Imagine using dental floss in the morning and getting information about a hormone involved in your body’s stress response.
It may sound futuristic, but researchers at Tufts University have developed an experimental dental-floss device that can measure cortisol directly in saliva.
The technology combines ordinary-looking dental floss with advanced materials, tiny fluid channels, and an electrochemical sensor. In laboratory testing, the device produced cortisol measurements in approximately 11–12 minutes.
The original findings, published in ACS Applied Materials & Interfaces in April 2025, demonstrated that this unconventional approach could accurately detect very small quantities of cortisol in human saliva.
Since then, further research published through October 2026 has expanded scientists’ understanding of portable saliva sensors and the challenges of interpreting cortisol measurements.
The results suggest that everyday objects could eventually become convenient tools for monitoring selected biological markers.
However, the dental-floss sensor is an experimental prototype, not an established device for diagnosing stress, anxiety, or other medical conditions.
Understanding the difference between measuring a hormone and diagnosing a health problem is essential to appreciating what this innovation can, and cannot, do.
What Is Saliva-Sensing Dental Floss?
Saliva-sensing dental floss is an experimental biosensor that collects saliva and measures cortisol concentrations.
Researchers developed the device to resemble a familiar floss pick, with a thread stretched between two small prongs.
Unlike conventional dental floss, it uses a specialized mechanism to move saliva toward a sensing area.
The design aims to make sample collection less disruptive than some conventional laboratory testing procedures.
A person uses the floss pick to collect a saliva sample. The liquid travels through the thread and reaches an electrochemical sensor, where cortisol is detected.
The prototype is connected to an electronic readout system that processes the measurement.
The technology does not determine stress simply by examining teeth or gums.
Instead, it uses saliva as a source of biological information.
The central idea is that collecting samples during an ordinary activity might make repeated hormone measurements more convenient.
Researchers hope this could eventually help people understand how their physiological state changes over time.
Why Does Cortisol Matter?
Cortisol is a hormone produced by the adrenal glands above the kidneys.
It plays important roles in several physiological processes, including:
- Regulating metabolism and energy availability.
- Supporting the body’s response to physical and psychological stressors.
- Influencing immune and inflammatory activity.
- Helping maintain normal blood pressure.
- Contributing to the body’s daily sleep-wake rhythm.
Cortisol is often called the stress hormone because its production can increase during challenging situations.
However, cortisol is not exclusively a marker of negative emotions.
It is an essential hormone involved in normal everyday functioning.
Cortisol Changes Throughout the Day
Cortisol concentrations usually follow a daily rhythm.
Levels often rise around waking and generally decline later in the day, although patterns vary between people.
Other factors can influence cortisol measurements, including sleep, exercise, illness, medication, food intake, and the timing of sample collection.
Consequently, a cortisol value cannot be interpreted without considering the context in which it was obtained.
Someone with a relatively high cortisol reading may not necessarily be experiencing psychological distress.
Likewise, a person reporting severe stress may not have an unusually high reading at a particular moment.
This is one reason researchers monitor cortisol patterns over time instead of relying solely on isolated measurements.
A September 2026 review in RSC Advances emphasized that salivary cortisol is best understood as an additional physiological measurement rather than a standalone diagnostic test for mental health disorders.
Why Measure Cortisol in Saliva?
Cortisol can be measured in blood, urine, and saliva.
Each method has specific clinical uses and limitations.
Saliva collection is attractive for frequent monitoring because it generally does not require needles or complex sample collection.
Salivary cortisol largely reflects the unbound fraction of cortisol available to enter saliva.
Scientists have investigated its use in endocrinology, stress research, and studies of sleep and daily physiological rhythms.
However, obtaining a reliable measurement can still be challenging.
Samples may need to be collected at specific times, stored properly, and analyzed with appropriate laboratory techniques.
One widely used analytical method is an enzyme-linked immunosorbent assay, or ELISA.
Such assays can measure cortisol concentrations, but laboratory processing may delay results.
Portable biosensors attempt to simplify this process by bringing the measurement closer to the point of sample collection.
The Tufts dental-floss device is one example of this emerging approach.
