Ultraviolet LED based compact and fast cortisol detector with ultra high sensitivity

A novel label free, compact, fast and noninvasive absorbance based optical sensing technique was devised for the first time to detect cortisol, a physical and psychological stress biomarker, using ultraviolet (UV) LEDs. LEDs at three different UV wavelengths were employed to demonstrate cortisol sensing with different cortisol concentration. From the differential photoresponse versus concentration curves, we calculated the sensitivity of the sensors to be 1 mV/μM, 0.15 mV/μM and 0.08 mV/μM at 240 nm, 250 nm and 260 nm wavelength respectively. The developed sensing technique can be easily incorporated with microfluidic system for point-of-care cortisol detection and such developed protocol can be used in personalized health monitoring.