Author: bcunning@illinois.edu

BY CLAUDIA LUTZ

July 15, 2026

Pictured left to right: Skye Shepherd, Han Keun Lee, Amanda Bacon, My Thi Tra Nguyen, and Brian Cunningham / Isaac Mitchell

Advances in medical technology have improved our health in part by bringing key aspects of care, once difficult to access, into the home. Tracking symptoms and even screening for certain types of illness outside of a laboratory or clinical setting puts more control into the hands of patients. New research from the University of Illinois is helping to provide a practical answer to the question, what does a holistic system need to look like in order to work outside the laboratory?

Research led by Han Keun Lee in the laboratory of electrical and computer engineering professor Brian Cunningham (CGD leader), in collaboration with bioengineering professor Xing Wang (CGD), was published in the IEEE Sensors Journal. Lee, Cunningham, Wang, and their coauthors shared the design and validation of a device that offers the capability to read and compare results from a variety of sensitive tests for pathogens or cancer-associated biomarkers, all within a housing similar in size and shape to an AirPods case. The study was supported by the National Institutes of Health and the U.S. Department of Veterans Affairs.

“I have an ambition that we can bring cancer detection to the home. Currently, detecting cancer often requires going to a hospital and having blood drawn,” requirements that can become barriers to accessing timely care, Lee said. “My job here is to be able to bring those tests out to the world so people can start utilizing them and have better access to the state-of-the-art technologies.”

Many home tests work similarly to pregnancy tests or infectious diseases tests such as COVID-19 antigen tests; labeled molecules generate a visible line when a substance of interest is present in the sample, producing a simple positive or negative result. This type of test is relatively affordable and easy to use, but it can have limited sensitivity and often provides only qualitative or semi-quantitative results. A new version of the test strip must also be developed for each new pathogen or biological molecule of interest.

Another type of test, commonly used in the laboratory, can be much more accurate and quantitative because it relies on the measurement of fluorescent dye whose signal can be amplified. But many existing instruments used to read fluorescent signals are not practical for home or point-of-care settings; they are large, expensive, and often require training to use correctly.

“There are many different ways of quantifying fluorescent assays. One example is using a camera to capture the whole reaction area. . . but this requires sophisticated instrumentation,” Lee said. “That was deviating from our point of view where we wanted something that’s very portable, small and inexpensive. We decided to stick with a photodetector,” a simple component that detects the intensity of light without capturing spatial information.

Using a simple light detector has its own drawbacks; a single detector does not allow a clear comparison between the sample that comes from the individual being tested and a control sample that provides a baseline negative result. Lee and his colleagues had previously designed a compact, user-friendly device they called the VPod that was able to detect fluorescence signals, but could measure only one sample at a time. Their present publication showcases their improved device, the VPodDuo, which supports a paired test-and-control workflow: this means that it is able to measure the two samples simultaneously.

VPodDuo, like the VPod before it, is also suited to point-of-care settings because of its compatibility with different molecular-assay formats. The device measures green-emitting fluorescence signals generated by several types of detection chemistry, allowing the same reader to be used with tests for different targets. The research team demonstrated that VPodDuo could accurately detect and measure quantities of genetic material from Zika virus, HIV, and methicillin-susceptible Staphylococcus aureus bacteria, as well as human genetic markers indicating the possible presence of cancer cells.

“There is a famous saying that medicine is blind without diagnostics,” Lee said. “The purpose of testing at the point-of-care is not necessarily to give a definitive diagnosis, but rather to allow more frequent testing so that someone has a better chance of receiving timely treatment.”

The VPodDuo’s versatility and accuracy make it a valuable piece of scientific equipment. To be practical for point-of-care applications, it also needed to be portable and easy to use. Lee and his coauthors designed the device to connect wirelessly to a mobile device, designed a software application with an intuitive user interface to aid with operation and result intepretation, and built in safeguards to protect against accidental misuse. All of these features are directed toward their overall goal of creating a point-of-care testing workflow that can be used outside of centralized laboratories.