The Original 2025 Tufts University Study
On April 17, 2025, researchers Atul Sharma, Nafize Ishtiaque Hossain, Ayanna Thomas, and Sameer Sonkusale published a study titled:
The research appeared in ACS Applied Materials & Interfaces, volume 17, issue 17, pages 25083–25096.
Scientists from engineering and psychology disciplines at Tufts University in Massachusetts worked together.
Their objective was to design a practical method to measure cortisol in saliva without relying on a conventional laboratory-based sample-collection system.
The researchers combined two main technologies:
- Thread-based microfluidics, which transports saliva through very small spaces.
- Molecularly imprinted polymers, which help the sensor recognize cortisol molecules.
They integrated these technologies with a graphene-based electrochemical sensing platform.
The resulting prototype offered a way to collect saliva with dental floss and measure cortisol in the sample.
How Does the Smart Dental Floss Actually Work?
The device uses a combination of fluid movement, molecular recognition, and electronic measurement.
Although the underlying science is sophisticated, its operation can be understood in four stages.
Step 1: Collecting Saliva During Flossing
When the floss contacts saliva, the liquid enters the thread.
The thread acts as a narrow pathway that can transport small amounts of fluid.
This process is possible because of capillary action, the movement of liquid through narrow spaces due to interactions between the liquid and surrounding surfaces.
Capillary action also helps water travel through paper towels and certain plant tissues.
Here, the same physical principle allows saliva to move through the sensing system.
Step 2: Transporting Saliva Toward the Sensor
Once collected, the saliva travels through the thread-based microfluidic pathway.
The fluid reaches a sensing region containing specially prepared electrodes.
The researchers designed this pathway to deliver samples consistently while reducing interference from the surrounding environment.
Consistent fluid transport matters because variations in sample volume or sensor contact can affect measurement reliability.
Step 3: Recognizing Cortisol Molecules
The sensor uses molecularly imprinted polymers, or MIPs, to recognize cortisol.
These synthetic polymers are prepared using a process that creates molecular binding sites shaped and chemically suited to a target substance.
In simple terms, the researchers build a material around cortisol molecules and then remove them.
The remaining binding sites can selectively interact with cortisol when a saliva sample enters the sensor.
This approach offers an alternative to recognition systems that rely on biological antibodies or other receptors.
Step 4: Generating an Electrical Measurement
The cortisol-sensitive material is integrated with an electrochemical electrode.
Cortisol interactions with the sensing layer change the measurable electrical response.
Electronic equipment processes the signal and estimates the cortisol concentration.
The research also explored wireless readout capability.
The result is a quantitative measurement of salivary cortisol, not a direct assessment of how someone feels emotionally.
What Makes Molecularly Imprinted Polymers Important?
Molecularly imprinted polymers are central to the Tufts design.
Many biological sensors use antibodies or biological receptors to detect target molecules.
Instead, MIPs create synthetic recognition sites designed for specific compounds.
This can offer potential advantages in manufacturing, storage stability, and sensor customization.
The Tufts researchers used electropolymerized molecularly imprinted polymers, often abbreviated as eMIPs.
They integrated these polymers with a porous laser-engraved graphene electrode.
Graphene is a carbon-based material with electrical properties that make it attractive for certain sensing applications.
The porous electrode increases the available surface area for sensor interactions.
Together, these features allowed researchers to detect cortisol at low concentrations.
The technology is promising because similar molecularly imprinted materials could potentially be developed for other biological targets.
Nevertheless, creating a sensor for another molecule requires its own experiments.
A cortisol sensor cannot automatically measure glucose, estrogen, inflammatory markers, or cancer-related biomarkers without appropriate changes and validation.
How Accurate Was the Dental-Floss Sensor?
The 2025 study reported encouraging analytical performance.
Researchers evaluated the device using artificial saliva and actual human saliva samples.
Several results were particularly notable.
1. Detection of Very Small Cortisol Concentrations
The researchers reported a detection limit of 0.048 picograms per milliliter (pg/mL).
A picogram is one-trillionth of a gram.
The low detection limit showed that the experimental sensor could respond to very small quantities of cortisol under the tested conditions.
However, a low detection limit alone does not establish clinical usefulness.
A medically useful sensor must also perform consistently across the concentrations encountered in real people.
