Identification of the Deprotonated Pyrrole Nitrogen of the Bilin-Based Photoreceptor by Raman Spectroscopy with an Advanced Computational Analysis

Crystallization of neptunyl(v) tetrachlorides over neptunyl(vi) species occurs simultaneously with charge assisted hydrogen bonding in our solid state materials, which we explored by DFT calculations, cyclic voltammograms, and Raman spectroscopy.

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IR/Raman characterization of Au-mercaptotriazole crystals

Bulgarian Chemical Communications ◽

10.34049/bcc.51.3.5003 ◽

2019 ◽

Vol 51 (3) ◽

pp. 358-364

Author(s):

S. B. Dimitrijević ◽

S. Č. Alagić ◽

M. M. Rajčić-Vujasinović ◽

S. P. Dimitrijević ◽

A. T. Ivanović

Keyword(s):

Raman Spectroscopy ◽

Ph Change ◽

Gold Complexes ◽

Ir And Raman Spectroscopy ◽

Ph Values ◽

Additional Coordination ◽

Ir And Raman ◽

Pyrrole Nitrogen ◽

Raman Characterization

The aim of this study was a characterization of the crystals of gold complexes based on mercaptotrazole, obtained from solutions with different pH values (2, 4, 7, and 9), using the methods of infrared (IR) and Raman spectroscopy. Both methods provided very useful information on the investigated systems and signalized existence of the Au-S bond in the complexes obtained at pH = 2 and 9. Recorded spectra clearly illustrated the changes that occur in the systems as a consequence of pH change. At the same time, the results also showed that the pyrrole nitrogen atoms stay protonated at pH = 9, which is not in favor of the assumption evolved from the previous UV-vis analysis of possible additional coordination between Au and possible deprotonated nitrogen atoms at this particular pH. Keywords: synthesis; gold-mercaptotriazole (Au-MT); IR and Raman spectroscopy

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DeltaPCA: A Statistically Robust Method for Detecting Protein Analyte Binding to Aptamer-Functionalised Nanoparticles using Surface-Enhanced Raman Spectroscopy

10.33774/chemrxiv-2021-j0r1x ◽

2021 ◽

Author(s):

Fiona Given ◽

Tamsyn Stanborough ◽

Mark Waterland ◽

Deborah Crittenden

Keyword(s):

Raman Spectroscopy ◽

Computational Analysis ◽

Surface Enhanced Raman Spectroscopy ◽

Analysis Procedure ◽

Indirect Detection ◽

Difference Spectra ◽

Data Set ◽

Technical Variability ◽

Surface Enhanced ◽

Surface Enhanced Raman

In this work, we introduce a novel joint experimental design and computational analysis procedure to reliably and reproducibly quantify protein analyte binding to DNA aptamer-functionalised silver nanoparticles using slippery surface-enhanced Raman spectroscopy. We employ an indirect detection approach, based upon monitoring spectral changes in the covalent bond-stretching region as intermolecular bonds are formed between the surface-immobilized probe biomolecule and its target analyte. Sample variability is minimized by preparing aptamer-only and aptamer-plus-analyte samples under the same conditions, and then analysing difference spectra. To account for technical variability, multiple spectra are recorded from the same sample. Our new DeltaPCA analysis procedure takes into account technical variability within each spectral data set while also extracting statistically robust difference spectra between data sets. Proof of principle experiments using thiolated aptamers to detect CoV-SARS-2 spike protein reveal that analyte binding is mediated through the formation of N-H...X and C-H...X hydrogen bonds between the aptamer (H-bond donor) and protein (H-bond acceptor). Our computational analysis code can be freely downloaded from https://github.com/dlc62/DeltaPCA.

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