Nitrob enzoic acid-functionalize d gold nanoparticles: DET promoter of multicopper oxidases and electrocatalyst for NAD-dependent glucose dehydrogenase

We report the synthesis of coated gold nanoparticles with nitrobenzoic moieties (AuNPs-TNB). They displayed small and narrow size distribution (2 nm) as shown by TEM imaging. These functionalized AuNPsTNB were physically adsorbed on multi-walled carbon nanotubes (MWCNTs) electrodes. Their stable adsorption was monitored by electrochemical methods. The stability of the activated hydroxylamine layer was enhanced compared to the adsorption of the dinitro precursor onto the CNTs layer. Unactivated AuNPs-TNB enhanced the oxygen reduction reaction catalyzed by multicopper oxidases through increased aromatic and electrostatic interactions with limiting current densities higher than 500 mu A cm(-2). Next, the electrocatalytic properties of the active form toward the oxidation of the reduced form of nicotinamide adenine dinucleotide (NADH) with low overpotential was shown at near neutral pH. Associated with a NAD-dependent glucose dehydrogenase, the bioelectrodes were assessed for glucose electrooxidation. A complete glucose/O-2 enzymatic fuel cell was developed based on unactived and activated AuNPs as cathodic DET promoter and anodic electrocatalyst respectively. The nanostructured assembly exhibited efficient glucose oxidation with current densities of 450 mu A cm(-2) in high glucose concentration and O-2 saturated conditions. In concentration close to those found in physiological fluids (0.04 to 4.00 mmol L-1), the enzymatic biofuel cell displayed a linear range for glucose concentration and a low limit of detection (2.5 +/- 0.9 mu mol L -1). (c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

In this study, coated gold nanoparticles with nitrobenzoic moieties were synthesized and physically adsorbed onto multi-walled carbon nanotubes electrodes. These functionalized nanoparticles exhibited good catalytic properties in oxygen reduction reaction and glucose oxidation, showing potential applications.