Use of polarization-dependent SERS from scratched gold films to monitor the electrochemically-driven desorption and readsorption of cysteine

Anema, Jason R.; Brolo, Alexandre G.

doi:10.1016/j.jelechem.2010.02.027

Cited by 15 publications

(21 citation statements)

References 20 publications

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“…Several pioneer experimental investigations on the subject claim that both the amino and carboxyl group are adsorbed on the gold surface, drawing conclusions based on surface enhanced Raman scattering (SERS) spectra, which show vibrational bands of both functional groups enhanced after cysteine adsorption on the metal surface. Conversely, other studies, also based on SERS and aided by density functional theory (DFT) calculations, reported two possible adsorption modes: through the thiol group alone or via the thiol group together with the carboxyl group (one or two of the oxygen atoms from the COO − group). However, considering that SERS bands are shifted with respect to Raman bands due to the molecule adsorption, the wavenumber analysis and band assignment is currently considered a challenge using this technique …”

Section: Introductionmentioning

confidence: 99%

Revisiting the conformational adsorption of L‐ and D‐cysteine on Au nanoparticles by Raman spectroscopy

Rodríguez‐Zamora

Salazar-Angeles

Buendía

et al. 2019

J Raman Spectroscopy

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Understanding the physical mechanisms of thiolated molecules adsorption on metal surfaces has required copious research, particularly on Au–cysteine systems due to the affinity of sulfur molecules to gold surfaces, as well as the interesting structural modifications that this strong interaction induces and the peculiar optical, chiroptical, and electronic properties of Au(SR) systems. Here, we present vibrational experimental data on the adsorption of L‐ and D‐cysteine on small gold nanoparticles (<2 nm) by means of Raman spectroscopy. L‐ and D‐cysteine molecules adopt the same strained conformation upon adsorption on colloidal gold nanoparticles, regaining structure due to the stabilization that the gold nanoparticle induces on the cysteine, reflected in the recuperation of vibrational bands from their polymorphically distinctive crystalline forms. Through the analysis of Raman vibrational modifications after adsorption, we found experimental evidence that confirms a stabilized cysteine conformation locating the carboxyl group in the antiposition (PC isomeric rotamer) for both molecules. This result is supported by extensive density functional theory (DFT) calculations and simulated Raman spectra, considering zwitterionic cysteine adsorbed on a Au34 cluster, emulating experimental nanoparticle sizes. Our Raman spectroscopy experimental and DFT results determine one of the oxygen atoms of the carboxyl group as a second adsorption site after the sulfur atom, confirming that independent of its polymorphism and enantiomerism, zwitterionic cysteine interacts with gold nanoparticles through the thiol group and the carboxyl group as adsorption sites.

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Section: Introductionmentioning

confidence: 99%

Revisiting the conformational adsorption of L‐ and D‐cysteine on Au nanoparticles by Raman spectroscopy

Rodríguez‐Zamora

Salazar-Angeles

Buendía

et al. 2019

J Raman Spectroscopy

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“…The glancing angle at which the deposited material encounters the surface produces an array of posts all oriented toward the evaporation source. These nanoposts were demonstrated to be efficient SERS substrates for analytical applications, showing an EF of 10 8 . , In addition, to generate a large SERS enhancement, the anisotropic and ordered nature of the nanorod structures make them sensitive to the polarization of the incident light. , Other reports have demonstrated the polarization response of SERS signals in various structures, such as nanogaps (e.g., nanoparticles dimers) and anisotropic nanoparticles. − Previous work by Brolo’s group has used the SERS polarization response of plasmonic microarrays to subtract unwanted background from Raman spectra. − …”

mentioning

confidence: 99%

SERS in Plain Sight: A Polarization Modulation Method for Signal Extraction

et al. 2019

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Surface-enhanced Raman spectroscopy (SERS) is a powerful analytical spectroscopy offering advantages ranging from "vibrational fingerprints" to multiplexed detection. However, the use of this technique in real-world applications has been limited due to difficulties in detecting inherently weak Raman signals often embedded in strong interfering background signals. A variety of plasmonics-active platforms have been developed to increase Raman signals but are not sufficient to extract weak SERS signals from intense interfering background signals. Herein, we describe a practical method, referred to as polarization modulation-SERS (PM-SERS), which utilizes the polarization dependence of anisotropic SERS-active nanostructures to modulate the plasmonic effect to extract SERS signals and remove background. The modulation is obtained by switching the polarization of the excitation source at a specific frequency involving addition of only few optical components such as liquid crystal polarizers to a typical Raman setup. In this work, we characterized the polarization-dependent response of the SERS substrates fabricated using the oblique angle evaporation (OAV) technique and their response under laser excitation using a polarization modulated source. We demonstrated that the PM-SERS method can extract the analyte weak SERS signals from the strong interfering background signal in different situations, involving a fluorescent sample and a strong background light, and we show the possibility of using PM-SERS at a quasi-real time rate (0.5 Hz). We believe that the PM-SERS method will help expand the translation of applications that utilize SERS-substrates to realworld settings.

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“…Cu 2 O presents a band at 615 cm -1 related to the Cu-O stretch, observed before and after the modification of the nanoparticles. But, after the modification, the intensification and enlargement of this band, probably due to C-S stretch, is expected to be in this region for Pt (Dourado et al 2017), Ag (Brolo et al 2002) and Au (Anema and Brolo 2010). The XPS measurements also verify that the thiol was in its thiolate form and Cu was locally reduced to Cu 0 (Azimi et al 2014), making it possible to observe the same equilibrium observed for thiols adsorbed onto Au.…”

Section: Amino Acid Interaction With Cu 2 Omentioning

confidence: 80%

The long and successful journey of electrochemically active amino acids. From fundamental adsorption studies to potential surface engineering tools.

Dourado

Pastrián

Torresi

2018

An. Acad. Bras. Ciênc.

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Proteins have been the subject of electrochemical studies. It is possible to apply electrochemical techniques to obtain information about their structure due to the presence of five electroactive amino acids that can be oriented to the outside of the peptidic chain. These amino acids are L-and L-Cysteine (L-Cys); their electrochemical behavior being subject of extensive research, but it is still controversial. No spectroscopic investigations have been reported on L-Trp, and due to the short life time of the intermediates, ex situ techniques cannot be employed, leading to a never-ending discussion about possible intermediates. In the L-Tyr and L-His cases, spectroelectrochemical studies were performed and different intermediates were observed, suggesting that some intermediates may be observed under specific conditions, as proposed for L-Cys. This amino acid is the most interesting among the electroactive ones because of the presence of a thiol moiety at its side chain, leading to a wide range of oxidation states. It can adsorb onto surfaces of different crystallographic orientation in stereoselective conformation, modifying the surface for different applications.as a surface engineering tool since it plays the role of as an anchor for the growing of nanocrystals inside proteic templates.

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Use of polarization-dependent SERS from scratched gold films to monitor the electrochemically-driven desorption and readsorption of cysteine

Cited by 15 publications

References 20 publications

Revisiting the conformational adsorption of L‐ and D‐cysteine on Au nanoparticles by Raman spectroscopy

Revisiting the conformational adsorption of L‐ and D‐cysteine on Au nanoparticles by Raman spectroscopy

SERS in Plain Sight: A Polarization Modulation Method for Signal Extraction

The long and successful journey of electrochemically active amino acids. From fundamental adsorption studies to potential surface engineering tools.

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