The Effect of Particle Size on the Direct Electron Transfer Reactions of Metalloproteins Using Au Nanoparticle-Modified Electrodes

Suzuki, Masato; Murata, Kenichi; Nakamura, Nobuhumi; Ohno, Hiroyuki

doi:10.5796/electrochemistry.80.337

Cited by 14 publications

(18 citation statements)

References 13 publications

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“…[1] Owing to their high affinity to thiols they are an excellent platform for introducing functional moieties and for the surfacea ttachment of biological speciesi nacontrolled manner.A uNPs provide variability of chemical and physical properties whicha re strongly dependent on the nanoparticle's size. [5] Similar conclusions were presented for smaller nanoparticles with diameters ranging from 5 [6] and 7 [7] nm. For diameters below this value, the plasmon bands diminish andn ew bands are developedc orresponding to electronic transitions.…”

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confidence: 80%

“…Optical effects, such as surface plasmon bands due to collective excitation of conduction electrons, are observed for nanoparticles with diameters above % 2nm. [5] Similar conclusions were presented for smaller nanoparticles with diameters ranging from 5 [6] and 7 [7] nm. [2] The electrochemical properties of AuNPs also vary with size and three types of behavior are observed:b ulk gold exhibits continuum behavior, small nanoparticles show quantum doublelayer charging, while the smallest-clusters, exhibit "moleculelike" behavior.V oltammograms of AuNPs, with diameters lower than 2nm, give voltammetry current peaks corresponding to a single electron transfer processes to or from the nanoparticle's metallicc ore, [3] whereas molecule-like processes are reflected in the oxidationa nd reduction signals, separated by ac learly developed HOMO-LUMOg ap.…”

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confidence: 80%

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Size Does Matter—Mediation of Electron Transfer by Gold Clusters in Bioelectrocatalysis

et al. 2018

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Metal nanostructures are often used in bioelectrocatalytic systems to increase the electrode surfacea rea or to improve the conductivity of biofilms.W ed emonstrate, that decreasing the size of gold nanoparticles below 2nmm ay result in ac hange of the mechanism of electron transfer (ET) between the enzyme active site and the electrode from direct to mediated ET.C lustersw ith diameters smaller than 2nme xhibited molecule-likeb ehavior reflected in the appearance of oxidation and reduction peaks separated by ac learly developed HOMO-LUMO gap. The redox activity of the nanoparticles was found to contributet ot he ET mechanism of fructosed ehydrogenase switching it to gold cluster mediated electron transfer instead of direct ET.I nt he presence of gold clusters at the electrode, the overpotential of the catalyzed fructose oxidation reaction was 100 mV lower andt he catalytic reaction rate constant was 2.5 times larger confirming the unique mediating role of the Au clusters.Gold nanoparticles (AuNPs)a nd their applicationsi nb ioelectrocatalysis, have raised as ignificant interest in the last few years. [1] Owing to their high affinity to thiols they are an excellent platform for introducing functional moieties and for the surfacea ttachment of biological speciesi nacontrolled manner.A uNPs provide variability of chemical and physical properties whicha re strongly dependent on the nanoparticle's size. Optical effects, such as surface plasmon bands due to collective excitation of conduction electrons, are observed for nanoparticles with diameters above % 2nm. For diameters below this value, the plasmon bands diminish andn ew bands are developedc orresponding to electronic transitions. [2] The electrochemical properties of AuNPs also vary with size and three types of behavior are observed:b ulk gold exhibits continuum behavior, small nanoparticles show quantum doublelayer charging, while the smallest-clusters, exhibit "moleculelike" behavior.V oltammograms of AuNPs, with diameters lower than 2nm, give voltammetry current peaks corresponding to a single electron transfer processes to or from the nanoparticle's metallicc ore, [3] whereas molecule-like processes are reflected in the oxidationa nd reduction signals, separated by ac learly developed HOMO-LUMOg ap. [4] Gold nanoparticles (AuNPs) are successfully utilized for nanostructuring electrode surfaces in protein-based electronics. In most cases, "planar" electrode surfaces withoutp orous nanostructure, show insufficiento rn oe lectron transfer (ET) between the immobilizede nzyme actives ites and the electrode. The commonly offered explanation for "enzyme nanowiring"i s ad esirable orientation of the proteins on the surface to shorten the ET distance. An increase in the catalytic current, originating from nanostructuration of the electrode surface, is typically observed. However,i ts houldb ee mphasized that the observede ffect is often related to an expansion of the real electrode surface, and is not ar esult of thermodynamics; such as a decreaseinthe overpotential ...

