부산대학교 도서관

Cortisol, a well-known psychological stress biomarker, produced by the hypothalamic-pituitary-adrenal (HPA) system, tends to intensify with stressors. Prolonged overexpression of cortisol leads to chronic stress that causes disparities in the proper functioning of the human body. Thus, there is a huge demand for developing a rapid cortisol detection system. Several point-of-care diagnostic techniques are available for rapid cortisol detection, such as electrochemical sensing, which works on changes in the electrical properties due to the binding of an analyte with a biorecognition element. Researchers have used different electrochemical methodologies, such as cyclic voltammetry (CV), chronoamperometry, and faradic electrochemical impedance spectroscopy (EIS), for the detection of cortisol. Still, the usage of external redox active reagents, low sensitivity, limited dynamic range, and electrode fouling nature limits their use. Hence, we reported a label-free and noninvasive cortisol detection using non-faradic EIS. A novel multilayer immunosensor was fabricated on poly(3,4-ethylene-dioxythiophene) polystyrene sulfonate (PEDOT:PSS)-coated indium-tin-oxide (ITO) glass by functionalizing with cortisol antibodies. Specific and rapid detection of cortisol was measured by monitoring the change in impedance in a dynamic range of 50–200 ng/mL. A robust correlation of 0.97 was observed between impedance values and cortisol concentration, highlighting the linearity and repeatability of the sensor. We envision that the developed immunosensor has the potential for new developments in stress monitoring, disease prognosis, and personalized care.