Ion Flow Crossing Over a Polyelectrolyte Diode on a Microfluidic Chip

Han, Ji-Hyung; Kim, Kwang Bok; Bae, Je Hyun; Kim, Beom Jin; Kang, Chung Mu; Kim, Hee Chan; Chung, Taek Dong

doi:10.1002/smll.201100827

Cited by 38 publications

(44 citation statements)

References 31 publications

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“…Our theory may not be effective for the cases in which electrochemical reactions at the electrodes are limited by the transport of reactants (for example, for the cases that counterions are the reactants or products of the electrochemical reactions 10,11,[24][25][26][27] ). Second, polyelectrolyte gels that are used to prepare PGDs are stiff enough; polyelectrolyte gels that do not have enough stiffness may locally collapse to neutralize electric charges on the electrodes 20,21,36 .…”

Section: Discussionmentioning

confidence: 99%

“…Nanochannels of asymmetric shapes were shown to rectify ion currents that are generated by Ag/AgCl electrodes [3][4][5][6] . Polyelectrolyte gel diodes (PGDs) that are the double layers of two oppositely charged polyelectrolyte gels (that are swollen in aqueous solutions), sandwiched by two symmetric metal electrodes, are another type of ionic diodes that rectify ion currents [7][8][9][10][11][12][13][14][15][16] . These diodes are designed to operate with a physical mechanism that is analogous to conventional semiconductor diodes-the asymmetry in the permeability of ions across the interfaces between the two oppositely charged gels [8][9][10][11][12] .…”

mentioning

confidence: 99%

“…Polyelectrolyte gel diodes (PGDs) that are the double layers of two oppositely charged polyelectrolyte gels (that are swollen in aqueous solutions), sandwiched by two symmetric metal electrodes, are another type of ionic diodes that rectify ion currents [7][8][9][10][11][12][13][14][15][16] . These diodes are designed to operate with a physical mechanism that is analogous to conventional semiconductor diodes-the asymmetry in the permeability of ions across the interfaces between the two oppositely charged gels [8][9][10][11][12] . However, in contrast to p-n diodes, where electrons and holes are the carriers of the entire systems, for the cases of PGDs, electric currents are carried by electrons in the external circuits and are carried by ions in the polyelectrolyte gels; PGDs do not show steady electric currents unless electrons are transferred between electrodes and reactants by electrochemical reactions.…”

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confidence: 99%

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Electrochemical mechanism of ion current rectification of polyelectrolyte gel diodes

Yamamoto

Doi

2014

Nat Commun

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Polyelectrolyte gel diodes that are double layers of two oppositely charged polyelectrolyte gels, sandwiched by two symmetric electrodes, are emergent ionic devices. These diodes are designed to rectify ion currents with a physical mechanism that is analogous to conventional semiconductor diodes-the asymmetry in the permeability of ions across the interfaces between the two oppositely charged gels. Here we show that polyelectrolyte gel diodes indeed rectify steady currents with a physical mechanism that is very different from conventional diodes by using a simple electrochemical model; electric currents are limited by electrochemical reactions that are driven by potential drops at electrodes and these potential drops markedly change with changing the direction of applied voltages due to the redistribution of non-reactive counterions, leading to rectified ion currents. This concept is relatively generic and thus may provide insight in the physics of analogous ionic and biomimetic systems that show electrochemical reactions.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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Electrochemical mechanism of ion current rectification of polyelectrolyte gel diodes

Yamamoto

Doi

2014

Nat Commun

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“…This causes an accumulation of ions inside the junction [25], as illustrated in Figure 3.9b. However, selectivity of an IEM is dependent on the surrounding ion concentration (Equation 3.3).…”

