Characterization of alkanethiol-self-assembled monolayers-modified gold electrodes by electrochemical impedance spectroscopy

Campuzano, Susana; Pedrero, Marı́a; Montemayor, Concepción; Fatás, Enrique; Pingarrón, José M.

doi:10.1016/j.jelechem.2005.09.007

Cited by 172 publications

(136 citation statements)

References 26 publications

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“…SAM desorption is one reason why a sensor might have a response to a blank solution. Boubour reported that over 40 hours of incubation was required to form a tightly-packed SAM, as determined by observing purely capacitive behavior at low frequencies [166], but others report 15 -20 hours depending on SAM composition [167] and as little as 2 hours [162].…”

Section: Self-assembled Monolayersmentioning

confidence: 99%

Label‐Free Impedance Biosensors: Opportunities and Challenges

2007

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Impedance biosensors are a class of electrical biosensors that show promise for point-of-care and other applications due to low cost, ease of miniaturization, and label-free operation. Unlabeled DNA and protein targets can be detected by monitoring changes in surface impedance when a target molecule binds to an immobilized probe. The affinity capture step leads to challenges shared by all label-free affinity biosensors; these challenges are discussed along with others unique to impedance readout. Various possible mechanisms for impedance change upon target binding are discussed. We critically summarize accomplishments of past label-free impedance biosensors and identify areas for future research.

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Section: Self-assembled Monolayersmentioning

confidence: 99%

Label‐Free Impedance Biosensors: Opportunities and Challenges

2007

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“…The characterisation was done using atomic force microscopy (AFM), voltammetry and electrochemical impedance spectroscopy (EIS). These techniques have been successfully used to investigate the microscopic properties of the modified electrode surfaces and to obtain detailed information about the interface [29][30][31][32][33]. The oxidation of ascorbic acid (AA), an important bioactive substance, which reaction is electrocatalyzed at poly(glutamic acid) film modified GCEs [18] was used as model.…”

Section: Chemical Structures: (A) Glutamic Acid and (B) Poly(glutamicmentioning

confidence: 99%

Poly(glutamic acid) nanofibre modified glassy carbon electrode: Characterization by atomic force microscopy, voltammetry and electrochemical impedance

Santos

Zanoni

Bergamini

et al. 2008

Electrochimica Acta

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Glassy carbon electrodes (GCE) were modified with poly(glutamic acid) acid films prepared using three different procedures: glutamic acid monomer electropolymerization (MONO), evaporation of poly(glutamic acid) (PAG) and evaporation of a mixture of poly(glutamic acid)/glutaraldehyde (PAG/GLU). All three films showed good adherence to the electrode surface. The performance of the modified GCE was investigated by cyclic voltammetry and differential pulse voltammetry, and the films were characterized by atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS). The three poly(glutamic acid) modified GCEs were tested using the electrochemical oxidation of ascorbic acid and a decrease of the overpotential and the improvement of the oxidation peak current was observed. The PAG modified electrode surfaces gave the best results. AFM morphological images showed a polymeric network film formed by well-defined nanofibres that may undergo extensive swelling in solution, allowing an easier electron transfer and higher oxidation peaks.

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“…Figure 5-9A shows typical voltammograms for porous Au electrodes. At positive potential scanning, the characteristic oxidation peak is observed at ~1.2 V. On reversing the scan, a characteristic peak for gold oxide reduction is observed at ~0.9 V. [126] The peak intensity is shown to be the highest for the porous Au bulk film, which is expected, although we must note that there are slight variations in thickness between samples (and on different points of the same sample). If we consider the interstitial voids of the opal electrodes, there are no remarkable differences in current per unit area among these electrode materials, regardless of differences in submicrometer architecture.…”

Section: Bimodal Nanoporous Gold Electrodesmentioning

confidence: 62%

Optimized nanoporous materials.

Langham¹,

Jacobs²,

Ong³

et al. 2009

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Nanoporous materials have maximum practical surface areas for electrical charge storage; every point in an electrode is within a few atoms of an interface at which charge can be stored. Metal-electrolyte interfaces make best use of surface area in porous materials. However, ion transport through long, narrow pores is slow. We seek to understand and optimize the tradeoff between capacity and transport. Modeling and measurements of nanoporous gold electrodes has allowed us to determine design principles, including the fact that these materials can deplete salt from the electrolyte, increasing resistance. We have developed fabrication techniques to demonstrate architectures inspired by these principles that may overcome identified obstacles. A key concept is that electrodes should be as close together as possible; this is likely to involve an interpenetrating pore structure. However, this may prove extremely challenging to fabricate at the finest scales; a hierarchically porous structure can be a worthy compromise.

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Characterization of alkanethiol-self-assembled monolayers-modified gold electrodes by electrochemical impedance spectroscopy

Cited by 172 publications

References 26 publications

Label‐Free Impedance Biosensors: Opportunities and Challenges

Label‐Free Impedance Biosensors: Opportunities and Challenges

Poly(glutamic acid) nanofibre modified glassy carbon electrode: Characterization by atomic force microscopy, voltammetry and electrochemical impedance

Optimized nanoporous materials.

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