Patent ID: 7455756

Claim:
A biosensor for separation-free enzyme immunoassays without washing, comprising: a microporous membrane support; a first electrode system consisting of a working electrode on which antibodies are immobilized, a first electrode connector, and a first lead outlet; a second electrode system consisting of a counter electrode, a second electrode connector and a second lead outlet; a pair of insulating films, covering surfaces of the first and second electrode systems except for the areas of the working electrode, the first electrode connector, the counter electrode and the second electrode connector; and a pad containing an enzyme-antibody conjugate on the top of the working electrode, and a pair of covers consisting of an upper cover having a hole and a lower cover having a hole, wherein, the first electrode system is formed on the surface of the microporous membrane support and the second electrode system is formed on the opposite surface of the microporous membrane support, wherein, the working electrode and the counter electrode are formed directly on the microporous membrane support, whereby the electrodes being microporous and allowing a sample liquid to pass through the surface of the working electrode to the surface of the counter electrode and a substrate to pass through the surface of the counter electrode to the surface of the working electrode, wherein a sample solution containing an analyte, introduced into the hole of the upper cover, reacts to form a bound enzyme-antibody conjugate with the antibodies and an unbound enzyme-antibody conjugate, the bound enzyme-antibody conjugate being formed in the working electrode, and wherein the substrate participates in the enzyme reaction with the enzyme from the bound enzyme-antibody conjugate to generate electrons transferable to the electrode and the unbound enzyme-antibody conjugate to generate electrons not transferable to the electrode.