Electrochemistry of immobilised redox droplets: Concepts and applications

Banks, Craig E.; Davies, Trevor J.; Evans, Russell G.; Hignett, Geraldine; Wain, Andrew J.; Lawrence, Nathan S.; Wadhawan, Jay D.; Marken, Frank; Compton, Richard G.

doi:10.1039/b307326m

Cited by 185 publications

(196 citation statements)

References 145 publications

Supporting

Mentioning

189

Contrasting

Unclassified

Order By: Relevance

“…Processes at liquid | liquid interfaces are of importance in analytical applications [1] and in many biological processes [2]. Electrochemical polarisation of liquid | liquid interfaces allows extraction of thermodynamic and kinetic data for ion transfer processes [3].…”

Section: Introductionmentioning

confidence: 99%

Coupled triple phase boundary processes: Liquid–liquid generator–collector electrodes

Vagin¹,

Karyakin²,

Vuorema³

et al. 2010

Electrochemistry Communications

Self Cite

View full text Add to dashboard Cite

Electrochemical processes at liquid | liquid | electrode interfaces involve simultaneous ion transfer and electron transfer. When driven at triple phase boundary electrode systems, electron and ion transfer occur in the same interfacial reaction zone. In this report, preliminary work with a novel electrode system based on two coupled triple phase boundary reaction zones is described. An inter-digitated gold band array with 7 µm gold bands separated by 13 µm gaps is employed immersed in aqueous electrolyte with a water immiscible solution of the redox system N,N-diethyl-N'N'-didodecylphenylenediamne (DDPD) in 4-(3-phenylpropyl)-pyridine (PPP) immobilised on the surface. Well-defined generator -collector feedback currents are observed which depend on the volume of deposit, the concentration of the redox system, and the nature of the aqueous electrolyte.

show abstract

Section: Introductionmentioning

confidence: 99%

Coupled triple phase boundary processes: Liquid–liquid generator–collector electrodes

Vagin¹,

Karyakin²,

Vuorema³

et al. 2010

Electrochemistry Communications

Self Cite

View full text Add to dashboard Cite

show abstract

“…It is worth noting that all these voltammetric features of Fura-2/AM closely resemble those of the substituted tetraalkylphenylenediamines redox liquids, which have been explored in detail by Compton, Marken et al [23][24][25][26]. NPOE itself can also show some electrochemical activity, if the electrolysis is performed at highly negative starting potentials (more negative than −0.9 V vs. Ag/AgCl) for certain accumulation times.…”

Section: Voltammetric Behaviour Of Fura-2/am In Ca 2+ -Free Solutionsmentioning

confidence: 99%

“…Considering the chemical structure of Fura-2/AM, it is plausible to assume that the amino groups (Phe-N-R) placed at the benzene ring are redox active centres [23][24][25][26]. Since both amino groups in the structure of Fura-2/AM are symmetrically positioned, their oxidation will appear at a same potential and will be portrayed in one voltammetric signal.…”

Section: Voltammetric Behaviour Of Fura-2/am In Ca 2+ -Free Solutionsmentioning

confidence: 99%

“…In aqueous solutions with pH ≤ 6, a chemically facilitated transfer of protons (accompanied by the chargecompensating uptake of anions) into the organic phase occurs [23][24][25][26] and leads to protonation of the N-R groups of the Fura molecules. The voltammetric responses of Fura-2/AM recorded at thin-film electrode mode, in aqueous media hav- ing pH from 6 to 2.5 are presented in Fig.…”

Section: Voltammetric Behaviour Of Fura-2/am In Ca 2+ -Free Solutionsmentioning

confidence: 99%

See 1 more Smart Citation

Redox properties of the calcium chelator Fura-2 in mimetic biomembranes

Gulaboski¹,

Pereira²,

Cordeiro³

et al. 2008

Cell Calcium

View full text Add to dashboard Cite

Fura-2 is one of the most commonly used fluorescent dyes to analyze the cytosolic Ca 2+ concentration ([Ca 2+ ] i ) of living cells. Fura-2-dependent measurements of [Ca 2+ ] i are susceptible to changes of pH, reactive oxygen species concentration and membrane potential. Fura-2 is often loaded over the lipophilic cell membrane into the cytosol of a cell in its esterified form (Fura-2/AM) which is then cleaved by endogenous esterases. We have analyzed the electrochemical properties of Fura-2/AM and Fura-2 salt by cyclic voltammetry ("three-phase" and "thin-film" electrode methods). Using Fura-2/AM as a redox facilitator, we were able to mimic the transport of various ions across a lipophilic barrier. We show that Fura-2/AM in this biomimetic set-up can be reversibly oxidized in a single electrochemical step. Its redox reaction was highly proton sensitive in buffers with pH ≤ 6. At physiological pH of around 7.0, the oxidation of Fura-2/AM was coupled to an uptake of mono-anions across the liquid-liquid interface. The voltage-dependence of the redox cycle was sensitive to the free Ca 2+ concentration, either after de-esterification of Fura-2/AM, or when Fura-2 salt was used. The complex between Fura-2 and Ca 2+ ions is ionic (complexation occurs via the dissociated negative groups of Fura forms), while the redox transformations in Fura-2 occurs at the nitrogen atoms of the amino groups. Our results suggest that redox transformations of the Fura-2 forms do not affect the binding ability toward Ca 2+ ions and thus do not interfere with [Ca 2+ ] i measurements.

show abstract

“…The approach for the detection of the glucose enzymatic products we present here is simple, fast, and consistent. It does not require additional modification and alteration of the set-up used by the studies of the common ion transfer reactions, described in previous publications [4,5,6,19,20,21,22,23,24].…”

Section: Introductionmentioning

confidence: 99%

Enzymatic formation of ions and their detection at a three-phase electrode

Gulaboski¹,

Pereira²,

Cordeiro³

et al. 2005

J Solid State Electrochem

View full text Add to dashboard Cite

An electrochemical method for the detection of enzymatically created anions is described that uses a thin-film electrode with decamethylferrocene as an electroactive redox probe. The enzymatic oxidation of glucose with enzyme glucose oxidase produces gluconic acid as a final product. The oxidation of decamethylferrocene dissolved in the thin-nitrobenzene film, that is spread on the working graphite electrode and submerged in the aqueous solution containing glucose and glucose oxidase, is followed by the up-take of gluconate anions from the aqueous phase to nitrobenzene. The peak currents of the square-wave voltammetric responses of that system are a linear function of the glucose concentration in the milimolar range from 0.1 mmol/L to 0.7 mmol/L (R 2 =0.994).

show abstract

Electrochemistry of immobilised redox droplets: Concepts and applications

Cited by 185 publications

References 145 publications

Coupled triple phase boundary processes: Liquid–liquid generator–collector electrodes

Coupled triple phase boundary processes: Liquid–liquid generator–collector electrodes

Redox properties of the calcium chelator Fura-2 in mimetic biomembranes

Enzymatic formation of ions and their detection at a three-phase electrode

Contact Info

Product

Resources

About