Carl R. Woese Institute for Genomic Biology

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.”