2018 |
Munoz-Gacitua, D; Garrido, C; Ruiz-Fernandez, A; Ahumada, H; Campos-Vallette, M; Araya-Maturana, R; Weiss-Lopez, B Molecular Dynamics Characterization of Silver Colloidal Interfaces for Sers Applications. Gallic Acid Test Artículo de revista Journal of Raman Spectroscopy, 49 (2), pp. 256-261, 2018, ISSN: 0377-0486. Resumen | Enlaces | BibTeX | Etiquetas: colloid, crystal dynamics, gallic molecular nanoparticles, pair potentials, sampling, sers, silver spectroscopy, umbrella @article{RN407, title = {Molecular Dynamics Characterization of Silver Colloidal Interfaces for Sers Applications. Gallic Acid Test}, author = { D. Munoz-Gacitua and C. Garrido and A. Ruiz-Fernandez and H. Ahumada and M. Campos-Vallette and R. Araya-Maturana and B. Weiss-Lopez}, url = {/brokenurl#<Go to ISI>://WOS:000425020500007}, doi = {10.1002/jrs.5274}, issn = {0377-0486}, year = {2018}, date = {2018-01-01}, journal = {Journal of Raman Spectroscopy}, volume = {49}, number = {2}, pages = {256-261}, abstract = {One of the most useful applications of silver colloidal solutions is in surface-enhanced Raman spectroscopy (SERS), because the amplification factor of about 10(6) allows the vibrational study and detection of highly diluted species in aqueous environment, and more recently in early diagnosis of cancer and imaging. A useful colloid for SERS is that reported by Leopold and Lendl (Colloid1). However, SERS response from anions or rich electron density molecules has been difficult to obtain in this colloid. Recently, a minor modification of the surface charge density (Colloid 2) allowed to observe reproducible SERS spectrum from gallate anion (GA(-)). In this work, the structure of both solid and solution interfaces were characterized using molecular dynamics. Experimental values of -potentials were reproduced by simulations, and the chemical potential of GA(-) approaching both interfaces was calculated using umbrella sampling and the weighted histograms analisys methodology (WHAM). The calculated barrier to approach the interface of Colloid 1 is 2.8kJmol(-1) greater than in Colloid 2, and the stability of GA(-) with Colloid 2 at the minimum is 3.5kJmol(-1) more stable than with Colloid 1. Finally, the calculated average orientation of GA(-) adsorbed onto the colloidal surface is in excellent agreement with the experimental SERS observations.}, keywords = {colloid, crystal dynamics, gallic molecular nanoparticles, pair potentials, sampling, sers, silver spectroscopy, umbrella}, pubstate = {published}, tppubtype = {article} } One of the most useful applications of silver colloidal solutions is in surface-enhanced Raman spectroscopy (SERS), because the amplification factor of about 10(6) allows the vibrational study and detection of highly diluted species in aqueous environment, and more recently in early diagnosis of cancer and imaging. A useful colloid for SERS is that reported by Leopold and Lendl (Colloid1). However, SERS response from anions or rich electron density molecules has been difficult to obtain in this colloid. Recently, a minor modification of the surface charge density (Colloid 2) allowed to observe reproducible SERS spectrum from gallate anion (GA(-)). In this work, the structure of both solid and solution interfaces were characterized using molecular dynamics. Experimental values of -potentials were reproduced by simulations, and the chemical potential of GA(-) approaching both interfaces was calculated using umbrella sampling and the weighted histograms analisys methodology (WHAM). The calculated barrier to approach the interface of Colloid 1 is 2.8kJmol(-1) greater than in Colloid 2, and the stability of GA(-) with Colloid 2 at the minimum is 3.5kJmol(-1) more stable than with Colloid 1. Finally, the calculated average orientation of GA(-) adsorbed onto the colloidal surface is in excellent agreement with the experimental SERS observations. |
2017 |