“It’s not just about the individual test for point-of-care use, it’s about the entire system,” Lee said. “We wanted to address this from a system-level engineering perspective for fluorescent molecular testing. That’s where I wanted to go, so that I can help bring all these great technologies out into the world to provide real benefit.”

WRITTEN BY CASSANDRA SMITH – March 2026

Timing is critical in diagnosing diseases such as cancer. Researchers within The Grainger College of Engineering at the University of Illinois Urbana-Champaign used a historically underappreciated tiny powerhouse to detect diseases sooner. 

“I’m using all my knowledge for cancer diagnostics. That’s a shared mission between me and Professor Cunningham. ”

Seemesh Bhaskar

Seemesh Bhaskar believes cancer detection should happen years before a diagnosis ever appears in a medical chart. 

The postdoctoral researcher in Professor Brian Cunningham’s Nanosensors Group is helping develop technology that could detect signs of cancer five to eight years earlier than traditional diagnostic tools by identifying molecular signals long before symptoms emerge. 

Bhaskar is using his multidisciplinary academic background in physics, environmental diagnostics, photonics, chemistry and nanotechnology to pursue that goal.

“I’m using all my knowledge for cancer diagnostics. That’s a shared mission between me and Professor Cunningham,” Bhaskar said.  

THE RESEARCH

Their work recently appeared in Chemical Reviews — the highest-impact-factor journal in chemistry, published by the American Chemical Society. The paper represents more than two years of research, including extensive reviews of discoveries spanning from 1900 to 1980, to better understand why there is often a large gap between cancer’s initial development and its formal diagnosis. 

When it comes to disease, the timing of a diagnosis is critical. Through a combination of photonics and nanotechnology, their research could enable much earlier detection: five to eight years sooner than traditional instruments, according to Bhaskar. Their tiny technology packs a big punch.

“Everything boils down to DNA and RNA,” Bhaskar said. “They must get flicked out and do something wrong. And that will lead to cancer.” 

While the reason for a cell’s mutation remains under active study, the Illinois researchers can detect signals that may predict a cell’s mutation years later. 

“We wanted to see if we could trace it back to a point where something is happening in the cell, and can we do the real detection there?” Bhaskar said. “That is where the power of photonics comes.” 

Indeed, there is power in photonics, and it works on a microlevel. 

“We have microorganisms, viruses and bacteria in our systems that attack the body from external sources,” Bhaskar said. “They are very small. Molecules are very tiny. So we cannot see the molecules or bacteria because they are so small. The resolution is not high enough. So we need something that can talk to them.” 

Enter nanomaterials. 

Nanotechnology is small enough to interact with microRNA. Light and nanomaterials can interact with one another, and the nanomaterials can also interact with biological systems. 

“Photonics has this very strong power where we can indirectly talk to the molecules and see how they are creating problems in terms of how the disease is spreading,” Bhaskar said. 

Once researchers identify the problem area, health professionals can detect the disease and pursue treatment. 

 

SHEDDING LIGHT ON WHAT WAS IGNORED

What took so long to shed light on this powerful detection method? Bhaskar said researchers largely ignored it.

“Earth is a giant magnetic field. Light is called electromagnetic radiation,” said Bhaskar. “For so many decades, we only talked about electric flux. We totally ignored the magnetic flux of the electromagnetic radiation that is traveling. Simply because the magnetic flux cannot be accessed, there were not many accessible tools.”

Bhaskar and his team created simulations using nano-assemblies made in the laboratory that could tap into that magnetic flux potential. 

“We engineered the photonic substrates and the nano-assemblies and made them talk to each other and did the detection of microRNA,” Bhaskar said. “So, if a patient is going to get cancer five years down the line, their body is going to have a few microRNAs or DNA that are actually creating the cancer five years down the line.”

A LAB BUILT ON MENTORSHIP

Publishing  in Chemical Reviews-the first time Bhaskar and Cunningham have appeared in the journal-is a source of pride for both. 

Bhaskar said the paper was successful in part because of the laboratory environment fostered by Cunningham. 

“He treats everyone like faculty,” Bhaskar said. 

