A new portable smartphone device could help make flying during the pandemic less of a headache for travelers.
According to the CDC’s latest travel regulations, all air passengers must have a negative COVID test before boarding a flight to the United States. What if you could test yourself at the airport, right before you’re handed your boarding pass?
A stamp-sized device developed by Rice University researchers could make this a reality. It plugs into your smartphone’s charging port and gives you the results in under an hour.
Nasal swabs for conventional PCR-based COVID tests aren’t fun, but more critically for jet-setting passengers, they take time to process the results. Here’s where the new “lab-on-a-chip” is a step ahead.
“What’s great about this device is that it doesn’t require a laboratory,” said Peter Lillehoj, mechanical engineer and one of the device’s inventors. “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 diagnostic device invented by Lillehoj and the team contains specialized nanobeads that bind to the N protein of SARS-CoV-2 present in a blood sample from a finger prick. The nanobeads are then pulled towards an ultrasensitive electrochemical sensor by capillary action. These sensors then detect even trace amounts of the viral biomarker.
Lillejoj and colleagues validated the device’s performance by logging the results from a library of serum samples taken from both COVID-positive and negative donors. They found an optimal time for incubating nanobeads with serum samples such that it reliably detected extremely low concentrations of the N protein: 55 minutes. Diluting the serum sample fivefold halved this time and allowed the system to flag even lower viral protein concentrations.
“There are standard procedures to modify the beads with an antibody that targets a particular biomarker,” explained Lillehoj. “When you combine them with a sample containing the biomarker, in this case, SARS-CoV-2 N protein, they bond together.”
The beads binding to capture antibodies present on the electrochemical sensors generate an electrical signal proportional to the amount of N protein in the serum sample. This signal is then transmitted to a phone app where the user can see the test’s result.
According to Lillehoj, commercial-scale manufacturing of such microfluidic chips is relatively straightforward, and modifying them to test for new COVID variants as they emerge would also be doable.