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New ultrasensitive electronic sensor array speeds up DNA detection

August 27, 2009

Singapore scientists developed cost-effective technology for disease diagnosis and biological research

A novel electronic sensor array for more rapid, accurate and cost-efficient testing of DNA for disease diagnosis and biological research has been developed by scientists at Singapore's Institute of Bioengineering and Nanotechnology (IBN).

In a recent Journal of the American Chemical Society, IBN scientists reported that based on laboratory results, their Nanogap Sensor Array has shown "excellent" sensitivity at detecting trace amounts of DNA.

"By saving time and lowering expenses, our newly developed Nanogap Sensor Array offers a scalable and viable alternative for DNA testing," said Zhiqiang Gao, Ph.D., Group Leader at IBN, the world's first bioengineering and nanotechnology research institute.

The biosensor translates the presence of DNA into an electrical signal for computer analysis. The distinctively designed sensor chip has the ability to detect DNA more efficiently by "sandwiching" the DNA strands between the two different surfaces.

"The novel vertical nanostructure design and two different surfaces of the sensor allow ultrasensitive detection of DNA," added Dr. Gao. "This sensitivity is best-in-class among electrical DNA biosensors. The design of the sensor also took into consideration the feasibility of mass production in a cost-effective way for expanded usage."

Conventionally, human DNA is detected through the use of polymerase chain reaction (PCR), which while effective, is also expensive, cumbersome and time-consuming for widespread use. The PCR technique amplifies a single piece of DNA across several orders of magnitude, duplicating millions or more copies of a particular DNA sequence, in order to detect the genetic material more easily.

Although effective, tests involving PCR may not be optimal for situations such as a pandemic outbreak, where results are needed quickly because PCR devices tend to be bulky and costly.

The Nanogap Sensor Array has a unique, vertically aligned nanostructure design and a two-surface configuration based on electronic transduction. The sensor comes with a pair of micro-sized metal electrodes separated by a nanogap (5 - 20 nm or about 1/50,000 the width of a human hair).

Another distinctive feature of the biosensor is its ability to capture DNA strands more effectively. This is possible because the two surfaces of the sensor are coated with a chemically treated "capture probe" solution through an electrochemical technique specially developed by IBN. This allows DNA strands to "stick" more easily to the sensor, resulting in a faster and more accurate analysis.

"This new biosensor holds significant promise to speed up on-going efforts in the detection and diagnosis of debilitating diseases such as cancer, cardiovascular problems and infectious viruses. We aim to make healthcare accessible to the masses with early disease diagnosis as the critical driving force behind the research we undertake here at IBN," added Jackie Y. Ying, Ph.D., Executive Director of IBN, one of the research institutes of Singapore's Agency for Science, Technology and Research (A*STAR).

Agency for Science, Technology and Research (A*STAR), Singapore