The influence of the shape of Au nanoparticles on the catalytic current of fructose dehydrogenase

Abstract

Graphite electrodes were modified with triangular (AuNTrs) or spherical (AuNPs) nanoparticles and further modified with fructose dehydrogenase (FDH). The present study reports the effect of the shape of these nanoparticles (NPs) on the catalytic current of immobilized FDH pointing out the different contributions on the mass transfer–limited and kinetically limited currents. The influence of the shape of the NPs on the mass transfer–limited and the kinetically limited current has been proved by using two different methods: a rotating disk electrode (RDE) and an electrode mounted in a wall jet flow-through electrochemical cell attached to a flow system. The advantages of using the wall jet flow system compared with the RDE system for kinetic investigations are as follows: no need to account for substrate consumption, especially in the case of desorption of enzyme, and studies of product-inhibited enzymes. The comparison reveals that virtually identical results can be obtained using either of the two techniques. The heterogeneous electron transfer (ET) rate constants (kS) were found to be 3.8 ± 0.3 s−1 and 0.9 ± 0.1 s−1, for triangular and spherical NPs, respectively. The improvement observed for the electrode modified with AuNTrs suggests a more effective enzyme-NP interaction, which can allocate a higher number of enzyme molecules on the electrode surface. Graphical abstractThe shape of gold nanoparticles has a crucial effect on the catalytic current related to the oxidation of D-(-)-fructose to 5-keto-D-(-)-fructose occurring at the FDH-modified electrode surface. In particular, AuNTrs have a higher effect compared with the spherical one. Electronic supplementary materialThe online version of this article (10.1007/s00216-019-01944-6) contains supplementary material, which is available to authorized users.

Enzyme-Based Biosensors: Tackling Electron Transfer Issues

“…Indeed, the FDH molecules are randomly adsorbed at the electrode surface in the absence of the anthracene grafted at SWCNTS. On the other hand, the hydrophobic pocket close to the heme groups of the cytochrome domain interact with the grafted anthracene due to the π-π interactions with the aromatic side chains of the amino acids present in the hydrophobic pocket of FDH [ 179 , 180 ]. This interaction results in the oriented deposition of the FDH molecules facilitating redox transformations for both heme groups according to the DET mechanism.…”

Recent advances in surface chemistry of electrodes to promote direct enzymatic bioelectrocatalysis

“…NPs are ideal matrixes for enzyme immobilization as their size and shape may tune enzyme adsorption, loading and wiring [17]. Functionalization of NPs in the way similar to chemical modification carried out on flat metal electrodes serves to specifically tune the adsorption of enzymes for DET.…”

Porous Gold: A New Frontier for Enzyme-Based Electrodes

“…In this paper, nano-PG was reported to be prepared through chemical dealloying of silver-gold alloy by using different temperatures and dealloying times in order to obtain different pore size. Nano-PG electrodes with average pore sizes FDH is a heterotrimeric membrane-bound enzyme complex, consisting of three subunits, especially subunit I (DH FDH ), which is the catalytic domain where D-fructose is involved in a 2H + /2e − oxidation to produce 5-dehydro-d-fructose, and subunit II (CYT FDH ), which acts as a built-in electron transfer unit between DH FDH and the electrode surface [85][86][87]. In this paper, nano-PG was reported to be prepared through chemical dealloying of silver-gold alloy by using different temperatures and dealloying times in order to obtain different pore size.…”