Differential-Mode Biosensor Using Dual Extended-Gate Metal–Oxide–Semiconductor Field-Effect Transistors

Abstract

In this paper, we present a differential-mode biosensor using dual extended-gate metal–oxide–semiconductor field-effect transistors (MOSFETs), which possesses the advantages of both the extended-gate structure and the differential-mode operation. The extended-gate MOSFET was fabricated using a 0.6 µm standard complementary metal oxide semiconductor (CMOS) process. The Au extended gate is the sensing gate on which biomolecules are immobilized, while the Pt extended gate is the dummy gate for use in the differential-mode detection circuit. The differential-mode operation offers many advantages such as insensitivity to the variation of temperature and light, as well as low noise. The outputs were measured using a semiconductor parameter analyzer in a phosphate buffered saline (PBS; pH 7.4) solution. A standard Ag/AgCl reference electrode was used to apply the gate bias. We measured the variation of output voltage with time, temperature, and light intensity. The bindings of self-assembled monolayer (SAM), streptavidin, and biotin caused a variation in the output voltage of the differential-mode detection circuit and this was confirmed by surface plasmon resonance (SPR) experiment. Biotin molecules could be detected up to a concentration of as low as 0.001 µg/ml.

Fabrication and Characterization of an Extended-Gate AlGaN/GaN-Based Heterostructure Field-Effect Transistor-Type Biosensor for Detecting Immobilized Streptavidin-Biotin Protein Complexes

“…The net negative charges of the reactive thiol head group introduce a negative surface potential on the gate electrode of the HFET. (9) In addition, the drain current decreased by 0.9 mA when streptavidin bound to the SAM, owing to the net negative charges of streptavidin. (7) The drain current decreased by 550 μA when biotin bound to streptavidin, owing to the decrease in capacitance following the binding between streptavidin and biotin.…”

“…Streptavidin can be attached to a SAM because it has an amine group. (9) After rinsing the biosensor in a new PBS solution, the drain current was measured. Biotin was injected to investigate the interaction between streptavidin and biotin.…”

“…The advantages of the extended-gate based biosensor are long-term stability, the flexibility of the shape of the sensing area, and simple methods of passivation and packaging. (9)(10)(11) In this study, we fabricate an extended-gate AlGaN/GaN-based heterostructure HFET-type biosensor for the detection of streptavidin-biotin complexes. We measure the drain current of this biosensor, which varies depending on the antibody-antigen reaction of biotin on streptavidin molecules.…”

Sensores químicos com transdução microeletrônica e ótica utilizando polianilina nanoestruturada

“…Desta forma, sensores do tipo EGFET no modo diferencial de operação possuem as vantagens da estrutura de porta estendida e a propriedade de ser insensível à variação de temperatura, luz, e concentração da solução [46]. A Figura 2.2.8 apresenta um diagrama de blocos para o funcionamento do sensor diferencial.…”

“…Dissertação Mestrado 38 filmes feitos de materiais diferentes com sensibilidades diferentes [46], [57], filme principal ou de contraste com camada polimérica depositada [50], filmes feitos do mesmo material com propriedades estruturais diferentes influenciando em suas sensibilidades [58], entre outras.…”