Antigen detection using microelectrode array microchips

Procedures and results are described for multiplexed immunochemical assays using semiconductor microchips. The microchips used here are miniaturized arrays of individually addressable microelectrodes controlled by active CMOS circuitry. Electrode densities exceed 1000percm2. The array chips are coated with a porous reaction layer material to provide a `biofriendlyʹ milieu overlaying the electrode array. Biotin is linked covalently to regions within the porous reaction layer proximate to selected microelectrodes. Covalent linkage is accomplished using reagents that are generated in situ by the microelectrodes. The covalent linkage of biotin within the porous reaction layer allowed traditional streptavidin (SA)-based immunoassay formats to be used on the biochips.