FET-Based Sensors Pave Way for Portable Diagnostic Devices Capable of Detecting Multiple Diseases

By LabMedica International staff writers
Posted on 17 Dec 2024

Image: Site-selective immobilization of different bioreceptors on individual field-effect transistors, achieved through the use of thermal scanning probe lithography (Photo courtesy of NYU Tandon)

In a world facing a wide range of health challenges, from rapidly spreading viruses to chronic diseases and drug-resistant bacteria, the demand for fast, reliable, and user-friendly home diagnostic tests is more critical than ever. Imagine a future where these tests can be conducted anywhere, by anyone, using a device as portable as a smartwatch. To make this a reality, microchips must be developed that can detect extremely low concentrations of viruses or bacteria in the air. New research shows that it is possible to design microchips capable of identifying multiple diseases from a single cough or air sample and to manufacture them at scale.

A team of researchers at NYU Tandon School of Engineering (Brooklyn, NY, USA) has introduced a groundbreaking technology using field-effect transistors (FETs), which are small electronic sensors that detect biological markers and convert them into digital signals. This technology presents an alternative to traditional color-based chemical tests, such as home pregnancy tests. The innovation allows for quicker results, simultaneous testing for multiple diseases, and instant data sharing with healthcare providers. FETs, widely used in modern electronics, are becoming essential in developing diagnostic tools. These miniature devices can be adapted as biosensors to detect specific pathogens or biomarkers in real-time, eliminating the need for chemical labels or lengthy laboratory procedures. By converting biological interactions into measurable electrical signals, FET-based biosensors provide a fast and versatile diagnostic platform.

Recent advancements have dramatically improved the sensitivity of FET biosensors, enabling them to detect concentrations as small as femtomolar levels, or one quadrillionth of a mole, by incorporating materials like nanowires, indium oxide, and graphene. However, despite their potential, FET sensors still face a significant hurdle: the challenge of detecting multiple pathogens or biomarkers simultaneously on a single chip. Existing methods, such as applying bioreceptors like antibodies to the FET’s surface, lack the precision and scalability needed for complex diagnostic tasks. To overcome this, the researchers are exploring new techniques to modify FET surfaces, allowing each transistor on a chip to detect a different biomarker, which would enable the parallel detection of multiple pathogens.

One promising solution is thermal scanning probe lithography (tSPL), a cutting-edge technology that allows for precise chemical patterning on a polymer-coated chip. This process enables the functionalization of individual FETs with different bioreceptors, such as antibodies or aptamers, at resolutions as fine as 20 nanometers, which matches the size of modern transistors. By enabling highly selective modifications of each transistor, this method could create FET-based sensors capable of detecting a wide array of pathogens on a single chip with exceptional sensitivity. In tests, FET sensors functionalized using tSPL demonstrated remarkable performance, detecting as few as 3 attomolar (aM) concentrations of SARS-CoV-2 spike proteins and identifying as few as 10 live virus particles per milliliter, all while distinguishing between various virus types, including influenza A.

The ability to accurately detect such minuscule amounts of pathogens with high specificity is a crucial step toward developing portable diagnostic devices for various settings, from hospitals to homes. As semiconductor technology continues to advance, it is becoming increasingly feasible to integrate billions of nanoscale FETs onto microchips. A universal, scalable approach for functionalizing FET surfaces with nanoscale precision would enable the creation of advanced diagnostic tools capable of detecting multiple diseases in real time with unmatched speed and accuracy, potentially revolutionizing modern healthcare. Following the study published in the journal Nanoscale, the research team is now focusing on developing wearable and home diagnostic devices that could detect illnesses.

“This study opens new horizons in the field of biosensing,” said NYU Tandon Professor Elisa Riedo. “Microchips, the backbone of smartphones, computers, and other smart devices, have transformed the way people communicate, entertain, and work. Similarly, today, our technology will allow microchips to revolutionize healthcare, from medical diagnostics, to environmental health.”