New biosensing platforms based on the layer-by-layer self-assembling of polyelectrolytes on Nafion/carbon nanotubes-coated glassy carbon electrodes

We report on the analytical performance of glassy carbon (GCE) electrodes modified with a dispersion of multiwall carbon nanotubes (CNT) in chitosan (CHIT) for the quantification of DNA. The electroanalytical response of the resulting electrodes was evaluated using differential pulse voltammetry, while the electrochemical reactivity of the film surface was characterized using scanning electrochemical microscopy. Different treatments of the modified GCE were evaluated to improve the stability of the film and the accumulation of DNA. The guanine oxidation signal of double stranded calf-thymus DNA after 3-min accumulation was 20 times higher at GCE/CHIT-CNT cross-linked with glutaraldehyde (GTA) than at bare GCE, while the peak potential was around 45 mV less positive. The guanine oxidation signal demonstrated to be highly reproducible, with 3.4% RSD for 5 different electrodes. The treatment with sodium hydroxide demonstrated to be not effective since the resulting films were less stable and the guanine oxidation signal was ten times smaller compared to electrodes prepared with the GTA treated films. The effect of chitosan molecular weight used to prepare the dispersion and the amount of carbon nanotubes dispersed were evaluated. The response of single stranded DNA and oligo(dG) 15 is also discussed.

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“…Polymers like Nafion [21,22], polyethylenimine [23] and chitosan [24] have been also used to disperse CNTs.…”

Section: Introductionmentioning

confidence: 99%

Electrooxidation of DNA at Glassy Carbon Electrodes Modified with Multiwall Carbon Nanotubes Dispersed in Chitosan

2007

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“…The reference was a Ag/AgCl, 3M NaCl (BAS, Model RE-5B) electrode and all the potentials are referred to that. The set up is similar to those described in previous work [40,41] Scanning electron microscope (SEM) images were obtained with a field Emission Scanning Electron Microscope, Zeiss Supra 40 Genimi.…”

Section: Apparatusmentioning

confidence: 99%

Screen-printed electrodes for electroanalytical sensing, of chromium VI in strong acid media

Miscoria

Jacq

Maeder

et al. 2014

Sensors and Actuators B: Chemical

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Highlights• Acid-resistant screen-printed electrodes (SPEs) for Cr(VI) detection were developed.• Carbon-based thick-film SPE pastes were formulated in-house with known composition.• A batch fabrication process allowed simple fabrication of robust sensors.• Cr(VI) at pH 1 was electroanalytically quantified with high sensitivity.• High reproducibility, wide linear range and low detection limit were achieved. AbstractSimple, low-cost and acid-resistant carbon-based screen-printed electrodes (SPEs) addressed to detection of hexavalent chromium species, Cr(VI), in sulfuric acid at pH about 1, were prepared and characterized. Working and counter electrodes were prepared jointly on the same substrate in a single strip (working-counter electrodes pair). The batch printing process allowed obtaining many working-counter electrode pairs in a unique step. The developed working electrodes are comprised of several layers deposited on an alumina substrate: (1) bottom silver conductor, (2) dense organic graphite composite conductor, (3) active layer consisting of a porous organic graphite composite which contains a Cr(III) ionophore for testing Cr(III) obtained after reducing Cr(VI), and (4) an insulating and protective dielectric. All materials except the bottom Ag conductor were made on an organic matrix based on a thermoplastic polymer, polyvinylbutyral (PVB). The amperometric determination of Cr(VI) species at pH 1 was performed over a wide concentration range (dynamic range 3 M 40 mM). The range for linear amperometric response is 3 M 10 mM, with sensitivity about 0.08 mA mM at the electrode surface after the reduction of Cr(VI) when diethylenetriamine-pentaacetic acid (DTPA), a complexing agent for Cr(III) is incorporated into the pastes.

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“…Evidently, other new synthetic schemes and more rigid materials are needed to broaden the application and market of CNT -based electrochemical sensors. CNT (bio)composites with a binder such as Nafi on [9,80] , Tefl on [81] , sol -gel [82] , poly(methyl methacrylate) [83] , redox hydrogel [84] , poly(dimethyldiallylammonium chloride) [85] , chitosan [86] , and electropolymerized fi lm [87] were prepared in order to improve the robustness of CNT electrodes and to facilitate immobilization of biocomponents. However, these methods indicate that enzymes and other biomolecules must receive careful treatment in order to retain their tertiary structure.…”

Section: Application Of Carbon Nanotubes As Biosensor Supportsmentioning

confidence: 99%

Enzyme‐Based Biosensors: Synthesis and Applications

Cao

Chen²,

Jin

et al. 2011

Biosensor Nanomaterials

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New biosensing platforms based on the layer-by-layer self-assembling of polyelectrolytes on Nafion/carbon nanotubes-coated glassy carbon electrodes

Cited by 61 publications

References 23 publications

Electrooxidation of DNA at Glassy Carbon Electrodes Modified with Multiwall Carbon Nanotubes Dispersed in Chitosan

Electrooxidation of DNA at Glassy Carbon Electrodes Modified with Multiwall Carbon Nanotubes Dispersed in Chitosan

Screen-printed electrodes for electroanalytical sensing, of chromium VI in strong acid media

Enzyme‐Based Biosensors: Synthesis and Applications

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