Patent ID: 8425745

Claim:
An assay device for detecting the analyte in a aqueous sample possibly containing an analyte, for use with the aqueous sample and an aqueous solution, wherein the aqueous sample and the aqueous solution may be the same or different fluids, the device comprising: (a) a first sensor platform including: (i) a working electrode configured to provide effective electrical interaction with a communicating fluid, the working electrode including a conductive base and an network of interconnected carbon nanotubes disposed on the conductive base; (ii) a counter electrode disposed in a spaced-apart arrangement from the working electrode, the spaced-apart arrangement configured to define a reaction zone for an electrochemical reaction in a communicating fluid, the reaction zone in communication with both working and counter electrodes; (iii) a first capture species bound on and/or adjacent the working electrode, the capture species having a binding affinity for the analyte; and (iv) wherein the working electrode and counter electrode are configured to electrically communicate with measurement circuitry; (b) a first elongate sorbent membrane having a proximal end and a distal end, (i) the proximal end having a first input portion configured for application of at least the aqueous sample; (ii) the distal end having a first delivery portion engaging the sensor platform in communication with the reaction zone; and (iii) the membrane composed, configured and supported so as to promote migration of the aqueous sample from the first input portion through the membrane to the first delivery portion so as to permit the aqueous sample to reach the reaction zone in a first time interval; and (c) a second elongate sorbent membrane having a proximal end and a distal end, (i) the proximal end having a second input portion configured for application of at least the aqueous solution; (ii) the distal end having a second delivery portion engaging the sensor platform in communication with the reaction zone; and (iii) the membrane composed, configured and supported so as to promote migration of the aqueous solution from the second input portion through the membrane to the second delivery portion so as to permit the aqueous sample to reach the reaction zone in a second time interval, wherein the working electrode and the counter electrode are spaced-apart by the first and second elongate sorbent membranes such that the distal ends of the first and second sorbent membranes are disposed between the working and counter electrodes.