BALTIMORE — Imagine being able to swab the inside of your mouth, place it in a device and quickly know whether you’re infected with COVID-19.

Johns Hopkins University researchers say they have developed a simple sensor that could quickly and accurately detect the virus that causes COVID-19 in saliva.

The sensor isn’t on the market yet, but soon could revolutionize testing, the researchers say. It could be stationed at the entrances of hospitals, airports and schools, and potentially be put into handheld and even wearable devices.

It also can detect other viruses.

In testing, the sensor was as accurate as PCR tests, the current gold standard in testing during the pandemic that requires lab processing. It also was as fast as rapid antigen tests, the at-home kits that have become prevalent but aren’t as good picking up cases.

“The technique is as simple as putting a drop of saliva on our device and getting a negative or a positive result,” said Ishan Barman, an associate professor of mechanical engineering at Johns Hopkins and a senior author on a study published this week in Nano Letters.

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The researchers said there is no sample preparation and it requires minimal operator expertise. They currently plan to use a swab test to acquire the saliva.

To process, the sensor uses machine learning and a combination of other technologies to detect viruses. That includes a process called nanoimprint fabrication and a kind of spectroscopy to analyze the saliva sample, which is using laser light to look at amplified molecules.

The process can detect even traces of virus, said David Gracias, a Hopkins professor of chemical and biomolecular engineering and another senior study author with Barman.

“Our platform goes beyond the current COVID-19 pandemic,” said Barman. “We can use this for broad testing against different viruses, for instance, to differentiate between SARS-CoV-2 and H1N1, and even variants. This is a major issue that can’t be readily addressed by current rapid tests.”

Johns Hopkins Technology Ventures has applied for patents for the technology and plans to commercialize the sensor.