Enhanced stability of short- and long-chain diselenide self-assembled monolayers on gold probed by electrochemistry, spectroscopy, and microscopy

Subramanian, S.; Sampath, S.

doi:10.1016/j.jcis.2007.03.021

Cited by 19 publications

(32 citation statements)

References 68 publications

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“…8 This observation is similar to earlier reports on the absence of longrange order in alkanethiol SAMs on Hg surfaces 33À38 and Hg exposed thiol SAMs on Au. 38 In this context, it should be noted that 38,43,45 presence of Hg will lead to the formation of nanometric amalgam islands and pits due to dissolution of gold as noted in the introduction.…”

Section: Resultssupporting

confidence: 91%

Mercury Segregation and Diselenide Self-Assembly on Gold

et al. 2012

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We have investigated the self-assembly of didecyldiselenide on gold containing mercury using X-ray photoelectron spectroscopy, cyclic voltammetry and infrared spectroscopy. The analysis of intensity and chemical shift of selected Se, Hg, and Au photoelectron lines on samples with increasing Hg content, show that didecyldiselenide adsorption strongly contributed to segregation of bulk Hg to the surface. The voltammetry results support this conclusion and suggest the formation of HgÀAu surface amalgam. The Hg surface segregation effect must be related to the restructuring of the surface following initial adsorption, and to the strong selenophilicity of Hg. The reflectance absorbance infrared spectroscopy studies show that the molecular layer on HgÀAu substrates lacks good order.

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Section: Resultssupporting

confidence: 91%

Mercury Segregation and Diselenide Self-Assembly on Gold

et al. 2012

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“…This behavior is consistent with a two-step mechanism in which the diselenide is first cleaved to yield a selenium-gold adsorbate (1) and then bulk selenocystine is reduced at the modified substrate (2). Formation of gold-selenium monolayers and films via Se-Se bond cleavage is well documented in the literature [33][34][35][36][37][38][39][40][41][42][43].…”

Section: Resultsmentioning

confidence: 88%

Voltammetric behavior of selenocystine at modified gold substrates

Walker

Karnaukh

Dewan

et al. 2016

Electrochemistry Communications

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The voltammetric response of seleno-L-cystine has been studied at gold substrates under physiological conditions. The reactivity of diselenides is utilized to generate a modified electrode surface, which in turn allows for electroanalysis of solution-based selenium species. Stable and reproducible voltammetry is observed for selenocystine reduction at pH 7 on selenium-modified gold substrates (E mid =-486 mV vs. Ag/AgCl) and is consistent with a diffusionally controlled process. Modification of the gold surface is readily achieved via electrochemical cycling in the presence of a diselenide source at conventional scan rates. These studies afford voltammetric characterization of the selenocystine / selenocysteine redox couple under physiologically relevant conditions and highlight the potential utility of selenium-modified substrates for electroanalysis of chalcogen-containing species.

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“…Au-thiol SAM formation has been widely studied, with a transition from disordered polymer films obtained for short-chain thiols (n < 8) to highly ordered two-dimensional arrays obtained for longer-chain thiols (n > 10) [43]. This results in higher ionic permeability of short-chain SAMs relative to longer-chain SAMs, and therefore considerably lower charge transfer resistance (R ct ) from EIS measurements at Au electrodes [44,45]. The current study provides an analogous reduction in R ct for direct immobilization onto Au electrodes, and backfilling with the MCH (n = 6), relative to SAM formation from 11-MUA (n = 11), as illustrated by the last column in Table 6.…”

Section: à/3àmentioning

confidence: 99%

Impedance Detection of 3‐Phenoxybenzoic Acid Comparing Wholes Antibodies and Antibody Fragments for Biomolecular Recognition

Pali

Suni

2018

Electroanalysis

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Antibody fragments for detection of 3‐phenoxybenzoic acid (3‐PBA) are created by disulfide bond cleavage with tris(2‐carboxyethyl)phosphine (TCEP). These antibody fragments are employed to improve the sensitivity for 3‐PBA detection by electrochemical impedance spectroscopy (EIS). The sensitivity and detection limit are compared for biomolecular recognition by both polyclonal antibodies and antibody fragments immobilized through amide bond formation atop a self‐assembled monolayer (SAM) on an Au electrode, as well as antibody fragments directly attached to Au through Au−S covalent bond formation. The detection limit for 3‐PBA is dramatically improved (1.1×10−8 M) for direct immobilization of antibody fragments through Au−S covalent bond formation relative to immobilization of either polyclonal antibodies (2.1×10−5 M) or antibody fragments (1.7×10−5 M) through amide bond formation. This can be attributed primarily to the much lower charge transfer resistance (Rct) and higher ionic permeability obtained at biosensor interfaces that do not include an Au‐thiol SAM, allowing easier detection of further changes in Rct. In addition, the exponential dependence of the electron tunnelling rate on biomolecular film thickness increases the sensitivity of the antibody fragments modestly relative to polyclonal antibodies. This is the first quantitative comparison of the use of antibodies and antibody fragments for biomolecular recognition within impedance biosensors.

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Enhanced stability of short- and long-chain diselenide self-assembled monolayers on gold probed by electrochemistry, spectroscopy, and microscopy

Cited by 19 publications

References 68 publications

Mercury Segregation and Diselenide Self-Assembly on Gold

Mercury Segregation and Diselenide Self-Assembly on Gold

Voltammetric behavior of selenocystine at modified gold substrates

Impedance Detection of 3‐Phenoxybenzoic Acid Comparing Wholes Antibodies and Antibody Fragments for Biomolecular Recognition

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