The review discloses the historical and technological evolution of enzyme-based field-effect transistors (EnFETs) underlying importance gate electrode modification toward implementation novel FETs configurations such as extended-gate FET (EG-FETs) or EG organic (EG-OFETs). working principle EnFETs postulated by Bergveld in 1970, who defined EnFET an ion-selective (ISFET) modified with enzyme-me...

In this work, both the static and dynamic behaviors as well as the signal read-out circuits of ISFETs were studied. The standard NMOS structure in conjunction with the insulator-electrolyte capacitor was used to model the ISFET under study. The site-binding theory was incorporated to describe the chemistry occurring at the insulator/electrolyte interface. The mechanism of the threshold voltage ...

A transistor pH electrode (pH-ISFET electrode) was placed in each of four human mouths and bacteria were allowed to accumulate on it for 1, 2 or 3 days. Changes of plaque pH were measured in situ after application of sucrose solution (0.1, 1 or 3%) and, then, quick pH recovery by mouth-rinses with water was estimated. Although the acidic pH after application of 0.1% sucrose was easily and quick...

Acid or base concentrations can be determined by performing an acid-base titration with coulometrically generated OHor H+ ions at a noble metal actuator electrode in close proximity to the pH-sensitive gate of an ISFET. It is shown, both theoretically and experimentally, that the relation between the acid or base concentration and the time needed to reach the equivalence point in the resulting ...

A novel single silicon thin film field-effect-transistor (FET) is developed for use as a sensor to monitor transport and chemical properties of liquids in microfluidic systems. The sensor elements which are compatible with existing (bio-)chemical sensor schemes based on ion-sensitive-field-effect-transistors (ISFET) can detect capillary filling speed and level in aqueous solutions. Using a tran...