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

Abstract

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 readout system for on-chip integration.

Drain Current Model of a Four-Gate Dielectric Modulated MOSFET for Application as a Biosensor

“…To simulate the effect of charge of the biomolecules, negative or positive interface fixed charges (N f = ±5 × 10 15 m −2 ) at the Si-SiO 2 interface of the device are considered. The calibration of model parameters used in the simulation has been performed according to the experimental results [9]. Various models used in the simulation are as follows: 1) the concentration dependent mobility; 2) the field-dependent mobility; and 3) the Shockley-Read-Hall recombination model.…”

“…F ET-BASED biosensors have received great attention due to their advantages, such as high scalability, cost-effective mass production, miniaturization, high sensitivity, label-free detection process, and CMOS technology [1]- [9]. In 1970, the first FET-based biosensor was investigated by Bergveld [1], i.e., ion-sensitive FETs (ISFETs).…”

Dielectric Modulated Bilayer Electrode Top Contact OTFT for Label Free Biosensing

“…Ion-sensitive field effect transistors (ISFETs) have difficulty identifying neutral biomolecules, so researchers came up with the concept of a dielectrically modulated field effect transistor (FET) biosensor. In this type of biosensor, a cavity area in the oxide dielectric layer is utilized for biomolecule sensing [10]. This is possible because the immobilization of biomolecules in the cavity causes a change in the effective gate capacitance of the proposed device.…”

“…The bandgap of DNTT is considered to be 3.38 eV [25], the electron affinity of DNTT is given to be 1.81 eV [25], and the relative permit- tivity of DNTT is taken to be 3.0 [24], [25]. The thickness of the etched cavity in the dielectric oxide layer varies from 10 nm to 5 nm because the thickness of the biomolecules being studied like biotin, streptavidin, and DNA lies in the 10 nm range [10], [28]. The gate oxide dielectric constant is assumed to be 3.37 [27].…”

A biristor based on a floating-body silicon nanowire for biosensor applications

“…As the applied gate voltage modulates the channel current in field-effect transistors, charged biomolecules on the NW surface affect the channel potential and accordingly change the channel current. Silicon nanowire (SiNW)-based sensors have been proposed several times for detection of DNA, 3,4 cancer markers, 5,6 and virus antibodies; 7,8 however, the sensing metric has only been the change of conductivity, i.e., current change.…”