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Using Fluorescent Viruses for Detecting Bacteria in Water

A method of detecting water-borne pathogenic bacteria is based partly on established molecular-recognition and fluorescent-labeling concepts, according to which bacteria of a species of interest are labeled with fluorescent reporter molecules and the bacteria can then be detected by fluorescence spectroscopy. The novelty of the present method lies in the use of bacteriophages (viruses that infect bacteria) to deliver the fluorescent reporter molecules to the bacteria of the species of interest. Bacteriophages that selectively infect that species are selected, and fluorescently labeled virus probes (FLVPs) are prepared by staining these bacteriophages with a fluorescent dye. The FLVPs are immobilized on an optical substrate, which could be a window or a waveguide.

Bacteria/bacteriophage complexes are formed when the substrate is exposed to water containing the bacteria of interest. These complexes exhibit a characteristic fluorescence spectrum, which can be measured to determine the concentration of the complexes and, thus, of the bacteria of interest. Biosensors based on this method could, potentially, enable rapid, selective, and potentially very sensitive detection of bacteria in water. Such biosensors could be used alternatively or complementarily to immunodiagnostic or nucleic acid-based biosensors.

This work was done by Mary Beth Tabacco, Xiaohua Qian, and Jaimie A. Russo of Echo Technologies, Inc., for Johnson Space Center.

In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to:

Echo Technologies, Inc.
5250 Cherokee Avenue
Alexandria, VA 22312

Refer to MSC-23371-1, volume and number of this NASA Tech Briefs issue, and the page number.