Field Effect Transistor Biosensor Research Articles

Ultrasensitive detection of miRNA based on single-walled carbon nanotube@MoS2 field-effect transistor regulated by atomic layer deposition

MicroRNAs (miRNAs) act as diagnostic markers for various diseases, and achieving ultra-sensitive detection of miRNAs has an important effect on early disease diagnosis. Field-effect transistor (FET) biosensor exhibits superior sensitivity compared to conventional clinical detection instruments in detecting biomolecules. However, developing high-sensitive FET biosensors for detecting microRNAs remains challenging. In this study, we developed a FET biosensor using MoS2 and a network film of semiconductor single-walled carbon nanotube (SWCNT) as channel materials. The MoS2 cycles were precisely controlled and optimized by atom layer deposition (ALD), and the optimized 3-cycle device exhibited the best performance. This adjustment is beneficial for enhancing the charge transfer between SWCNT and MoS2, as well as improving the on/off ratio and mobility of FET devices. Additionally, the SWCNT@MoS2 structure offers a larger specific surface area, providing more active binding sites on the sensing interface. These two favorable factors contribute to the realization of linear detection miRNA-21 from 1 × 10−17 to 1 × 10−10 mol L−1 in biosensors. The theoretical detection limit of the biosensor is 1.9 × 10−18 mol L−1. This work develops a novel approach to achieve highly sensitive detection of miRNA for high-performance FET biosensors.

Field-effect transistor biosensor with signal amplification by ternary initiation complexes for detection of wide-range RNA concentration

Electrical detection of RNAs using transistor-based biosensors has attracted attention as a strategy for medical diagnosis and environmental monitoring. Herein, we demonstrated a proof-of-concept for specific, sensitive, and label-free RNA detection using a field-effect transistor (FET) biosensor with signal amplification by ternary initiation complexes (SATIC), which is an isothermal one-step nucleic acid amplification initiated by the combination of target RNA, circular DNA template and DNA primer. The SATIC system-applied FET biosensor specifically and quantitatively detected the target RNA with a single-nucleotide difference via the negative charges derived from the amplification products formed by a nucleic acid amplification reaction with φ29 DNA polymerase on the gate surface. In particular, the control of the amplification time allowed the detection of target RNA molecules over a wide concentration range, resulting in a detection limit of up to 6 copies/μL. Therefore, a transistor-based bioassay using the SATIC system could be useful for simple and sensitive nucleic acid analysis.

A Drug Molecule-Modified Graphene Field-Effect Transistor Nanosensor for Rapid, Label-Free, and Ultrasensitive Detection of Estrogen Receptor α Protein.

Estrogen receptor α (ERα) is an important biomarker in breast cancer diagnosis and treatment. Sensitive and accurate detection of ERα protein expression is crucial in guiding selection of an appropriate therapeutic strategy to improve the effectiveness and prognosis of breast cancer treatment. Herein, we report a liquid-gated graphene field-effect transistor (FET) biosensor that enables rapid, sensitive, and label-free detection of the ERα protein by employing a novel drug molecule as a capture probe. The drug molecule was synthesized and subsequently immobilized onto the sensing surface of the fabricated graphene FET, which was able to distinguish the ERα-positive from the ERα-negative protein. The developed sensor not only demonstrated a low detection limit (LOD: 2.62 fM) but also achieved a fast response to ERα protein samples within 30 min. Moreover, depending on the relationship between the change of dirac point and the ERα protein concentrations, the dissociation constant (Kd) was estimated to be 7.35 ± 0.06 pM, indicating that the drug probe-modified graphene FET had a good affinity with ERα protein. The nanosensor was able to analyze ERα proteins from 36 cell samples lysates. These results show that the graphene FET sensor was able to differentiate between ERα-positive and ERα-negative cells, indicating a promising biosensor for the ultrasensitive and rapid detection of ERα protein without antibody labeling.

