This SBIR Phase I application will focus on the development of a simple and inexpensive, handheld, battery-operated biosensor integrating microfluidics and molecular biology to rapidly detect Mycobacterium tuberculosis, the etiologic agent of tuberculosis (TB) in humans. With as many as 9 million new cases of TB and approximately 2 million deaths per year and the difficulties encountered in resource-limited countries to accurately diagnose TB, the World Health Organization has urged the development of new diagnostic platforms for the detection of M. tuberculosis. Relying upon 100-year old microscopic methods that lack sensitivity, resource-limited countries represent a major market for a successful product. Furthermore, the risk of transmission of multi-drug resistant TB to industrialized nations via the availability of air travel makes this a global health issue. With almost $ 1.0 Billion spent every year to perform TB testing, the commercial market potential for an easy-to-use test for M. tuberculosis is immediate and will have broad implications for improving a worldwide health issue. ? ? In order to exploit modern molecular biology detection methods without imposing a need for expensive equipment and time-consuming analytical steps, we propose to utilize two different sets of oligonucleotide probes complementary to a M. tuberculosis rRNA sequence. One set will be bound to magnetic beads while a second set will be conjugated to liposomes that encapsulate enzyme substrates. The resulting hybridization complex will be immobilized via a magnet within a microfluidic device. Liposomes will then be lysed allowing the now released enzyme substrates to drive an electrochemical reaction that will be quantitated by an integrated interdigitated ultramicroelectrode array (IDUA). Thus, the IDUA will transduce the biological signal into a digital electronic signal. The accomplishment of these goals and objectives will permit the direct detection of M. tuberculosis rRNA without the need for time-consuming enrichment or gene amplification steps. Furthermore, it is anticipated that this easy-to-use diagnostic test will permit near-patient testing by individuals who will not require extensive training and background in molecular biology. ? ? Successful completion of the proposed Phase I effort will result in a unique biosensor, capable of rapidly detecting Mycobacterium tuberculosis, the causative agent of TB. Inasmuch as more than two-thirds of the world's TB cases are found in resource-limited countries that lack the financial or technical resources to accurately diagnose new TB cases or monitor treatment of existing cases, such a biosensor will have an immediate and dramatic impact on improving the health of individuals living in such countries. Furthermore, since TB can be efficiently spread by airborne transmission, the ability to control TB in those portions of the world with high infection rates will also reduce the risk of spreading TB, including that caused by multi-drug resistant strains of M. tuberculosis, to industrialized nations. ? ? ?
