Electrochemical biosensing of galactose based on carbon materials: graphene versus multi-walled carbon nanotubes

Dalkıran, Berna; Erden, Pınar Esra; Kılıç, Esma

doi:10.1007/s00216-016-9532-x

Cited by 33 publications

(28 citation statements)

References 52 publications

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“…The fast electron transfer ability, excellent thermal conductivity, strong mechanical strength and biocompatibility make the GR a promising material for biosensing applications . Graphene based biosensors generally show higher sensitivities and a lower detection limits than conventional carbon electrode based biosensors , . For these reasons, graphene is regarded as an ideal material to fabricate high performance biosensors.…”

Section: Introductionmentioning

confidence: 49%

Graphene/Poly(vinylferrocene) Composite Based Amperometric Biosensor for L‐lysine Determination

2017

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A novel and sensitive amperometric biosensor for L‐lysine determination based on a glassy carbon electrode (GCE) modified with graphene (GR) and redox polymer poly(vinylferrocene) (PVF) was constructed. L‐lysine‐α‐oxidase was immobilized onto the modified GCE by a glutaraldehyde/bovine serum albumin cross‐linking procedure. SEM, CV and EIS were used for the characterization of the surface morphology and stepwise fabrication processes of PVF/GR composite. Optimal composition of the biosensor and experimental conditions that affect the performance of the biosensor are discussed. The effect of buffer pH on biosensor response was studied in detail over a wide pH range. L‐lysine biosensor displayed a linear range of 9.9×10−7 ‐ 3.1×10−4 M with a low detection limit of 2.3×10−7 M and KMapp value of 0.4 mM. The L‐lysine biosensor was tested using pharmaceutical sample and cheese with satisfactory results.

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Section: Introductionmentioning

confidence: 49%

Graphene/Poly(vinylferrocene) Composite Based Amperometric Biosensor for L‐lysine Determination

2017

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“…9 GO is also an important component in electrochemical biosensors of galactose that are used for various biotechnology applications. 10–12 Despite accomplishing 2e − reduction of O 2 , the active site of GO contains only a single Cu. To provide the additional redox equivalent required for turnover, the active-site Cu is coordinated by a unique cysteinylated tyrosine (Cys-Tyr) ligand that serves as a second redox-active cofactor.…”

Section: Introductionmentioning

confidence: 99%

Structure of the Reduced Copper Active Site in Preprocessed Galactose Oxidase: Ligand Tuning for One-Electron O₂ Activation in Cofactor Biogenesis

et al. 2016

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Galactose oxidase (GO) is a copper-dependent enzyme that accomplishes 2e− substrate oxidation by pairing a single copper with an unusual cysteinylated tyrosine (Cys-Tyr) redox cofactor. Previous studies have demonstrated that the post-translational biogenesis of Cys-Tyr is copper- and O2-dependent, resulting in a self-processing enzyme system. To investigate the mechanism of cofactor biogenesis in GO, the active-site structure of Cu(I)-loaded GO was determined using X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopy, and density-functional theory (DFT) calculations were performed on this model. Our results show that the active-site tyrosine lowers the Cu potential to enable the thermodynamically unfavorable 1e− reduction of O2, and the resulting Cu(II)-O2•− is activated towards H-atom abstraction from cysteine. The final step of biogenesis is a concerted reaction involving coordinated Tyr ring deprotonation where Cu(II) coordination enables formation of the Cys-Tyr crosslink. These spectroscopic and computational results highlight the role of the Cu(I) in enabling O2 activation by 1e− and the role of the resulting Cu(II) in enabling substrate activation for biogenesis.

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“…Further we compared published GaOx based systems with our proposed system based on PyOx‐MTs, acceptable and comparable results were found (Table ). For example Tkac et al., in their study suggested single walled carbon nanotubes dispersed in a chitosan matrix using GaOx for the design of a galactose biosensor .…”

Section: Resultsmentioning

confidence: 99%

Amperometric Flow Injection Analysis of Glucose and Galactose Based on Engineered Pyranose 2‐Oxidases and Osmium Polymers for Biosensor Applications

et al. 2018

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In the present study, wild type and three mutants of pyranose 2‐oxidase (PyOx‐WT, PyOx‐MT1, PyOx‐MT2, PyOx‐MT3), which showed improved properties for D‐galactose oxidation, were investigated for their oxidising ability when immobilised on graphite electrodes. Four different flexible Os polymers with formal potentials ranging between −0.140 and 0.270 V vs. Ag|AgCl0.1 M KCl were applied together with the various forms of PyOx to wire graphite electrodes using polyethylene glycol diglycidyl ether as crosslinking reagent. The pH profiles for the electrodes modified with wild type and all PyOx mutants in combination with the Os polymers were investigated with both glucose and galactose, respectively, since the PyOx variants showed an improved catalytic activity for galactose. All modified electrodes showed highest response in the pH range between 8.5–10 and KM, Imax values for both glucose and galactose were determined. To prove the catalytic activity, the biosensors were also characterized with cyclic voltammetry. A protein amount 0.26 U was found optimum for PyOx‐WT, 0.36 U for PyOx‐MT1, 0.41 U for PyOx‐MT2 and 0.28 U for PyOx‐MT3 and the analytical characterization of the enzyme electrodes was performed for glucose and galactose under optimized conditions.

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Electrochemical biosensing of galactose based on carbon materials: graphene versus multi-walled carbon nanotubes

Cited by 33 publications

References 52 publications

Graphene/Poly(vinylferrocene) Composite Based Amperometric Biosensor for L‐lysine Determination

Graphene/Poly(vinylferrocene) Composite Based Amperometric Biosensor for L‐lysine Determination

Structure of the Reduced Copper Active Site in Preprocessed Galactose Oxidase: Ligand Tuning for One-Electron O₂ Activation in Cofactor Biogenesis

Amperometric Flow Injection Analysis of Glucose and Galactose Based on Engineered Pyranose 2‐Oxidases and Osmium Polymers for Biosensor Applications

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Electrochemical biosensing of galactose based on carbon materials: graphene versus multi-walled carbon nanotubes

Cited by 33 publications

References 52 publications

Graphene/Poly(vinylferrocene) Composite Based Amperometric Biosensor for L‐lysine Determination

Graphene/Poly(vinylferrocene) Composite Based Amperometric Biosensor for L‐lysine Determination

Structure of the Reduced Copper Active Site in Preprocessed Galactose Oxidase: Ligand Tuning for One-Electron O2 Activation in Cofactor Biogenesis

Amperometric Flow Injection Analysis of Glucose and Galactose Based on Engineered Pyranose 2‐Oxidases and Osmium Polymers for Biosensor Applications

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Structure of the Reduced Copper Active Site in Preprocessed Galactose Oxidase: Ligand Tuning for One-Electron O₂ Activation in Cofactor Biogenesis