Phthalocyanine-functionalized field-effect transistor biosensor for in situ monitoring of cell-released hydrogen sulfide

Hydrogen sulfide (H2S) is an important endogenous gas transmitter that is closely associated with human pathological and physiological states. Therefore, the accurate and quantitative detection of H2S has attracted great research interest in the biomedical field. In this paper, we report a phthalocyanine-functionalized field-effect transistor (FET) biosensor for ultra-sensitive, in situ, real-time monitoring of H2S released from cells. The reduced graphene oxide (RGO) and cobalt phthalocyanine RGO nanocomposites (CoGPCs) were layer to layer assembled on a prefabricated FET device surface. The excellent electrical conductivity of graphene and the high catalytic property and specificity of metal phthalocyanines ensure sensitive and specific detection of H2S. The biosensor was capable of detecting H2S in the range of 10 pM to 1 mM with detection limit down to 10 pM. In addition, the sensor exhibited good selectivity and biocompatibility. The excellent performance allowed the sensor to in situ and real-time monitor H2S release from different cell lines, and investigate the effect of inhibitors on H2S release from colon cancer cells. This FET biosensor provides a new approach for in situ and real-time monitoring of H2S release, which may help us understand the function of H2S in biological and pathological processes and contribute to drug screening development studies.

Dual-Mode Graphene Field-Effect Transistor Biosensor with Isothermal Nucleic Acid Amplification.

Despite a substantial increase in testing facilities during the pandemic, access remains a major obstacle, particularly in low-resource and remote areas. This constraint emphasizes the need for high-throughput potential point-of-care diagnostic tools in environments with limited resources. Loop-mediated isothermal amplification (LAMP) is a promising technique, but improvements in sensitivity are needed for accurate detection, especially in scenarios where the virus is present in low quantities. To achieve this objective, we present a highly sensitive detection approach of a dual-mode graphene-based field-effect transistor (G-FET) biosensor with LAMP. The G-FET biosensor, which has a transparent graphene microelectrode array on a glass substrate, detects LAMP products in less than 30 min using both observable color changes and Dirac point voltage measurements, even in samples with low viral concentrations. This dual-mode G-FET biosensor emerges as a potential alternative to conventional RT-PCR for severe acute respiratory syndrome-associated coronavirus (SARS-CoV)-2 detection or point-of-care testing, particularly in resource-constrained scenarios such as developing countries. Moreover, its capacity for colorimetric detection with the naked eye enhances its applicability in diverse settings.

Enhancing graphene field-effect transistor biosensors with DNA-mediated protein orientation

Enhancing graphene field-effect transistor biosensors with DNA-mediated protein orientation

Solution-Induced Degradation of the Silicon Nanobelt Field-Effect Transistor Biosensors.

Field-effect transistor (FET)-based biosensors are powerful analytical tools for detecting trace-specific biomolecules in diverse sample matrices, especially in the realms of pandemics and infectious diseases. The primary concern in applying these biosensors is their stability, a factor directly impacting the accuracy and reliability of sensing over extended durations. The risk of biosensor degradation is substantial, potentially jeopardizing the sensitivity and selectivity and leading to inaccurate readings, including the possibility of false positives or negatives. This paper delves into the documented degradation of silicon nanobelt FET (NBFET) biosensors induced by buffer solutions. The results highlight a positive correlation between immersion time and the threshold voltage of NBFET devices. Secondary ion mass spectrometry analysis demonstrates a gradual increase in sodium and potassium ion concentrations within the silicon as immersion days progress. This outcome is ascribed to the nanobelt's exposure to the buffer solution during the biosensing period, enabling ion penetration from the buffer into the silicon. This study emphasizes the critical need to address buffer-solution-induced degradation to ensure the long-term stability and performance of FET-based biosensors in practical applications.

Asymmetric Schottky Barrier-Generated MoS2/WTe2 FET Biosensor Based on a Rectified Signal.

