Original Date: 11/03/1996
Revision Date: 01/18/2007

Researchers at Oak Ridge National Laboratory (ORNL) have devised a self-contained miniature deoxyribonucleic acid (DNA) biosensor to detect specific DNA targets. The biosensor will detect hybridized DNA without any external monitoring or signal transmission. Biosensors of this type have potential applications in medicine, forensics, agriculture, and environmental bioremediation. Ultimately the size of a transistor chip, the biosensor microchip incorporates multiple biological sensing elements (e.g. DNA probes), excitation microlasers, a sampling waveguide equipped with optical detectors (fluorescence and Raman), integrated electro-optics, and a biotelemetric radio frequency signal generator.

Semiconductor microlaser arrays are incorporated into a device which has oligonucleotides of specific DNA sequences attached to the surface. Free DNA sequences with fluorescent labels then are allowed to hybridize to those oligonucleotides with matching homologic sequence. When illuminated at its optimum wavelength, the fluorescently- labeled DNA will emit light. The microlasers contained in the device will illuminate each pixel on the surface, and the detector array will identify pixels with attached fluorescently-labeled DNA sequences.

DNA biosensor technology can rapidly detect microorganisms from multiple environmental samples. A sensitive, accurate sensor has been developed to identify a Pseudomonas organism for use in bioremediation and the human p53 cancer tumor suppressor gene. Other applications under development include a biosensor for tuberculosis, human immunodeficiency virus, salmonella, legionella, giardlia lamblia, lyme disease, hepatitis, toxoplasmosis, and biological warfare detection.

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