METALS CAN "BRIGHTEN" SENSING OF DNA FOR GENOMICS, ASSAYS

SAN DIEGO, Calif.--Fluorescence researchers now say that using metal particles, such as silver or gold, could further "revolutionize the DNA technology of many biomedical and biotechnology procedures," by boosting weak or non-fluorescent molecules such as DNA to fluoresce up to 2000 thousands times better.

University of Maryland Biotechnology Institute (UMBI) and the U. of Md. School of Medicine (UMSM) researchers report that using metals with new Radiative Decay Engineering, or RDE, technology results in "highly useful emissions from non-fluorescent molecules such as DNA and other molecules." If widely adapted, the innovation would have profound implications for the use of fluorescence in basic research and technology, they say. High sensitivity detection of DNA is essential for advancing genomics.

"It is a highly unusual effect and will improve DNA sequencing and analysis, as well as in different kinds of immunoassays," says Joseph Lakowicz, who directs the National Center for Fluorescence Spectroscopy, which is supported in part by the National Institute's of Health's National Center for Research Resources. Lakowicz has a joint appointment with UMBI and UMSM.

Fluorescence spectroscopy is already one of the dominant research tools today, having largely enabled current advances in medical diagnostics, DNA sequencing and genomics. Comments Lakowicz, "In spectroscopy, we usually have no significant control over the radiative rate." However, he reports that RDE, by modifying a rate of how intrinsically weak fluorescent molecules radiate, will enhance DNA hybridization, drug discovery and fluorescence immunoassays. The use of metal particles could greatly increase the sensitivity of the assays, he says.

"By describing our concept of Radiative Decay Engineering and its implications, we hope to spark interdisciplinary work between physicists, engineers, chemists and biologists to design and construct appropriate nanoscale or mesoscale devices and make the complex spectral observations needed to stimulate the field," says Lakowicz.

"We believe our results with DNA suggest the occurrence of increased radiative rates near metallic surfaces," he summarizes. The completion of the human genome sequence is driving development of a wide variety of new approaches to DNA analysis, such as DNA arrays or gene chips, PCR-based assays and hybridization assays. The researchers say metal-enhanced methods may now be used to probe longer range structures in DNA, RNA or ribosomes.

"While the human genome and genomes of other organisms have been sequenced, there is still a need for faster, cheaper and more sensitive DNA sequences," concludes Lakowicz. He explains that RDE could allow base detection and identification without conventional labeling.

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The University of Maryland Biotechnology Institute was mandated by the state of Maryland legislature in 1985 as "a new paradigm of state economic development in biotech-related sciences." With five major research and education centers across Maryland, UMBI is dedicated to advancing the frontiers of biotechnology. The centers are the Center for Advanced Research in Biotechnology in Rockville; Center for Agricultural Biotechnology in College Park; and Center of Marine Biotechnology, Medical Biotechnology Center, and the Institute of Human Virology, all in Baltimore.