Invited Paper BP-SuA5
Development of a Point-of-Care Diagnostics System for the Developing World

Sunday, October 14, 2007, 4:20 pm, Room 609

Microfluidics and related fields have progressed to the point that one can now tackle the technical challenges of miniaturizing complex bioassays for use in point-of-care diagnosis. The potential for improving health is great, but in the developing world the final system must be simple, robust, operable without the need for supporting infrastructure, and extremely inexpensive. We are engaged in a 5-year project for development of such a diagnostic system for use in the developing world. Supported by the Bill & Melinda Gates Foundation’s Grand Challenges in Global Health initiative, this is a team effort led by the University of Washington that includes PATH, Nanogen, Inc., and Micronics, Inc.  In many resource-limited settings, patients presenting with fever are treated on the basis of a presumptive clinical diagnosis due to unavailability of complex diagnostic assays, and the patients are, therefore, often treated incorrectly. The initial focus of this project is on a panel of tests for detection (from a few drops of blood) of a range of infectious agents that cause rapid-onset fever: malarial parasites, the bacteria Salmonella typhi and Rickettsia, and viruses including those that cause dengue, measles and influenza. The technical aim is to develop an integrated system that includes a portable battery-powered reader and small disposable single-use microfluidic cards; the cards allow the system to perform both immunoassays and nucleic acid amplification assays on this panel of infectious disease targets simultaneously and within a few minutes. The instrument itself remains dry; the disposable card is pre-loaded with all necessary reagents (in either dry or wet form) to perform in parallel both immunoassays for antigens and pathogen-specific IgM levels and amplification and detection of both RNA and DNA from pathogens. Optical imaging of absorption is used for the immunoassays, and fluorescence is used for the nucleic acids. After adding the sample, the card will be inserted into the reader, which activates the fluid movements, thermal cycling, and other preparatory and analytical activities. The disposable card will contain molecular systems for sample concentration and controlled delivery of reagents, and will be made of cost effective materials for low-cost volume production. All reagents on the card will be storable at ambient conditions for at least 1 year. This platform eventually is intended to ultimately accommodate a wide range of analytical panels tailored for region-specific and disease-specific diagnostic problems.