Researchers from Tufts University and Stanford University unveiled a smart dental floss that not only cleans teeth but also monitors stress levels in real time by measuring cortisol, the quintessential stress hormone. The saliva is analyzed through electrodes placed on the floss and sent to a mobile application via an internal sensor, according to a press release published on EurekAlert.

"We didn't want the measurement to create an additional source of stress, so we asked ourselves: can we create a detection device that becomes an integral part of the daily routine?" said Sameer Sonkusale, the chief developer of the device and a professor of electrical and computer engineering at Tufts University.

Unchecked chronic stress can lead to health conditions such as heart disease, increased blood pressure, cardiovascular disease, and mental disorders, including depression and anxiety. Many people are not aware of their stress level until physical or emotional symptoms appear, and over time, stress and anxiety can build to a point where life's challenges become overwhelming and cause physical effects, including decreased immune function.

Current stress monitoring tools often rely on self-reported questionnaires, which are subjective, and psychiatric evaluations, making them imprecise or expensive. The smart dental floss detects stress levels by analyzing saliva through integrated chemical sensors, making it a useful tool for monitoring chronic diseases and early detection of health changes over time.

Because cortisol, the stress hormone, is found in saliva, dental floss is an ideal tool for measuring its levels. The prototype resembles classic dental floss, featuring a taut thread on two tips extending from a flat plastic handle approximately the size of an index finger. When used, saliva is picked up by capillary action through a very narrow channel in the floss. The fluid is drawn into the pick handle and an attached tab, where it spreads across electrodes capable of detecting cortisol.

The recognition of cortisol on the electrodes is achieved using electropolymerized molecularly imprinted polymer technology (eMIPs). This involves embossing cortisol molecules into an electrically conductive film and then removing them, similar to a shoe leaving an impression in wet cement. The binding sites created by eMIPs have a physical and chemical shape 'memory' of the target molecule, allowing them to bind free incoming molecules.

"The eMIP approach is a game changer," Sonkusale stated. "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." He emphasized that eMIP does not rely on a lot of investment in making antibodies or receptors, greatly reducing production costs and offering advantages in speed and versatility compared to traditional antibody-based sensors.

Laboratory validation demonstrated that the accuracy of the cortisol sensors is comparable to the best-performing devices on the market or in development. This allows for daily monitoring of the user's health without additional effort, enabling people to control their health by leveraging a routine action like using dental floss.

There is potential for detecting multiple biomarkers in saliva at the same time using this technology. "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," Sonkusale explained. Other molecules that can be detected include estrogen for fertility tracking, glucose for diabetes monitoring, or markers for cancer.

"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 added. Detecting multiple biomarkers can allow for more accurate monitoring of stress, cardiovascular disease, cancer, and other conditions.

Although the prototype has only been tested in a laboratory environment and has not yet been tried with real users, the results are promising. The researchers acknowledge limitations in the device and note that further development is needed for real user experience. Sonkusale and his colleagues are creating a startup to try and bring the product to market, with scientists estimating it could be available in one or two years at an affordable price.

Bringing this device into the home and into the hands of individuals without the need for training could fold stress monitoring into many aspects of health care. The smart dental floss addresses the problem of tracking stress, which is difficult to measure properly. Current cortisol analysis relies on blood samples and lab work, which are not feasible for daily monitoring. The smart floss offers a practical and user-friendly alternative to traditional laboratory analyses.

While the prototype stands out for being practical and suitable for everyday use, further clinical testing is necessary. The researchers are optimistic about the potential impact of this technology on personal health monitoring.

Research advancements are leading to more innovations aimed at caring for user well-being. The integration of eMIP-based sensors into everyday objects opens the door to new applications in personal health monitoring. This expands the potential of the smart dental floss beyond stress control, positioning it as a useful tool for monitoring chronic diseases and the early detection of health changes.

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