Microvoltammetric techniques and sensors for monitoring neurochemical dynamics in vivo. A review

O’Neill, Robert

doi:10.1039/an9941900767

Cited by 272 publications

(140 citation statements)

References 280 publications

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“…By implanting a microelectrode in a specific brain region, applying a suitable potential profile and recording the resulting Faradaic current, changes in the concentration of a variety of ECF species can be monitored. LIVE offers excellent spatial (∼10 μm) and temporal (millisecond) resolutions, and a major advantage of long-term stability (continuous monitoring in vivo over several weeks) (Lowry and O'Neill, 2005;O'Neill, 1994;O'Neill et al, 1998;Stamford and Justice, 1996). This contrasts with measurements achieved by brain microdialysis which suffers from relatively large probe size (minimum ∼200 μm), variable in vivo recovery which is dependent on flow rate and tissue stabilisation/probe fouling, the need to collect finite volumes of dialysates depending on the chosen detection method, and poor time resolution (1-10 min).…”

Section: Introductionmentioning

confidence: 99%

Real-time electrochemical monitoring of brain tissue oxygen: A surrogate for functional magnetic resonance imaging in rodents

et al. 2010

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Long-term in-vivo electrochemistry (LIVE) enables real-time monitoring and measurement of brain metabolites. In this study we have simultaneously obtained blood oxygenation level dependent (BOLD) fMRI and amperometric tissue O 2 data from rat cerebral cortex, during both increases and decreases in inspired O 2 content. BOLD and tissue O 2 measurements demonstrated close correlation (r = 0.7898) during complete (0%) O 2 removal, with marked negative responses occurring ca. 30 s after the onset of O 2 removal. Conversely, when the inspired O 2 was increased (50, 70 and 100% O 2 for 1 min) similar positive rapid changes (ca. 15 s) in both the BOLD and tissue O 2 signals were observed. These findings demonstrate, for the first time, the practical feasibility of obtaining real-time metabolite information during fMRI acquisition, and that tissue O 2 concentration monitored using an O 2 sensor can serve as an index of changes in the magnitude of the BOLD response. As LIVE O 2 sensors can be used in awake animals performing specific behavioural tasks the technique provides a viable animal surrogate of human fMRI experimentation.

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Section: Introductionmentioning

confidence: 99%

Real-time electrochemical monitoring of brain tissue oxygen: A surrogate for functional magnetic resonance imaging in rodents

et al. 2010

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“…glutathione and ascorbic acid), all of which may affect the performance (e.g. the stability and response) of the implanted sensor (O'Neill, 1994). Other problems include restriction of mass-transport to the electrode surface by brain tissue, the biochemical effects of depletion of a chemical species from this matrix and the availability of suitable enzymes for the specific substrates of interest.…”

Section: Introductionmentioning

confidence: 99%

An amperometric glucose-oxidase/poly(o-phenylenediamine) biosensor for monitoring brain extracellular glucose: in vivo characterisation in the striatum of freely-moving rats

Lowry

Miele

O’Neill

et al. 1998

Journal of Neuroscience Methods

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Amperometric glucose biosensors based on the immobilization of glucose oxidase (GOx) on Pt electrodes with electropolymerized o-phenylenediamine (PPD) were implanted in the right striatum of freely-moving rats. Carbon paste electrodes for the simultaneous monitoring of ascorbic acid (AA) and/or tissue O 2 were implanted in the left striatum. A detailed in vivo characterization of the Pt/PPD/GOx signal was carried out using various pharmacological manipulations. Confirmation that the biosensor responded to changing glucose levels in brain extracellular fluid (ECF) was obtained by intraperitoneal (i.p.) injection of insulin that caused a decrease in the Pt/PPD/GOx current, and local administion of glucose (1 mM) via an adjacent microdialysis probe that resulted in an increase in the biosensor current. An insulin induced increase in tissue O 2 in the brain was also observed. Interference studies involved administering AA and subanaesthetic doses of ketamine i.p. Both resulted in increased extracellular AA levels with ketamine also causing an increase in O 2 . No significant change in the Pt/PPD/GOx current was observed in either case indicating that changes in O 2 and AA, the principal endogenous interferents, have minimal effect on the response of these first generation biosensors. Stability tests over a successive 5-day period revealed no significant change in sensitivity. These in vivo results suggest reliable glucose monitoring in brain ECF.

