Molecularly imprinted sensor base on CNFs/CNTs aerogel for cortisol detection

Rapid, sensitive testing for the steroid hormone cortisol can help prevent chronic diseases caused by stress. This paper describes a molecularly imprinted polymer (MIP) electrochemical sensor based on cellulose nanofiber multiwall-carbon nanotube composite aerogel (CCA) for real-time, reliable and non-invasive detection of cortisol in humans. CCA-modified electrodes, which possess high electrical conductivity and a large specific surface area, enhance the electrode surface's charge transfer capability, expand the sensor's electrically active area, and boost the specific recognition sites for cortisol. Consequently, the sensor's sensing capability is improved. Through optimizing the preparation conditions, the sensor's current response exhibits a good linear relationship with the cortisol concentration. A wide detection range of 50 fM to 10 mu M and a low detection limit of 4.75 x 10-14 M are achieved. Moreover, it demonstrates good specificity towards other interfering substances and steroid hormones in human body fluids. Furthermore, the sensor's capability to detect cortisol in saliva has been experimentally confirmed. This simple and sensitive cortisol sensor is anticipated to have broader applications in health monitoring.