A Dual-Gate Field-Effect Transistor for Label-Free Electrical Detection of Avian Influenza

A dual-gate silicon nanowire field-effect transistor (FET) fabricated on a bulk substrate is designed to perform label-free electrical detection of the avian influenza antibody. A region of a FET channel that is conventionally covered by a gate electrode is intentionally left open in the dual-gate configuration, to provide a binding site for biological species. As a result, the channel potential at this open area is affected by the polarity and charge of the biological species that binds to the opened channel. The proposed device can be used as a biosensor by comparing its electrical characteristics before and after exposing the device to biological species of interest. This detection mechanism is verified using numerical simulation and by attaching charged polyelectrolytes (PAH and PSS) to the opened channel. Additionally, the avian influenza antibody is successfully detected without a labeling step using the proposed dual-gate FET. As a biomedical diagnostic tool, the proposed biosensor offers the advantages of label-free detection capability, low-cost compatibility with the complementary metal-oxide semiconductor fabrication process, and a read-out system for on-chip integration.