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confidence: 80%

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confidence: 80%

Size Does Matter—Mediation of Electron Transfer by Gold Clusters in Bioelectrocatalysis

et al. 2018

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“…1b; ESI †). Contrary to previous studies, in which AuNPs were adsorbed by drop-coating on electrode surfaces, 13,17,20,21 aerosol AuNPs were deposited with an average density of 80 particles mm geom À2 (i.e. number of particles per geometric area, A geom , also called 2D projected area, Fig.…”

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confidence: 99%

“…20,21 These contradictions indicate difficulties in setting up an experimental system by which the effect of the size of NPs on the thermodynamics and kinetics of redox reactions at enzyme-NP modied electrodes can be indisputably addressed.…”

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The influence of nanoparticles on enzymatic bioelectrocatalysis

et al. 2014

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In nearly all papers concerning enzyme-nanoparticle based bioelectronic devices, it is stated that the presence of nanoparticles on electrode surfaces per se enhances bioelectrocatalysis, although the reasons for that enhancement are often unclear. Here, we report detailed experimental evidence that neither an overpotential of bioelectrocatalysis, nor direct electron transfer and bioelectrocatalytic reaction rates for an adsorbed enzyme depend on the size of nanoparticles within the range of 20-80 nm, i.e. for nanoparticles that are considerably larger than the enzyme molecules.Bioelectronics is a rapidly progressing interdisciplinary research eld 1 that aims to integrate biomaterials and electronic elements into functional devices which, among many other applications, can be used in high-tech, environmental, pharmaceutical and biomedical industries for sensing and power-generation purposes. High-performance direct electron transfer (DET)-based bioelectrocatalytic reactions at low overpotentials are needed to design sensitive, selective, and efficient third-generation (DET-based) bioelectronic devices, e.g. biosensors 2,3 and biofuel cells, 4,5 since third-generation bioelectronics are simple, non-toxic, and potentially miniaturisable down to nm scale. Nanostructuring electrode surfaces for enzyme-based bioelectronics is important because, in most cases, "planar" biodevices, i.e. designed without articial nanodecoration of electrodes, show very little or no electron transfer (ET) between immobilised redox enzymes and unmodied surfaces. The commonly offered explanation for "enzyme nanowiring" is an appropriate orientation of proteins on nanomaterials for ET reactions. Facile and effective bioelectrocatalysis has been shown in many papers, where different mono-and multi-centre redox enzymes, such as horseradish peroxidase, 6 glucose oxidase, 7-10 superoxide dismutase, 11 and cellobiose dehydrogenase, 12 with blue multicopper oxidases (MCOs), 13-18 respectively, are immobilised on different nanomaterials, e.g. metal and carbon nanoparticles (NPs) and nanotubes, graphene, nanoporous materials, etc. As a major proof for the enhancement of bioelectrocatalytic reactions, large bioelectrocatalytic currents that originate from nanostructured electrodes modied with oxidoreductases are usually presented. However, it should be emphasised that electrocatalysis is not actually related to the current increase, but should result in the decrease of an overpotential, which is quite rarely addressed in the case of bioelectrocatalytic reactions. Moreover, even for a particular enzyme, e.g. Trametes hirsuta laccase (ThLc), and a particular material, e.g. gold (Au), contradictory situations for different nanostructures can be found in the literature: the use of gold NPs (AuNPs) and nanoporous Au was shown to facilitate the DET-based bioelectrocatalytic reduction of oxygen (O 2 ), 13,18 whereas Aumodied nano-/microstructured silicon chips with the immobilised enzyme displayed very limited DET-based activity. 19Furthermore, two op...

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“…The large surface area of these nanostructures leads to high enzyme loading, which can improve the power density of enzymatic biofuel cells. Electrodes can have a large effective surface area after adding a concentrated solution of AuNPs to the surface [34]. The Au surface can be chemically modified with thiols.…”

Section: Ppadh Modified Nanostructured Electrode Using Pic and Pga-amfcmentioning

confidence: 99%

Immobilization of Pyrroloquinoline Quinone-Dependent Alcohol Dehydrogenase with a Polyion Complex and Redox Polymer for a Bioanode

et al. 2017

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Abstract:A bioanode for ethanol oxidation was prepared by immobilizing the recombinant pyrroloquinoline quinone (PQQ)-dependent alcohol dehydrogenase from Pseudomonas putida KT 2440 (PpADH) with polyion complex (PIC) and redox polymer. The PIC based on poly-L-lysine (PLL) and poly-L-glutamic acid (PGA) was suitable for immobilizing PpADH on the electrode. PpADH was immobilized using only one redox polymer, aminoferrocene, which was attached to the PGA backbone (PGA-AmFc) on the electrode. The anodic current density at 0.6 V (vs. Ag/AgCl) was 22.6 µA·cm −2 . However, when the number of the cycles was increased, the catalytic current drastically decreased. PpADH was immobilized using PGA-AmFc and PIC on the electrode. The anodic current density at 0.5 V (vs. Ag/AgCl) was 47.3 µA·cm −2 , and the performance maintained 74% of the initial value after five cycles. This result indicated that the combination of PIC and PGA-AmFc was suitable for the immobilization of PpADH on the electrode. In addition, the long-term stability and catalytic current density were improved by using the large surface area afforded by the gold nanoparticles.

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The Effect of Particle Size on the Direct Electron Transfer Reactions of Metalloproteins Using Au Nanoparticle-Modified Electrodes

Cited by 14 publications

References 13 publications

Size Does Matter—Mediation of Electron Transfer by Gold Clusters in Bioelectrocatalysis

Size Does Matter—Mediation of Electron Transfer by Gold Clusters in Bioelectrocatalysis

The influence of nanoparticles on enzymatic bioelectrocatalysis

Immobilization of Pyrroloquinoline Quinone-Dependent Alcohol Dehydrogenase with a Polyion Complex and Redox Polymer for a Bioanode

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