University of Arkansas researchers are working together, with support from the National Institutes of Health, to make that prospect of graphene-based sensors that sequence a patient's genome to predict diseases more realistic. Steve Tung, professor of mechanical engineering, and Jin-Woo Kim, professor of biological engineering, have received a grant (of approximately $400,000) from the NIH's Human Genome Research Institute to develop nanoscale technology designed to make DNA sequencing faster, cheaper and easier.

The base of the research builds on the concept of nanochannel measurement, in which individual strands of DNA pass through a tiny channel. The passage of those strands interrupts an electrical current and a sensor detects the nature of the interruption, telling scientists which nucleotide has passed through the channel.

The challenge, Tung said, is the size. "With sensors, you generally want the sensor to be smaller than the thing it's sensing," he said. "So when you're sensing DNA, that means you're at less than 1 nanometer". If the sensor is too large, Tung said, it diminishes the accuracy of the results.

The research aims to use graphene to build the sensor, but to do that, Tung and Kim will have to find a way to reduce a sheet of graphene to a single strand. Researchers believe a single chain will be more effective at recording the DNA sequence.

The second issue Tung and Kim will face is how to draw single strands of DNA through the measurement channel in a consistent way. Their answer to that problem is a unique convergence of atomic force microscopy, or AFM, and a protein known as DNA polymerase or DNA helicase. "We're looking at using AFM to drag the DNA, while the enzyme unwinds DNA, across the sensing element in a way that can control the speed and orientation of the DNA to help ensure accurate measurement," Kim said.

"It is an excellent example of interdisciplinary approach to solve problems," Kim said. Kim describes himself as a "hybrid" who was trained both as a biologist and as a biological and chemical engineer. He said the project is a perfect fit to his research thrust, advancing science and engineering through novel hybrid technology developments by cleverly interfacing biology and engineering.



Tung's involvement in the project is unique, he said. It's rare for mechanical engineers to receive funding from the National Institutes of Health, because NIH projects typically fall more directly under the field of biomedical engineering.

Tung and Kim said they think interdisciplinary approach is the future of engineering, and the NIH award will allow the pair to bring in graduate students and a postdoctoral researcher to assist with the project.

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