Thermoelectric lab-on-a-chip ELISA

We report a new, thermoelectric method for performing enzyme-linked immunosorbent assay (ELISA) in a microfluidic device. The concentration of the analyte is determined by measuring the heat of an enzymatic reaction between glucose and glucose oxidase using thin-film antimony/bismuth thermopile. The feasibility of lab-on-a-chip thermoelectric ELISA is demonstrated by measuring the concentration of 8-hydroxy-2-deoxyguanosine (8OHdG) in urine samples from amyloid precursor protein transgenic mice. The detection method is based on formation of a complex between 8OHdG, anti-8OHdG capture antibody and glucose oxidase linked IgG antibody. The complex is immobilized at the lower channel wall of the microfluidic device, over the measuring junctions of the thermopile. The amount of heat detected by the thermoelectric sensor is inversely proportional to the concentration of 8OHdG. Standard calibration curve was created using synthetic 8OHdG. The regression line equation of the standard calibration curve was used to estimate the concentration of 8OHdG in mouse urine.