Abstract: The present invention provides a substrate for a microfluidic device comprising a polymeric base plate, at least one sensor formed over the polymeric base plate for detecting at least one target analyte from a sample, the sensor comprising at least one reference electrode and at least one working electrode, wherein a plurality of nanostructures deposited over the working electrode for increasing the surface area of the working electrode, and at least one recognition element bound to or deposited over the nanostructures. The microfluidic device of the present invention is a point-of-care, self calibrated, self contained hand-held device for rapid screening and diagnosis of various disease markers.

Abstract: The present invention is directed to methods of detecting filling of the capillary channel of a biosensor test strip. In one embodiment the biosensor test strip has three electrodes: a first reference electrode, a working electrode and a second reference electrode, which are arranged sequentially within the capillary channel of a biosensor test strip and perpendicular to the axis thereof. A test sample containing an analyte of interest is applied to the test strip. A first voltage (V1) is applied between the first reference electrode and the working electrode, and a first current (i1) is detected. If i1 is detected, a second voltage (V2) is applied between the working electrode and the second reference electrode. A second current (i2) is detected, indicating that an applied sample has covered the first and second reference electrodes and the working electrodes. The measuring device then conducts the assay for the presence or amount of the analyte of interest in the test sample.