Source: NYU Tandon School of Engineering (December 12, 2024). AI-generated summary by biochip.com, published . Not independently reviewed.
Key takeaways
- NYU Tandon used thermal scanning probe lithography to place different bioreceptors on individual field-effect transistors for multiplexed sensing.
- The FET sensors detected SARS-CoV-2 spike protein at 3 attomolar concentrations and 10 live virus particles per milliliter.
- The work does not establish performance in finished wearable or home diagnostic devices using real-world samples.
NYU Tandon researchers have developed a method for turning individual transistors on a microchip into distinct biological sensors, potentially allowing one device to test for several diseases from a cough or air sample. The approach uses field-effect transistors, or FETs, miniature electronic components that can detect biological markers and convert those encounters into digital signals. By pairing FETs with a nanofabrication method called thermal scanning probe lithography, the team selectively placed different disease-recognizing molecules on different transistors. In reported tests, the resulting sensors detected SARS-CoV-2 spike protein at concentrations as low as 3 attomolar and detected 10 live virus particles per milliliter. They also distinguished SARS-CoV-2-related targets from influenza A, an important test of specificity. The work addresses a central hurdle for chip-based diagnostics: putting many precisely tailored sensors on one chip without relying on imprecise, difficult-to-scale coating methods. NYU Tandon professors Davood Shahrjerdi, Elisa Riedo, and Giuseppe de Peppo contributed to the research, published in Nanoscale by the Royal Society of Chemistry. The technology remains a step toward portable diagnostic products, but its combination of multiplexing, electrical readout, and chip-scale fabrication could help make disease sensing more compact and connected.
Giving Each Transistor a Different Job
A conventional home test often works through a visible color change, like a pregnancy test. An FET biosensor works more like a tiny electronic switch: when a target molecule binds to a recognition molecule on its surface, that interaction changes an electrical signal that the chip can measure.
FETs are already basic building blocks of phones and computers, but researchers can adapt them for sensing by attaching bioreceptors to their surfaces. These bioreceptors can be antibodies or aptamers, short molecules designed to bind particular biological targets. The result is a sensor that can identify a pathogen or biomarker without chemical labels or lengthy laboratory procedures.
The Multiplexing Challenge
High sensitivity alone is not enough for a useful diagnostic device. A person with respiratory symptoms, for example, may need testing for more than one virus, and environmental monitoring may require a device to distinguish among several biological threats at once.
That capability is called multiplexing, meaning that multiple targets are measured in parallel. Existing approaches often place bioreceptors on a transistor by drop-casting, essentially depositing a small liquid drop onto the device. That method lacks the placement precision and scalability needed to reliably assign a different receptor to each transistor across a more complex chip.
Patterning at the Nanoscale
The NYU Tandon team used thermal scanning probe lithography, or tSPL, to address that problem. Like an extremely fine-tipped pen working on a polymer-coated surface, tSPL can create chemical patterns where they are needed, allowing the researchers to functionalize individual FETs with selected bioreceptors.
The technique operates at resolutions as fine as 20 nanometers, comparable to dimensions found in advanced semiconductor chips. That level of control lets neighboring transistors carry different biological recognition molecules, rather than all being coated with the same material. Elisa Riedo, who helped develop and advance tSPL technology, said the commercially available lithographic method was key to functionalizing each FET with different bioreceptors for multiplexed sensing.
What the Sensors Detected
The functionalized FET sensors detected SARS-CoV-2 spike proteins at 3 attomolar concentrations. An attomolar measurement is extraordinarily small: one attomole is one quintillionth of a mole, so this result reflects the device's ability to register very low amounts of its intended target.
The sensors also detected 10 live virus particles per milliliter and distinguished between viruses that included influenza A. Specificity matters because a diagnostic tool must do more than react to biological material in general. It needs to produce a different, reliable electrical response when the target of interest is present instead of a closely related or competing signal.
From Chip Fabrication to Possible Devices
Shahrjerdi, director of the NYU Nanofabrication Cleanroom, described the FET approach as an alternative to color-based chemical tests. Because the output is digital, the platform could in principle deliver rapid results, run multiple disease tests simultaneously, and transmit data to health care providers. Riedo and Shahrjerdi also co-direct NYU's NanoBioX initiative.
The work received support from Mirimus, a Brooklyn biotechnology company, and LendLease, an Australian multinational construction and real estate company. Mirimus is working with the NYU Tandon team on illness-detecting wearables, while LendLease is working with the team on home devices. Those collaborations place the fabrication research in the context of potential consumer and environmental-health applications.
Why This Matters
Many promising biosensors work well as one-off laboratory demonstrations but become harder to manufacture when they need many sensors, each with a different biological target. The tSPL process directly tackles that manufacturing problem by making receptor placement an addressable, transistor-by-transistor step. If that precision can be carried into practical devices, a small electronic chip could perform several pathogen checks from a single sample.
The immediate result is a platform for highly sensitive, multiplexed FET biosensors, not a finished home diagnostic product. Still, the research points toward devices that merge semiconductor manufacturing with molecular recognition, much as a camera chip combines millions of light-sensitive pixels into one compact component. The next stage will be translating that controlled chip chemistry into durable wearable, household, and clinical systems that can handle real samples outside a research setting.
Topics: Biosensors · Diagnostics & precision medicine · Infectious diseases
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