Weighing DNA

Researchers at

have built nanoelectromechanical (NEMS) oscillators small enough to sense the mass of a single DNA molecule. The devices could be made even more sensitive through increased miniaturisation, the researchers say.

The technology, they suggest, can be combined with microfluidics to perform genetic analysis of very small samples of DNA, even the amount present in a single cell. Current techniques for genetic analysis require small samples of DNA to be replicated many times through a process called PCR amplification. DNA analysis can be used, among other things, to detect genetic markers for cancer susceptibility.

The mass of DNA, proteins and other organic molecules is usually expressed in Daltons. A Dalton, also known as an atomic mass unit, is roughly the mass of a single proton or neutron.

While DNA molecules are relatively large compared to other molecules, they are still a step smaller than most viruses, which consist of a DNA core surrounded by a protein coat. The Cornell researchers believe their technology could be used to identify even smaller organic molecules, including proteins, and could have widespread applications in medical and forensic diagnosis.