Bhaskar said Cunningham takes a holistic approach to mentoring researchers. 

“Working with him is gripping,” Bhaskar said. “Once you talk to him about what you want to do, he will go back to the same point of how it is beneficial to the society.” 

Cunningham supports researchers personally by asking during team meetings about something positive that happened in their lives that week and showing genuine interest in their well-being. 

For Bhaskar, the goal of the research ultimately comes back to people. 

“If we can detect the signals earlier, we give doctors more time,” he said. “More time means more options for treatment and a better chance for patients.” 

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Grainger Affiliations

Professor Brian T. Cunningham is an Intel Alumni Endowed Chair Professor in the Department of Electrical & Computer Engineering; Program Leader for the Cancer Center at Illinois in the Office of the Vice Chancellor for Research and Innovation; Professor in the Department of Bioengineering; Professor within the Holonyak Micro & Nanotechnology Lab; Professor of Biomedical and Translational Sciences; Professor in the Department of Nutritional Sciences;Affiliate in the Department of Chemistry;Professor in the Beckman Institute for Advanced Science and Technology;Affiliate Professor in the Carl R. Woese Institute for Genomic Biology.

A century of photonics research shapes the future of healthcare diagnostics

BY KATIE BRADY

October 23, 2025

The authors highlighted their collaborative team effort by sporting their Illini Orange and Blue. From left to right: Hankeun Lee, Joseph Tibbs, Amanda Bacon, Takhmina Ayupova, Leyang Liu, Anqi Tan, Wang-Chien Chen, Saurabh Umrao, Seemesh Bhaskar, Brian Cunningham, Xing Wang / Isaac Mitchell

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Diagnostic testing is essential in modern healthcare settings. By sensing biological molecules called biomarkers, clinicians can gain insights into what is happening in the body, invisible to the eye. Recently, a collaborative team from the Carl R. Woese Institute for Genomic Biology published a comprehensive review on photonic crystal grating resonance, or PCGR, a promising technology for improving diagnostic biosensors and early disease detection. 

The review article, published in the journal Chemical Reviews, provides a comprehensive overview of PCGR-based biosensors and their widespread applications—from pathogen detection and wearable diagnostics to environmental monitoring and toxin biosensing. It also dives into the past century of research that built the foundation for today’s technology and future advancements.

“It cites landmark works from 1907, 1947, 1956, and many more, connecting them to current breakthroughs in microRNA detection, lipid biosensing, circulating tumor DNA diagnostics, and beyond,” said Seemesh Bhaskar, first author of the paper and an IGB Postdoctoral Fellow in Professor of Electrical and Computer Engineering Brian Cunningham’s (CGD leader) research group. “To understand where we are going, it is essential to know where we have been. This review stands as a reminder that scientific foresight begins with historical awareness.” 

The first grating photonic substrate was reported in 1902. Since then, these advanced nanomaterials have become much more sophisticated, with researchers designing and fabricating specialized substrates for different applications. Photonic grating crystals are particularly beneficial for diagnostic biosensing due to their ability to manipulate how light is absorbed and reflected on the nanoscale. This helps to amplify the biosensor’s fluorescence signal and uncover ultra-low levels of molecular biomarkers such as proteins, viruses, or nucleic acids.

“One of the real strengths of this review is not just its comprehensive content, figures, and references, but also its carefully curated tables,” said Saurabh Umrao, a postdoctoral researcher in Associate Professor of Bioengineering Xing Wang’s lab. The first table of the review, for example, outlines advancements in the field over the past 20 years. Drawing on insights from over 100 studies, it provides a comprehensive list of diagnostic technologies that use one-dimensional photonic crystals. 

“In that sense, the review feels almost like an encyclopedia for the field, making it a valuable resource for both experts and newcomers,” Umrao said.

The field of diagnostics is highly broad and interdisciplinary, requiring knowledge from many areas including biology, chemistry, biomedical engineering, and materials science. A strength of this review is its holistic perspective that touches on each of these different areas, with an emphasis on not only sharing relevant information, but also providing critical analysis by experts.

