Scientists are developing ‘DNA chips’ that can detect a genetic mutation or change which lead to diseases like cancer.

Jacqueline K Barton from the California Institute of Technology in Pasadena in her research suggested that DNA or deoxyribonucleic acid uses its electrical properties to signal repair proteins that fix DNA damage and if the DNA is no longer conducting electricity properly, that would be a signal for repair proteins to play their part.

These chips would take advantage of DNA’s natural electrical conductivity and its ability to bind to other strands of DNA that have a complementary sequence of base units, and thus probe that sequence for damage.

Barton had won the US National Medal of Science, the nation’s highest honour for scientific achievement, for discovering that cells use the double strands of the DNA helix like a wire for signalling, which is critical to detecting and repairing genetic damage.

“Damage is constantly occurring to DNA — damage that skin cells, for instance, receive from excessive exposure to sunlight or that lung cells get hit with from carcinogens in cigarette smoke,” Barton said.

“Cells have a natural repair system in which special proteins constantly patrol the spiral-staircase architecture of DNA. They monitor the 3 billion units, or ‘base pairs’, in DNA, looking for and mending damage from carcinogens and other sources,” she added.

“It’s like a stack of copper pennies,” said Barton. “And when in good condition and properly aligned, that stack of copper pennies can be conductive. But if one of the pennies is a little bit awry — if it’s not stacked so well — then you’re not going to be able to get good conductivity in it. But if those bases are mismatched or if there is any other damage to the DNA, as can happen with damage that leads to cancer, the wire is interrupted and electricity will not flow properly,” Burton said in a statement.

Barton’s team established that the electrons that comprise a flow of electricity can move from one end of a DNA strand to the other, just as they do through an electrical wire.

In one recent advance, the team was able to send electricity down a 34-nanometre-long piece of DNA.

The topic — DNA wires and their potential use in identifying people at risk for certain diseases was discussed in the 244th National Meeting & Exposition of the American Chemical Society.

(This article was published on August 20, 2012)
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