New Sensor to Detect Stress From Sweat, Saliva

Hyderabad:Tracking stress may soon no longer require needles or lab visits, with researchers at BITS Pilani, Hyderabad, developing a flexible biosensor that can detect the stress hormone cortisol from sweat and saliva in real time.

The device has been developed at the MEMS, Microfluidics, and Nanoelectronics (MMNE) Laboratory and is designed to work outside hospitals or laboratories.

By relying on non-invasive body fluids, the sensor allows cortisol monitoring without blood sampling, a limitation that has long restricted routine stress assessment.

Cortisol is released by the body in response to physical or psychological stress and is closely linked to mental health conditions, heart disease, and immune problems. Currently, cortisol testing largely depends on laboratory analysis of blood samples, which makes frequent or on the spot monitoring difficult.

“Our aim was to create a simple measurement platform that works in real time and does not depend on invasive procedures or complex laboratory infrastructure,” said Sanket Goel, principal investigator at the MMNE Laboratory. “This makes stress monitoring more practical for everyday settings.”

The sensor is built on a thin, flexible plastic base coated with a transparent conductive layer. Gold nanoparticles are added to improve signal strength, while cortisol specific antibodies are fixed on the surface to ensure selective detection. The device is also connected to a small microfluidic system that allows controlled analysis of sweat.

The professor said that tests showed that the sensor can reliably measure cortisol levels across the range normally found in the human body. It remained stable for nearly a month and produced accurate results when tested with real sweat and saliva samples.

Lead researcher Sonal Fande said the focus was on usability. “We wanted a sensor that could eventually be worn on the body and still give dependable readings,” she said. “Using sweat and saliva makes that possible.”

Because of its flexible design and low power requirements, the sensor can be integrated with wearable electronics such as patches or bands.

Fande said the new sensor could help in early stress detection, personalised health tracking, and future point of care diagnostics, particularly for people who need regular monitoring but have limited access to clinical testing.