Proof-of-Concept for Card-based CD4 Cell Counting

DESCRIPTION (provided by applicant): The long-term objective of this proposed research is to develop a simple, inexpensive point-of-care device that will perform absolute and percent CD4+ T cell counts from whole blood. This will be accomplished by adaptin g and testing a novel hybrid approach to microfluidic sample preparation and analysis. One-time use thin-film laminated microfluidic cassettes will collect, count, and store the blood sample while the required cocktail reagents will be stored and injecte d into the cassettes from a bench-top unit. The integrated system will perform a total white blood cell count, absolute CD4+ T cell count, and percent CD4 count using a new volumetric combination electric impedance/fluorescence sensor contained on a dispos able microfluidic cassette. Toward this objective, Phase II will expand on our Phase I effort and focus on system optimization and validation. Aim one will optimize the microfluidic cassette design and CD4 blood labeling protocol for automated, on-card CD4 + T cell counting. Aim two will focus on fabrication and testing of the integrated bench-top system. Aim three will test and validate the completed CD4 enumeration system, using both modified commercially available normal human whole blood and clinical sam ples from HIV+ patients, and begin the bench-top studies required to obtain FDA clearance for a Class II medical device. The resulting device, when fully validated and evaluated in the proposed scenarios of use, will be simple, robust, and unique in that i t provides a fully quantitative CD4+ T cell analysis with an instrument costing less than 1000. This is many times below the cost of established flow cytometry devices. Reagent and disposable costs will also be lower than that of any currently available d evice with per-test total costs of less than 1.50. The tool will find immediate application in all levels of the public health care system, particularly in resource-poor areas and developing countries, for monitoring persons with human immunodeficiency vi rus (HIV), formulating differential diagnoses, and making therapeutic decisions regarding anti-retroviral drug treatment regimes, including the highly active anti-retroviral therapy (HAART) approach. PUBLIC HEALTH RELEVANCE The successful completion of an inexpensive, portable CD4 counter would constitute a significant breakthrough in HIV monitoring and treatment by offering healthcare providers a less expensive, mobile platform to conduct the most common CD4 diagnostic test currently performed in the world . Such a breakthrough will dramatically improve testing efficiencies with its single-use, disposable test cartridges and will make it possible to rapidly test patients at bedside, in remote locations, or in areas with limited healthcare resources. Finally, this new point-of-care system could significantly reduce current CD4 equipment and per-test costs, thereby resulting in millions of dollars saved in the US healthcare and insurance industries, with even greater worldwide healthcare impacts in developing c ountries.