This reduction process can be chemical, electrochemical, or thermal. There is evidence that reduction by electrochemical methods generates better electroactivity than chemical methods. This is contributed to defects produced in the GO by the electrochemical process which consequently become active sites for electroactivity . Thermal reduction has demonstrated even greater electroactivity, however the morphology of the rGO will depend on the reduction strategy and this needs to be considered when selecting a reduction method. Graphene and its derivatives have been widely used as matrixes for the development of electrochemical biosensors . Very recently, reported an impedimetric biosensor based on graphene for real-time monitoring the cytokine storm in serum which is suitable for screening COVID-19 patients. For this purpose, a graphene/copper working electrode on a sensor device was fabricated along with gold reference and gold electrodes.