Non-invasive cortisol detection in saliva by using molecularly cortisol imprinted fullerene-acrylamide modified screen printed electrodes

Abstract In this study, we developed an impedimetric sensor system by using molecularly cortisol imprinted acrylamide polymers on fullerene modified carbon electrode to detect cortisol in real saliva samples. The polymer layer was formed on fullerene modified screen printed carbon electrodes with the ratio of 1:2 (cortisol:acrylamide) and ammonium persulfate (APS) was used as the initiator of polymerization. The sensor surface was investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Scanning Electron Microscopy (SEM). Performances of the electrode were determined as follows; calibration curve was calculated between 0.5 nM and 64 nM, R2 = 0.9939, LOD and LOQ were 0.14 nM and 0.44 nM, respectively. Real human saliva samples were obtained from 15 participants between 25 and 32 ages regardless of gender. The samples, which were collected at least 30 min after waking up and the new sensor method analysis were compared tandem mass spectroscopy coupled liquid chromatography system (LC-MS/MS). The sensor analysis showed a significant correlation with LC-MS/MS results (R2 = 0.9727).