Carbon Nanofiber and Meldola Blue Based Electrochemical Sensor for NADH: Application to the Detection of Benzaldehyde

Abstract

Nanomaterials used in tandem with electrochemical mediators on screen‐printed electrodes enable sensitive, low cost detection of NADH with minimal interferences in real‐world samples. In this work we investigated the combination between the mediator Meldola Blue and several types of commercial screen‐printed carbon electrodes, i. e. modified with mesoporous carbon, single wall carbon nanotubes, graphene or carbon nanofibers (CNF) as NADH detectors. The sensors were compared with bare carbon electrodes and with commercially available Meldola Blue‐modified electrodes. The best sensitivity for NADH detection by amperometry was observed for Meldola Blue/CNF electrodes, and further improvement was obtained by mixing the mediator with graphene oxide prior to dropcasting. The “MB‐erGO/CNF” sensors obtained were characterized by a detection limit of 0.5 μM, a linear range of 1–300 μM and a sensitivity of 80.0±2.5 μA cm−2 mmol−1 L, 10 times higher than that of commercial sensors. While the use of graphene oxide lead to enhanced sensitivity and wider linear range, it didn't improve the operational stability as the mediator gradually desorbed from the electrodes. Furthermore, the sensors were coupled with a new NAD+‐dependent aldehyde dehydrogenase from a psychrophilic bacterium for the analysis of benzaldehyde and proven to be advantageous over commercial electrodes with Meldola Blue in circumstances where the detection was limited by NADH detection, i. e. at pH 9.5.

Voltammetric Determination of Phenylalanine Using Chemically Modified Screen-Printed Based Sensors

“…These results correspond to those obtained when using other voltammetric sensors for the indirect detection of electroinactive compounds [39,43,44,47,48,50].…”

“…of biosensors based on dehydrogenase, due to its ability to mediate the oxidation of nicotinamide adenine dinucleotides [37][38][39][40][41][42][43]. Cobalt Phthalocyanine, an organic semiconductor ensuring sensor stability and sensitivity is another modifier used in the development of CMEs [44][45][46][47].…”

Addressing the Selectivity of Enzyme Biosensors: Solutions and Perspectives

“…Examples include single walled carbon nanotubes promoting DET of cellobiose dehydrogenase from Corynascus thermophilus , [ 113 ] AuNPs [ 130 ] or PANI nanotubes [ 131 ] for glucose oxidase, zinc oxide nanodisks for superoxide dismutase [ 132 ], tungsten oxide (WO 3 ) NPs for cytochrome C nitrite reductase [ 133 ] etc. enable the attachment of mediators [ 134 ]. lower the overpotential required for the detection using dehydrogenases [ 135 ] or oxidases [ 136 ], thus influencing the selectivity of the assay.…”

Advances in the Detection of Dithiocarbamate Fungicides: Opportunities for Biosensors

“…The reduced cofactor can be sensitively detected by electrochemical oxidation at the surface of carbon electrodes. Furthermore, the electrochemical detection of NADH is efficiently accomplished using electrochemical mediators or various carbon nanomaterials such as carbon nanotubes, graphene, nanofibers, etc., which decrease the potential required for NADH oxidation [ 89 ]. By measuring at low potentials, close to 0 V, the risk of potential interferences from other electrochemically active compounds in samples is minimal, supporting the accuracy of the detection.…”

“…Moreover, the homologous recombinant enzyme from the same family originating from the Antarctic Flavobacterium PL002 strain was recently used in an electrochemical test and in a biosensor for the detection of benzaldehyde [ 89 , 103 ]. The enzyme has wide substrate specificity and was shown to be inhibited by thiram [ 104 ], thus it appears to be a good candidate as a biorecognition element in a biosensor for DTFs.…”