Nitrobenzoic acid-functionalized 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 AuNPs-TNB were physically adsorbed on multi-walled carbon nanotubes (MWCNTs) electrodes. Their stable adsorption was monitored electrochemical methods. The stability activated hydroxylamine layer enhanced compared to dinitro precursor onto CNTs layer. Unactivated oxygen reduction reaction catalyzed multicopper oxidases through increased aromatic electrostatic interactions limiting current densities higher than 500 µA cm−2. Next, electrocatalytic properties active form toward oxidation reduced nicotinamide adenine dinucleotide (NADH) low overpotential at near neutral pH. Associated a NAD-dependent glucose dehydrogenase, bioelectrodes assessed for electrooxidation. A complete glucose/O2 enzymatic fuel cell developed based unactived AuNPs cathodic DET promoter anodic electrocatalyst respectively. nanostructured assembly exhibited efficient 450 cm−2 in high concentration O2 saturated conditions. In close those found physiological fluids (0.04 4.00 mmol L−1), biofuel linear range limit detection (2.5 ± 0.9 µmol L−1).