Elisa Riedo

In a world grappling with a multitude of health threats — ranging from fast-spreading viruses to chronic diseases and drug-resistant bacteria — the need for quick, reliable, and easy-to-use home diagnostic tests has never been greater. Imagine a future where these tests can be done anywhere, by anyone, using a device as small and portable as your smartwatch. To do that, you need microchips capable of detecting miniscule concentrations of viruses or bacteria in the air. 

Now, new research from NYU Tandon faculty including Professor of Electrical and Computer Engineering Davood Shahrjerdi; Herman F. Mark Professor in Chemical and Biomolecular Engineering Elisa Riedo; and Giuseppe de Peppo, Industry Associate Professor in Chemical and Biomolecular Engineering and who was previously at Mirimus, shows it’s possible to develop and build microchips that can not only identify multiple diseases from a single cough or air sample, but can also be produced at scale. 

“This study opens new horizons in the field of biosensing. 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” says Riedo,

“The innovative technology demonstrated in this article uses field-effect transistors (FETs) — miniature electronic sensors that directly detect biological markers and convert them into digital signals — offering an alternative to traditional color-based chemical diagnostic tests like home pregnancy tests,” said Shahrjerdi. “This advanced approach enables faster results, testing for multiple diseases simultaneously, and immediate data transmission to healthcare providers” says Sharjerdi, who is also the Director of the NYU Nanofabrication Cleanroom, a state-of-the-art facility where some of the chips used in this study were fabricated. Riedo and Shahrjerdi are also the co-directors of the NYU NanoBioX initiative.

Field-effect transistors, a staple of modern electronics, are emerging as powerful tools in this quest for diagnostic instruments. These tiny devices can be adapted to function as biosensors, detecting specific pathogens or biomarkers in real time, without the need for chemical labels or lengthy lab procedures. By converting biological interactions into measurable electrical signals, FET-based biosensors offer a rapid and versatile platform for diagnostics.

Recent advancements have pushed the detection capabilities of FET biosensors to incredibly small levels — down to femtomolar concentrations, or one quadrillionth of a mole — by incorporating nanoscale materials such as nanowires, indium oxide, and graphene. Yet, despite their potential, FET-based sensors still face a significant challenge: they struggle to detect multiple pathogens or biomarkers simultaneously on the same chip. Current methods for customizing these sensors, such as drop-casting bioreceptors like antibodies onto the FET’s surface, lack the precision and scalability required for more complex diagnostic tasks.

To address this, these researchers are exploring new ways to modify FET surfaces, allowing each transistor on a chip to be tailored to detect a different biomarker. This would enable parallel detection of multiple pathogens.

Enter thermal scanning probe lithography (tSPL), a breakthrough technology that may hold the key to overcoming these barriers. This technique allows for the precise chemical patterning of a polymer-coated chip, enabling the functionalization of individual FETs with different bioreceptors, such as antibodies or aptamers, at resolutions as fine as 20 nanometers. This is on par with the tiny size of transistors in today’s advanced semiconductor chips. By allowing for highly selective modification of each transistor, this method opens the door to the development of FET-based sensors that can detect a wide variety of pathogens on a single chip, with unparalleled sensitivity.

Riedo, who was instrumental in the development and proliferation of tSPL technology, sees its use here to be further evidence of the groundbreaking way this nanofabrication technique can be used in practical applications. “tSPL, now a commercially available lithographic technology, has been key to functionalize each FET with different bio-receptors in order to achieve multiplexing,” she says.

In tests, FET sensors functionalized using tSPL have shown remarkable performance, detecting as few as 3 attomolar (aM) concentrations of SARS-CoV-2 spike proteins and as little as 10 live virus particles per milliliter, while effectively distinguishing between different types of viruses, including influenza A. The ability to reliably detect such minute quantities of pathogens with high specificity is a critical step toward creating portable diagnostic devices that could one day be used in a variety of settings, from hospitals to homes.

The study, now published by the Royal Society of Chemistry in Nanoscale, was supported by Mirimus, a Brooklyn-based biotechnology company, and LendLease, a multinational construction and real estate company based in Australia. They are working with the NYU Tandon team to develop illness-detecting wearables and home devices, respectively.

“This research shows off the power of the collaboration between industry and academia, and how it can change the face of modern medicine,” says Prem Premsrirut, President and CEO of Mirimus. “NYU Tandon’s researchers are producing work that will play a large role in the future of disease detection.”

“Companies such as Lendlease and other developers involved in urban regeneration are searching for  innovative solutions like this to sense biological threats in buildings.” says Alberto Sangiovanni Vincentelli of UC Berkeley, a collaborator on the Project. “Biodefense measures like this will be a new infrastructural layer for the buildings of the future”

As semiconductor manufacturing continues to advance, integrating billions of nanoscale FETs onto microchips, the potential for using these chips in biosensing applications is becoming increasingly feasible. A universal, scalable method for functionalizing FET surfaces at nanoscale precision would enable the creation of sophisticated diagnostic tools, capable of detecting multiple diseases in real time, with the kind of speed and accuracy that could transform modern medicine.

