Sensors for biomolecular detection and cell classification

A method for detecting an ionic analyte in a sample in which an analyte is bound to a detection reagent to form a bound complex, comprising the steps of:

• (A) providing a sensor device comprising:
• (a) a sample (5) comprising an ionic analyte and a detection reagent in a conductive fluid, wherein the detection reagent has a net charge different from the analyte;
• (b) a first permeable polymeric hydrogel plate (3) and a first spacer plate (8), which plates provide a compartment for the sample;
• (c) an anode (1) juxtaposed to the outside of the first hydrogel plate and not in contact with the sample;
• (d) a cathode (9) juxtaposed to the outside of the first spacer plate and not in contact with the sample;
• (e) a voltage generator (10) to apply an electric potential to the anode and cathode;
• and
• (f) a detector (11);
• and
• (B) adding the ionic analyte and detection reagent in the conductive fluid to the compartment;
• (C) applying an electrical potential via the voltage generator;
• and
• (D) detecting via the detector the bound complex formed from the analyte because the bound complex has a charge that causes it to migrate in a direction opposite from that of the unbound analyte when the electric potential is applied.