The development of biosensors based on field-effect transistors (FETs) using atomically thick carbon nanotubes (CNTs) as a channel material has the potential to revolutionize the related field due to their small size, high sensitivity, label-free detection, and real-time monitoring capabilities. Despite extensive research efforts to improve the sensitivity, selectivity, and practicality of CNT FET-based biosensors, their commercialization has not yet been achieved due to the non-uniform and unstable device performance, difficulties in their fabrication, the immaturity of sensor packaging processes, and a lack of reliable modification methods. This review article focuses on the practical applications of CNT-based FET biosensors for the detection of ultra-low concentrations of biologically relevant molecules. We discuss the various factors that affect the sensors’ performance in terms of materials, device architecture, and sensor packaging, highlighting the need for a robust commercial process that prioritizes product performance. Additionally, we review recent advances in the application of CNT FET biosensors for the ultra-sensitive detection of various biomarkers. Finally, we examine the key obstacles that currently hinder the large-scale deployment of these biosensors, aiming to identify the challenges that must be addressed for the future industrialization of CNT FET sensors.

In food safety analysis, the detection and control of foodborne pathogens and their toxins are of great importance. Monitoring of virus transmission is equally important, especially in light of recent findings that coronaviruses have been detected in frozen foods and packages during the current global epidemic of coronavirus disease 2019. In recent years, field-effect transistor (FET) biosensors have attracted considerable scholarly attention for pathogenic microorganisms and toxins detection and sensing due to their rapid response time, high sensitivity, wide dynamic range, high specificity, label-free detection, portability, and cost-effectiveness. FET-based biosensors can be modified with specific recognition elements, thus providing real-time qualitative and semiquantitative analysis. Furthermore, with advances in nanotechnology and device design, various high-performance nanomaterials are gradually applied in the detection of FET-based biosensors. In this article, we review specific detection in different biological recognition elements are immobilized on FET biosensors for the detection of pathogenic microorganisms and toxins, and we also discuss nonspecific detection by FET biosensors. In addition, there are still unresolved challenges in the development and application of FET biosensors for achieving efficient, multiplexed, in situ detection of pathogenic microorganisms and toxins. Therefore, directions for future FET biosensor research and applications are discussed.

Accurate, real‐time detection of neurotransmitters is crucial for elucidating the mechanisms of brain function and tracking the progression of neurological diseases. Biosensors usually face poor reusability induced by difficulties in probe‐target separation, hindering their application for continuous monitoring. In this work, a semiconducting carbon nanotube (CNT) film field‐effect transistor (FET) biosensor is developed using pH‐sensitive aptamers as probes to capture targets. Through tuning the potential of on‐chip palladium electrodes, the biosensor facilitates in situ pH modulation and recovery of the sensor interface, which enables an electrically resettable biosensor. The fabricated sensor demonstrates exceptional sensitivity (with femtomolar‐level detection limits), high selectivity (specific responses are 20 times stronger than non‐specific ones), and excellent reusability (over ten reuse cycles). Furthermore, in vitro detection demonstrates that the biosensor arrays, incorporating regional modifications and pH‐sensitive probes, enable the simultaneous detection of several neurotransmitters, including dopamine, serotonin, histamine, and glutamate in complex biological samples. The combination of microfluidic techniques further lowers non‐specific adsorption and cross‐reactivity, ensuring reliable, repeatable real‐time detection. The resettable CNT FET biosensor array holds significant promise for advancing the monitoring of neurotransmitter dynamics, serving as a powerful tool for the early diagnosis and management of neurological disorders.