A Flexible Platform of Electrochemically Functionalized Carbon Nanotubes for NADH Sensors

Abstract

A flexible electrode system entirely constituted by single-walled carbon nanotubes (SWCNTs) has been proposed as the sensor platform for β-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.

Dopamine-functionalized graphene oxide as a high-performance material for biosensing

“…Conversely, optical absorbance can measure in a more selective manner changes in NADH concentration in the close proximity of the electrode surface, due to the oxidation process. For this reason, we decided to perform UV-Vis spectroelectrochemical experiments in parallel configuration to directly monitor the presence of chemical species produced or consumed during the electrochemical process [43,44]. This allowed us to study the role of 1,2-dihydroxyphenyl residues covalently linked to EGO nanosheets.…”

Spectroelectrochemical Sensing: Current Trends and Challenges

“…From this point of view, SEC is a really powerful analytical technique. SEC can be used with many different purposes, and excellent examples can be found in literature in different fields such as organic molecules , molecules of biological interest , inorganic complexes , conducting polymers , carbon nanotubes , graphene , fullerenes , metal nanoparticles , quantum dots , etc. A huge variety of information can be obtained using SEC, for example, formal potentials , electron transfer rate constants , diffusion coefficients , number of electrons , molar absorption coefficients , band‐gaps , among many others.…”

“…UV/Vis‐SEC can also be very useful in the preparation of sensors. During the last years nanomaterials are being widely used to determine a number of molecules . For example, electrodeposition of NPs is a well‐stablished method to prepare sensors.…”

A water-soluble boronic acid sensor for caffeic acid based on double sites recognition

“…10 Therefore, quantitative detection of caffeic acid is of great signicance for comprehend our daily diet and early diagnosis of diseases. 11 To date, several analytical methods have been reported to determine caffeic acid, including chromatography (HPLC, GC), [12][13][14][15] capillary electrophoresis, 16 voltammetry, [17][18][19] electrochemical methods, [20][21][22][23] and UV-Visible spectrophotometry, 24,25 etc. However, there are still some limitations, such as needing expensive instruments, complex sample pretreatment, lengthy analysis time and high cost, etc.…”