2. A Broad Analytical Detection Range
The reported detection range extended from approximately 0.10 to 10,000 pg/mL.
The researchers observed a strong calibration relationship under their experimental conditions.
This suggests that the system could respond across a wide span of cortisol concentrations.
But calibration performance in controlled testing does not guarantee reliable interpretation of every sample collected in everyday life.
3. Results Within Approximately 11–12 Minutes
The dental-floss system produced measurements in approximately 11–12 minutes.
This is substantially faster than workflows that require samples to be transported to a laboratory for later analysis.
Still, the result is not instantaneous.
In the study, “real-time” means obtaining on-demand measurements with the sensing system rather than waiting for a conventional laboratory process.
It should not be confused with uninterrupted, continuous monitoring.
4. Strong Agreement With Laboratory Measurements
When researchers compared the sensor’s results with conventional ELISA measurements in human saliva samples, they reported a correlation coefficient of r = 0.9910.
The study also reported recovery values between 98.64% and 102.4%, with a relative standard deviation of 5.01% in its experimental analyses.
These findings suggest strong analytical agreement under the tested conditions.
However, the results do not establish that the device can diagnose chronic stress or distinguish people with anxiety disorders from those without them.
Such claims would require separate, appropriately designed clinical validation studies.
What Did Researchers Actually Test in Humans?
The original study tested human saliva collected under an approved research protocol.
The purpose was to evaluate the sensor’s ability to detect cortisol in authentic biological samples.
The researchers also investigated changes in a controlled, stress-related research setting.
Comparisons with laboratory assays supported the device’s analytical performance.
This provides a more meaningful assessment than testing only purified cortisol solutions.
Human saliva is chemically complex, containing proteins, electrolytes, enzymes, and many other substances.
A sensor that works in a laboratory buffer may perform differently in actual saliva.
However, several limitations remain.
The study did not establish that the prototype could reliably identify mental health conditions.
It did not demonstrate improvements in patient treatment, health outcomes, or stress-related illnesses.
Nor did it show how the device would perform in a large, diverse population used repeatedly at home.
The research is best understood as an encouraging proof of concept for noninvasive cortisol measurement.
March 2026 Update: Tufts Explains the Broader Vision
On March 20, 2026, Tufts University published a detailed feature about biomedical sensing technologies developed by Professor Sameer Sonkusale and his research team.
The feature described the dental-floss system as part of a broader effort to make biological monitoring less disruptive.
According to the university, the prototype uses a specialized floss pick that draws saliva through a narrow channel.
After collection, the pick can be inserted into a separate electronic device that displays cortisol measurements.
The team also described a monitoring platform that could incorporate additional measurements such as heart rate and blood oxygen saturation.
This clarification is important.
The sensing system is not simply ordinary dental floss that produces a reading on its own.
It requires engineered sensing components and an electronic measurement system.
The researchers suggested that routine sampling could eventually help people examine relationships between biological measurements and daily activities.
For instance, repeated cortisol measurements might let scientists investigate patterns linked to sleep, environmental conditions, or stressful tasks.
However, such applications would require appropriate interpretation and further validation.
Read the March 2026 Tufts University feature.
July 2026: Another Approach to Salivary Cortisol Monitoring
The Tufts dental-floss sensor is not the only emerging technology aimed at simplifying cortisol measurements.
In 2026, researchers published a study in Talanta investigating a hydrogel-based biosensor for continuous salivary cortisol monitoring without sample pretreatment.
The paper, titled PEGDA Hydrogel-Based Biosensor for Continuous Salivary Cortisol Monitoring Without Pre-Treatment, explored another way to integrate biological sensing with materials designed to function in saliva.
The work demonstrates that researchers are examining multiple strategies for portable hormone monitoring.
Some use electrochemical recognition layers, while others investigate hydrogels, wearable formats, or different biochemical sensing methods.
The scientific goal is to obtain reliable measurements while reducing the need for complex sample preparation.
However, this was a separate research project, not a clinical validation study of the Tufts dental-floss prototype.
September 2026: New Graphene Sensor Research
Another relevant development appeared in Small Science on September 27, 2026.
