Electrochemical detection of cortisol in sweat for sports performance analysis using graphene oxide-silicon carbide nanocomposites.

An advanced electrochemical immunosensor platform was designed for the precise quantification of cortisol. The sensor design integrates graphene oxide-silicon carbide (GO-SiC) nanocomposites onto a glassy carbon electrode (GCE). Denatured bovine serum albumin (d-BSA) and an anti-cortisol antibody were immobilized on the GO-SiC/GCE surface as part of the immunosensor's design. The GO-SiC nanocomposite offers excellent biocompatibility, with hydroxy and amine functional groups facilitating stable antibody immobilization while minimizing nanocomposite leaching from the electrode. The GO nanosheets contribute to superior electrical conductivity and structural stability. Moreover, the integration of SiC nanorods further enhances stability and biocompatibility. To assess electrochemical properties, CV, EIS, and DPV methods were performed. The immunosensor successfully measured cortisol levels, showing ability to detect very low amounts with high accuracy and a wide range of concentration, down to 90 fg/mL. Additionally, selectivity and stability experiments confirmed the strong affinity of the immunosensor and long-term stability toward cortisol. These findings suggest that the proposed immunosensor offers a highly efficient and reliable approach for biomarker detection strategies in sports science.