Researchers develop dental floss capable of measuring stress

Fraser Macdonald, Dental Tribune International

Mon. 23. June 2025

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MEDFORD, Mass., US: Stress can present as a wide range of physical, emotional and social symptoms, such as irritability, headache, anxiety and elevated heart rate. In addition to these manifestations, salivary cortisol serves as a well-established biomarker of physiological stress, reflecting levels found in the bloodstream. Since stress is of a damaging and pervasive nature in the precarious, time-sensitive, incessant world in which we live, a tool capable of quickly and accurately measuring cortisol levels in saliva would be highly efficacious. As outlined in a recent study, a team of researchers at Tufts University in the US has developed a floss pick that can do just that.

Stress is without question a bane of our time, and recent studies have shown not only that it is globally pervasive but that its intensity is increasing with each passing year. While blood work remains the most precise means of measuring stress, few are willing or able to regularly accommodate such procedures in their daily lives. It is precisely this niche that the researchers at Tufts sought to fill with their dental floss. Speaking in a university press release, co-author Dr Sameer Sonkusale, professor of electrical and computer engineering, said: “We didn’t want measurement to create an additional source of stress, so we thought, can we make a sensing device that becomes part of your day-to-day routine? Cortisol is a stress marker found in saliva, so flossing seemed like a natural fit to take a daily sample.”

Dental flosser for at-home stress monitoring. (Image: American Chemical Society)

The researchers’ device looks like a regular floss pick, but it is anything but. When the pick is used, saliva is drawn up by capillary action through a very narrow channel in the floss and into the pick handle and an attached sensor, where it spreads across electrodes that detect cortisol. Cortisol detection on the electrodes is achieved using an impressive technology that originated nearly 30 years ago, known as electro-polymerised molecularly imprinted polymers (eMIPs). This method involves forming a polymer around a target molecule—cortisol in this case—which is later removed, leaving the polymer with tiny cavities—binding sites—that match cortisol’s shape and chemical properties. These sites retain a memory of the cortisol molecule, allowing them to selectively recognise and capture free-floating cortisol molecules that come into contact.

According to Dr Sonkusale: “The eMIP approach is a game-changer. Biosensors have typically been developed using antibodies or other receptors that pick up the molecule of interest. Once a marker is found, a lot of work has to go into bioengineering the receiving molecule attached to the sensor.” However, “eMIP does not rely on a lot of investment in making antibodies or receptors,” he continued, so “if you discover a new marker for stress or any other disease or condition, you can just create a polymer cast in a very short period of time”.

While the everyday functionality of the device is thus highly significant, Dr Sonkusale was also careful to point out that the device is best suited for tracking existing conditions as opposed to providing initial diagnoses. “For diagnostics, blood is still the gold standard, but once you are diagnosed and put on medication, if you need to track, say, a cardiovascular condition over time to see if your heart health is improving, then monitoring with the sensor can be easy and allows for timely interventions when needed,” he said.

The paper, titled “Saliva-sensing dental floss: An innovative tool for assessing stress via on-demand salivary cortisol measurement with molecularly imprinted polymer and thread microfluidics integration”, was published on 30 April 2025 in ACS Applied Materials and Interfaces.