| CPC G01N 27/30 (2013.01) [G01N 27/327 (2013.01)] | 5 Claims |
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1. A biosensor for detecting an analyte of interest in a biological sample, comprising:
an insulating substrate having a sample addition end, an electrical contact end distal from the sample addition end, and an upper surface having a first axis extending from the sample addition end to the electrical contact end and a second axis perpendicular to the first axis extending from a first lateral side of the insulating substrate to a second lateral side of the insulating substrate;
a channel forming layer overlying the upper surface of the insulating substrate and comprising an opening defining a sample receiving space proximal to the sample addition end and a detection channel extending from the sample receiving space along the first axis of the insulating substrate, wherein the detection channel terminates at an end position proximal to the electrical contact end;
an upper cover layer overlying the channel forming layer and comprising a sample addition port in fluid communication with the sample receiving space and a vent hole in fluid communication with the end position of the detection channel, wherein the channel forming layer and the upper cover layer together define a capillary space overlying the insulating substrate such that fluid introduced into the sample addition port flows to the end position of the detection channel by capillary force;
an electrode system on the upper surface comprising
a first electrical contact and a second electrical contact proximal to the electrical contact end,
a first resistance element electrically connected to the first electrical contact and positioned between the sample receiving space and the electrical contact end, the first resistance element providing a first conductive trace extending along the first axis and a plurality of first resistance units spaced apart from one another along the first axis, wherein each first resistance unit extends from the first conductive trace partially across the upper surface along the second axis,
a second resistance element electrically connected to the second electrical contact and positioned between the sample receiving space and the electrical contact end, the second resistance element providing a second conductive trace extending along the first axis and a plurality of second resistance units spaced apart from one another along the first axis, wherein each second resistance unit extends from the second conductive trace across the upper surface along the second axis in a second direction opposite to the first direction,
wherein the plurality of second resistance units interdigitate with the plurality of first resistance units and wherein the capillary space overlies the interdigitated first and second resistance units such that the interdigitated first and second resistance units are in fluid communication with the capillary space; and
a reaction reagent positioned within the capillary space proximal to the sample addition end,
wherein the reaction reagent is configured and arranged to control the rate of flow of the biological sample from the sample addition port through the capillary space based on the concentration of the analyte of interest in the biological sample by participating in a coagulation reaction with the analyte of interest, whereby the concentration of the analyte of interest produces a change in an electrical parameter determined between the first electrical contact and the second electrical contact resulting from the number of interdigitated first and second resistance units contacted by the biological sample in a given time.
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