Field-effect transistor (FET) biosensors can be used to measure the charge information carried by biomolecules. However, insurmountable hysteresis in the long-term and large-range transfer characteristic curve exists and affects the measurements. Noise signal, caused by the interference coefficient of external factors, may destroy the quantitative analysis of trace targets in complex biological systems. In this report, a "rectified signal" in the output characteristic curve, instead of the "absolute value signal" in the transfer characteristic curve, is obtained and analyzed to solve these problems. The proposed asymmetric Schottky barrier-generated MoS2/WTe2 FET biosensor achieved a 105 rectified signal, sufficient reliability and stability (maintained for 60 days), ultra-sensitive detection (10 aM) of the Down syndrome-related DYRK1A gene, and excellent specificity in base recognition. This biosensor with a response range of 10 aM-100 pM has significant application potential in the screening and rapid diagnosis of Down syndrome.

Nanostructured interface-engineered field-effect transistor biosensors for sensitive detection of serum miRNAs

<p>The efficient detection of disease-relevant biomolecules in untreated clinical samples is highly desired, especially for acute diseases. Field-effect transistor (FET) biosensors allow label-free and rapid detection of biomolecules through the measurement of their intrinsic charges. However, the sensitivity of FET biosensors would be undermined by the charge screening effect in practical biological media with high ionic strength. Here, we report the design and performance of a nanostructured interface-engineered field effect transistor (NIE FET) biosensor for highly sensitive detection of cardiovascular disease (CVD)-associated miRNAs in serum samples. Molecular dynamic simulations and electrochemical characterizations demonstrate that the nanostructured interface with concave regions alleviates the charge screening effect and enlarges the Debye length. The rationally designed NIE FET biosensor exhibits high sensitivity and reproducibility in detecting miRNA in untreated serum samples with a detection limit of pM level. Benefiting from its excellent detection capabilities, NIE FET reveals the relationship between miRNAs and CVDs and realizes the effective classification of different CVD types with the help of machine learning algorithms. The construction of NIE FET defines a robust strategy for electrical biomolecular detection in practical clinical samples.</p>

An integrated wearable sticker based on extended-gate AlGaN/GaN high electron mobility transistors for real-time cortisol detection in human sweat.

Cortisol hormone imbalances can be detected through non-invasive sweat monitoring using field-effect transistor (FET) biosensors, which provide rapid and sensitive detection. However, challenges like skin compatibility and integration with sweat collection have hindered FET biosensors as wearable sensing platforms. In this study, we present an integrated wearable sticker for real-time cortisol detection based on an extended-gate AlGaN/GaN high electron mobility transistor (HEMT) combined with a soft bottom substrate and flexible channel for sweat collection. The developed devices exhibit excellent linearity (R2 = 0.990) and a high sensitivity of 1.245 μA dec-1 for cortisol sensing from 1 nM to 100 μM in high-ionic-strength solution, with successful cortisol detection demonstrated using authentic human sweat samples. Additionally, the chip's microminiature design effectively reduces bending impact during the wearable process of traditional soft binding sweat sensors. The extendedgate structure design of the HEMT chip enhances both width-to-length ratio and active sensing area, resulting in an exceptionally low detection limit of 100 fM. Futhermore, due to GaN material's inherent stability, this device exhibits long-term stability with sustained performance within a certain attenuation range even after 60 days. These stickers possess small, lightweight, and portable features that enable real-time cortisol detection within 5 minutes through direct sweat collection. The application of this technology holds great potential in the field of personal health management, facilitating users to conveniently monitor their mental and physical conditions.

Applications of Graphene Field Effect Biosensors for Biological Sensing.

This chapter provides a comprehensive overview of the principles, applications, and advancements in graphene field-effect transistor (gFET) biosensors for biological sensing. The unique properties of graphene that make it ideal for biosensing, including its high conductivity, chemical stability, and ability to facilitate label-free detection, will be discussed. The chapter also explores various applications of gFET biosensors, from detecting pH and salinity changes to complex protein-protein interactions and DNA/RNA sensing. It also addresses the challenges and future directions in gFET biosensor technology, emphasizing the need for scalable manufacturing, sophisticated surface chemistry, and the integration of multiomics approaches to enhance biosensing capabilities.

Ion-sensitive field effect transistor biosensors for biomarker detection: current progress and challenges.