When beginning the process of drafting the review, Bhaskar and Cunningham quickly realized that it was building into a much larger project than initially planned. This led them to recruit more people, and what was initially a four-person project, grew into a large team effort that played to everyone’s strengths.

Bhaskar said, “We thought the best approach was to incorporate people who have expertise in that domain. Anybody who looks at it will get a comprehensive picture, and that was only possible by having multiple people’s experience.” Bhaskar, in particular, worked on the technical background of photonics and plasmonics and personally took an interest in historical perspectives, while Cunningham used his extensive knowledge for higher level analysis like addressing current challenges and future considerations for the field. 

With background at the interface of biology and engineering, Umrao found it rewarding to write the diagnostics sections and explore emerging photonics-based technologies. Other members of the team contributed sections focused on substrate engineering or added chapters on machine learning.  

“This collaborative approach is precisely what makes the review both comprehensive and authoritative, and I’m confident it will resonate with the community,” said Leyang Liu, a graduate student in Cunningham’s lab. Liu wrote a chapter on hybrid structures, focusing on plasmonic films, Bragg mirrors, and dielectric gratings. “It’s been a pleasure to contribute to this review, and the process has been energizing and genuinely enriching.” 

As modern research has become increasingly complex and driven by discipline-specific work, the team hopes the review article can also inspire future interdisciplinary collaboration to develop new diagnostics. “Places like IGB are the best. You are put in a place where you can talk to interdisciplinary researchers. When this becomes part of life for scientists, many new ideas can come up,” Bhaskar said.

Another key aspect for advancing future PCGR-based diagnostic technologies is to addressing current pitfalls. Bhaskar and his colleagues did this by discussing topics like biosensor fabrication limitations and regulatory gaps. By identifying these issues, it can help to spark conversations that eventually lead to creative and innovative solutions.

Bhaskar said, “With a vibrant team of co-authors and collaborators, and with the support of our research centers and departments, we are excited about the continued journey of PCGR technologies and their potential to transform health diagnostics for all.”

The publication, “Photonic Crystal Grating Resonance and Interfaces for Health Diagnostic Technologies” can be found at https://doi.org/10.1021/acs.chemrev.4c00653 and was supported by the National Institutes of Health and National Science Foundation.

BY KATIE BRADY

July 1, 2025

(from left) Professor Brian Cunningham, Amanda Bacon , Joseph Tibbs , Leyang Liu, Seemesh Bhaskar, Weinan Liu  / Isaac Mitchell

Traditional medical tests often require clinical samples to be sent off-site for analysis in a time-intensive and expensive process. Point-of-care diagnostics are instead low cost, easy-to-use, and rapid tests performed at the site of patient care. Recently, researchers at the Carl R. Woese Institute for Genomic Biology reported new and optimized techniques to develop better biosensors for the early detection of disease biomarkers.

People have long been fascinated with iridescence of peacock feathers, appearing to change color as light hits them from different angles. With no pigments present in the feathers, these colors are a result of light interactions with nanoscopic structures, called photonic crystals, patterned across the surface of the feathers. 

Inspired by biology, scientists have harnessed the power of these photonic crystals for biosensing technologies due to their ability to manipulate how light is absorbed and reflected. Because their properties are a result of their nanostructure, photonic crystals can be precisely engineered for different purposes.

The Nanosensors Group at the University of Illinois Urbana-Champaign, led by Professor of Electrical and Computer Engineering Brian Cunningham (CGD leader), previously developed photonic crystal-based biosensors that amplify the fluorescence using gold nanoparticles, which act as tags for sensing various molecular biomarkers. But while this innovative technology enables low-level detection of biomarker molecules, it still has room for further improvement.

“Traditionally, metal nanoparticles, especially gold, offer the potential for fluorescence enhancement, but suffer from a fundamental flaw at close range,” said Seemesh Bhaskar, an IGB fellow in the CGD research theme and lead author of the study. “These nanoparticles can quench— or decrease—the very fluorescence signals they aim to amplify. This creates a dead zone of detection, limiting the sensitivity of biosensors.”