The study, Selective and Fast Cortisol Sensing in Human Saliva Using Graphene-Based On-Chip Field-Effect Transistors, examined a different graphene-based technology for detecting cortisol.
The researchers developed on-chip sensors using graphene field-effect transistors combined with cortisol-recognition components.
The research illustrates the continuing interest in portable electronic devices that can detect biological molecules in saliva.
Although the sensing mechanism differs from the Tufts floss device, both approaches aim to make biochemical measurements faster and more accessible.
Neither study, on its own, establishes that a portable cortisol sensor can accurately diagnose psychological stress.
Read the September 2026 research in Small Science.
What a Major September 2026 Review Revealed
A scientific review published in RSC Advances in September 2026 examined developments in salivary cortisol monitoring.
The authors evaluated different sensing approaches, including electrochemical systems, lateral-flow assays, wearable technologies, and optical methods.
The review highlighted several challenges that remain important for devices such as saliva-sensing dental floss.
Cortisol Varies Naturally
Measurements can change according to time of day, sleep patterns, medications, acute stressors, and individual physiology.
A device must therefore do more than produce an accurate number.
Users and healthcare professionals also need a scientifically appropriate way to interpret that number.
Laboratory Sensitivity Is Not Enough
A very low detection limit may be impressive, but it does not guarantee usefulness under everyday conditions.
Real-world performance also depends on reproducibility, accurate calibration, resistance to interference, and agreement with established laboratory methods.
Clinical Validation Is Essential
Researchers need to determine whether a device provides meaningful information in the population and setting where it would be used.
Monitoring a hormone and diagnosing a medical condition are separate scientific tasks.
The review emphasized that cortisol measurements should complement clinical assessment rather than replace it.
Read the full 2026 RSC Advances review.
Can Dental Floss Tell You How Stressed You Are?
Not in the straightforward way that some headlines imply.
The prototype measures cortisol concentration in saliva.
It does not directly measure emotions, anxiety, mental exhaustion, or psychological well-being.
Stress is a complex experience involving emotional, physiological, behavioral, and environmental factors.
Two people may respond differently to similar challenges.
Likewise, cortisol responses can vary even when people report similar stress.
A single measurement may therefore be difficult to interpret.
For example, a morning cortisol value may naturally be higher than one measured in the evening.
Physical exercise, disrupted sleep, and certain medications may also affect readings.
A future consumer device would need to account for these factors to offer reliable insights into personal stress patterns.
This is why repeated measurements, interpreted in context, may be more informative than treating a single cortisol result as a universal stress score.
Could Smart Dental Floss Help Detect Other Diseases?
Researchers have suggested that the molecular sensing technology could potentially be adapted to detect other substances in saliva.
Early research communications mention examples such as glucose, reproductive hormones, and disease-related biomarkers.
The broader idea is that a familiar oral-care device could eventually act as a platform for monitoring selected molecules.
However, different biomarkers require different sensing chemistry, analytical validation, and clinical interpretation.
A device that measures cortisol cannot automatically diagnose diabetes, cancer, or cardiovascular disease.
There is also a difference between identifying a molecular marker and determining whether someone has a medical condition.
For many diseases, diagnosis requires a combination of medical history, clinical examination, laboratory testing, and other assessments.
The most credible future applications are those supported by independent evidence showing that a measurement is reliable and clinically meaningful.
What Are the Biggest Challenges Before Home Use?
Several obstacles remain before this technology could become a dependable everyday healthcare product.
1. Reliable Sample Collection
People use dental floss differently.
The amount of saliva collected may vary with oral conditions, hydration, and how the device is handled.
Researchers must determine whether ordinary users can obtain consistent samples without professional assistance.
2. Sensor Calibration
Electrochemical sensors require reliable calibration.
Measurements may drift because of changes in sensor materials, storage conditions, temperature, or repeated use.
Any consumer system needs a dependable way to manage these sources of variability.
3. Clinical Interpretation
Cortisol levels differ between individuals and throughout the day.
Researchers must determine how readings should be interpreted in specific contexts.
Without that information, a technically accurate measurement may still mislead the user.
4. Device Cost and Manufacturing
Building a laboratory prototype differs from manufacturing a reliable consumer product at scale.
Researchers must assess material costs, manufacturing consistency, electronic components, and quality control.