Marcaida, I; Maguregui, M; Morillas, H; Garcia-Florentino, C; Pintus, V; Aguayo, T; Campos-Vallette, M; Madariaga, J Optimization of Sample Treatment for the Identification of Anthraquinone Dyes by Surface-Enhanced Raman Spectroscopy Artículo de revista Analytical and Bioanalytical Chemistry, 409 (8), pp. 2221-2228, 2017, ISSN: 1618-2642. Resumen | Enlaces | BibTeX | Etiquetas: anthraquinone, dyestuffs, extraction, lake lake, liquid-liquid madder nanoparticles, pigment, pigments, purple, raman scattering, sers, silver, spectroscopy, surface-enhanced @article{marcaida2017optimization, title = {Optimization of Sample Treatment for the Identification of Anthraquinone Dyes by Surface-Enhanced Raman Spectroscopy}, author = { I. Marcaida and M. Maguregui and H. Morillas and C. Garcia-Florentino and V. Pintus and T. Aguayo and M. Campos-Vallette and J. Madariaga}, url = {/brokenurl#<Go to ISI>://WOS:000395057500024}, doi = {10.1007/s00216-016-0169-6}, issn = {1618-2642}, year = {2017}, date = {2017-01-01}, journal = {Analytical and Bioanalytical Chemistry}, volume = {409}, number = {8}, pages = {2221-2228}, abstract = {The study and characterization of old artifacts such as pigments requires the use of techniques that need a small amount of sample to perform the analysis because of the high value of these samples. In recent years, organic molecules such as anthraquinone dyes have been identified by surface-enhanced Raman spectroscopy (SERS). However, different sample treatments must be applied to isolate the organic dye from the mordant, which produces great fluorescence in the Raman measurements. In this work, optimization of sample treatment for the SERS analysis of anthraquinone dyes was performed. Sample mass, the organic solvent, and its volume were optimized and different slide materials and excitation lasers were compared to choose the best conditions for the identification of the dyes. The optimization of sample treatment resulted in 5 mg of sample as the optimum amount. Further, two consecutive extractions with 0.5 mL of ethyl acetate was the best option for the extraction of the dye. A quartz slide was used instead of a glass slide to reduce background signal, and an excitation laser of 532 nm offers better results than one of 785 nm. The optimized method was applied to the characterization of the dyes used in Pompeian pink and purple lake pigments. Alizarin and purpurin anthraquinone dyes, obtained from madder lake, were identified as the organic colorants. The SERS results were confirmed by those obtained by means of UV-visible spectroscopy.}, keywords = {anthraquinone, dyestuffs, extraction, lake lake, liquid-liquid madder nanoparticles, pigment, pigments, purple, raman scattering, sers, silver, spectroscopy, surface-enhanced}, pubstate = {published}, tppubtype = {article} } The study and characterization of old artifacts such as pigments requires the use of techniques that need a small amount of sample to perform the analysis because of the high value of these samples. In recent years, organic molecules such as anthraquinone dyes have been identified by surface-enhanced Raman spectroscopy (SERS). However, different sample treatments must be applied to isolate the organic dye from the mordant, which produces great fluorescence in the Raman measurements. In this work, optimization of sample treatment for the SERS analysis of anthraquinone dyes was performed. Sample mass, the organic solvent, and its volume were optimized and different slide materials and excitation lasers were compared to choose the best conditions for the identification of the dyes. The optimization of sample treatment resulted in 5 mg of sample as the optimum amount. Further, two consecutive extractions with 0.5 mL of ethyl acetate was the best option for the extraction of the dye. A quartz slide was used instead of a glass slide to reduce background signal, and an excitation laser of 532 nm offers better results than one of 785 nm. The optimized method was applied to the characterization of the dyes used in Pompeian pink and purple lake pigments. Alizarin and purpurin anthraquinone dyes, obtained from madder lake, were identified as the organic colorants. The SERS results were confirmed by those obtained by means of UV-visible spectroscopy. |
Celis, F; Garcia, M; Diaz-Fleming, G; Campos-Vallette, M A Review of Raman, Surface-Enhanced Raman Scattering (Sers) and Related Spectroscopic Techniques Applied to Biomolecules in Biomaterials Artículo de revista Journal of the Chilean Chemical Society, 62 (3), pp. 3627-3632, 2017, ISSN: 0717-9707. Resumen | Enlaces | BibTeX | Etiquetas: adsorption, biomolecules, bone, calcium-phosphate, cells, fragments, gold living nanoparticles, peptide raman, sers, silver terminal ultraviolet @article{RN368, title = {A Review of Raman, Surface-Enhanced Raman Scattering (Sers) and Related Spectroscopic Techniques Applied to Biomolecules in Biomaterials}, author = { F. Celis and M. Garcia and G. Diaz-Fleming and M. Campos-Vallette}, url = {/brokenurl#<Go to ISI>://WOS:000417443500015}, issn = {0717-9707}, year = {2017}, date = {2017-01-01}, journal = {Journal of the Chilean Chemical Society}, volume = {62}, number = {3}, pages = {3627-3632}, abstract = {The development of new biomaterials has gained increasing attention in the last decade. One of the most important aspects in the development of these new materials is to understand the chemical cues presents in the native niche. Among all the techniques currently available for measuring those interactions, Raman spectroscopy offers a unique and non-invasive tool for exploring the behavior of the components within a given biomaterial and their surrounding microenvironment. This technique exploits the unique molecular vibrational fingerprints for pinpointing those interactions. The vibrational response can be improved to the single molecule level, in the presence of metal nanoparticles (NPs) with plasmonic properties (silver, gold and copper) in the so-called SurfaceEnhanced Raman Scattering (SERS), which can be used for in-situ measurements. Another technique recently developed is the Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy (SHINERS), which overcomes signal contamination from chemical interactions between biomolecules and the metal surface; it does this by coating the metal surface with an inert layer of alumina or silica. In the present contribution, the role and the applications of Raman, SERS and related spectroscopic techniques in the study of biomolecules in biomaterials are reviewed and discussed.}, keywords = {adsorption, biomolecules, bone, calcium-phosphate, cells, fragments, gold living nanoparticles, peptide raman, sers, silver terminal ultraviolet}, pubstate = {published}, tppubtype = {article} } The development of new biomaterials has gained increasing attention in the last decade. One of the most important aspects in the development of these new materials is to understand the chemical cues presents in the native niche. Among all the techniques currently available for measuring those interactions, Raman spectroscopy offers a unique and non-invasive tool for exploring the behavior of the components within a given biomaterial and their surrounding microenvironment. This technique exploits the unique molecular vibrational fingerprints for pinpointing those interactions. The vibrational response can be improved to the single molecule level, in the presence of metal nanoparticles (NPs) with plasmonic properties (silver, gold and copper) in the so-called SurfaceEnhanced Raman Scattering (SERS), which can be used for in-situ measurements. Another technique recently developed is the Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy (SHINERS), which overcomes signal contamination from chemical interactions between biomolecules and the metal surface; it does this by coating the metal surface with an inert layer of alumina or silica. In the present contribution, the role and the applications of Raman, SERS and related spectroscopic techniques in the study of biomolecules in biomaterials are reviewed and discussed. |
2016 |
Aliaga, A E; Leyton, P; Clavijo, E; Campos-Vallette, M Fluorescence and Surface-Enhanced Vibrational Spectroscopies of Lawsone and Plumbagin Artículo de revista Spectroscopy Letters, 49 (5), pp. 326-335, 2016, ISSN: 0038-7010. Resumen | Enlaces | BibTeX | Etiquetas: behavior, calculations, enhanced fluorescence, infrared-absorption, lawsone, nanoparticles, plumbagin, quinones raman raman-scattering, reduction, scattering, selection, sers, silver spectrum, surface theoretical @article{RN318, title = {Fluorescence and Surface-Enhanced Vibrational Spectroscopies of Lawsone and Plumbagin}, author = { A.E. Aliaga and P. Leyton and E. Clavijo and M. Campos-Vallette}, url = {/brokenurl#<Go to ISI>://WOS:000405754400002}, doi = {10.1080/00387010.2016.1146772}, issn = {0038-7010}, year = {2016}, date = {2016-01-01}, journal = {Spectroscopy Letters}, volume = {49}, number = {5}, pages = {326-335}, abstract = {The natural dyes lawsone and plumbagin (1,4-naphthoquinones) were studied by using fluorescence, Raman, infrared (IR), surface-enhanced Raman scattering (SERS), and surface-enhanced IR absorption. From the absorption spectrum, it was possible to infer that the enol-lawsone tautomer concentration decreases in silver colloidal solution. Plumbagin dimers, both in water and in silver colloidal solution, were identified from the fluorescence band profile and surface-SERS spectrum. The SERS spectrum of lawsone was obtained by using silver colloidal solution after 12-hour settle; the keto and enol lawsone silver colloid interaction occurs. The assignment of Raman and IR bands of both dyes was calculated with density functional theory calculations. Only a monomeric structure of lawsone interacting with a silver cluster model was predicted. The monomer adopts a nearly coplanar orientation onto the silver surface; the shortest distance is 3.2 angstrom, suggesting an electrostatic interaction.