At a Glance
Filiz Yesilkoy, PhD, assistant professor, UW–Madison College of Engineering, Department of Biomedical Engineering, and co-principal investigators Irene Ong, PhD, assistant professor, Department of Obstetrics and Gynecology and Miriam Shelef, MD, PhD, associate professor, Department of Medicine, developed a user-friendly, cost-effective, point-of-care serology test for monitoring protective immunity against COVID-19. By developing this biosensor platform, investigators can more easily assess vaccination status, past infection status and protective immunity to inform communities in Wisconsin of the risk of COVID-19.
The Challenge
Serology tests, which detect antibodies against viral antigens, play a crucial role in understanding past exposures and immune response to vaccinations. Findings from serology tests can inform public health measures and help contain the spread of COVID-19. Conventional serology tests require central clinical laboratory facilities and trained personnel. However, approximately one-third of Wisconsin’s population live in rural areas and have limited access to frequent testing. In addition, communities of color in urban populations have limited access to healthcare. Developing a simple and accurate point-of-care (POC) serology test is important for widespread protective immunity monitoring against COVID-19.
Project Goals
The primary goal of this project was to develop and validate a POC COVID-19 serologic test to advance the management of the COVID-19 pandemic. Widespread immunity monitoring can inform individuals and policymakers of the risk of SARS-CoV-2 infection.
The PIs identified two specific aims:
- Develop a POC biosensor platform that can quantitatively profile anti-SARS-CoV-2 antibodies against a cohort of immunologically significant antigens, including recently discovered viral epitopes and proteins from emerging variants.
- Demonstrate that the POC biosensor can identify past COVID-19 infection, vaccination, and immunity based on the quantitative antibody profiling measurements.
Results
The researchers developed a new POC biosensor platform to measure antibodies against SARS-CoV-2 virus. Specifically, they built an optical reader and a fluidic cartridge for on-site plasma extraction. They determined best-practice protocol to optimize the POC biosensor’s performance, achieving measures proven to be suitable for serological immunity detection and that correlate well with established methods.
They measured human serum samples from various COVID-19 immunity groups against the wild-type and Omicron variant of SARS-CoV-2 antigens. They used the antibody profiles from the immunity groups to train a machine learning (ML) algorithm. Using the trained ML algorithm, they then classified 100 blind human serum samples based on their antibody concentration profiles against various viral antigens. The past infection, vaccination, and Omicron rates estimated by their approach showed strong correlation with the Wisconsin Health Department’s epidemiological data. This supports the biosensor’s ability to identify past infection, vaccination, and infection from different variants and its use for immunity surveillance of WI communities.
Lasting Impact
This new rapid and compact serological test platform could enable the monitoring of COVID-19 immunity to be accessible for broad Wisconsin populations and beyond.
The success of the biosensor approach motivated the team to develop new types of novel sensor chips that can be manufactured using sustainable materials and high-throughput semiconductor chip production facilities to reduce their cost and broaden their accessibility. This effort can make a large impact in broad serology test based clinical diagnostics by decreasing cost per test drastically.
The biosensor technology developed under this project is well suited for rapid screening of various protein-based disease markers. Also, the biosensor technology was proposed to detect biomarkers for traumatic brain injury for a Department of Defense grant, which is approved for funding. The outcomes of this project were used in various proposals for federal funding.
