Screen printed graphite macroelectrodes for the direct electron transfer of cytochrome c

We report the direct electrochemistry of cytochrome c at screen printed graphite electrodes which exhibits quasi-reversible voltammetric responses without the need for any chemical or electrochemical pre-treatment, use of mediators or nanomaterials. Through voltammetric studies and X-ray photoelectron spectroscopy (XPS) it is shown that carbonyl and carboxylic surface oxygenated species likely residing at edge plane like-sites/defects of the graphite comprising the screen printed electrodes are responsible for the favourable interaction of the cytochrome c with that of the screen printed electrochemical sensing platform.