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Physicists have created weighing individual protein molecules


French physicists gathered microscopic scales of the four electrodes and connection to the vibrating plate is sensitive enough to measure the mass of individual protein chains, and issued “instructions” for assembly in the journal Nature Nanotechnology.

The precise measurement of the mass of microscopic bodies, atoms and molecules is a daunting engineering and physical problems. At the level of individual molecules in the measuring instruments begin to affect features of microphysics, including Brownian motion, Van der Waals forces, and other factors that could significantly distort the readings.

A group of physicists led by Michael Roux (Michael Roukes) from the California Institute of Technology, Pasadena (USA) has developed a universal that allow to weigh individual molecules with minimal errors.

A key element of this device is vibrating or “bridge” in the terminology of the authors, was created Roux and his colleagues back in 2009. It is a thin strip of metal, whose variations are read by multiple microelectrodes.

When this construction is close to the molecule, “bridge” starts to vibrate, and these vibrations are read electrodes. Strength and frequency of vibration data depends on the mass of the molecule, which allows us to calculate it, even in that case, if the “bridge” is only one particle.

In the first prototype of a “bridge” was a major drawback – the mass of the molecule is strongly distorted in those cases when the particle was not conducted at the center of the bridge, and on the edges. Therefore, the scientists had to measure the mass of at least 500 individual molecules to minimize errors.

In the new work Roux and his colleagues have eliminated this deficiency by learning to calculate the position of the molecule on the differences in the individual harmonic vibrations in the “bridge.” This technique has allowed physicists to calculate the exact weight of the individual molecules with high speed and accuracy.


The authors examined the work of his invention by measuring the mass of immunoglobulins are antibodies-proteins that specialize in neutralizing various foreign particles, including bacteria and viruses. The high sensitivity of the device allowed researchers not only to calculate the mass of protein particles, but also to determine their type.

According to physicists data can be produced using industrial technologies used to build silicon chips. This significantly reduces the cost of the device and allows you to use even in relatively small laboratories.