In a paper published in MRS Bulletin, the research team aimed to overcome this limitation by introducing a new class of cryosoret nanoassemblies; these organized structures comprised of gold nanoparticle subunits are formed via rapid cryogenic freezing. 

“Self-assembly is a fundamental principle of nature, whether it’s the formation of planetary systems in cosmology or the precise organization of nucleotides in DNA,” Bhaskar said. “What individual nanoparticles cannot accomplish alone becomes possible through their collective organization. At its core, it’s about engineering optical behavior—both structurally and functionally—through deliberate design.”

By integrating these cryosoret nanoassemblies with specially designed photonic crystals, the fluorescence demonstrated a 200-fold signal enhancement compared to the photonic crystal alone. This showed that fluorescence quenching was effectively minimized, making this technology a promising avenue for detecting low concentrations of biomarkers.

Building upon this work, the team next sought to introduce magnetic tunability into the nanoassemblies, with the long-term goal of developing intelligent, responsive biosensors.

Light is a specific frequency range of electromagnetic radiation; other examples include radio waves, microwaves, and X-rays. Electromagnetic radiation travels through space in the form of waves, and as its name suggests, consists of both electrical and magnetic components. While many biosensing systems take advantage of the electrical component of light, the magnetic component is largely overlooked.

In a study reported in the journal APL Materials, Bhaskar and his colleagues designed magneto-plasmonic cryosoret nanoassemblies. They integrated these nanoassemblies onto a photonic crystal interface and found that it successfully harnessed both the electric and magnetic components of light. They tested their platform using a common fluorophore, which resulted in ultra-sensitive detection in the attomolar range, while still minimizing fluorescence quenching. 

Overall, this dual-mode interaction allows for enhanced control over light-matter interactions at the nanoscale, offering a new method to design highly sensitive and tunable biosensing platforms.

“This work represents a hybrid optical platform where photons are not merely emitted—they are orchestrated,” Cunningham said. “This convergence of photonic-plasmonic simulations, advanced nanofabrication, and chemical engineering principles has far-reaching implications, particularly in the realm of medical diagnostics.”

Moving forward, the researchers plan to continue optimizing the cryosoret nanoassemblies to target specific biomarkers, like microRNAs, circulating tumor DNA, and viral particles, for early detection of cancer and infectious disease. They hope that with further improvement, point-of-care technologies can meet the pressing need for sensitive, accessible, and deployable biosensing systems.

The publication in MRS Bulletin “Photonic-crystal-enhanced fluorescence: Template-free gold cryosoret nanoassembly steering, dequenching, and augmenting the quenched emission from radiating dipoles” can be found at https://doi.org/10.1557/s43577-024-00850-2

The publication in APL Materials “Photonic crystal band edge coupled enhanced fluorescence from magneto-plasmonic cryosoret nano-assemblies for ultra-sensitive detection” can be found at https://doi.org/10.1063/5.0251312 

The work was supported by the National Institutes of Health, National Science Foundation, and Cancer Center at Illinois.

BY KATIE BRADY

June 16, 2025

Graduate student in electrical and computer engineering Han Lee (left) and Professor Brian Cunningham (right) / Julia Pollack

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What if people could detect cancer and other diseases with the same speed and ease of a pregnancy test or blood glucose meter? Researchers at the Carl R. Woese Institute for Genomic Biology are a step closer to realizing this goal by integrating machine learning-based analysis into point-of-care biosensing technologies. 

The new method, dubbed LOCA-PRAM, was reported in the journal Biosensors and Bioelectronics and improves the accessibility of biomarker detection by eliminating the need for technical experts to perform the image analysis.

Traditional medical diagnostic techniques require doctors to send patients’ blood or tissue samples to clinical laboratories where expert scientists carry out the testing procedures and data analysis. 

“Current technologies require patients to visit hospitals to get diagnostics which takes time. A lot of people also have barriers where more appointments may not be financially or spatially feasible,” said Han Lee, first author of the study and a graduate student in the Nanosensors research group. “I think that we can make a difference by developing more point-of-care technologies that are available for people.”