The ion-sensitive field effect transistor (ISFET) has emerged as a crucial sensor device, owing to its numerous benefits such as label-free operation, miniaturization, high sensitivity, and rapid response time. Currently, ISFET technology excels in detecting ions, nucleic acids, proteins, and cellular components, with widespread applications in early disease screening, condition monitoring, and drug analysis. Recent advancements in sensing techniques, coupled with breakthroughs in nanomaterials and microelectronics, have significantly improved sensor performance. These developments are steering ISFETs toward a promising future characterized by enhanced sensitivity, seamless integration, and multifaceted detection capabilities. This review explores the structure and operational principles of ISFETs, highlighting recent research in ISFET biosensors for biomarker detection. It also examines the limitations of these sensors, proposes potential solutions, and anticipates their future trajectory. This review aims to provide a valuable reference for advancing ISFETs in the field of biomarker measurement.

Graphene and coltan

The clean and renewable energy scenario has gone through a transformation process with the discovery of new generation sources and devices for their storage. Sustainable and efficient solutions are sought to satisfy the growing energy demand of today's population. The environmental problems related to fossil fuels are recognized throughout the world, but to abandon them and for renewable energies to cover current demand, they must not only deliver enough energy but must also be accumulated and transported. In this perspective, batteries play an important role in different areas, from energy storage to powering electronic devices, electric vehicles, etc. Electronic devices use relatively little power, so even small improvements in batteries have driven big changes in their performance and daily use. The functionalities of graphene and coltan make them ideal for a variety of applications, which are at the same time development opportunities for Colombia, such as water purification and desalination, catalyzing systems for the production of hydrogen and foams for lighting purposes, and a rapid heating element; graphene used as a photocatalytic coating material in smart buildings can purify the air in cities; It is also a promising material in the fields of printed electronics, sensors, graphene-based field-effect transistor (GFET) biosensors, optical biosensors, and photovoltaic cells. The possibility of incorporating graphene microchips implanted in teeth for bacterial detection and monitoring of oral hygiene is currently being studied, which could facilitate the study and prevention of periodontal diseases in the future; At the University of Manchester, new graphene condoms were obtained thanks to graphene composite polymers, which provide a higher heat transfer rate, improving sensitivity and the ability to disperse active drugs to prevent sexually transmitted diseases uniformly, pregnancy or even increase sexual pleasure. Graphene sheets have also recently been used to measure blood glucose levels through sweat and deliver pharmacological doses through the skin. This research focuses on a case study: the sizing of a Lithium battery with graphite in both electrodes as an alternative solution for greater energy storage. In this process, the participation of graphite in both electrodes is expanded, specifically in the coating of the cathode through layers to reduce losses and thereby improve battery storage. With this proposal, both the anode and the cathode will be made up of intercalator materials (graphite), different from the metallic lithium anode, which is dangerous, and the Li+1 ion can travel reversibly between them. As a result of the work, the structure of the new battery that will be built and tested in the following stages of the research was designed in SolidWorks software.

Nanomaterials-Based Field-Effect Transistor for Protein Sensing: New Advances.

It is crucial for early stage medical diagnostics to identify disease biomarkers at ultralow concentrations. A wide range of analytes can be identified using low-dimensional materials to build highly sensitive, targeted, label-free, field-effect transistor (FET) biosensors. Two-dimensional (2D) materials are preferable for high-performance biosensing because of their dramatic change in resistivity upon analyte adsorption or biomarker detection, tunable electronic properties, high surface activities, adequate stability, and layer-dependent semiconducting properties. We give a succinct overview of interesting applications for protein sensing with various architectural styles, such as 2D transition metal dichalcogenides (TMDs)-based FETs that include carbon nanotubes (CNTs), graphene (Gr), reduced graphene oxide (rGr), 2D transition-metal carbides (MXene), and Gr/MXene heterostructures. Because it might enable individuals to perform better, this review will be an important contribution to the field of medical science. These achievements demonstrate point-of-care diagnostics' abilities to detect biomarkers at ultrahigh performance levels. A summary of the present opportunities and challenges appears in the conclusion.

Ultrasensitive biosensing platform for Mycobacterium tuberculosis detection based on functionalized graphene devices.

