, a team at the California Institute of Technology in Pasadena was able to boost the resonant frequency of the vibrations sixfold, allowing the detection of masses 1000 times smaller. They hope the technology will lead to medical or environmental sensors that can identify single molecules by their mass.
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