Ultra-sensitive Detection of Analytes

A device for detection of one or more analytes of interest in a biological or environmental sample, said device comprising

• a device body and an interchangeable and replaceable platform chip or cartridge, wherein the device body is adapted to accept the interchangeable and replaceable platform chip;
• wherein the device body comprises a battery, input means, and readout or output means;
• wherein the platform chip or cartridge comprises
• (1) a sample reservoir, a reservoir for a metal-labeled antibody, and at least one wash solution reservoir, wherein the metal-labeled antibody is specific to a first epitope of the one or more analytes of interest and the metal-labeled antibody contains an electrically conductive metal bound thereto;
• (2) a plurality of sample wells containing an area of capture antibodies specific to a second epitope of the one or more analytes of interest, wherein the capture antibodies are bound to the sample wells;
• (3) individual microelectrical circuits across each of the sample wells such that there is a nanoscale gap for each of the plurality of sample wells in the area of the capture antibodies, wherein the nanoscale gap is about 10 to about 200 nanometers;
• and
• (4) at least one microfluidic pump adapted to individually move the sample, the metal-labeled antibody, and the one or more wash solution in a preselected order, through microfluidic channels into the sample wells at preselected times, hold within the sample wells for preselected periods, and remove from the sample wells at preselected times;
• whereby the sample can be applied to the sample well to contact the capture antibodies and maintained therein for a sufficient time for analyte of interest, if present, to react with its corresponding capture antibody and be bound thereto to form an analyte-capture antibody complex, after which wash solution can be pumped through the sample well to remove unbound sample, after which metal-labeled antibody can be can be pumped into the sample well to contact any and maintained therein for a sufficient time for metal-labeled antibody to react with the analyte-capture antibody complex, if present, and be bound thereto form a metal-labeled antibody-analyte-capture antibody complex, after which wash solution can pumped through the sample well to remove unbound metal-labeled antibody, after which an electrical current can be passed across sample well such that if the analyte of interest was present, the metal-labeled antibody-analyte-capture antibody complex will allow the electrical current to pass over the nanoscale gap, thereby indicating the presence of the analyte of interest in the sample.