Researchers at Rice University have developed a microfluidic device that can test for the presence of SARS-CoV-2 in a drop of blood and display its results once plugged into a cell phone. The test runs in under an hour, and works by detecting SARS-CoV-2 nucleocapsid protein using antibody-studded magnetic nanobeads. In tests, the device could detect very low levels of the protein, suggesting that it could function as a sensitive diagnostic tool.
The fight against COVID-19 continues, and testing is one of our most commonly deployed and useful weapons in stopping the spread of the virus. PCR remains the gold standard test for the virus, but it is time consuming and requires highly trained lab technicians and equipment. Rapid tests, that can be performed in doctors’ clinics, airports, or even in pharmacies, would be very useful in helping to prevent transmission.
These issues have inspired this latest device, which can detect a viral protein in a small drop of blood, such as that from a finger prick. People may have personal preferences with regard to a finger prick or nasal swab, but it may be nice not to have to insert a large swab deep inside your nose to determine your COVID status. One of the other big benefits of the device is its portability.
“What’s great about this device is that doesn’t require a laboratory,” said Peter Lillehoj, a researcher involved in the study, in a Rice announcement. “You can perform the entire test and generate the results at the collection site, health clinic or even a pharmacy. The entire system is easily transportable and easy to use.”
The microfluidic chip contains magnetic nanobeads studded with antibodies against the SARS-CoV-2 nucleocapsid protein. “There are standard procedures to modify the beads with an antibody that targets a particular biomarker,” said Lillehoj. “When you combine them with a sample containing the biomarker, in this case SARS-CoV-2 N protein, they bond together.”
An external magnet draws the beads towards an electrochemical sensor that generates a current in response to the captured protein. When plugged into a standard smartphone, the device sends these data to an app for easy interpretation of the results. The test is rapid, providing results in as little as 55 minutes, and can detect as little as 50 picograms of the protein per milliliter.