A flu test you can chew

Why Detecting Flu Early Matters

Staying home is one of the best ways to stop viruses from spreading, but people with influenza can be contagious before they even feel sick. Current diagnostic tools, such as nasal swab-based PCR tests, are highly accurate yet costly and slow. At-home lateral flow tests, similar to those used for COVID-19, are cheaper and more convenient but often miss infections during the early, pre-symptomatic stage.

Lorenz Meinel and his colleagues aimed to close this gap, writing that they sought to improve flu detection "by switching away from complex detectors and machinery and toward a detector that is available for anyone, everywhere and anytime: the tongue."

Turning Taste Into a Diagnostic Tool

The research team created a molecular sensor that releases a detectable flavor -- thymol, a compound found in the herb thyme. The sensor is designed to respond to neuraminidase, a glycoprotein on the surface of the influenza virus (the "N" in H1N1). This enzyme helps the virus break certain chemical bonds on host cells to infect them.

To mimic that process, the scientists synthesized a neuraminidase substrate and attached a thymol molecule to it. Thymol produces a distinctive herbal taste. In theory, if a person carrying the flu virus chews gum containing the sensor, viral activity would cleave the thymol molecules, releasing their flavor in the mouth.

In laboratory tests, the sensor produced free thymol within 30 minutes when mixed with saliva samples from people who had the flu. Tests on human and mouse cells showed that it did not alter normal cell function. The researchers now plan to move toward human clinical trials in about two years to confirm whether people infected with influenza can detect the thymol flavor both before and after symptoms appear.

Gum and Lozenges Could Be the Next Testing Frontier

If successful, the technology could turn something as ordinary as chewing gum into a quick and accessible flu screening tool. "This sensor could be a rapid and accessible first-line screening tool to help protect people in high-risk environments," Meinel explains.

The study was supported by the Federal Ministry of Research and Education (now called the Federal Ministry of Research, Technology and Space), and the researchers have filed a patent with the European Patent Office for this innovative detection method.