Multifunctional Integrated Biosensors Based on Two-Dimensional Field-Effect Transistors.

In recent years, field-effect transistor (FET) sensing technology has attracted significant attention owing to its noninvasive, label-free, real-time, and user-friendly detection capabilities. Owing to the large specific surface area, high flexibility, and excellent conductivity of two-dimensional (2D) materials, FET biosensors based on 2D materials have demonstrated unique potential in biomarker analysis and healthcare applications, driving continuous innovation and transformation in the field. Here, we review recent trends in the development of 2D FET biosensors based on key performance metrics and main characteristics, and we also discuss structural designs and modification strategies for biosensing devices utilizing graphene, transition metal dichalcogenides, black phosphorus, and other 2D materials to enhance key performance metrics.

Supercapacitively Liquid-Solid Dual-State Optoelectronics.

Photo-transduction of solid-state optoelectronics occurs in semiconductors or their interfaces. Considering the confined active area and interfacial capacitance of solid-state materials, solid-state optoelectronics faces inherent limitations in photo-transduction, especially for bionic vision, and the performance is lower than that of living systems. For example, a photoreceptor generates pA-level photocurrent when absorbing a single photon.

Enzymatic cascade reactors on carbon nanotube transistor detecting trace prostate cancer biomarker.

Biosensors based on carbon nanotube field-effect transistors (CNT-FETs) have shown great potential in biomarker detection due to their high sensitivity because of appreciable semiconducting electrical properties. However, background signal interferences in complex mediums may results in low signal-to-noise ratio, which may impose challenges for precise biomarker detection in physiological fluids. In this work, we develop an enzymatic CNT-FET, with scalable production at wafer scale, for detection of trace sarcosine that is a biopsy-correlated biomarker of prostate cancer.

DNA Logical Computing on a Transistor for Cancer Molecular Diagnosis.

Given the high degree of variability and complexity of cancer, precise monitoring and logical analysis of different nucleic acid markers are crucial for improving diagnostic precision and patient survival rates. However, existing molecular diagnostic methods normally suffer from high cost, cumbersome procedures, dependence on specialized equipment and the requirement of in-depth expertise in data analysis, failing to analyze multiple cancer-associated nucleic acid markers and provide immediate results in a point-of-care manner. Herein, we demonstrate a transistor-based DNA molecular computing (TDMC) platform that enables simultaneous detection and logical analysis of multiple microRNA (miRNA) markers on a single transistor.

One-base-mismatch CRISPR-based transistors for single nucleotide resolution assay.

An effective strategy for accurately detecting single nucleotide variants (SNVs) is of great significance for genetic research and diagnostics. However, strict amplification conditions, complex experimental instruments, and specialized personnel are required to obtain a satisfactory tradeoff between sensitivity and selectivity for SNV discrimination. In this study, we present a CRISPR-based transistor biosensor for the rapid and highly selective detection of SNVs in viral RNA.

Photovoltaic nanocells for high-performance large-scale-integrated organic phototransistors.

A high-performance large-scale-integrated organic phototransistor needs a semiconductor layer that maintains its photoelectric conversion ability well during high-resolution pixelization. However, lacking a precise design for the nanoscale structure, a trade-off between photoelectric performance and device miniaturization greatly limits the success in commercial application. Here we demonstrate a photovoltaic-nanocell enhancement strategy, which overcomes the trade-off and enables high-performance organic phototransistors at a level beyond large-scale integration.

Artificial Tactile Receptor System for Sensitive Pressure-Neural Spike Conversion.

An artificial tactile receptor is crucial for e-skin in next-generation robots, mimicking the mechanical sensing, signal encoding, and preprocessing functionalities of human skin. In the neural network, pressure signals are encoded in spike patterns and efficiently transmitted, exhibiting low power consumption and robust tolerance for bit error rates. Here, we introduce a highly sensitive artificial tactile receptor system integrating a pressure sensor, axon-hillock circuit, and neurotransmitter release device to achieve pressure signal coding with patterned spikes and controlled neurotransmitter release.

Electrically Oriented Antibodies on Transistor for Monitoring Several Copies of Methylated DNA.

An antibody transistor is a promising biosensing platform for the diagnosis and monitoring of various diseases. Nevertheless, the low concentration and short half-life of biomarkers require biodetection at the trace-molecule level, which remains a challenge for existing antibody transistors. Herein, we demonstrate a graphene field-effect transistor (gFET) with electrically oriented antibody probes (EOA-gFET) for monitoring several copies of methylated DNA.

Antibody Nanotweezer Constructing Bivalent Transistor-Biomolecule Interface with Spatial Tolerance.

Establishing a multivalent interface between the biointerface of a living system and electronic device is vital to building intelligent bioelectronic systems. How to achieve multivalent binding with spatial tolerance at the nanoscale remains challenging. Here, we report an antibody nanotweezer that is a self-adaptive bivalent nanobody enabling strong and resilient binding between transistor and envelope proteins at biointerfaces.

