Researchers improve nanofabrication

Today, sequencing a human genome costs about $300 million. However, a multidisciplinary team of University researchers is improving a technology called nanofabrication that could one day cut the price to $1,000.

The leaders of the pioneering research, which allows scientists to study and understand DNA more effectively, come from three departments and include physics professor Bob Austin, electrical engineering professor James Sturm and molecular biology professor Edward Cox.

They are working to create "nanochannels," which are as narrow as a strand of DNA and several centimeters long, Austin said. The channels are used to stretch DNA molecules out so that the genetic material can be electronically sequenced.

Strum explained that they can construct these nanochannel chips by first dramatically diminishing the size of a particular pattern by a process called photographic reduction. He likened this process to looking into a microscope and seeing a much smaller image.

"Then, a chemical process using light to melt away layers of solid material creates the desired pattern," he said.

Sturm credits electrical engineering professor Stephen Chou with developing a way to overcome the limitations of light wavelength on channel width. Chou will receive The Institute of Electrical and Electronic Engineers' 2004 Cledo Brunetti Award Dec. 14 for his work in nanotechnology.

To create even smaller channels, the layers of material can be physically deformed with the pressure of a ridged stamp. "While current processes have enabled us to construct nanochannels of about 10 nanometers [in width], we need to get down to 2 nanometers, the true size of DNA, so that we can identify base pairs," Austin said.

The DNA molecule's hydrogen ion groups make a folded structure like a ball of yarn, Sturm explained.

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"The yarn will remain in a ball if left in a room ten feet wide. However, making the channel narrow enough forces it to be stretched out and held in place," he said.

According to Austin, the research will provide two main benefits — one biological, the other economic.

First, nanofabrication techniques enable researchers to provide information about cellular behavior. Researchers can identify where molecules that turn on genes and produce proteins attach to DNA.

Reducing the cost of sequencing human genetic material will also make it easier to study the role genes play in human diseases. "The thrust for faster sequencing methods relates to personal health reasons, providing the ability to make better drugs and facilitate diagnosis," Sturm said.

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While Austin and Sturm believe traditional methods of DNA sequencing are too indirect, Cox said that many molecular biologists will be reluctant to accept the new technology until it is proven to be superior.

"Though we have the principles, they need to be turned into something we can physically use," he said.

Nevertheless, Cox credits the advancements that have been made. "The research has made big improvements in our understanding of how things work. The rate at which we're going is pretty promising and this work undoubtedly contributes to the future state of the art," Cox said.