As the BA.5 omicron variant continues to spread, health experts are increasingly preparing for a future in which such COVID-19 variants emerge, rise, and recede like the seasonal flu. An important component of staying on top of these changes will be the ability to rapidly monitor the virus at “population scale,” an effort that will require accurate and lightning-fast testing.
To help meet this challenge, researchers at the IUPUI School of Science are developing a novel biosensor with the potential to achieve the speed and efficiency required for the future of COVID-19 testing.
The work was recently reported in Applied hardware interfaces, a journal of the American Chemical Society. It is led by Rajesh Sardar, a professor of chemistry and chemical biology in the School of Science, and Adrianna Masterson, a graduate student in Sardar’s lab at the time of the study.
“Everyone is looking for high-throughput testing; this kind of high-speed analysis is essential for the future of the fight against COVID-19,” Sardar said. “Our technology has many advantages in particular: it is fast, efficient, accurate and of unprecedented sensitivity. »
In terms of speed, Sardar’s lab’s COVID-19 test can currently analyze samples from 96 people in less than three hours, he said. In terms of efficiency, the system requires only 10 microliters of blood.
By comparison, a typical blood panel order by a primary care physician collects 10 milliliters of blood, or more than 1,000 times more.
The sensor also works with other sample types, such as saliva, Sardar said. But the study was conducted using blood because it is the most complex bodily fluid and therefore the best indicator of a sensor’s accuracy. All test samples were obtained from the Indiana Biobank, which provided 216 blood samples, including 141 samples from COVID-19 patients and 75 healthy control samples.
Based on a blinded analysis, the IUPUI researchers found that their biosensor’s accuracy rate was 100% and its specificity rate was 90%. In other words, the sensor never reported a false negative and only reported a false positive in 1 out of 10 samples. For public safety purposes, Sardar said the absence of false negatives is more important than false positives, because a person with a false negative can unknowingly infect others, while a person with a false positive is not a danger.
Additionally, Sardar said the sensor has proven to be very accurate in measuring the body’s COVID-19 antibody concentration. This is because it not only detects the spike protein of the virus, but also proteins created by the body to protect against the virus – immunoglobin G or IgG.
He also said the ability to measure COVID-19 antibodies is important because many COVID-19 antibody tests currently approved under FDA Emergency Use Authorization do not provide specific numbers. specific antibodies, despite the fact that this number indicates the strength of a person’s immunity to infection.
“Accurately measuring patient immunity levels will be key to protecting against COVID-19 in the future,” Sardar said. “This is clearly seen in our current situation, as variants like omicron – and, more recently, BA.5 – infect even fully vaccinated and boosted individuals. »
To achieve its results, Sardar’s lab biosensor uses chemically synthesized triangular gold nanoprisms, which provide a unique and powerful optical response even to minute amounts of IgG. It also means that the sensor can detect antibodies in the early stages of infection.
The work, which began at the start of the pandemic, builds on promising initial results published in June 2021. Next, Sardar aims to further refine the technology, with the aim of eventually being able to process 384 samples in less than an hour. – – or 5,000 samples per day, if used in a larger test center.
“This research is about preparing for the future,” said Sardar, who is also a researcher at Indiana University Melvin and the Bren Simon Comprehensive Cancer Center. “The H1N1 strain of influenza is almost 100 years old. I expect the coronavirus to be with us for a long time as well. Looking ahead, we need to find ways to measure the infections or infection risks of many people quickly, easily, and efficiently in order to stay ahead of the virus. »
This work was supported in part by the NIH’s National Center for Advancing Translational Science through a grant from Indiana’s CTSI.