Large volumes of blood (milliliters) are required for diagnostics with large instruments, latrogenic blood loss or """"""""bleeding into the laboratory"""""""" is an important reason for administration of small volume transfusions in very low birth weight, premature infants. A direct correlation was found between the volume of blood drawn for diagnostics and subsequent volume transfused. In neonatal infants, there may not be enough collected blood sample to perform all the necessary tests. Also, conventional laboratory analysis of blood samples while in the field (accidents, disasters, battlefield, etc.) is impractical. A handheld, automated, inexpensive, multi-analyte and multiplexed blood chemistry analyzer will help reduce the blood analysis volume from milliliters to nanoliters, reduce the need for further transfusions, and make the analyzer available at the point-of-care (clinics, operating and emergency rooms, intensive care units, and in the field). Based on our previous demonstrations of electrowetting manipulation of nanoliter-sized droplets of reagents and sample for dispensing from on-chip reservoirs, high-speed transport, mixing, splitting and dilution, and colorimetric detection of the assays, a disposable lab-on-a-chip will be developed. Ultimately, a disposable lab-on-a-chip for blood chemistry will be developed where 1 microliter of human blood will be the input to the handheld system and it outputs the blood chemistry in a completely automated fashion. Phase I work will focus on fabricating a microfluidic platform upon which nanoliters of blood serum droplets, reference standards, and reagent droplets will be dispensed from microliter-sized source drops, transported in 2 dimensions, mixed, assayed, and disposed. Assays specific to the microfluidic regime will be developed. Colorimetric assays of four important and common analytes (blood urea nitrogen, creatinine, glucose, and lactate) in human blood serum will be demonstrated establishing just feasibility of a nanoliter lab-on-a-chip for blood chemistry.