}, keywords = {behavior, calculations, enhanced fluorescence, infrared-absorption, lawsone, nanoparticles, plumbagin, quinones raman raman-scattering, reduction, scattering, selection, sers, silver spectrum, surface theoretical}, pubstate = {published}, tppubtype = {article} } The natural dyes lawsone and plumbagin (1,4-naphthoquinones) were studied by using fluorescence, Raman, infrared (IR), surface-enhanced Raman scattering (SERS), and surface-enhanced IR absorption. From the absorption spectrum, it was possible to infer that the enol-lawsone tautomer concentration decreases in silver colloidal solution. Plumbagin dimers, both in water and in silver colloidal solution, were identified from the fluorescence band profile and surface-SERS spectrum. The SERS spectrum of lawsone was obtained by using silver colloidal solution after 12-hour settle; the keto and enol lawsone silver colloid interaction occurs. The assignment of Raman and IR bands of both dyes was calculated with density functional theory calculations. Only a monomeric structure of lawsone interacting with a silver cluster model was predicted. The monomer adopts a nearly coplanar orientation onto the silver surface; the shortest distance is 3.2 angstrom, suggesting an electrostatic interaction. |
Celis, F; Campos-Vallette, M; Gomez-Jeria, J S; Clavijo, E; Jara, G P; Garrido, C Surface-Enhanced Raman Scattering and Theoretical Study of the Bilichromes Biliverdin and Bilirubin Artículo de revista Spectroscopy Letters, 49 (5), pp. 336-342, 2016, ISSN: 0038-7010. Resumen | Enlaces | BibTeX | Etiquetas: analysis, bilichromes, bilirubin, biliverdin, dimethyl ester nanoparticles, normal-coordinate raman, sers, silver spectroscopic @article{RN319, title = {Surface-Enhanced Raman Scattering and Theoretical Study of the Bilichromes Biliverdin and Bilirubin}, author = { F. Celis and M. Campos-Vallette and J.S. Gomez-Jeria and E. Clavijo and G.P. Jara and C. Garrido}, url = {/brokenurl#<Go to ISI>://WOS:000405754400003}, doi = {10.1080/00387010.2016.1154076}, issn = {0038-7010}, year = {2016}, date = {2016-01-01}, journal = {Spectroscopy Letters}, volume = {49}, number = {5}, pages = {336-342}, abstract = {The surface-enhanced Raman scattering spectra of biliverdin and bilirubin were obtained and analyzed; a physical silver ligand interaction was inferred. The structural conformation of biliverdin is practically the same when passing from the dry to solution relative to that observed in Raman solid. However, the surface effect induces a different molecular orientation on the surface in dry and in solution. The conformational structure of bilirubin is modified when passing from dry to solution conditions; the orientation of the analyte on the surface is different in both media. The carboxylate groups interact with the surface more closely in bilirubin than in biliverdin. The unsaturated methine bridge in biliverdin confers an additional stability by delocalizing the pi-electronic cloud. Both sides of the molecule could be in the same plane. On contrary, bilirubin with a tetrahedric carbon ( methylene bridge) confers the whole system a rather free rotation of each side of the whole molecule. Theoretical model calculations of the biliverdin and bilirubin onto the silver surface predict a nearly coplanar orientation of the whole molecules and non-bonded interaction.}, keywords = {analysis, bilichromes, bilirubin, biliverdin, dimethyl ester nanoparticles, normal-coordinate raman, sers, silver spectroscopic}, pubstate = {published}, tppubtype = {article} } The surface-enhanced Raman scattering spectra of biliverdin and bilirubin were obtained and analyzed; a physical silver ligand interaction was inferred. The structural conformation of biliverdin is practically the same when passing from the dry to solution relative to that observed in Raman solid. However, the surface effect induces a different molecular orientation on the surface in dry and in solution. The conformational structure of bilirubin is modified when passing from dry to solution conditions; the orientation of the analyte on the surface is different in both media. The carboxylate groups interact with the surface more closely in bilirubin than in biliverdin. The unsaturated methine bridge in biliverdin confers an additional stability by delocalizing the pi-electronic cloud. Both sides of the molecule could be in the same plane. On contrary, bilirubin with a tetrahedric carbon ( methylene bridge) confers the whole system a rather free rotation of each side of the whole molecule. Theoretical model calculations of the biliverdin and bilirubin onto the silver surface predict a nearly coplanar orientation of the whole molecules and non-bonded interaction. |