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“…DA is involved in the functioning of the central nervous system, in addition to the cardiovascular, renal and hormonal systems, and plays an important role in drug addiction and Parkinson's disease. 12,13 Similarly, AA (vitamin C) has been used in preventing and treating cold, mental illness, infertility, cancer and other diseases. 14 In the mammalian brain, AA is present along with several neurotransmitters including dopamine, with a concentration of 100-1000 times higher than that of DA.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous voltammetric determination of dopamine and ascorbic acid using multivariate calibration methodology performed on a carbon paste electrode modified by a mer-[RuCl3(dppb)(4-pic)] complex

Santos¹,

Sandrino²,

Moreira³

et al. 2007

J. Braz. Chem. Soc.

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A preparação e caracterização eletroquímica do eletrodo de pasta de carbono (EPC) modificado com o mer- [RuCl 3 (dppb)(4-pic)] (dppb= Ph 2 P(CH 2 ) 4 PPh 2 , 4-pic= CH 3 C 5 H 4 N), denominado Rupic, foi investigada. O sistema EPC/Rupic apresentou apenas um par de picos com potencial médio de 0,28 V vs. Ag/AgCl, o qual foi atribuído ao processo de transferência de elétrons do Ru III /Ru II . Este eletrodo modificado apresentou a propriedade de eletrocatalisar a oxidação da dopamina (DA) e do ácido ascórbico (AA) em 0,35 V e 0,30 V, respectivamente. Como a oxidação dos analitos, AA e DA, ocorreu praticamente no mesmo potencial, não foi possível a distinção dos sinais voltamétricos utilizando-se a voltametria cíclica. Esta limitação foi resolvida empregando-se a Regressão de Mínimos Quadrados Parciais (PLSR), a qual permitiu a determinação de quatro amostras sintéticas, com erros de previsão (RMSEP) de 5,55×10 -5 mol L -1 e 7,48×10 -6 mol L -1 para DA e AA, respectivamente.The preparation and electrochemical characterization of a carbon paste electrode (CPE) modified with mer-[Ru0Cl 3 (dppb)(4-pic)] (dppb=Ph 2 P(CH 2 ) 4 PPh 2 , 4-pic=CH 3 C 5 H 4 N), referred to as Rupic, were investigated. The CPE/Rupic system displayed only one pair of redox peaks, with a midpoint potential at 0.28 V vs. Ag/AgCl, which were ascribed to Ru III /Ru II charge transfer. This modified electrode presented the property of electrocatalysing the oxidation of dopamine (DA) and ascorbic acid (AA) at 0.35 V and 0.30 V vs. Ag/AgCl, respectively. Because the oxidation for both AA and DA practically occurred at the same potential, distinguishing between them was difficult with cyclic voltammetry. This limitation was overcome using Partial Least Square Regression (PLSR), which allowed us, with the optimised models, to determine four synthetic samples with prediction errors (RMSEP) of 5.55×10 -5 mol L -1 and 7.48×10 -6 mol L -1 for DA and AA, respectively. Keywords: carbon paste electrodes, ruthenium complexes, dopamine, ascorbic acid, multivariate calibration methodology IntroductionConsiderable progress has been made over the last few years on chemically modified carbon paste electrodes, having an easier and faster procedure to assemble and renew the paste surfaces, low cost, background currents and possibility to incorporate a series of materials. [1][2][3][4][5] Among the materials that may be used in conjunction with carbon paste are the ruthenium-containing compounds such as oxides, mixed valence compounds and complexes. These Ru-based materials possess electrocatalytic properties, which have been used to modify electrodes for electroanalysis of ascorbic acid, 6,7 L-dopa, 8 glucose, 9 benzylic compounds 10 and dopamine. 11 Dopamine (DA) and ascorbic acid (AA), in particular, are relevant from the biomedical and neurochemical point of view, for their importance to human metabolism. DA is involved in the functioning of the central nervous system, in addition to the cardiovascular, renal and hormonal systems, and plays an important role in ...

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Microvoltammetric techniques and sensors for monitoring neurochemical dynamics in vivo. A review

Abstract: Very rough guide; depends on electrode material and its state of 9 Very rough guide of non-stimulated values; depends on brain Paper 31'046426

Cited by 272 publications

References 280 publications

Real-time electrochemical monitoring of brain tissue oxygen: A surrogate for functional magnetic resonance imaging in rodents

Real-time electrochemical monitoring of brain tissue oxygen: A surrogate for functional magnetic resonance imaging in rodents

An amperometric glucose-oxidase/poly(o-phenylenediamine) biosensor for monitoring brain extracellular glucose: in vivo characterisation in the striatum of freely-moving rats

Simultaneous voltammetric determination of dopamine and ascorbic acid using multivariate calibration methodology performed on a carbon paste electrode modified by a mer-[RuCl3(dppb)(4-pic)] complex

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