The electrolyte - oxide-semiconductor field - effect transistor (English, short EOSFET, dt " electrolyte - oxide - semiconductor field-effect transistor " ) is a special field-effect transistor with insulated gate ( IGFET ). In contrast to conventional metal-oxide- semiconductor field effect transistors (MOSFETs ) is realized not by a metal layer but through an electrolyte solution, the gate electrode.

EOSFETs example, are used for detection of neural activity, such as brain-computer interfaces.