Tuberculosis (TB) has high morbidity as a chronic infectious disease transmitted mainly through the respiratory tract. However, the conventional diagnosis methods for TB are time-consuming and require specialists, making the diagnosis of TB with point-of-care (POC) detection difficult. Here, we developed a graphene-based field-effect transistor (GFET) biosensor for detecting the MPT64 protein of Mycobacterium tuberculosis with high sensitivity as a POC detection platform for TB. For effective conjugation of antibodies, the graphene channels of the GFET were functionalized by immobilizing 1,5-diaminonaphthalene (1,5-DAN) and glutaraldehyde linker molecules onto the graphene surface. The successful immobilization of linker molecules with spatial uniformity on the graphene surface and subsequent antibody conjugation were confirmed by Raman spectroscopy and X-ray photoelectron spectroscopy. The GFET functionalized with MPT64 antibodies showed MPT64 detection with a detection limit of 1fg/mL in real-time, indicating that the GFET biosensor is highly sensitive. Compared to rapid detection tests (RDT) and enzyme-linked immunosorbent assays, the GFET biosensor platform developed in this study showed much higher sensitivity but much smaller dynamic range. Due to its high sensitivity, the GFET biosensor platform can bridge the gap between time-consuming molecular diagnostics and low-sensitivity RDT, potentially aiding in early detection or management of relapses in infectious diseases.

Biosensing with Surface-Charge-Modulated Graphene Field-Effect Transistors beyond Nonlinear Electrolytic Screening.

In field-effect transistor (FET) biosensors, charge screening in electrolyte solutions limits the sensitivity, thereby restricting the applicability of FET sensors. This is particularly pronounced in graphene FET (GFET) biosensors, where the bare graphene surface possesses a strongly negative charge, which impedes the high sensitivity of GFETs owing to nonlinear electrolytic screening at the interfaces between graphene and liquid. In this study, we counteracted the negative surface charge of graphene by decorating positively charged compounds and demonstrated the sensing of C-reactive protein (CRP) with surface-charge-modulated GFETs (SCM-GFETs). We integrated multiple SCM-GFETs with anti-CRP antibodies and nonfunctionalized GFETs into a chip and measured differentials to eliminate background changes to improve measurement reliability. The FET response corresponded to the fluorescence images, which visualized the specific adsorption of CRP. The estimated dissociation constant was consistent with previously reported values; this supports the conclusion that the results are attributed to specific adsorption. Conversely, the signal in GFETs without decoration was obscured by noise because of nonlinear electrolytic screening, further emphasizing the significance of surface-charge modulation. The limit of detection of the system was determined to be 2.9 nM. This value has the potential to be improved through further optimization of the surface charges to align with specific applications. Our devices effectively circumvent nonlinear electrolytic screening, opening the door for further advancements in GFET biosensor technology.

Interface-Engineered Field-Effect Transistor Electronic Devices for Biosensing.

Promising advances in molecular medicine have promoted the urgent requirement for reliable and sensitive diagnostic tools. Electronic biosensing devices based on field-effect transistors (FETs) exhibit a wide range of benefits, including rapid and label-free detection, high sensitivity, easy operation, and capability of integration, possessing significant potential for application in disease screening and health monitoring. In this perspective, the tremendous efforts and achievements in the development of high-performance FET biosensors in the past decade are summarized, with emphasis on the interface engineering of FET-based electrical platforms for biomolecule identification. First, an overview of engineering strategies for interface modulation and recognition element design is discussed in detail. For a further step, the applications of FET-based electrical devices for in vitro detection and real-time monitoring in biological systems are comprehensively reviewed. Finally, the key opportunities and challenges of FET-based electronic devices in biosensing are discussed. It is anticipated that a comprehensive understanding of interface engineering strategies in FET biosensors will inspire additional techniques for developing highly sensitive, specific, and stable FET biosensors as well as emerging designs for next-generation biosensing electronics.

