Miniarray Detection of MTB Complex Species

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DESCRIPTION (provided by applicant): Tuberculosis is the most important cause of death worldwide from a single pathogen. Diagnosis primarily occurs by microscope analysis of stained sputum smears and from growing cultures for biological tests. While staining is quick, it is uncertain, and while culturing is definitive, it is slow. Proprietary tests based on nucleic acid amplification are fast and reliable, but they require equipment and reagents only suited to advanced labs in developed countries. A new miniarray test system is proposed that combines the speed and sensitivity advantages of amplification-based assays but employs a simplified microarray detection platform, called miniarrays, that reduces cost and complexity and that provides discrimination of multiple species in a single test. Features of this miniarray platform also promise to overcome the need for PCR amplification in latter versions of the assay by employing proprietary signal amplification methods and reagents. Thus, two product lines are expected: 1. a high-tech version for developed countries to provide greater diagnostic capability as well as a fast and more reliable front-line test, and 2. a Iow-tech bench-top analysis version for developing countries that enables fast discrimination of multiple species but achieves diagnosis without PCR equipment, high-resolution microarray scanners or fluorescent microscopes. Phase I will focus on developing and testing two prototype miniarrays for discriminating major MTB complex subspecies. While the initial miniarray prototypes remain based on PCR amplification, they will demonstrate visually-simple, species-specific diagnostic patterns reflecting the presence and absence of critical gene segments that characterize a series of related but discrete species or subspecies. Phase II will bring these products to market, extend them to the diagnosis of other important pathogens, and will initiate development of similar Iow-tech miniarrays for developing countries. This technology is based on proprietary, patent-pending reagents and procedures that convert genomic DNA samples into amplified target copies that are modified with universal linkers. These special linkers then enable global amplification of the set of targets with a single primer set, and they also provide means to increase signaling by virtue of binding long DNA-based reporters called GeneTAGs. The associated miniarray platform also offers a path to developing a variety of similar diagnostic biochips for discriminating other pathogens. This miniarray system will be rapid (<2 hrs), sensitive (equal to PCR), inexpensive, and easy to perform. The worldwide market for TB testing is $900M with amplification-based tests constituting approximately 1/3rd of the total. Based on a survey of potential customers and diagnostics professionals, the market potential of our system is over $100M. Successful achievement of developmental milestones could push that potential higher.