Electrochemical Sensor Based on Laser-Induced Graphene for Cortisol Detection in Physiological Media

As a key biomarker for regulating stress levels, timely detection of cortisol can provide an immediate indication of a person’s current stress status and serve as a valuable reference for preventing related diseases. In this study, a laser-induced graphene (LIG)-based electrochemical sensor for rapid cortisol detection was developed. The prepared LIG/Au/Nafion interface exhibits higher electrocatalytic activity toward cortisol than the LIG/Au interface, attributed to the sulfonate-rich interfacial microenvironment of Nafion, which facilitates the interfacial conduction and removal of the protons liberated during cortisol dehydrogenation. Under optimal conditions, the obtained sensor shows a good linear relationship for detecting cortisol solutions over a wide linear range (20–2000 nM) and a low detection limit (1.02 nM). Furthermore, the sensor exhibited a good linear relationship with artificial sweat samples, and the recovery rate for cortisol in actual sweat samples ranged from 96.76% to 113.14%, offering a promising new technical pathway for rapid detection of cortisol in physiological media.