Specific and Amplified Voltammetric Detection of Dopamine at Nitrilotriacetic acid-Iron Modified Gold Electrode

Sandwich-type biosensor is one of the major analytical techniques for sensitive and selective detection of biomolecules. In this format, the crucial step is the capture and identification of analytes. In this work, we reported a sandwich-type electrochemical biosensor for the detection of dopamine (DA). Nitrilotriacetic acids complexing Fe(III) were immobilized onto gold electrodes to capture DA. The amino groups of DA were derivatized by biotin for the attachment of gold nanoparticle/streptavidin conjugates capped with multiple ferrocene tags. Well-defined voltammetric peaks of high signal intensity were obtained. DA concentrations ranging from 0.5 to 20 nM can be readily determined. A detection limit of 0.1 nM was achieved, which is lower than those achievable using the modified electrodes reported so far. This method was demonstrated to be highly sensitive, accurate and reproducible.