Selective electrochemical detection of cysteine in complex serum by graphene nanoribbon

► Graphene nanoribbon and Nafion nanocomposite was used for the sensitive electrochemical detection of cysteine. ► The sensor could discriminate cysteine from other bio-relevant reagents and other biothiols. ► The good selectivity and high sensitivity was due to the co-interaction of the GNR and the negatively charged Nafion. Selective detection of cysteine in serum samples was achieved on a graphene nanoribbon (GNR) and Nafion nanocomposite modified electrode with high precision. The superior conductivity and abundant amount of active chemical oxygen groups on the edge of GNR led to extremely highly electrocatalytic activity of GNR towards the electrochemical oxidation of cysteine at +0.025 V. The electrocatalytic behavior was further used for sensitive detection of cysteine by differential pulse voltammetry. Under optimized conditions, the calibration curve was linear in the range from 25 nM to 500 μM. The electrochemical sensor showed strong antifouling ability, good stability and selectivity. It could effectively exclude the interferences from other kinds of biothiols and the biological relevant species, thus had great perspective for in vivo analysis of biological samples.