Ion Accumulation and Migration Effects on Redox Cycling in Nanopore Electrode Arrays at Low Ionic Strength

Ma, Chaoxiong; Xu, Wei; Wichert, William R. A.; Bohn, Paul W.

doi:10.1021/acsnano.6b00049

Cited by 54 publications

(57 citation statements)

References 49 publications

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“…Previous research on molecular redox species indicates that ion accumulation inside NEAs is strongly dependent on surface charge, electrode potential, and nanopore size . Logically then, this concept might be extended to control the motion of nanoparticles within attoliter‐volume NEAs by adjusting these same parameters.…”

Section: Resultsmentioning

confidence: 99%

Voltage‐Gated Nanoparticle Transport and Collisions in Attoliter‐Volume Nanopore Electrode Arrays

Han

Crouch

et al. 2018

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Single nanoparticle analysis can reveal how particle‐to‐particle heterogeneity affects ensemble properties derived from traditional bulk measurements. High‐bandwidth, low noise electrochemical measurements are needed to examine the fast heterogeneous electron‐transfer behavior of single nanoparticles with sufficient fidelity to resolve the behavior of individual nanoparticles. Herein, nanopore electrode arrays (NEAs) are fabricated in which each pore supports two vertically spaced, individually addressable electrodes. The top ring electrode serves as a particle gate to control the transport of silver nanoparticles (AgNPs) within individual attoliter volume NEAs nanopores, as shown by redox collisions of AgNPs collisions at the bottom disk electrode. The AgNP‐nanoporeis system has wide‐ranging technological applications as well as fundamental interest, since the transport of AgNPs within the NEA mimics the transport of ions through cell membranes via voltage‐gated ion channels. A voltage threshold is observed above which AgNPs are able to access the bottom electrode of the NEAs, i.e., a minimum potential at the gate electrode is required to switch between few and many observed collision events on the collector electrode. It is further shown that this threshold voltage is strongly dependent on the applied voltage at both electrodes as well as the size of AgNPs, as shown both experimentally and through finite‐element modeling. Overall, this study provides a precise method of monitoring nanoparticle transport and in situ redox reactions within nanoconfined spaces at the single particle level.

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Section: Resultsmentioning

confidence: 99%

Voltage‐Gated Nanoparticle Transport and Collisions in Attoliter‐Volume Nanopore Electrode Arrays

Han

Crouch

et al. 2018

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“…Since a significant proportion of the sealing process take place in the nanopores of the anodic aluminum oxide layer of typical diameters in the range of 7-20 nm, the sealing process can be viewed as a process taking place in nanoconfined spaces (i.e., in a nanoporous electrode) [273][274][275][276], which are most likely to display peculiarities quite different from similar processes in/on micro-and macro-electrodes [277][278][279][280]. Taking the nano-dimensions of the pores of anodic aluminum oxide into consideration, Rocca et al [78,87] had studied the possible effects of such dimensions on both mass transport into the pores and chemical reactivity of the pore walls and reported interesting results.…”

Section: Effect Of the Nano-dimension Of The Pores And The Surface Chmentioning

confidence: 99%

The Sealing Step in Aluminum Anodizing: A Focus on Sustainable Strategies for Enhancing Both Energy Efficiency and Corrosion Resistance

2020

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Increasing demands for environmental accountability and energy efficiency in industrial practice necessitates significant modification(s) of existing technologies and development of new ones to meet the stringent sustainability demands of the future. Generally, development of required new technologies and appropriate modifications of existing ones need to be premised on in-depth appreciation of existing technologies, their limitations, and desired ideal products or processes. In the light of these, published literature mostly in the past 30 years on the sealing process; the second highest energy consuming step in aluminum anodization and a step with significant environmental impacts has been critical reviewed in this systematic review. Emphasis have been placed on the need to reduce both the energy input in the anodization process and environmental implications. The implications of the nano-porous structure of the anodic oxide on mass transport and chemical reactivity of relevant species during the sealing process is highlighted with a focus on exploiting these peculiarities, in improving the quality of sealed products. In addition, perspective is provided on plausible approaches and important factors to be considered in developing sealing procedures that can minimize the energy input and environmental impact of the sealing step, and ensure a more sustainable aluminum anodization process/industry.Coatings 2020, 10, 226 2 of 55 sealing methods. Furthermore, the applicability of another hitherto popular sealing process; chromate sealing, is currently limited to essential parts in the aerospace industry due to toxicological, health, and environmental implications traced to Cr(VI) employed in the process [7][8][9][10][11][12][13][14][15][16]. On the other hand, the advantages of another industrially utilized sealing process; the nickel fluoride (cold) sealing process is limited by the toxicity of nickel salts which narrows its range of application, and introduces added costs due to post-sealing wastewater treatments and management [17][18][19][20]. Further efforts at sealing anodized aluminum at temperatures lower than that used in hydrothermal (high temperature) sealing, have led to much variety in the chemical constitution and operating temperatures of sealing baths [21]. On the basis of temperature at which the sealing step is carried out, sealing can be classified into three major categories; high temperature, mid-temperature, and room-temperature or cold sealing. In this work sealing at temperatures from 0 to 40 • C is classified as low temperature sealing, from ≥ 40 • C to 70 • C as intermediate or mid temperature sealing, and sealing at temperatures > 70 • C as high temperature sealing.

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“…However, these devices are typically fabricated in clean‐room facilities using either optical or e‐beam lithography, prohibiting rapid prototyping of low‐cost biosensors. Further approaches relying on vertical arrangement of two independently addressable electrode layers include nanocavity and nanoporous redox‐cycling devices . Nevertheless, most fabrication methods aim to integrate the electrodes within the same plane, which avoids problems with multilayer electrode fabrication.…”

Section: Introductionmentioning

confidence: 99%

Flexible Microgap Electrodes by Direct Inkjet Printing for Biosensing Application

et al. 2017

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A rapid fabrication method of microgap electrodes using inkjet printing is described. In this approach, the lateral spacing between two printed electrode lines is precisely controlled down to 1 µm without any surface modification or substrate patterning. The strong confinement, well below typical resolution of inkjet printing, relies on complete solvent evaporation between the printing of adjacent electrode structures, which is achieved by controlling the printing speed and temperature profiles. The feasibility of this method is demonstrated by writing electrode structures with two distinct inks, based on carbon and silver nanoparticles, with comparable results. As an application proof-of-principle, arrays of microgap electrodes are fabricated using a carbon nanoparticle ink for electrochemical detection based on redox-cycling, a technique in which the sensitivity of the device depends on the distance between the two electrodes. The redox-cycling amplification of electrochemical signals is demonstrated and it is shown that the printed microgap device can be used as an electrochemical biosensor for the determination of human immunodeficiency virus (HIV)-related single-stranded DNA. This work presents a promising new approach for fabricating low-cost and label-free redox-cycling biosensors using all-inkjet-printed electrodes. www.adv-biosys.com

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Ion Accumulation and Migration Effects on Redox Cycling in Nanopore Electrode Arrays at Low Ionic Strength

Cited by 54 publications

References 49 publications

Voltage‐Gated Nanoparticle Transport and Collisions in Attoliter‐Volume Nanopore Electrode Arrays

Voltage‐Gated Nanoparticle Transport and Collisions in Attoliter‐Volume Nanopore Electrode Arrays

The Sealing Step in Aluminum Anodizing: A Focus on Sustainable Strategies for Enhancing Both Energy Efficiency and Corrosion Resistance

Flexible Microgap Electrodes by Direct Inkjet Printing for Biosensing Application

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