Garrido, C; Weiss-Lopez, B; Campos-Vallette, M Surface-Enhanced Raman Scattering Activity of Negatively Charged Bio-Analytes from a Modified Silver Colloid Artículo de revista Spectroscopy Letters, 49 (1), pp. 11-18, 2016, ISSN: 0038-7010. Resumen | Enlaces | BibTeX | Etiquetas: bio-analytes, charged colloidal fluorescein, nanoparticles, negatively peptides, raman reduction scattering, sers, silver spectroscopy, surface, surface-enhanced @article{RN323, title = {Surface-Enhanced Raman Scattering Activity of Negatively Charged Bio-Analytes from a Modified Silver Colloid}, author = { C. Garrido and B. Weiss-Lopez and M. Campos-Vallette}, url = {/brokenurl#<Go to ISI>://WOS:000364784800003}, doi = {10.1080/00387010.2015.1046606}, issn = {0038-7010}, year = {2016}, date = {2016-01-01}, journal = {Spectroscopy Letters}, volume = {49}, number = {1}, pages = {11-18}, abstract = {A modification to the traditional synthesis of reduced silver metal nanoparticles with hydroxylamine hydrochloride is proposed. The new colloid, obtained by decreasing the concentration of hydroxide and chloride ions, is stable in a large pH range. The low negative surface charge density of the nanoparticles allowed to obtain surface-enhanced Raman scattering (SERS) spectral activity of bio-analytes containing negatively charged groups in aqueous solution. The new colloidal system, characterized by electronic spectroscopy, atomic force microscopy, and zeta potential measurements, was used in the SERS study of the bio-analytes aspartic acid, four oligopeptides, one polypeptide and a probe, the organic dye fluorescein.}, keywords = {bio-analytes, charged colloidal fluorescein, nanoparticles, negatively peptides, raman reduction scattering, sers, silver spectroscopy, surface, surface-enhanced}, pubstate = {published}, tppubtype = {article} } A modification to the traditional synthesis of reduced silver metal nanoparticles with hydroxylamine hydrochloride is proposed. The new colloid, obtained by decreasing the concentration of hydroxide and chloride ions, is stable in a large pH range. The low negative surface charge density of the nanoparticles allowed to obtain surface-enhanced Raman scattering (SERS) spectral activity of bio-analytes containing negatively charged groups in aqueous solution. The new colloidal system, characterized by electronic spectroscopy, atomic force microscopy, and zeta potential measurements, was used in the SERS study of the bio-analytes aspartic acid, four oligopeptides, one polypeptide and a probe, the organic dye fluorescein. |
Garrido, C; Diaz-Fleming, G; Campos-Vallette, M Sers Spectrum of Gallic Acid Obtained from a Modified Silver Colloid Artículo de revista Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy, 163 , pp. 68-72, 2016, ISSN: 1386-1425. Resumen | Enlaces | BibTeX | Etiquetas: calculations, chemical colloid, dft enhanced gallic identification modified quantum raman-scattering, sers, silver @article{RN317, title = {Sers Spectrum of Gallic Acid Obtained from a Modified Silver Colloid}, author = { C. Garrido and G. Diaz-Fleming and M. Campos-Vallette}, url = {/brokenurl#<Go to ISI>://WOS:000375501500010}, doi = {10.1016/j.saa.2016.03.028}, issn = {1386-1425}, year = {2016}, date = {2016-01-01}, journal = {Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy}, volume = {163}, pages = {68-72}, publisher = {2016 Elsevier B.V.}, abstract = {Two different crystals of the gallic acid were microscopically separated from a p.a. commercial product. The Raman spectra analysis allowed distinguishing monomeric and dimeric structures. The vibrational wave numbers were computed using DFT quantum chemical calculations. The data obtained from wave number calculations are used to assign vibrational bands obtained in the Raman spectrum. The dimer, characterized as ellagic acid, involves the carboxyl and hydroxyl moieties. The Raman spectrum in Water solution of each species is dominated by the monomeric form. A low negatively charged Ag colloid allowed obtain to the best of our knowledge, the first surface enhanced Raman scattering (SERS) spectrum of the gallic acid. The possible electrophilic attacking sites of the title molecule are identified using MEP surface plot study and the orientation of the analyte on the metal surface is proposed tilted to the surface.