5. Safety and Regulatory Requirements
A device intended to provide medical information may need appropriate regulatory evaluation, depending on its claims and where it is marketed.
Testing would also need to establish that the sensing components are suitable for routine contact with the mouth and that the system performs reliably under normal conditions.
6. Privacy and Data Protection
If future devices connect to smartphones or online health platforms, they may generate sensitive personal information.
Responsible implementation would require clear data-protection practices, appropriate security measures, and transparency about how measurements are stored or shared.
Is Saliva-Sensing Dental Floss Available to Buy in 2026?
The research described here concerns an experimental sensor platform.
The Tufts researchers have discussed efforts to bring the technology toward commercial development.
However, the available sources do not establish that the original cortisol-sensing floss system has completed clinical validation or become a generally available, medically approved consumer product.
Readers should be cautious about advertisements suggesting that ordinary smart dental floss can already diagnose stress-related disorders.
Commercial availability, regulatory authorization, and clinical effectiveness are different milestones.
A company announcing plans to manufacture a device does not mean that the device has been approved for medical use.
What Could the Future of Personal Health Monitoring Look Like?
The Tufts project reflects a broader trend in medical engineering: making biological measurements possible outside conventional laboratories.
Researchers are investigating devices that collect information from saliva, sweat, tears, and other accessible body fluids.
These systems could eventually make selected measurements more convenient, especially when repeated monitoring is beneficial.
But convenience must be matched by reliability.
A useful sensor must provide accurate measurements, work consistently in real-world conditions, and generate information that can be interpreted appropriately.
For cortisol monitoring, the next important questions involve long-term performance, measurement consistency, meaningful interpretation, and independent clinical testing.
Research will also need to establish whether giving people access to frequent hormone measurements improves healthcare decisions or quality of life.
The most valuable innovation may not be measuring more biomarkers, but measuring the right biomarkers accurately and using them responsibly.
Final Takeaway
Saliva-sensing dental floss is an inventive example of how everyday objects might become tools for future health monitoring.
The 2025 Tufts University study demonstrated that a specialized floss pick could collect saliva and measure cortisol using molecularly imprinted polymers and an electrochemical sensor.
The prototype produced results in approximately 11–12 minutes and showed strong agreement with conventional laboratory assays under the tested conditions.
Research published throughout 2026 has reinforced interest in portable saliva sensors while highlighting major challenges involving clinical validation, calibration, and biological interpretation.
The breakthrough is not that dental floss can diagnose someone’s stress level. Instead, scientists have demonstrated a practical way to measure a stress-related hormone using a familiar oral-care format.
Whether that capability becomes a useful everyday healthcare tool will depend on further research.
References
1. Sharma, A., Hossain, N. I., Thomas, A., & Sonkusale, S. (2025). Saliva-Sensing Dental Floss: An Innovative Tool for Assessing Stress via On-Demand Salivary Cortisol Measurement with Molecularly Imprinted Polymer and Thread Microfluidics Integration. ACS Applied Materials & Interfaces, 17(17), 25083–25096.
https://doi.org/10.1021/acsami.5c02988
2. Tufts University (May 23, 2025). A Dental Floss That Can Measure Stress.
https://now.tufts.edu/index.php/2025/05/23/dental-floss-can-measure-stress
3. Tufts University (March 20, 2026). What’s Going on Inside You? These Inventions Keep Track.
https://now.tufts.edu/2026/03/20/whats-going-inside-you-these-inventions-keep-track
4. Lee, S., et al. (2026). PEGDA Hydrogel-Based Biosensor for Continuous Salivary Cortisol Monitoring Without Pre-Treatment. Talanta, 304, 129518.
https://doi.org/10.1016/j.talanta.2026.129518
5. Kok, G. W. X., Ortega, E., Kee, M. Z. L., & Chan, L. C. Z. (2026). Advances in Salivary Cortisol Monitoring for Healthcare Applications. RSC Advances, 16, 52095–52111.
https://doi.org/10.1039/d6ra06259h
6. Shkodra, B., et al. (2026). Selective and Fast Cortisol Sensing in Human Saliva Using Graphene-Based On-Chip Field-Effect Transistors. Small Science, 6, e70405.