Characterization of octadecanethiol-coated gold electrodes as microarray electrodes by cyclic voltammetry and ac impedance spectroscopy

Finklea, Harry O.; Snider, Daniel A.; Fedyk, J.D.; Sabatani, Eyal; Gafni, Yael; Rubinstein, Israel

doi:10.1021/la00036a050

Cited by 425 publications

(427 citation statements)

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“…This electrochemical pre-treatment serves to further remove any physically adsorbed species on the surface of the modified electrodes not removed by the rinsing process described in the experimental and, most importantly, to give an insight into the electrochemical stability of these electrodes which is crucial to their studies and application in aqueous solutions. , [22], [23], [24], [25] and [26]. The modification of the Au with any of the species resulted in increased capacitive charging current of the bare gold electrode.…”

Section: Electrochemical Properties Of the Self-assembled Filmsmentioning

confidence: 99%

“…Self-assembly may simply be described as a spontaneous, coordinated chemical reaction of individual molecular building blocks (especially alkanethiols and thiol-derivatised organomolecules) to create stable, well-organized arrays of ultrathin superstructure films on coinage metals, notably gold [21], [22], [23], [24], [25] and [26]. The formation of self-assembled monolayers (SAMs) of organomolecules on gold surfaces has continued to attract considerable research interests due to their crucial importance in biology, chemistry and supramolecular nanotechnology.…”

Section: Introductionmentioning

confidence: 99%

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Insights into the surface and redox properties of single-walled carbon nanotube—cobalt(II) tetra-aminophthalocyanine self-assembled on gold electrode

Ozoemena

Nyokong

Nkosi

et al. 2007

Electrochimica Acta

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Section: Electrochemical Properties Of the Self-assembled Filmsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Insights into the surface and redox properties of single-walled carbon nanotube—cobalt(II) tetra-aminophthalocyanine self-assembled on gold electrode

Ozoemena

Nyokong

Nkosi

et al. 2007

Electrochimica Acta

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“…Mass transport in this model accounts for the possible defects present in the multilayer leading to nonlinear diffusion. [37][38][39][40][41][42][43] There is substantial experimental evidence on the existence of defects and preferential paths for diffusion at the first stages in the growth of PEMUs. 44,45 We also demonstrate here the existence of defects in the early and intermediate stages of the build-up process of PE/Au NP multilayers by means of the AFM technique, thus supporting the validity of the CMM.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Characterization of Polyelectrolyte/Gold Nanoparticle Multilayers Self-Assembled on Gold Electrodes

et al. 2005

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Polyelectrolyte/gold nanoparticle multilayers composed of poly(L-lysine) (pLys) and mercaptosuccinic acid (MSA) stabilized gold nanoparticles (Au NPs) were built up using the electrostatic layer-by-layer self-assembly technique upon a gold electrode modified with a first layer of MSA. The assemblies were characterized using UV-vis absorption spectroscopy, cyclic and square-wave voltammetry, electrochemical impedance spectroscopy, and atomic force microscopy. Charge transport through the multilayer was studied experimentally as well as theoretically by using two different redox pairs [Fe(CN) 6 ] 3-/4-and [Ru(NH 3 ) 6 ] 3+/2+ . This paper reports a large sensitivity to the charge of the outermost layer for the permeability of these assemblies to the probe ions. With the former redox pair, dramatic changes in the impedance response were obtained for thin multilayers each time a new layer was deposited. In the latter case, the multilayer behaves as a conductor exhibiting a strikingly lower impedance response, the electric current being enhanced as more layers are added for Au NP terminated multilayers. These results are interpreted quite satisfactorily by means of a capillary membrane model that encompasses the wide variety of behaviors observed. It is concluded that nonlinear slow diffusion through defects (pinholes) in the multilayer is the governing mechanism for the [Fe(CN) 6 ] 3-/4-species, whereas electron transfer through the Au NPs is the dominant mechanism in the case of the [Ru(NH 3 ) 6 ] 3+/2+ pair.

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“…If the SAMs do not contain pinhole defects, it means that the only way by which the electron transfer process can occur is by electron-tunneling across the redox-inactive insulating barrier (i.e., thin layers at collapsed sites or thick layers in well-assembled domains). Assuming that electron-transfer processes occur only at the bare spots of the electrodes and that diffusion of the redox probe to these defect sites is planar, the apparent fractional coverage (y app ) of the modifier could be estimated from eqn (3): 45,46 …”

Section: Impedimetric Assessment Of Structural Disordermentioning

confidence: 99%

Electron transfer dynamics across self-assembled N-(2-mercaptoethyl) octadecanamide/mycolic acid layers: impedimetric insights into the structural integrity and interaction with anti-mycolic acid antibodies

Ozoemena

Mathebula

Pillay

et al. 2010

Phys. Chem. Chem. Phys.

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The integrity and properties of mycolic acid (MA) antigens integrated into a self-assembled monolayer (SAM) of N-(2-mercaptoethyl)octadecanamide, (MEODA), on a gold electrode have been interrogated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). EIS data showed that Au-MEODA and Au-MEODA-MA behave as microelectrode arrays, with pinholes acting as the microelectrodes that permit electron transport between a redox-active probe in solution and the underlying gold surface. The average radii of the pinholes (r a ) and half the distance between the centers of the neighbouring pinholes (r b ), were estimated from EIS using the pore size model, and discussed. Anti-MA antibodies present in a tuberculosis (TB)-infected patient (co-infected with HIV) strongly interact with Au-MEODA-MA showing a rather compact and stable bio-complex structure that is virtually defect-free. The electrochemical impedimetric properties associated with the ability of the Au-MEODA-MA to discriminate between TB positive and negative human sera are also discussed. We prove that the Au-MEODA and Au-MEODA-MA electrodes, as well as the MA-anti-MA antibody interactions, are characterized with time-constant dispersion, typical of microstructures with grain/grain boundary phases. These crucial physico-electrochemical insights into the behaviour of surface-confined MA should provide a useful basis for the design and development of a potential impedimetric immunosensing platform for active tuberculosis.

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Characterization of octadecanethiol-coated gold electrodes as microarray electrodes by cyclic voltammetry and ac impedance spectroscopy

Cited by 425 publications

References 0 publications

Insights into the surface and redox properties of single-walled carbon nanotube—cobalt(II) tetra-aminophthalocyanine self-assembled on gold electrode

Insights into the surface and redox properties of single-walled carbon nanotube—cobalt(II) tetra-aminophthalocyanine self-assembled on gold electrode

Electrochemical Characterization of Polyelectrolyte/Gold Nanoparticle Multilayers Self-Assembled on Gold Electrodes

Electron transfer dynamics across self-assembled N-(2-mercaptoethyl) octadecanamide/mycolic acid layers: impedimetric insights into the structural integrity and interaction with anti-mycolic acid antibodies

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