Electro-Optical Multiclassification Platform for Minimizing Occasional Inaccuracy in Point-of-Care Biomarker Detection.

On-site diagnostic tests that accurately identify disease biomarkers lay the foundation for self-healthcare applications. However, these tests routinely rely on single-mode signals and suffer from insufficient accuracy, especially for multiplexed point-of-care tests (POCTs) within a few minutes. Here, this work develops a dual-mode multiclassification diagnostic platform that integrates an electrochemiluminescence sensor and a field-effect transistor sensor in a microfluidic chip.

An Alternating Current Electroosmotic Flow-Based Ultrasensitive Electrochemiluminescence Microfluidic System for Ultrafast Monitoring, Detection of Proteins/miRNAs in Unprocessed Samples.

Early diagnosis of acute diseases is restricted by the sensitivity and complex process of sample treatment. Here, an ultrasensitive, rapid, and portable electrochemiluminescence-microfluidic (ECL-M) system is described via sandwich-type immunoassay and surface plasmonic resonance (SPR) assay. Using a sandwich immunoreaction approach, the ECL-M system employs cardiac troponin-I antigen (cTnI) as a detection model with a Ru@SiO NPs labeled antibody as the signal probe.

Ultra-fast supercritically solvothermal polymerization for large single-crystalline covalent organic frameworks.

Crystalline polymer materials, e.g., hyper-crosslinked polystyrene, conjugate microporous polymers and covalent organic frameworks, are used as catalyst carriers, organic electronic devices and molecular sieves.

The Application of Graphene Field-Effect Transistor Biosensors in COVID-19 Detection Technology: A Review.

Coronavirus disease 2019 (COVID-19) is a disease caused by the infectious agent of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2). The primary method of diagnosing SARS-CoV-2 is nucleic acid detection, but this method requires specialized equipment and is time consuming. Therefore, a sensitive, simple, rapid, and low-cost diagnostic test is needed.

Chemical Sensors Based on Covalent Organic Frameworks.

Covalent organic frameworks (COFs) are a type of crystalline porous polymer composed of light elements through strong covalent bonds. COFs have attracted considerable attention due to their unique designable structures and excellent material properties. Currently, COFs have shown outstanding potential in various fields, including gas storage, pollutant removal, catalysis, adsorption, optoelectronics, and their research in the sensing field is also increasingly flourishing.

Ultra-Fast Single-Nucleotide-Variation Detection Enabled by Argonaute-Mediated Transistor Platform.

"Test-and-go" single-nucleotide variation (SNV) detection within several minutes remains challenging, especially in low-abundance samples, since existing methods face a trade-off between sensitivity and testing speed. Sensitive detection usually relies on complex and time-consuming nucleic acid amplification or sequencing. Here, a graphene field-effect transistor (GFET) platform mediated by Argonaute protein that enables rapid, sensitive, and specific SNV detection is developed.

A closed-loop catalytic nanoreactor system on a transistor.

Precision chemistry demands miniaturized catalytic systems for sophisticated reactions with well-defined pathways. An ideal solution is to construct a nanoreactor system functioning as a chemistry laboratory to execute a full chemical process with molecular precision. However, existing nanoscale catalytic systems fail to in situ control reaction kinetics in a closed-loop manner, lacking the precision toward ultimate reaction efficiency.

Catalytic Hairpin Assembly-Enhanced Graphene Transistor for Ultrasensitive miRNA Detection.

MicroRNAs (miRNAs) have emerged as powerful biomarkers for disease diagnosis and screening. Traditional miRNA analytical techniques are inadequate for point-of-care testing due to their reliance on specialized expertise and instruments. Graphene field-effect transistors (GFETs) offer the prospect of simple and label-free diagnostics.

Highly Bionic Neurotransmitter-Communicated Neurons Following Integrate-and-Fire Dynamics.

In biological neural networks, chemical communication follows the reversible integrate-and-fire (I&F) dynamics model, enabling efficient, anti-interference signal transport. However, existing artificial neurons fail to follow the I&F model in chemical communication, causing irreversible potential accumulation and neural system dysfunction. Herein, we develop a supercapacitively gated artificial neuron that mimics the reversible I&F dynamics model.

Molecular-electromechanical system for unamplified detection of trace analytes in biofluids.

Biological research and diagnostic applications normally require analysis of trace analytes in biofluids. Although considerable advancements have been made in developing precise molecular assays, the trade-off between sensitivity and ability to resist non-specific adsorption remains a challenge. Here, we describe the implementation of a testing platform based on a molecular-electromechanical system (MolEMS) immobilized on graphene field-effect transistors.

Electrical Nanobiosensors for Nucleic Acid Based Diagnostics.

Recent advances in nanotechnologies have promoted the iterative updating of nucleic acid sensors. Among various sensing technologies, the electrical nanobiosensor is regarded as one of the most promising prospects to achieve rapid, precise, and point-of-care nucleic acid based diagnostics. In this Perspective, we introduce recent progresses in electrical nanobiosensors for nucleic acid detection.