Carbon Nanotube Field-Effect Transistor Biosensor with an Enlarged Gate Area for Ultra-Sensitive Detection of a Lung Cancer Biomarker

Abstract

Carcinoembryonic antigen (CEA) is a recognized biomarker for lung cancer and can be used for early detection. However, the clinical value of CEA is not fully realized due to the rigorous requirement for high-sensitivity and wide-range detection methods. Field-effect transistor (FET) biosensors, as one of the potentially powerful platforms, may detect CEA with a significantly higher sensitivity than conventional clinical testing equipment, while their sensitivity and detection range for CEA are far below the requirement for early detection. Here, we construct a floating gate FET biosensor to detect CEA based on a semiconducting carbon nanotube (CNT) film combined with an undulating yttrium oxide (Y2O3) dielectric layer as the biosensing interface. Utilizing an undulating biosensing interface, the proposed device showed a wider detection range and optimized sensitivity and detection limit, which benefited from an increase of probe-binding sites on the sensing interface and an increase of electric double-layer capacitance, respectively. The outcomes of analytical studies confirm that the undulating Y2O3 provided the desired biosensing surface for probe immobilization and performance optimization of a CNT-FET biosensor toward CEA including a wide detection range from 1 fg/mL to 1 ng/mL, good linearity, and high sensitivity of 72 ag/mL. More crucially, the sensing platform can function normally in the complicated environment of fetal bovine serum, indicating its great promise for early lung cancer screening.

Ultrasensitive Graphene Field-Effect Biosensors Based on Ferroelectric Polarization of Lithium Niobate for Breast Cancer Marker Detection

“…For FET biosensor, a larger gate capacitance means a stronger control of gate over the channel, and their sensitivity is related to the gate capacitance and can be described by the following formula: response = false[ normalΔ false( V Dirac false) q false] / { ln nobreak0em0.25em⁡ 10 · k T [ 1 + ( C Q C EDL + C Q C ox ) ] } where V Dirac is the Dirac voltage, k is the Boltzmann constant, T is the thermodynamic temperature, q is the electron charge, C Q is the quantum capacitance, C ox is the gate oxide capacitance, and C EDL is the EDL capacitance.…”

CNT and Graphene-Based Transistor Biosensors for Cancer Detection: A Review

“…However, the full clinical potential of CEA has yet to be realized due to the demanding requirements for high sensitivity and broad detection capabilities. To address this challenge, Li et al [57] developed an innovative biosensing approach using a floating gate FET combined with a semiconducting CNT film and an undulating yttrium oxide (Y 2 O 3 ) dielectric layer as the biosensing interface (Figure 5). The introduction of the rippling biosensing interface in the proposed device significantly expanded the detection range, enabling detection from ultra-low concentrations of 1 fg/mL to 1 ng/mL.…”