Electrochemical Non-Enzymatic Biosensing of Cortisol Using ZnO-Graphene Nanocomposite

Cortisol is a key factor in developmental and behavioural research, measured widely in blood, urine, and saliva. Electrochemical sensing has emerged as a reliable technique in the development of point-of-care devices for detecting cortisol. Here, a ZnO/Graphene coated graphite was used as a sensing electrode for the detection of cortisol. The performance of the sensing electrode was tested in the presence of cortisol using electrochemical techniques and the impact of scan rate, concentration, cycle numbers, linear range, and limit of detection is reported. The fabricated ZnO/Graphene/PGE sensing electrode demonstrated excellent performance for cortisol detection, exhibiting a linear response over a wide concentration range of 10.874 to 173.981 mg ml −1 and a low limit of detection of 6.162 μg ml −1 . Additionally, the sensor displayed high stability over 60 days, with good repeatability and reproducibility. This shows that the ZnO/Graphene nanocomposite can be used as a non-enzymatic sensor providing a more reliable and effective cortisol sensing.