Electrochemical sensing of cortisol by gold nanoparticle incorporated carboxylated graphene oxide based molecularly imprinted polymer

In this work, we report a simple electrochemical biosensor for cortisol (Cor) detection using a molecularly imprinted polymer (MIP). MIP was prepared by graft copolymerization method on allylated gold nanoparticle (Au) incorporated carboxylated graphene oxide (allylated Au/GO-COOH) polymerized along with the template molecule Cor. Cor is one of the important corticosteroid hormones in human physiology. Cor, the stress hormone, is a steroid hormone that comes under the class of glucocorticoid hormones and is produced as a part of our body's stress response. This Cor imprinted polymer (Cor-MIP) was chosen to modify the working glassy carbon electrode surface. Thereby developing a highly selective and sensitive electrochemical biosensor. Electrochemical Impedance Spectroscopy and Cyclic Voltammetry explored the electrochemical properties of the developed electrochemical biosensor. The investigation reports from the electrochemical studies revealed that the current value increases proportionally with increasing concentration of Cor. This confirmed the excellent electrocatalytic activity of the prepared Cor-MIP based biosensor toward Cor. The nanomaterials as well as the electroactive sites on Cor-MIP together enhancing the electron transfer rate and lower detection. Differential Pulse Voltammetry is used to find the limit of detection and quantification, and were obtained as, 0.61 x 10-14 M and 2.02 x 10-14 M, respectively. With excellent specificity, stability, and selectivity, this newly developed electrochemical biosensor has been successfully used for Cor measurements in human blood serum samples.