Graphene, a single layer of carbon atoms arranged in a two-dimensional honeycomb lattice, is known for its exceptional properties: incredible strength (about 200 times stronger than steel), light weight, flexibility, and excellent conduction of electricity and heat. These properties have made graphene increasingly important in applications across various fields, including electronics, energy storage, medical technology, and, most recently, quantum computing.

Graphene’s quantum properties, such as superconductivity and other unique quantum behaviors, are known to arise when graphene atomic layers are stacked and twisted with precision to produce “ABC stacking domains.” Historically, achieving ABC stacking domains required exfoliating graphene and manually twisting and aligning layers with exact orientations—a highly intricate process that is difficult to scale for industrial applications.

Now, researchers at NYU Tandon School of Engineering led by Elisa Riedo, Herman F. Mark Professor in Chemical and Biomolecular Engineering, have uncovered a new phenomenon in graphene research, observing growth-induced self-organized ABA and ABC stacking domains that could kick-start the development of advanced quantum technologies. The findings, published in a recent study in the Proceedings of the National Academy Of Sciences (PNAS), demonstrate how specific stacking arrangements in three-layer epitaxial graphene systems emerge naturally — eliminating the need for complex, non-scalable techniques traditionally used in graphene twisting fabrication.

These researchers, including Martin Rejhon, previously a post-doctoral fellow at NYU, have now observed the self-assembly of ABA and ABC domains within a three-layer epitaxial graphene system grown on silicon carbide (SiC). Using advanced conductive atomic force microscopy (AFM), the team found that these domains form naturally without the need for manual twisting or alignment. This spontaneous organization represents a significant step forward in graphene stacking domains fabrication.

The size and shape of these stacking domains are influenced by the interplay of strain and the geometry of the three-layer graphene regions. Some domains form as stripe-like structures, tens of nanometers wide and extending over microns, offering promising potential for future applications. 

“In the future we could control the size and location of these stacking patterns through pregrowth patterning of the SiC substrate,” Riedo said.

These self-assembled ABA/ABC stacking domains could lead to transformative applications in quantum devices. Their stripe-shaped configurations, for example, are well-suited for enabling unconventional quantum Hall effects, superconductivity, and charge density waves. Such breakthroughs pave the way for scalable electronic devices leveraging graphene's quantum properties.

This discovery marks a major leap in graphene research, bringing scientists closer to realizing the full potential of this remarkable material in next-generation electronics and quantum technologies.

The funding for this research came from the Army Research Office, a directorate of U.S. Army Combat Capabilities Development Command Army Research Laboratory under Award # W911NF2020116. This research also included researchers from Charles University, Prague.

Jason Lipton, a Ph.D. candidate under the guidance of Taylor, was lead author. Elisa Riedo (chemical and biomolecular engineering)  and researchers from Drexel University and the Brookhaven National Laboratory also participated.

The proliferation and miniaturization of electronics in devices, wearables medical implants and other applications has made technologies for blocking electromagnetic interference (EMI) especially important, while making their implementation more challenging. While EMI can cause disruptions in communication in critical applications, resulting in potentially disastrous consequences, traditional EMI shields require large thicknesses to be effective, hampering design flexibility. 

One solution resides in MXenes, a family of 2D transition metal carbides, nitrides, and carbonitrides with potential for blocking EMI demonstrate high conductivity and excellent EMI shielding properties. The key to the commercialization of these materials is industry-scale manufacturing.

A multi-institution research team led by Andre ́ D. Taylor, professor of chemical and biomolecular engineering at the NYU Tandon School of Engineering demonstrated a novel approach to MXene fabrication that could lead to methods for at-scale production of MXene freestanding films: drop-casting onto pre-patterned hydrophobic substrates. Their method led to a 38% enhancement of EMI shielding efficiency over conventional methods. The work suggests that micropatterned MXene films, prepared using a method that is scalable and allows for high throughput, can be readily used in EMI shielding, energy storage, and optoelectronics applications.

The team cast aqueous dispersions of MXene nanosheets (with the formula Ti3C2Tx) on hydrophobic polystyrene substrates and dried them. After drying, the resulting free-standing films could be easily peeled off, a method demonstrating a variety of advantages over the conventional vacuum-assisted filtration method with regards to time efficiency, operation simplicity, and surface smoothness. 

The drop-casting method allows for modulation of micrometer-scale 3D patterns on the film surface by utilizing pre-patterned substrates (such as a vinyl record, retroreflective packaging, and retroreflective tape). 

The research, “Scalable, Highly Conductive, and Micropatternable MXene Films for Enhanced Electromagnetic Interference Shielding,” is published in the first-anniversary issue of the Cell Press publication Matter.