Stochastic electrochemistry with electrocatalytic nanoparticles at inert ultramicroelectrodes—theory and experiments

Kwon, Seong Jung; Zhou, Hongjun; Fan, Fu Ren F.; Vorob'yev, V.D.; Zhang, Bo; Bard, Allen J.

doi:10.1039/c0cp02543g

Cited by 158 publications

(222 citation statements)

References 16 publications

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“…Second, the frequency of collision can be calculated theoretically by assuming a diffusionlimited flux of particles to the electrode surface and experimentally by counting the number of collision events over time. The frequency of collision based on diffusion (28), f D, theoretical , is given by f D,theoretical = 4DCr e N A , [1] where N A is Avogadro's number, r e is the radius of the electrode, C is the concentration of colloid in solution, and D is the diffusion coefficient of the particular particle. The concentrations of the MCMV and MHV-68 (a virus used for negative control in gaining specificity with the primary antibody) were determined using nanoparticle tracking analysis (NTA), which tracks individual particles and determines a size distribution based on the diffusion coefficient using the random walk model.…”

Section: Significancementioning

confidence: 99%

Electrochemical detection of a single cytomegalovirus at an ultramicroelectrode and its antibody anchoring

Dick

Hilterbrand

Boika

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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We report observations of stochastic collisions of murine cytomegalovirus (MCMV) on ultramicroelectrodes (UMEs), extending the observation of discrete collision events on UMEs to biologically relevant analytes. Adsorption of an antibody specific for a virion surface glycoprotein allowed differentiation of MCMV from MCMV bound by antibody from the collision frequency decrease and current magnitudes in the electrochemical collision experiments, which shows the efficacy of the method to size viral samples. To add selectivity to the technique, interactions between MCMV, a glycoprotein-specific primary antibody to MCMV, and polystyrene bead "anchors," which were functionalized with a secondary antibody specific to the Fc region of the primary antibody, were used to affect virus mobility. Bead aggregation was observed, and the extent of aggregation was measured using the electrochemical collision technique. Scanning electron microscopy and optical microscopy further supported aggregate shape and extent of aggregation with and without MCMV. This work extends the field of collisions to biologically relevant antigens and provides a novel foundation upon which qualitative sensor technology might be built for selective detection of viruses and other biologically relevant analytes.collisions | cytomegalovirus | electrochemistry | murine cytomegalovirus | virus O ver the past decade, the study of discrete collision events on ultramicroelectrodes (UMEs) has gained attention due to the interest in understanding stochastic phenomena by electrochemistry. By observing the collisions of small particles, there is the possibility that information can be deduced that is not available in ensemble measurements. The electrochemical study of single collision events has been applied to a wide range of hard nanoparticles (NPs), which include metal, metal oxide, and organic NPs [platinum (1), silver (2), gold (3), nickel (4), copper (5), iridium oxide (6), cerium oxide (7), titanium oxide (8), silicon oxide (9), indigo (10), polystyrene (11), and relatively large aggregates of fullerene (12)]. Recently, collisions of soft particles have been investigated, such as toluene droplets (13) and liposomes (14). Also, collisions of toluene and tri-n-propylamine droplets were observed simultaneously by both electrochemical and electrogenerated chemiluminescent (ECL) measurements (15).Similarly, a variety of techniques have been developed to observe these collision events. The interested reader can consult the references for a discussion on each of the techniques used to observe stochastic events electrochemically: blocking (9, 13), electrocatalytic amplification (1), open circuit potential (16), droplet blocking/reactor (13,14), and ECL (15,17,18). The simplest and most reproducible method of observing collisions is a technique termed blocking, which is so named because particles, which are brought to the electrode by a diffusion-limited flux and/or electrophoretic migration, irreversibly adsorb (1) to the electrode surface, blocking the flux of red...

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Section: Significancementioning

confidence: 99%

Electrochemical detection of a single cytomegalovirus at an ultramicroelectrode and its antibody anchoring

Dick

Hilterbrand

Boika

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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143

132

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“…1-3 An interesting approach for observing the electrochemical properties of catalytic NPs is to monitor their impact (or landing) from solution onto a collector electrode, as introduced by Bard et al,4,5 and developed by several groups. [6][7][8][9][10][11][12] In order to resolve such impacts, the use of a small-sized ultramicroelectrode (UME) is mandatory to reduce both background currents and the impact frequency.…”

