Modified Carbon Nanotube Paste Electrode for Voltammetric Determination of Carbidopa, Folic Acid, and Tryptophan

Baghbamidi, Sakineh Esfandiari; Beitollahi, Hadi; Karimi-Maleh, Hassan; Soltani-Nejad, Somayeh; Soltaninejad, Vahhab; Roodsaz, Sara

doi:10.1155/2012/305872

Cited by 15 publications

(1 citation statement)

References 44 publications

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“…Cys yielded the poorest selectivity because it is electroactive; however, when channel subtraction (self-referencing) between glutamate oxidase-coated sites and sentinel sites was applied, the selectivity improved to 250 ± 80. Others have previously reported the direct oxidation and quantification of amino acids: Arg, , Cys, , Met, Trp, − and Tyr . The control sites were less sensitive (83 ± 7% of glutamate response for Arg, Cys, His, Met, Trp, and Tyr), possibly because of coating differences between the control and glutamate sensitive sites.…”

Section: Resultsmentioning

confidence: 96%

Glutaraldehyde Cross-Linked Glutamate Oxidase Coated Microelectrode Arrays: Selectivity and Resting Levels of Glutamate in the CNS

Burmeister

Davis

Quintero

et al. 2013

ACS Chem. Neurosci.

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Glutaraldehyde is widely used as a cross-linking agent for enzyme immobilization onto microelectrodes. Recent studies and prior reports indicate changes in enzyme activity and selectivity with certain glutaraldehyde cross-linking procedures that may jeopardize the performance of microelectrode recordings and lead to falsely elevated responses in biological systems. In this study, the sensitivity of glutaraldehyde cross-linked glutamate oxidase-based microelectrode arrays to 22 amino acids was tested and compared to glutamate. As expected, responses to electroactive amino acids (Cys, Tyr, Trp) were detected at both nonenzyme-coated and enzyme-coated microelectrodes sites, while the remaining amino acids yielded no detectable responses. Electroactive amino acids were effectively blocked with a m-phenylene diamine (mPD) layer and, subsequently, no responses were detected. Preliminary results on the use of poly(ethylene glycol) diglycidyl ether (PEGDE) as a potentially more reliable cross-linking agent for the immobilization of glutamate oxidase onto ceramic-based microelectrode arrays are reported and show no significant advantages over glutaraldehyde as we observe comparable selectivities and responses. These results support that glutaraldehyde-cross-linked glutamate oxidase retains sufficient enzyme specificity for accurate in vivo brain measures of tonic and phasic glutamate levels when immobilized using specific "wet" coating procedures.

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Section: Resultsmentioning

confidence: 96%

Glutaraldehyde Cross-Linked Glutamate Oxidase Coated Microelectrode Arrays: Selectivity and Resting Levels of Glutamate in the CNS

Burmeister

Davis

Quintero

et al. 2013

ACS Chem. Neurosci.

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Applications for Drug Assays

Özkan

Kauffmann

Zuman

2015

Monographs in Electrochemistry

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Mediated bioelectrochemical system for biosensing the cell viability of Staphylococcus aureus

Hassan

Wollenberger

2015

Anal Bioanal Chem

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Staphylococcus aureus is one of the most dangerous human pathogens and is the cause of numerous illnesses ranging from moderate skin infections to life-threatening diseases. Despite advances made in identifying microorganisms, rapid detection methods for the viability of bacteria are still missing. Here, we report a rapid electrochemical assay for cell viability combining the use of double redox mediators and multiwall carbon nanotubes-screen printed electrodes (MWCNTs-SPE), ferricyanide (FCN) and 2,6-dichlorophenolindophenol (DCIP), which served as electron shuttle to enable the bacterial-electrode communications. The current originating from the metabolically active cells was recorded for probing the activity of the intracellular redox centers. Blocking of the respiratory chain pathways with electron transfer inhibitors demonstrated the involvement of the electron transport chain in the reaction. A good correlation between the number of the metabolically active cells and the current was obtained. The proposed assay has been exploited for monitoring cell proliferation of S. aureus during the growth. The sensitivity of the detection method reached 0.1 OD600. Therefore, the technique described is promising for estimating the cell number, measuring the cell viability, and probing intracellular redox center(s).

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Modified Carbon Nanotube Paste Electrode for Voltammetric Determination of Carbidopa, Folic Acid, and Tryptophan

Cited by 15 publications

References 44 publications

Glutaraldehyde Cross-Linked Glutamate Oxidase Coated Microelectrode Arrays: Selectivity and Resting Levels of Glutamate in the CNS

Glutaraldehyde Cross-Linked Glutamate Oxidase Coated Microelectrode Arrays: Selectivity and Resting Levels of Glutamate in the CNS

Applications for Drug Assays

Mediated bioelectrochemical system for biosensing the cell viability of Staphylococcus aureus

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