Electrochemical assay of melanoma biomarker in human blood

We report here an electrochemical assay to detect S100B, a serum biomarker of melanoma. This assay takes advantage of the 1:2 binding between S100B and its specific binding peptide. The first peptide immobilized on a gold electrode can capture Si 008, while a second peptide modified with Gly-His-Lys copper ion chelating motif can generate signal. The chelated copper ion can also amplify the signal by catalyzing the oxidation of o-phenylenediamine (OPD) to electroactive 3-diaminophenazine (DAP). By using square wave voltammetry, a limit of detection as low as 0.1 nM can be achieved. This method has also demonstrated favorable recovery in the complex serum sample, indicating potential clinical application in the future. (C) 2013 Elsevier B.V. All rights reserved.