A new fluorescence analytical device, similar in size to an AirPods case, promises to revolutionize the way rapid and practical molecular tests can be performed in the home environment. The technology aims to facilitate access to important diagnostics outside of the traditional laboratory environment.
Innovations in the area of medical technology have contributed significantly to improving health, by making crucial aspects of care, previously difficult to access, more present in everyday life. Monitoring symptoms and screening for various diseases, outside of laboratories or clinics, gives patients greater autonomy.
In this context, recent research from the University of Illinois has been dedicated to offering a practical solution to the question of how a comprehensive diagnostic system could operate outside the confines of a laboratory.
The investigation was led by Han Keun Lee in the laboratory of electrical and computer engineering professor Brian Cunningham, in partnership with bioengineering professor Xing Wang. The results of the study were published in the IEEE Sensors Journal.
Lee, Cunningham, Wang and their collaborators presented the design and validation of a device capable of reading and comparing sensitive test results for pathogens or biomarkers linked to cancer, all in a compact format that resembles an AirPods case. The study, which has the potential to democratize access to early detection of serious diseases such as cancer, was funded by the National Institutes of Health (NIH) and the US Department of Veterans Affairs.
Challenges with Existing Home Testing Methods
“My ambition is to make it possible to detect cancer at home. Currently, identifying the disease often requires going to hospitals and having blood drawn,” Lee explained, noting that these requirements can be major obstacles to affordable and timely care. “My work here is to expand the use of these tests globally, so that people can use them and have better access to cutting-edge technologies.”
Many home tests available today work similarly to pregnancy tests or antigen tests for infectious diseases such as COVID-19. They use labeled molecules that generate a visible line when the substance of interest is present in the sample, delivering a binary result, positive or negative. Although these tests are relatively inexpensive and easy to use, their sensitivity can be limited and they often provide only qualitative or semiquantitative results.
Furthermore, for each new pathogen or biological molecule of interest, a new version of the test strip needs to be specifically developed.
Another test modality, widely used in laboratories, offers greater precision and quantitative capacity, based on the measurement of a fluorescent dye whose signal can be intensified. However, most existing equipment for reading fluorescent signals is not suitable for home or point-of-care use as they are large, expensive and often require specialized training for correct operation.
Development of a compact reader for comparative analysis
“There are several ways to quantify fluorescence assays. One involves using a camera to record the entire reaction area, but this requires complex instrumentation,” said Lee.
“Such an approach was far from our objective of creating something portable, small and accessible. We therefore chose to maintain the photodetector”, a simpler component that measures light intensity without capturing spatial information.
However, the use of a single light detector has its own limitations, as it does not allow a clear comparison between the tested sample and a control sample, which would serve as a negative reference.
Lee and his collaborators had already developed a compact and intuitive device, the VPod, which could detect fluorescence signals, but measured only one sample at a time. Current research introduces VPodDuo, an enhanced version that enables a paired test and control workflow, allowing simultaneous measurement of both samples.
The VPodDuo, like its predecessor the VPod, is also suitable for point-of-care use due to its compatibility with multiple molecular assay formats. The device is capable of measuring green fluorescence signals emitted by different types of detection reagents, which allows the same reader to be used in tests for different targets.
The research team was able to demonstrate that VPodDuo can accurately detect and quantify genetic material from viruses such as Zika and HIV, the bacteria Staphylococcus aureus resistant to methicillin, and also human genetic markers that signal the possible presence of cancer cells.
Building a complete diagnostics workflow
“There is a well-known saying that medicine is blind without a diagnosis,” commented Lee. “The purpose of point-of-care testing is not necessarily to provide a definitive diagnosis, but rather to enable more frequent testing, increasing the chances of the patient receiving treatment in a timely manner.”
The versatility and high precision of the VPodDuo qualify it as scientific equipment of great value. To be practical in direct patient care applications, the device also needed to be portable and easy to use.
Lee and his co-authors designed the device to connect wirelessly to a mobile device, developed an app with an intuitive interface to aid in operation and interpretation of results, and integrated security measures to prevent accidental misuse. All of these features are designed with the primary goal of creating a point-of-care testing workflow that can be employed outside of centralized laboratories.
“This isn’t just about an individual test for point-of-care use, it’s about the entire system,” Lee emphasized. “Our intention was to approach this from a systems engineering perspective for fluorescent molecular testing. That’s where I wanted to go, to be able to help bring all of these great technologies to the world and provide real benefits.”
