Towards Seamless Stress Monitoring: A Microneedle-Enabled Electrochemical Cortisol Sensor

 Everyday life stress quietly shapes our mood, cognition, and long-term health. Cortisol, the body’s primary “stress hormone”, offers a biochemical window into these fluctuations, yet today’s clinical assays require venipuncture or bulky lab equipment that capture only isolated snapshots in time. Continuous, real-world cortisol tracking remains an unsolved challenge.

In our work, we are developing a miniaturized electrochemical cortisol sensor built on aerosol-jet-printed electrodes. By harnessing the high resolution and material efficiency of aerosol jet printing, we create flexible electrode patterns that preserve electrochemical performance. To transform the sensor into a truly wearable platform, we are integrating it with a microneedle patch that painlessly samples interstitial fluid (ISF) just below the skin surface. The patch’s hollow microneedles are too shallow to reach blood vessels, allowing continuous ISF extraction without discomfort or risk of infection.

Continuous cortisol curves could revolutionize the management of endocrine disorders, optimise training and recovery in athletes, and provide objective biomarkers for mental-health apps. By combining additive manufacturing, microneedle technology, and bio-electrochemistry, our project aims to push wearable diagnostics beyond step counts and toward seamless, minimally invasive biochemical monitoring.