Thermal reduction synthesis approach of reduced graphene oxide for the preparation of a label-free and prompt immuno sensing of Salmonella enterica via electrochemical techniques

This work comprises an immunosensor fabrication decorated with reduced graphene oxide (rGO) onto Indium tin oxide (ITO) coated electrodes to detect Salmonella enterica antigen. The rGO was synthesized with a modified Hummer technique and characterized via UV, XRD, FTIR, RAMAN and SEM techniques. The synthesized rGO was optimized at different concentrations to develop an immunosensor. An EDC-NHS interaction immobilized the monoclonal antibody against the selected antigen. Electrochemical techniques such as electrochemical impedance spectroscopy and cyclic voltammetry were deployed to characterize the modified electrodes in 5 mM Zobell's solution, followed by a differential pulse voltammetry analysis for sensor validation. The fabricated sensor has a 44 CFU/mL detection limit (LoD) and a 135 CFU/mL quantification limit (LoQ) with a linear range of 10¹–10⁷ CFU/mL. This proposed immunosensor can be applied to any sample containing traces of Salmonella enterica.