New ultrasensitive electronic sensor array speeds up DNA detection

Scientists at Singapore's Institute of Bioengineering and Nanotechnology (IBN), the world's first bioengineering and nanotechnology research institute, have successfully developed a novel electronic sensor array for more rapid, accurate and cost-efficient testing of DNA for disease diagnosis and biological research. This study was published recently in a leading international chemistry journal, Journal of the American Chemical Society[1].

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.

Called the "Nanogap Sensor Array," IBN's newly developed device 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 approximately 1/50,000 the width of a human hair). The biosensor will translate 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. Based on laboratory results, the sensor 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. The novel vertical nanostructure design and two different surfaces of the sensor allow ultrasensitive detection of DNA. 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," said Zhiqiang Gao, Ph.D., IBN Group Leader.

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 Professor Jackie Y. Ying, IBN Executive Director.

The research was published on Aug. 5, 2009, in a paper titled, "Mass-Produced Nanogap Sensor Arrays for Ultrasensitive Detection of DNA," in the Journal of the American Chemical Society.

[1] S. Roy, X. J. Chen, M.-H. Li, Y. F. Peng, F. Anariba and Z. Q. Gao, Journal of the American Chemical Society, (2009) DOI: 10.1021/JA901704T.

The Institute of Bioengineering and Nanotechnology (IBN) was established in 2003 as a national research institute under the Agency for Science, Technology and Research, Singapore, by Executive Director, Professor Jackie Yi-Ru Ying. Prof. Ying was a Professor of Chemical Engineering at the Massachusetts Institute of Technology (1992 – 2005). In 2008, Professor Ying was recognized as one of "One Hundred Engineers of the Modern Era" by the American Institute of Chemical Engineers for her groundbreaking work on nanostructured systems, nanoporous materials and host matrices for quantum dots and wires. Under her direction, IBN conducts research at the cutting-edge of bioengineering and nanotechnology. IBN's research programs are geared towards linking multiple disciplines across engineering, science and medicine to produce research breakthroughs that will improve healthcare and our quality of life.

IBN's research activities are focused in the following areas:

• Drug and Gene Delivery, where the controlled release of therapeutics involve the use of functionalized polymers, hydrogels and biologics for targeting diseased cells and organs, and for responding to specific biological stimuli.
• Cell and Tissue Engineering, where biomimicking materials, stem cell technology, microfluidic systems and bioimaging tools are combined to develop novel approaches to regenerative medicine and artificial organs.
• Biosensors and Biodevices, which involve nanotechnology and microfabricated platforms for high-throughput biomarkers screening, automated biologics synthesis, and rapid disease diagnosis.
• Pharmaceuticals Synthesis and Nanobiotechnology, which encompasses the efficient catalytic synthesis of chiral pharmaceuticals, and new nanocomposite materials for sustainable technology and alternative energy generation. IBN's innovative research is aimed at creating new knowledge and intellectual properties in the emerging fields of bioengineering and nanotechnology to attract top-notch researchers and business partners to Singapore. Since 2003, IBN researchers have published a total of 502 papers. IBN also plays an active role in technology transfer and spinning off companies, linking the research institute and industrial partners to other global institutions. As of June 2009, IBN has filed 714 patent applications on its inventions and the Institute is currently looking for partners for collaboration and commercialization of its portfolio of technologies. IBN's current staff strength stands at ~ 180 scientists, engineers and medical doctors. With its multinational and multidisciplinary research staff, the institute is geared towards generating new biomaterials, devices, systems, equipment and processes to boost Singapore's economy in the fast-growing biomedical sector.

IBN is also committed to nurturing young minds, and the institute acts as a training ground for PhD students and undergraduates. In October 2003, IBN initiated a Youth Research Program to open its doors to university students, as well as students and teachers from various secondary schools and junior colleges. It has since reached out to more than 31,075 students and teachers from 205 local and overseas schools and institutions.

For more information, please log on to www.ibn.a-star.edu.sg