Bio-FET

A field-effect transistor-based biosensor, also known as a biosensor field-effect transistor (Bio-FET or BioFET), field-effect biosensor (FEB), or biosensor MOSFET, is a field-effect transistor (based on the MOSFET structure) that is gated by changes in the surface potential induced by the binding of molecules. When charged molecules, such as biomolecules, bind to the FET gate, which is usually a dielectric material, they can change the charge distribution of the underlying semiconductor material resulting in a change in conductance of the FET channel. A Bio-FET consists of two main compartments: one is the biological recognition element and the other is the field-effect transistor. The BioFET structure is largely based on the ion-sensitive field-effect transistor (ISFET), a type of metal–oxide–semiconductor field-effect transistor (MOSFET) where the metal gate is replaced by an ion-sensitive membrane, electrolyte solution, and reference electrode.

thumbnail| In a typical BioFET, an electrically and chemically insulating layer (e.g. Silica) separates the analyte solution from the semiconducting device. A polymer layer, most commonly [[APTES, is used to chemically link the surface to a receptor which is specific to the analyte (e.g. biotin or an antibody). Upon binding of the analyte, changes in the electrostatic potential at the surface of the electrolyte-insulator layer occur, which in turn results in an electrostatic gating effect of the semiconductor device, and a measurable change in current between the source and drain electrodes.]]