Two-dimensional-material-based field-effect transistor biosensor platform for rapid, sensitive, and selective pathogen detection

Background

The field of pathogen detection is critical for public health, particularly in the context of rapidly spreading infectious diseases such as COVID-19. Early and accurate identification of pathogens enables timely intervention, effective patient management, and containment of outbreaks. Traditional diagnostic methods, such as reverse transcription polymerase chain reaction (RT-PCR), are highly sensitive but require complex sample preparation, specialized equipment, and trained personnel, leading to long turnaround times and limited accessibility in point-of-care settings. As a result, there is a pressing need for rapid, sensitive, and selective diagnostic technologies that can be easily integrated into portable platforms for widespread use.

Current approaches to biosensing, including conventional field-effect transistor (FET) biosensors, face significant limitations that hinder their practical deployment. Graphene-based FETs, while offering high sensitivity due to their large surface area, suffer from intrinsic drawbacks such as zero bandgap, which leads to high off-state leakage currents and reduced signal-to-noise ratio. Other 2D semiconducting materials, like transition metal dichalcogenides, show promise but are typically fabricated using high-temperature processes such as chemical vapor deposition (CVD) or molecular beam epitaxy (MBE). These methods are not compatible with standard photolithographic microfabrication, restricting scalability and integration with existing electronic manufacturing workflows. Additionally, achieving uniform, defect-controlled films with tunable properties remains challenging, limiting the reproducibility and calibration of biosensors for reliable pathogen detection.

Technology

This technology is a field-effect transistor (FET) biosensor platform that leverages a monolayer or few-layer two-dimensional (2D) metal chalcogenide—such as tungsten diselenide (WSe₂)—as the active sensing channel for rapid and sensitive pathogen detection. The 2D channel is functionalized with a specific biorecognition element, such as an antibody, which is covalently attached using a chemical linker (11-mercaptoundecanoic acid, MUA) that binds to chalcogen vacancies on the material’s surface. The biosensor is fabricated through a process involving pulsed laser ablation to deposit an amorphous 2D material at low temperature, followed by thermal crystallization, all compatible with photolithographic patterning of interdigitated source and drain electrodes. When a target pathogen binds to the antibody on the channel, the electrical current across the FET changes, providing a direct and measurable detection signal. The platform is adaptable for various targets by simply changing the biorecognition element.

This solution is differentiated by its integration of tunable 2D semiconducting materials and a manufacturing process that is both scalable and compatible with standard microfabrication techniques. Unlike graphene-based FETs, which suffer from off-state leakage due to their zero bandgap, the use of semiconducting metal chalcogenides provides high sensitivity and selectivity with a well-defined bandgap. The pulsed laser ablation method enables precise control over the composition, thickness, and defect density of the 2D material, which is critical for optimizing sensor performance and functionalization. Additionally, the low-temperature process allows for direct integration with photolithographically patterned substrates, supporting batch fabrication and device uniformity. The result is a highly sensitive, selective, and versatile biosensor platform capable of detecting extremely low concentrations of pathogens, such as the SARS-CoV-2 spike protein, with rapid electrical readout and minimal cross-reactivity.

Benefits

• High sensitivity and selectivity for pathogen detection, capable of detecting SARS-CoV-2 spike protein at ultra-low concentrations (down to 25 fg/μL).
• Rapid, label-free electrical detection enabling fast diagnostics compared to traditional methods like RT-PCR.
• Use of tunable two-dimensional metal chalcogenide materials with suitable bandgap, overcoming limitations of graphene-based sensors.
• Low-temperature pulsed laser deposition process compatible with photolithographic patterning and standard microfabrication techniques.
• Scalable and CMOS-compatible manufacturing method allowing batch fabrication with uniform device performance.
• Adaptable biosensor platform by changing the biorecognition element to detect various pathogens or biomarkers.
• Enhanced device stability and functionalization through covalent attachment of antibodies via a chemical linker to vacancy sites on the 2D material.

Applications

• Rapid infectious disease diagnostics
• Point-of-care pathogen detection
• Environmental pathogen monitoring
• Food safety testing
• Biomarker-based health screening

Additional info

This field-effect transistor biosensor utilizes a 2D metal chalcogenide channel, functionalized with a specific biorecognition element via an MUA linker. Pathogen binding to the element alters the channel’s electrical current, providing a detection signal. Manufacturing involves pulsed laser ablation of amorphous 2D material, followed by thermal crystallization, compatible with photolithography for sensitive and selective pathogen detection.