A flexible electrode system entirely constituted by single-walled carbon nanotubes
(SWCNTs) has been proposed as the sensor platform for -nicotinamide adenine dinucleotide
(NADH) detection. The performance of the device, in terms of potential at which the electrochemical
process takes place, significantly improves by electrochemical functionalization of the carbon-based
material with a molecule possessing an o-hydroquinone residue, namely caffeic acid. Both the
processes of SWCNT functionalization and NADH detection have been studied by combining
electrochemical and spectroelectrochemical experiments, in order to achieve direct evidence of the
electrode modification by the organic residues and to study the electrocatalytic activity of the resulting
material in respect to functional groups present at the electrode/solution interface. Electrochemical
measurements performed at the fixed potential of +0.30 V let us envision the possible use of the
device as an amperometric sensor for NADH detection. Spectroelectrochemistry also demonstrates
the effectiveness of the device in acting as a voltabsorptometric sensor for the detection of this same
analyte by exploiting this different transduction mechanism, potentially less prone to the possible
presence of interfering species.