Point-of-care diagnostics are performed and yield results at the site of patient care, whether at home, the doctor’s office, or anywhere in between. This allows for lower cost, easy-to-use, and rapid tests that can help inform next steps. Some examples already adopted in everyday life include urine pregnancy tests, COVID-19 antigen testing kits, and blood glucose meters which allow people with diabetes to respond to dips and spikes in their blood glucose levels throughout the day.

In the point-of-care field, researchers are investigating new ways to integrate these types of technologies into patient care settings, such as appointments with specialists like oncologists or oral surgeons. This would help to reduce the time and financial burden on patients, while improving real-time decision making for physicians.

“Physicians say they would like something similar to when you go in with bacterial infection. They do a test on you right there and then send you home from your appointment with the right antibiotics that will treat the particular bacteria that you have,” said Brian Cunningham (CGD leader), a professor of electrical and computer engineering. “So why not do a similar thing for choosing the right anti-cancer drug or determining if the drug you’ve been taking for a couple weeks is starting to work or not.”

Previously, the group reported a new biosensing method called Photonic Resonator Absorption Microscopy, or PRAM, to detect molecular biomarkers—molecules in the body whose presence and levels indicate healthy or disease states. PRAM enables the detection of single biomarker molecules including nucleic acids, antigens, and antibodies; common biosensing techniques instead detect the cumulative signal of hundreds to thousands of molecules. 

Cunningham said, “Basically, what we’re doing is shining a red LED light at the bottom of a sensor. Then on the top of the sensor, molecules are landing and getting detected whenever they have a tiny particle made out of gold—which we call gold nanoparticles or AuNPs—attached to it.”

The images generated using PRAM depict a red background with little black spots sprinkled across it. But while these images themselves seem relatively simple, obtaining an accurate count requires a trained eye that can decipher what spots truly correspond to the AuNP-tagged biomarker molecules.

“There are many kinds of artifacts such as dust particles or aggregates of the nanoparticles. If you don’t have a lot of experience, it’s hard to distinguish them,” Lee said. “The conventional counting algorithm that we’ve been using requires adjusting a lot of parameters to get rid of those artifacts.”

In order to move this process out of the laboratory and make it better suited for point-of-care environments, Lee proposed integrating machine learning into the image analysis process.

“Han really on his own developed an interest in machine learning after taking a class here at the university just to learn about it,” Cunningham said. “He came to me one day and said that he thought he could make a machine learning algorithm count our black spots more accurately.”

Compared to other biosensing techniques, PRAM lends itself well for incorporating deep learning algorithms because it generates microscope images, rather than just detecting optical signals. But because these algorithms are only as good as the data that trained it, Lee decided to image the same samples using both PRAM and scanning electron microscopy. 

The AuNPs, which are 1000 times smaller than human hair and only show up as small black spots in the PRAM images, can be more clearly visualized on the electron microscope. In a time intensive process, Lee cross referenced every spot in the PRAM images with the electron microscope images to obtain highly accurate data for the machine learning training set. 

“Finding the right spot to compare to was actually very challenging because it’s like finding a needle in a desert. One way that I devised was to create a reference point, like a lighthouse in a sea. Then from there we can find the exact same spot for registrations,” Lee said.

The resulting deep learning-based method, called Localization with Context Awareness, integrated with PRAM, enables real-time, high precision detection of molecular biomarkers without needing the eyes and experience of a technical expert. When tested, the team found that LOCA-PRAM surpassed conventional techniques in accuracy, detecting lower levels of the biomarkers and minimizing rates of false-positive and negatives.

“The whole journey of my PhD was started because I wanted to make changes in the point-of-care field,” Lee said. “I just want to do everything in my power to develop more advanced technologies that can be impactful in the future.”

The publication, “Physically grounded deep learning-enabled gold nanoparticle localization and quantification in photonic resonator absorption microscopy for digital resolution molecular diagnostics” can be found at https://doi.org/10.1016/j.bios.2025.117455 and was supported by the National Institutes of Health, USDA AFRI Nanotechnology grant, and National Science Foundation.