Graphene transistor-based biosensors for rapid detection of SARS-CoV-2

Field-effect transistor (FET) biosensors use FETs to detect changes in the amount of electrical charge caused by biomolecules like antigens and antibodies. COVID-19 can be detected by employing these biosensors by immobilising bio-receptor molecules that bind to the SARS-CoV-2 virus on the FET channel surface and subsequent monitoring of the changes in the current triggered by the virus. Graphene Field-effect Transistor (GFET)-based biosensors utilise graphene, a two-dimensional material with high electrical conductivity, as the sensing element. These biosensors can rapidly detect several biomolecules including the SARS-CoV-2 virus, which is responsible for COVID-19. GFETs are ideal for real-time infectious illness diagnosis due to their great sensitivity and specificity. These graphene transistor-based biosensors could revolutionise clinical diagnostics by generating fast, accurate data that could aid pandemic management. GFETs can also be integrated into point-of-care (POC) diagnostic equipment. Recent advances in GFET-type biosensors for SARS-CoV-2 detection are discussed here, along with their associated challenges and future scope.

Gate electrode stacked source/drain SON trench MOSFET for biosensing application

This work inspects a dielectrically modulated (DM) stacked source/drain SiGe dual-metal trench gate silicon on nothing (SON) metal–oxide–semiconductor field-effect transistor (SiGe-DMTG SON MOSFET) biosensor to enhance the sensing capability of the device. A nano-cavity is implanted in the either side of gate area for immobilization of biomolecules which can modulate the gate capacitance and dielectric constant of the nanocavity area. Thus the device undergoes a threshold voltage shift which has a great impact on device sensitivity. So SiGe-DMTG SON MOSFET biosensor is proposed to identify the sensing performance of various analytes like Uricase (k = 1.54), Streptavidin (k = 2.1), Biotin (k = 2.63), 3-aminopropyltriethoxysilane (APTES) (k = 3.57) and protein (k = 8) using DM technique. The electrostatic properties of the neutral biomolecules such as electrostatic potential, electric field, On current, switching ratio, threshold voltage, On current sensitivity, threshold voltage sensitivity, and subthreshold performance of SiGe-DMTG SON MOSFET biosensor have been evaluated using 2D ATLAS device simulator. Further, the parasitic capacitances of the proposed biosensor has been investigated for different biomolecules in the nano-cavity region in order to observe the sensing performance of the device. From the result analysis it has been observed that for protein (k = 8), the proposed SiGe-DMTG SON MOSFET biosensor offers a threshold voltage sensitivity of 0.581 and On current sensitivity of 1.765. Apart from this, protein (k = 8) offers a strong threshold voltage shift of 104.8 mV with respect to k = 1 shows best suited for biosensing application.

Electrohydrodynamic-printed ultrathin Ti3C2Tx-MXene field-effect transistor for probing aflatoxin B1

Microarray patterns fabricated using printing technology have attracted significant research interest for the production of portable, implantable, feasible, wearable, and flexible electronics. Electrohydrodynamic (EHD) printing is an emerging, simple, and rapid electrode-patterning technology for academic and industrial applications. The development of devices composed of MXenes, 2D hexagonal crystals, which demonstrate great potential for electronic and energy storage applications, is one of the main focuses of current research efforts. Herein, we report the EHD-printed Ti3C2Tx MXene-based field-effect transistors (FET) as promising biosensors for aflatoxin B1 (AFB1) detection. The printing cycles and ink concentration were considered as the optimization objectives, and the optimized FET was validated using the output and transfer characteristics of the device. The optimized EHD-printed FET exhibited good adhesion to the substrate, high electrical conductivity, and an ideal range of resistance. The biosensor was created by functionalizing the EHD-printed MXene layers with a specific antibody against AFB1. This FET biosensor could detect the AFB1 at a concentration of 0.01 ppb with a linearity range of 0.7–20 ppb in a water medium (limit of detection = 5.689 ppb). In addition, the FET biosensor successfully detected AFB1 in food samples, such as peanut butter and meju. Thus, we have successfully demonstrated a promising EHD-printed FET biosensor for AFB1. The device is a highly selective and sensitive immunoanalytical method for AFB1 that requires no complex sample preparation steps compared with high-performance liquid chromatography.