Electrooxidation of NADH on Modified Screen-Printed Electrodes: Effects of Conducting Polymer and Nanomaterials

Commercially available screen-printed carbon electrodes (SPCE) have been modified with multiwalled carbon nanotubes (MWCNTs), gold nanoparticles (AuNPs) and polyneutral red (PNR) film. Modifications of SPCEs by nanomaterials (NMs) were achieved by layer-by-layer (LBL) method. PNR film was formed by electropolymerization of neutral red (NR) on bare electrodes or on electrodes already modified with NMs. The amounts of NMs and the thickness of PNR film have been optimized based on some electrochemical characterization parameters such as electrode surface area (A(ea)) of NM modified electrode or anodic peak current (I-pa) and potential (E-pa) for electrooxidation of PNR. The effects of various individual or combinations of modifications of SPCEs on their electrochemical sensor properties toward oxidation of NADH have been investigated by cyclic voltammetry. The results were discussed on the basis of changes in current intensity and potential for the electrooxidation of NADH on various modified SPCEs. These changes were attributed to the changes in conductivity and electrocatalytic activity of the electrodes upon modifications. The best performance was obtained with the SPCE which is modified first with MWCNT, then with AuNP and then covered with PNR film. This electrode was tested for amperometric detection of NADH at 0.2 V vs Ag pseudo reference electrode. (C) 2015 Elsevier Ltd. All rights reserved.