Abstract: A glucose sensitive FET sensor is provided which includes a substrate, a source electrode formed in the substrate, a drain electrode formed in the substrate, a hydrogen ion sensitive film formed on the substrate to cover the source electrode and the drain electrode, and a thin enzyme immobilized membrane formed on the hydrogen ion sensitive film and containing glucose oxidase and gluconolactonase. Also provided is a method of producing a glucose sensitive FET sensor which includes the steps of preparing an enzyme immobilized membrane as a thin film containing glucose oxidase and gluconolactonase and forming the membrane on a hydrogen ion sensitive film which is formed on a substrate to cover a source electrode and a drain electrode, both of which are formed in the substrate.

Abstract: A membrane containing an immobilized enzyme for a semiconductor sensor is prepared containing a water soluble photosensitive resin including a high molecular weight polyvinyl pyrrolidone crosslinked to 2, 5-bis (4'-azide-2'-sulfobenzal) cyclopentanone sodium salt, and an enzyme. Glutaraldehyde and bovine serum albumin, polyamino acid or polyamino amino acid copolymer may also be present to provide chemical crosslinking. The enzyme may be glucose oxidase, urease or lipase. The membrane can be directly formed on ion-sensitive protions of a pH-ion sensitive field effect transistor to form a semiconductor sensor by coating an aqueous solution of the resin and enzyme on the ion-sensitive portion, drying and irradiating with light such as ultraviolet light to provide photo crosslinking.