Unit operations for fully automated microfluidic paper-based analytical devices for diagnostic and biosensing

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The overall goal of this research program is to create inexpensive, and portable ready-to-use microfluidic paper-based analytical devices (uPADs) for biosensing and diagnostics. Through this Discovery Grant, the focus will be on the development of a set of unit operations for microfluidic paper-based devices to serve as a toolbox to rapidly build ready-to-use assay-kits for environmental (soil, and water) monitoring, and biomedical applications. A team of 17 students (including 2 Ph.D.s, 5 M.Sc.s, and 10 undergraduates students) from different backgrounds (including Chemical Engineering, Materials Engineering, Mechanical Engineering, Electrical Engineering, and Biochemistry) will benefit from training under this interdisciplinary research program. Goal A. Unit Operations on microfluidic paper-based devices include: (A.1) Development of externally controllable valves/ flow regulators. Light or heat activated gels are good candidates. (A.2) Development of externally controllable heat exchanger not only to control the temperature as needed but more importantly for consistency between tests; as in the majority of assays, the reaction rates and the generated signals from the sensors are temperature sensitive. (A.3) Development of a set of separators to serve as a separation step for the isolation of different components. We will create a family of low-cost devices to serve as a separator on the sensors in the field. (A.4) Development of an electronic interface for monitoring a paper-supported microfluidic device operation. Develop/improve the signal reporting approach to offer a more user-friendly reporting method. Goal B. Assay kits for point-of-use applications in environmental monitoring and biomedical diagnostic. The proposed unit operations (from goal A) are to be implemented on paper-based devices to run complex analytical protocols including: (B.1) Fully automated microfluidic paper-based assay kit for selective detection of the heavy metals in drinking water. Taking advantages of the proposed unit operations, an easy-to-use fully automated heavy metal sensor will be developed while minimizing the user intervention. (B.2) Paper-based assay kit for detection of soil contamination. So far, I, in collaboration with others, have done several works on detection of contaminants (including pesticide, and microorganism) in drinking water and fluid samples only, but not in a solid phase (like soil) samples ever. To develop such assay kits, a few critical unit operations (including separators as listed above, and extractor of-course), are highly needed to be designed and implemented on paper-based microfluidic devices. (B.3) Paper based assay kit for prothrombin time (PT) test. This test measures the time it takes the blood to clot (coagulation rate). This is an important assay to check whether blood-thinning medication (anticoagulant) warfarin to prevent blood clots is working.