Their results, published in the journal Proceedings of the National Academy of Sciences, demonstrate for the first time, the possibility of directly identifying these mutations, or single nucleotide polymorphisms (SNPs), by means of measuring the electrical conductance of a single DNA molecule.
SNPs are buried in the 3 billion DNA bases of the human genome. On average, SNPs occur about once in every 1,000 DNA bases, though not every SNP found will necessarily cause a disease mutation. Cataloging these subtle DNA differences among the populace will aid the ongoing quest to understand and prevent disease.
"There is a high demand to track mutations for cancer research or future applications in personalized medicine," said Zhang, an associate research professor of the Center for Single Molecule Biophysics in the Biodesign Institute at ASU. "Currently, the main issue in doing this type of detection is that it is still costly and time consuming."
The team's breakthrough relies on an intrinsic physical property of DNA, conductivity, or how well the molecule can carry an electrical current. Depending on the experimental conditions, DNA has been previously shown to act as both a conductor and insulator.
"We have developed a technology that allows us to wire single molecules into an electrical circuit," said Tao, professor of electrical engineering in the Ira A. Fulton School of Engineering and also a researcher in the Center for Solid State Electronics Research. "We can now directly read the biological information in a single DNA molecule."
Measurement of DNA conductivity first requires wiring the molecule into an electrical circuit. "There are two things required to make a reliable measurement," said Tao. "One is that the DNA has to be tethered between two electrodes and the ot
Source:Arizona State University