In experiments with potentially broad health care implications, a research team led by a University of Washington physicist has devised a method that works at a very small scale to sequence DNA quickly and relatively inexpensively.
That could open the door for more effective individualized medicine, for example providing blueprints of genetic predispositions for specific conditions and diseases such as cancer, diabetes or addiction.
"The hope is that in 10 years people will have all their DNA sequenced, and this will lead to personalized, predictive medicine," said Jens Gundlach, a UW physics professor and lead author of a paper describing the new technique published the week of Aug. 16 in the Proceedings of the National Academy of Sciences.
The technique creates a DNA reader that combines biology and nanotechnology using a nanopore taken from Mycobacterium smegmatis porin A. The nanopore has an opening 1 billionth of a meter in size, just large enough to measure a single strand of DNA as it passes through.
The scientists placed the pore in a membrane surrounded by potassium-chloride solution. A small voltage was applied to create an ion current flowing through the nanopore, and the current's electrical signature changed depending on the nucleotides traveling through the nanopore. Each of the nucleotides that are the essence of DNA cytosine, guanine, adenine and thymine produced a distinctive signature.
The team had to solve two major problems. One was to create a short and narrow opening just large enough to allow a single strand of DNA to pass through the nanopore and for only a single DNA molecule to be in the opening at any time. Michael Niederweis at the University of Alabama at Birmingham modified the M. smegmatis bacterium to produce a suitable pore.
The second problem, Gundlach said, was that the nucleotides flowed through the nanopore at a rate of one every millionth of a second, far
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