Carbon Nanotube-Based Field-Effect Transistor Biosensors for Biomedical Applications: Decadal Developments and Advancements (2016-2025)

Abstract

Advancements in carbon nanotube-based FET (CNT-FET) biosensors from 2016 to 2025 have boosted their sensitivity, specificity, and rapid detection performance for biomedical purposes. This review highlights key innovations in transducer materials, functionalization strategies, and device architectures, including floating-gate CNT-FETs for detecting cancer biomarkers, infectious disease antigens, and neurodegenerative disease markers. Novel approaches, such as dual-microfluidic field-effect biosensor (dual-MFB) structures and carboxylated graphene quantum dot (cGQD) coupling, have further expanded their diagnostic potential. Despite significant progress, challenges in scalability, reproducibility, and long-term stability remain. Overall, this work highlights the transformative potential of CNT-FET biosensors while outlining a roadmap for translating laboratory innovations into practical, high-impact biomedical applications.

Keywords: CNT-FET biosensors; biomarker detection; commercialization; device architectures; functionalization strategies.

Scheme 1

Overview of CNT-FET-based biosensors for detecting biomarkers across major disease categories, including infectious, cancerous, neurological, and cardiovascular/metabolic disorders.

Figure 1

The nanostructure of a multi-wall carbon nanotube (MWCNT) (left) and a single-wall carbon nanotube (SWCNT) (right) (adapted with permission from Ref [17]).

Figure 2

Device structure of a CNT-FET (reproduced with permission from [36]).

Figure 3

Research trends for CNT-FET biosensors based on data retrieved from Scopus (Elsevier) using the following search query: TITLE (cnt OR ‘carbon nanotube’ AND fet OR ‘field effect transistor’ AND biosensor).

Figure 4

Graphical representation of the ultrasensitive detection of exosomal miR-21 employing a DNA-functionalized CNT-FET biosensor (reproduced with permission from [48]).

Figure 5

Detection of CEA using the proposed CNT-FET biosensor with an undulating interface in a complex matrix: (a) The transfer characteristics of the CNT-FET biosensor were systematically monitored in a 10% fetal bovine serum (FBS) matrix following the addition of CEA at concentrations ranging from 1 fg/mL to 1 ng/mL, demonstrating the sensor’s performance in biologically relevant conditions. (b) Corresponding calibration curves illustrating the relative current change (ΔI/I₀) as a function of increasing CEA concentration were generated, with error bars representing the standard deviation across eight independently fabricated devices (n = 8), underscoring measurement reproducibility and device reliability (reproduced with permission from [5]).

Figure 6

A schematic representation of the CNT-FET biosensor and the testing procedure for SARS-CoV-2 S1. The sensor utilizes SWCNT as the sensing nanomaterial, with anti-SARS-CoV-2 S1 immobilized on the CNT via the PBASE linker. The detection mechanism relies on changes in electrical signal properties induced by the interaction between the biosensor and the SARS-CoV-2 spike protein (reproduced with permission from [47]).

Figure 7

Development and analysis of the CNT-FET biosensor. (a) Conceptual representation of an aptamer-modified CNT-FET biosensor designed for detecting AD serum biomarkers. (b) Schematic depiction of the immobilization process, wherein an aptamer probe is anchored onto FG via a conventional Au linker, subsequently enabling hybridization with Aβ peptides. (c) Raman spectroscopy image illustrating the distribution of sorted CNTs. (d) Scanning electron microscopy (SEM) image displaying the CNT-FET biosensor array, with a scale bar of 100 μm. (e) SEM image highlighting the core active region of the biosensor, with a scale bar of 20 μm. (f) Transfer characteristics of 80 CNT-FETs under liquid-gated conditions following the deposition of Au nanoparticles, measured at V_ds = −0.1 V. (g) Fluorescence microscopy image revealing Cy5-labeled Aβ₄₂ aptamers hybridized to Au-NPs immobilized on the CNT-FG-FET channel surface (reproduced with permission from [54]).

Figure 8

Detection of CRTAC1 protein: (a) The biosensor’s response was evaluated using clinical serum samples from patients with severe (S1–S4), moderate (M5–M6), and mild (L7) osteoarthritis (OA), as well as from healthy individuals (H1–H4), with each group comprising 10 replicates (n = 10). (b) A comparative analysis was conducted between CRTAC1 concentrations measured by the biosensor and those determined via ELISA. (c) A statistically significant difference in biosensor signal intensity was observed between OA patients and healthy controls (n = 10), with p < 0.001. Results are expressed as mean ± standard deviation (SD). (d,e) Quantitative detection of CRTAC1 levels in serum samples using the biosensor (d) and ELISA (e). Box plots represent interquartile ranges (25th to 75th percentiles), with whiskers indicating the 10th to 90th percentiles; medians are denoted by horizontal lines within the boxes (reproduced with permission from [55]).

Figure 9

Schematic diagram of enzyme-modified FET for cholesterol detection (reproduced with permission from [49]).

Figure 10

A schematic representation of the PAMAM-functionalized SWCNT-FET biosensor is presented, accompanied by an SEM image depicting the SWCNT network bridging gold source and drain electrodes spaced 3 μm apart (reproduced with permission from [56]).