Nanoporous Layer Integration for the Fabrication of ISFET and Related Transistor-Based Biosensors

More and more chemosensors and biosensors are turning to electronic transistors, as they are ideal transducers, precise in current response, miniaturized in size and capable of providing sub-picomolar detection limits. Among these devices, ISFET transistors—Ion-Sensitive Field-Effect Transistors—have the capacity of integrating ion-sensitive layers together with field effect transistors of ultimate generations. Recent studies have indicated that nanoporous materials deposited or grown within the transistor gate space offer a dual advantage—a favorable environment for an optimal capture of liquid state receptors through capillary effects, but also of direct anchoring of these nanoporous structures on a Si wafer. This article aims to review the constructive evolutions of ISFET transistors, along with some newer nanowire devices, as well as their co-integration techniques with nanoporous materials, which are beneficial in the optimization of many chemosensors but of enzymatic biosensors in particular.