METHOD FOR ELECTRICAL DETECTION OF A BINDING REACTION

摘要

A method of detecting a substance in a test sample, which substance is one of a pair of substances that undergo a specific binding reaction with each other, includes the steps of reacting the test sample with a reagent comprising the other of the pair of substances and determining the extent of reaction therebetween. Particles having a first one of the pair of substances bound to the surfaces thereof are contacted with a layer of the second substances which substantially spans a path between a pair of spacedapart electrical conductors superposed on a substantially non-electrically conductive base. Each of the conductors is connected to means forming an electrical circuit which includes the conductors and the path therein. The binding reaction between said first and second substances causing the particles to be bound to the bottom wall to form aggregates. Unbound particles are removed, and exposed outer surfaces of said aggregates are coated with an electrically conductive substance. A change in the electrical current flow through the circuit caused by formation of the coated aggregates on the path is measured. This electrical change indicates the level of the substance to be detected in the test sample.