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Decoding Network Structure in On-Chip Integrated Flow Cells with Synchronization of Electrochemical Oscillators

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ABSTRACT

The analysis of network interactions among dynamical units and the impact of the coupling on self-organized structures is a challenging task with implications in many biological and engineered systems. We explore the coupling topology that arises through the potential drops in a flow channel in a lab-on-chip device that accommodates chemical reactions on electrode arrays. The networks are revealed by analysis of the synchronization patterns with the use of an oscillatory chemical reaction (nickel electrodissolution) and are further confirmed by direct decoding using phase model analysis. In dual electrode configuration, a variety coupling schemes, (uni- or bidirectional positive or negative) were identified depending on the relative placement of the reference and counter electrodes (e.g., placed at the same or the opposite ends of the flow channel). With three electrodes, the network consists of a superposition of a localized (upstream) and global (all-to-all) coupling. With six electrodes, the unique, position dependent coupling topology resulted spatially organized partial synchronization such that there was a synchrony gradient along the quasi-one-dimensional spatial coordinate. The networked, electrode potential (current) spike generating electrochemical reactions hold potential for construction of an in-situ information processing unit to be used in electrochemical devices in sensors and batteries.

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Schematics of three commonly used dual-electrode configurations.(a) Traditional (ipsilateral) placement of reference and counter electrodes. (b) Upstream (contralateral) reference and counter electrode placements. (c) Dual reference electrode configuration. WE1,2: Ni working electrodes embedded in epoxy; RE and RE2: Ag/AgCl/3 M NaCl reference electrode; CE: Pt counter-electrode. RE1: Ni reference electrode for working electrode 1.
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f1: Schematics of three commonly used dual-electrode configurations.(a) Traditional (ipsilateral) placement of reference and counter electrodes. (b) Upstream (contralateral) reference and counter electrode placements. (c) Dual reference electrode configuration. WE1,2: Ni working electrodes embedded in epoxy; RE and RE2: Ag/AgCl/3 M NaCl reference electrode; CE: Pt counter-electrode. RE1: Ni reference electrode for working electrode 1.

Mentions: Our general strategy to explore the electrical coupling among the electrode is as follows. First, we consider cell geometries defined as number of working electrodes, and placement of reference/counter electrodes. (Figure 1 shows the schematics of the three considered configurations with two working electrodes). A typical device has a flow channel in which a number of electrodes are placed. The chemical reactions take place on the surfaces of the electrodes, and the rate of the reaction strongly depends on the local electrode potential drop that drives the reaction. The electrochemical reaction generates current, that flows to the counter electrode placed in the reservoir. A potentiostat sets the potentials of the electrodes, such that the potential differences between the working and reference electrodes are constant. Because the current flow between the electrodes introduces potential drops through the electrolyte, the reaction rates measured on the electrodes depend on each other, and the dependence is affected by the spacing of the electrodes and the placement of the counter electrode (which defines the direction of the current) and the reference electrode (which defines a potential with respect to the electrodes are polarized).


Decoding Network Structure in On-Chip Integrated Flow Cells with Synchronization of Electrochemical Oscillators
Schematics of three commonly used dual-electrode configurations.(a) Traditional (ipsilateral) placement of reference and counter electrodes. (b) Upstream (contralateral) reference and counter electrode placements. (c) Dual reference electrode configuration. WE1,2: Ni working electrodes embedded in epoxy; RE and RE2: Ag/AgCl/3 M NaCl reference electrode; CE: Pt counter-electrode. RE1: Ni reference electrode for working electrode 1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5384074&req=5

f1: Schematics of three commonly used dual-electrode configurations.(a) Traditional (ipsilateral) placement of reference and counter electrodes. (b) Upstream (contralateral) reference and counter electrode placements. (c) Dual reference electrode configuration. WE1,2: Ni working electrodes embedded in epoxy; RE and RE2: Ag/AgCl/3 M NaCl reference electrode; CE: Pt counter-electrode. RE1: Ni reference electrode for working electrode 1.
Mentions: Our general strategy to explore the electrical coupling among the electrode is as follows. First, we consider cell geometries defined as number of working electrodes, and placement of reference/counter electrodes. (Figure 1 shows the schematics of the three considered configurations with two working electrodes). A typical device has a flow channel in which a number of electrodes are placed. The chemical reactions take place on the surfaces of the electrodes, and the rate of the reaction strongly depends on the local electrode potential drop that drives the reaction. The electrochemical reaction generates current, that flows to the counter electrode placed in the reservoir. A potentiostat sets the potentials of the electrodes, such that the potential differences between the working and reference electrodes are constant. Because the current flow between the electrodes introduces potential drops through the electrolyte, the reaction rates measured on the electrodes depend on each other, and the dependence is affected by the spacing of the electrodes and the placement of the counter electrode (which defines the direction of the current) and the reference electrode (which defines a potential with respect to the electrodes are polarized).

View Article: PubMed Central - PubMed

ABSTRACT

The analysis of network interactions among dynamical units and the impact of the coupling on self-organized structures is a challenging task with implications in many biological and engineered systems. We explore the coupling topology that arises through the potential drops in a flow channel in a lab-on-chip device that accommodates chemical reactions on electrode arrays. The networks are revealed by analysis of the synchronization patterns with the use of an oscillatory chemical reaction (nickel electrodissolution) and are further confirmed by direct decoding using phase model analysis. In dual electrode configuration, a variety coupling schemes, (uni- or bidirectional positive or negative) were identified depending on the relative placement of the reference and counter electrodes (e.g., placed at the same or the opposite ends of the flow channel). With three electrodes, the network consists of a superposition of a localized (upstream) and global (all-to-all) coupling. With six electrodes, the unique, position dependent coupling topology resulted spatially organized partial synchronization such that there was a synchrony gradient along the quasi-one-dimensional spatial coordinate. The networked, electrode potential (current) spike generating electrochemical reactions hold potential for construction of an in-situ information processing unit to be used in electrochemical devices in sensors and batteries.

No MeSH data available.