Section: Ion Accumulation and Co-ion Crossingmentioning

confidence: 99%

Monopolar and Bipolar Membranes in Organic Bioelectronic Devices

Gabrielsson¹

2014

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In the 1970s it was discovered that organic polymers, a class of materials otherwise best know as insulating plastics, could be made electronically conductive. As an alternative to silicon semiconductors, organic polymers offer many novel features, characteristics, and opportunities, such as producing electronics at low costs using printing techniques, using organic chemistry to tune optical and electronic properties, and mechanical flexibility. The conducting organic polymers have been used in a vast array of devices, exemplified by organic transistors, light-emitting diodes, and solar cells. Due to their softness, biocompatibility, and combined electronic and ionic transport, organic electronic materials are also well suited as the active material in bioelectronic applications, a scientific and engineering area in which electronics interface with biology. The coupling of ions and electrons is especially interesting, as ions serve as signal carriers in all living organisms, thus offering a direct translation of electronic and ionic signals. To further enable complex control of ionic fluxes, organic electronic materials can be integrated with various ionic components, such as ion-conducting diodes and transistors.This thesis reports a background to the field of organic bioelectronic and ionic devices, and also presents the integration of ionic functions into organic bioelectronic devices. First, an electrophoretic drug delivery device is presented, capable of delivering ions at high spatiotemporal resolution. The device, called the organic electronic ion pump, is used to electronically control amyloid-like aggregation kinetics and morphology of peptides, and offers an interesting method for studying amyloids in vitro. Second, various ion-conducting diodes based on bipolar membranes are described. These diodes show high rectification ratio, i.e. conduct ions better for positive than for negative applied voltage. Simple ion diode based circuits, such as an AND gate and a full-wave rectifier, are also reported. The AND gate is intended as an addressable pH pixel to regulate for example amyloid aggregation, while the full-wave rectifier decouples the electrochemical capacity of an electrode from the amount of ionic charge it can generate. Third, an ion transistor, also based on bipolar membranes, is presented. This transistor can amplify and control ionic currents, and is suitable for building complex ionic logic circuits. Together, these results provide a basic toolbox of ionic components that is suitable for building more complex and/or implantable organic bioelectronic devices.v Populärvetenskaplig SammanfattningItalienaren Luigi Galvani experimenterade under 1700-talet med vad han kallade animalisk elektricitet, eller bioelektricitet. Genom att vidröra en död grodas benmuskler med olika metallelektroder kunde Galvani framkalla rörelser i grodans ben. Detta kan anses vara starten för användandet av elektricitet för att studera, mäta eller stimulera levande biologiska system och processer. Det senaste århu...

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“…For this type of BM, the interface quickly becomes saturated with ions during forward bias, leading to Donnan exclusion failure and transport of ions across the BM. 4 Thus, less charge needs to be extracted to deplete the BM, allowing for faster fall times and significantly reduced hysteresis.…”

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confidence: 99%

Polyphosphonium-based bipolar membranes for rectification of ionic currents

Gabrielsson

Berggren

2013

Biomicrofluidics

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Bipolar membranes (BMs) have interesting applications within the field of bioelectronics, as they may be used to create non-linear ionic components (e.g., ion diodes and transistors), thereby extending the functionality of, otherwise linear, electrophoretic drug delivery devices. However, BM based diodes suffer from a number of limitations, such as narrow voltage operation range and/or high hysteresis. In this work, we circumvent these problems by using a novel polyphosphonium-based BM, which is shown to exhibit improved diode characteristics. We believe that this new type of BM diode will be useful for creating complex addressable ionic circuits for delivery of charged biomolecules. Combined electronic and ionic conduction makes organic electronic materials well suited for bioelectronics applications as a technological mean of translating electronic addressing signals into delivery of chemicals and ions. 1 For complex regulation of functions in cells and tissues, a chemical circuit technology is necessary in order to generate complex and dynamic signal gradients with high spatiotemporal resolution. One approach to achieve a chemical circuit technology is to use bipolar membranes (BMs), which can be used to create the ionic equivalents of diodes 2-5 and transistors. 6-8 A BM consists of a stack of a cation-and an anionselective membrane, and functions similar to the semiconductor PN-junction, i.e., it offers ionic current rectification 9,10 (Figure 1(a)). The high fixed charge concentration in a BM configuration make them more suited in bioelectronic applications as compared to other non-linear ionic devices, such as diodes constructed from surface charged nanopores 11 or nanochannels, 12 as the latter devices typically suffers from reduced performance at elevated electrolyte concentration (i.e., at physiological conditions) due to reduced Debye screening length. 13 However, a unique property of most BMs, as compared to the electronic PN-junction and other ionic diodes, is the electric field enhanced (EFE) water dissociation effect. 10,14 This occurs above a threshold reverse bias voltage, typically around À1 V, as the high electric field across the ion-depleted BM interface accelerates the forward reaction rate of the dissociation of water into H þ and OH À ions. As these ions migrate out from the BM, there will be an increase in the reverse bias current. The EFE water dissociation is a very interesting effect and is commonly used in industrial electrodialysis applications, 15 where highly efficient water dissociating BMs are being researched. 16 Also, BMs have also been utilized to generate H þ and OH À ions in lab-on-a-chip applications. 2,17 However, the EFE water dissociation effect diminishes the diode property of BMs when operated outside the 61 V window, which is unwanted in, for instance, chemical circuits and addressing matrices for delivery of complex gradients of chemical species. The effect can be suppressed by incorporating a neutral electrolyte inside the BM, 10,18 for instance, poly(ethylene glyc...

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Ion Flow Crossing Over a Polyelectrolyte Diode on a Microfluidic Chip

Cited by 38 publications

References 31 publications

Electrochemical mechanism of ion current rectification of polyelectrolyte gel diodes

Electrochemical mechanism of ion current rectification of polyelectrolyte gel diodes

Monopolar and Bipolar Membranes in Organic Bioelectronic Devices

Polyphosphonium-based bipolar membranes for rectification of ionic currents

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