Insights of adsorption mechanisms of Trp-peptides on plasmonic surfaces by SERS

daFonseca, Bruno G.; Costa, Luiz Antônio S.; Sant’Ana, Antônio Carlos

doi:10.1016/j.saa.2017.09.039

Cited by 18 publications

(13 citation statements)

References 55 publications

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“…Others have reported a similar SERS spectrum from Trp on gold nanoparticles. In the absence of experiments to assess aggregation, they attributed changes in the UV–vis spectrum to nanoparticle coupling, and the changes in the SERS spectrum are attributed to adsorptive interactions. , In our previous paper, we performed dynamic light scattering with UV–vis absorption to demonstrate the nanoparticles were unaggregated and the new resonance was associated with the presence of tryptophan . This supported assigning the new SERS peaks and peak shifts to the corresponding bands in the simulated Raman spectrum for the Trp radical anion (Trp •– ) species .…”

Section: Discussionmentioning

confidence: 69%

“…It was reported that the indole ring has H-bonding interactions with negatively charged gold nanoparticles (AuNPs); however, a computational study showed that the interation with the Au surface was favorable through either the carboxylic acid moiety or the pyrrole ring . A more recent work also noted SERS bands attributable to the shifted indole ring, attributing these spectral changes to interactions between the gold surface and the indole ring …”

Section: Introductionmentioning

confidence: 99%

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Plasmonically Generated Tryptophan Radical Anion on Gold Nanoparticles Investigated by Combined Surface-Enhanced Raman Scattering and Density Functional Theory Calculations

et al. 2021

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Surface-enhanced Raman scattering (SERS) offers increases in chemical sensitivity associated with the Raman signal from molecules interacting with plasmonic nanoparticles and with use for diverse applications. This signal enhancement is the result of a combination of the enhanced electromagnetic field generated at the surface of the metal nanostructures and possible chemical enhancements specific to the molecule being detected. These chemical effects can alter the chemical identity of the analyte and manifest as differences in the SERS spectrum relative to the spontaneous Raman spectrum. In this work, we examine changes in the vibrational spectrum resulting from the previously hypothesized formation of a radical anion of the amino acid tryptophan on gold (Au) nanoparticles. Density functional theory calculations are used to model changes in the vibrational frequencies attendant to the tryptophan radical anion and correlated with the experimentally observed vibrational modes in the SERS spectrum of tryptophan (Trp) on Au nanoparticles. The calculated vibrational frequencies are in close agreement with the experimental data. N-Acetyltryptophanamide (NATA) is shown to have the same trends in the calculated and experimental vibrations, indicating that the captured electron is localized to the indole ring structure. Changes in the SERS spectrum with pH are readily explained by the calculations, further indicating that the observed signal originates from the ground-state radical anion in these experiments. This evidence for the capture of a hot electron by tryptophan and the resulting changes in the vibrational spectrum are important for molecular understanding of proteins and other molecules as detected by SERS.

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Section: Discussionmentioning

confidence: 69%

Section: Introductionmentioning

confidence: 99%

Plasmonically Generated Tryptophan Radical Anion on Gold Nanoparticles Investigated by Combined Surface-Enhanced Raman Scattering and Density Functional Theory Calculations

et al. 2021

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“…The reference RS and FT-IR spectra of the dried Trp solution (10 −2 M Trp/PBS, pH 3.0) are shown in Figures 4a and 5a, respectively. The proposed band assignments were based on many theoretical and experimental data from the literature on the molecular structure of Trp and Trp derivatives obtained under various conditions [42,[52][53][54][55][56][57][58][59][60][61][62][63][64][65][66]. As mentioned in our previous paper [28], the preparation of samples for experiments may affect the information obtained from spectral patterns (i.e., the state of the sample condition, pH of the surrounding environment).…”

Section: Spectroscopic Results Of the Surface Adsorption Geometry Of Tryptophan On Corroded 316l Stainless Steelmentioning

confidence: 99%

Spectroscopic Investigations of 316L Stainless Steel under Simulated Inflammatory Conditions for Implant Applications: The Effect of Tryptophan as Corrosion Inhibitor/Hydrophobicity Marker

et al. 2021

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In this paper, the conformational changes of tryptophan (Trp) on the corroded 316 L stainless steel (SS) surface obtained under controlled simulated inflammatory conditions have been studied by Raman (RS) and Fourier-transform infrared (FT-IR) spectroscopy methods. The corrosion behavior and protective efficiency of the investigated samples were performed using the potentiodynamic polarization (PDP) technique in phosphate-buffered saline (PBS) solution acidified to pH 3.0 at 37 °C in the presence and absence of 10−2 M Trp, with different immersion times (2 h and 24 h). The amino acid is adsorbed onto the corroded SS surface mainly through the lone electron pair of the nitrogen atom of the indole ring, which adopts a more/less tilted orientation, and the protonated amine group. The visible differences in the intensity of the Fermi doublet upon adsorption of Trp onto the corroded SS surface, which is a sensitive marker of the local environment, suggested that a stronger hydrophobic environment is observed. This may result in an improvement of the corrosion resistance, after 2 h than 24 h of exposure time. The electrochemical results confirm this statement—the inhibition efficiency of Trp, acting as a mixed-type inhibitor, is made drastically higher after a short period of immersion.

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“…Peptides with tryptophan in different chain positions were also investigated with SERS and supported by DFT calculations. It was determined that the interaction of these peptides with AgNPs occurs through the carboxylate and amino moieties, while the interaction with AuNPs occurs through the indole ring [ 49 ].…”

Section: Neurological Diseasesmentioning

confidence: 99%

In Vitro and In Vivo SERS Biosensing for Disease Diagnosis

et al. 2018

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For many disease states, positive outcomes are directly linked to early diagnosis, where therapeutic intervention would be most effective. Recently, trends in disease diagnosis have focused on the development of label-free sensing techniques that are sensitive to low analyte concentrations found in the physiological environment. Surface-enhanced Raman spectroscopy (SERS) is a powerful vibrational spectroscopy that allows for label-free, highly sensitive, and selective detection of analytes through the amplification of localized electric fields on the surface of a plasmonic material when excited with monochromatic light. This results in enhancement of the Raman scattering signal, which allows for the detection of low concentration analytes, giving rise to the use of SERS as a diagnostic tool for disease. Here, we present a review of recent developments in the field of in vivo and in vitro SERS biosensing for a range of disease states including neurological disease, diabetes, cardiovascular disease, cancer, and viral disease.

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Insights of adsorption mechanisms of Trp-peptides on plasmonic surfaces by SERS

Cited by 18 publications

References 55 publications

Plasmonically Generated Tryptophan Radical Anion on Gold Nanoparticles Investigated by Combined Surface-Enhanced Raman Scattering and Density Functional Theory Calculations

Plasmonically Generated Tryptophan Radical Anion on Gold Nanoparticles Investigated by Combined Surface-Enhanced Raman Scattering and Density Functional Theory Calculations

Spectroscopic Investigations of 316L Stainless Steel under Simulated Inflammatory Conditions for Implant Applications: The Effect of Tryptophan as Corrosion Inhibitor/Hydrophobicity Marker

In Vitro and In Vivo SERS Biosensing for Disease Diagnosis

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