Section: Introductionmentioning

confidence: 99%

Time-Resolved Detection and Analysis of Single Nanoparticle Electrocatalytic Impacts

et al. 2015

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ABSTRACT:There is considerable interest in understanding the interaction and activity of single entities, such as (electro)catalytic nanoparticles (NPs), with (electrode) surfaces. Through the use of a high bandwidth, high signal/noise measurement system, NP impacts on an electrode surface are detected and analyzed in unprecedented detail, revealing considerable new mechanistic information on the process. Taking the electrocatalytic oxidation of H2O2 at ruthenium oxide (RuOx) NPs as an example, the rise time of currenttime transients for NP impacts is consistent with a hydrodynamic trapping model for the arrival of a NP with a distancedependent NP diffusion-coefficient. NP release from the electrode appears to be aided by propulsion from the electrocatalytic reaction at the NP. High frequency NP impacts, orders of magnitude larger than can be accounted for by a single pass diffusive flux of NPs, are observed that indicate the repetitive trapping and release of an individual NP that has not previously recognized. The experiments and models described could readily be applied to other systems and serve as a powerful platform for detailed analysis of NP impacts.An important frontier in electrochemistry is measuring the behavior of individual nano-entities such as nanoparticles (NPs), nanowires and nanorods and relating this to other properties such as size, structure and electronic characteristics, so as to develop fundamental understanding and rational applications. 1-3 An interesting approach for observing the electrochemical properties of catalytic NPs is to monitor their impact (or landing) from solution onto a collector electrode, as introduced by Bard et al.,4,5 and developed by several groups. [6][7][8][9][10][11][12] In order to resolve such impacts, the use of a small-sized ultramicroelectrode (UME) is mandatory to reduce both background currents and the impact frequency. To enhance the impact signal to background current, electrode surfaces have been modified with Hg or Bi 7 and borondoped diamond 12 has also been used as an UME material. Alternatively, scanning electrochemical cell microscopy (SECCM) functioning as an ultramicro-electrochemical cell system offers particularly low background currents by reducing the area of the collector electrode, as well as offering the widest range of support electrodes. This is because the electrochemical cell is formed by meniscus confinement, rather than electrode encapsulation (Figure 1). 13 Despite these innovations, detailed analysis of the form of the current-time profile which is the primary signal for the landing (and detachment) of a single NP on an electrode has not yet been forthcoming, but would represent a huge advance towards understanding the impact process. Herein, we are able to analyze this process as never before and deduce key information on the NP arrival and release process from individual impact transients. Moreover, we show that impact frequencies can be orders of magnitude higher than expected based on single pass diffusion due to the repetitiv...

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“…On the Au UME, the current transient signal could be observed, but is also not very reproducible and it was not observed on the C fiber UME. [3][4][5] As like this, the observation of NP collision is very sensitive to the UME material and treatment.…”

Section: 7mentioning

confidence: 99%

“…5 The adsorption constant on the Pt UME was about 3.6 times larger than that of the Cu UME. The synthesized IrO x NP has poor size distribution.…”

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confidence: 99%

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Observation of Electrocatalytic Amplification of Iridium Oxide (IrO_x) Single Nanoparticle Collision on Copper Ultramicroelectrodes

Choi¹,

Jung²,

Joo³

et al. 2014

Bulletin of the Korean Chemical Society

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Recently, the observation of the electrocatalytic behavior of individual nanoparticles (NPs) by electrochemical amplification method has been reported. For example, the Iridium oxide (IrO x ) NP collision on the Pt UME was observed via electrocatalytic water oxidation. However, the bare Pt UME had poor reproducibility for the observation of NP collision signal and required an inconvenient surface pre-treatment for the usage. In this manuscript, we has been investigated other metal electrode such as Cu UME for the reproducible data analysis and convenient use. The IrO x NP collision was successively observed on the bare Cu UME and the reproducibility in collision frequency was improved comparing with previous case using the NaBH 4 pre-treated Pt UME. Also, the adhesion coefficient between NP and the Cu UME was studied for better understanding of the single NP collision system.

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Stochastic electrochemistry with electrocatalytic nanoparticles at inert ultramicroelectrodes—theory and experiments

Cited by 158 publications

References 16 publications

Electrochemical detection of a single cytomegalovirus at an ultramicroelectrode and its antibody anchoring

Electrochemical detection of a single cytomegalovirus at an ultramicroelectrode and its antibody anchoring

Time-Resolved Detection and Analysis of Single Nanoparticle Electrocatalytic Impacts

Observation of Electrocatalytic Amplification of Iridium Oxide (IrO_x) Single Nanoparticle Collision on Copper Ultramicroelectrodes

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Stochastic electrochemistry with electrocatalytic nanoparticles at inert ultramicroelectrodes—theory and experiments

Cited by 158 publications

References 16 publications

Electrochemical detection of a single cytomegalovirus at an ultramicroelectrode and its antibody anchoring

Electrochemical detection of a single cytomegalovirus at an ultramicroelectrode and its antibody anchoring

Time-Resolved Detection and Analysis of Single Nanoparticle Electrocatalytic Impacts

Observation of Electrocatalytic Amplification of Iridium Oxide (IrOx) Single Nanoparticle Collision on Copper Ultramicroelectrodes

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Product

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Observation of Electrocatalytic Amplification of Iridium Oxide (IrO_x) Single Nanoparticle Collision on Copper Ultramicroelectrodes