}, keywords = {calculations, chemical colloid, dft enhanced gallic identification modified quantum raman-scattering, sers, silver}, pubstate = {published}, tppubtype = {article} } Two different crystals of the gallic acid were microscopically separated from a p.a. commercial product. The Raman spectra analysis allowed distinguishing monomeric and dimeric structures. The vibrational wave numbers were computed using DFT quantum chemical calculations. The data obtained from wave number calculations are used to assign vibrational bands obtained in the Raman spectrum. The dimer, characterized as ellagic acid, involves the carboxyl and hydroxyl moieties. The Raman spectrum in Water solution of each species is dominated by the monomeric form. A low negatively charged Ag colloid allowed obtain to the best of our knowledge, the first surface enhanced Raman scattering (SERS) spectrum of the gallic acid. The possible electrophilic attacking sites of the title molecule are identified using MEP surface plot study and the orientation of the analyte on the metal surface is proposed tilted to the surface. |
2015 |
Celis, F; Campos-Vallette, M; Vega, J C; Gomez-Jeria, J S; Aliaga, C Raman and Surface Enhanced Raman Signals of the Sensor 1-(4-Mercaptophenyl)-2,4,6-Triphenylpyridinium Perchlorate Artículo de revista Journal of the Chilean Chemical Society, 60 (2), pp. 2944-2948, 2015, ISSN: 0717-9707. Resumen | Enlaces | BibTeX | Etiquetas: density dft dyes, dynamics, eht halochromism, hydrocarbons, perchlorate, raman, scattering, sers, shiners, silver, solvent spectroscopy @article{RN261, title = {Raman and Surface Enhanced Raman Signals of the Sensor 1-(4-Mercaptophenyl)-2,4,6-Triphenylpyridinium Perchlorate}, author = { F. Celis and M. Campos-Vallette and J.C. Vega and J.S. Gomez-Jeria and C. Aliaga}, url = {/brokenurl#<Go to ISI>://WOS:000361545700018}, doi = {10.4067/S0717-97072015000200018}, issn = {0717-9707}, year = {2015}, date = {2015-01-01}, journal = {Journal of the Chilean Chemical Society}, volume = {60}, number = {2}, pages = {2944-2948}, abstract = {The sensor 1-(4-mercaptophenyl)-2,4,6-triphenylpyridinium perchlorate compound was vibrationally characterized using Raman and the Surface-Enhanced Raman techniques, SERS and Shell-Isolated Nanoparticles-Enhanced Raman Spectroscopy (SHINERS). The Raman spectrum was analyzed and the band assignment was supported using DFT data at the B3LYP/6-31G(d) level. SERS data allowed infer about the orientation of the analyte on the naked Ag surface. EHT calculations for an Ag/analyte model represent well the SERS spectrum supporting the Ag-S bond formation. The SHINERS spectrum was obtained by using Ag @SiO2 nanoparticles prepared at two different time of the SiO2 coating process. The most intense SHINERS spectral signals of the compound (100 nM) were obtained after 20 minutes of the Ag @SiO2 formation. No charge-transfer was concluded from the SHINERS experiments.}, keywords = {density dft dyes, dynamics, eht halochromism, hydrocarbons, perchlorate, raman, scattering, sers, shiners, silver, solvent spectroscopy}, pubstate = {published}, tppubtype = {article} } The sensor 1-(4-mercaptophenyl)-2,4,6-triphenylpyridinium perchlorate compound was vibrationally characterized using Raman and the Surface-Enhanced Raman techniques, SERS and Shell-Isolated Nanoparticles-Enhanced Raman Spectroscopy (SHINERS). The Raman spectrum was analyzed and the band assignment was supported using DFT data at the B3LYP/6-31G(d) level. SERS data allowed infer about the orientation of the analyte on the naked Ag surface. EHT calculations for an Ag/analyte model represent well the SERS spectrum supporting the Ag-S bond formation. The SHINERS spectrum was obtained by using Ag @SiO2 nanoparticles prepared at two different time of the SiO2 coating process. The most intense SHINERS spectral signals of the compound (100 nM) were obtained after 20 minutes of the Ag @SiO2 formation. No charge-transfer was concluded from the SHINERS experiments. |
Vera, A M; Carcamo, J J; Aliaga, A E; Gomez-Jeria, J S; Kogan, M J; Campos-Vallette, M Interaction of the Clpffd Peptide with Gold Nanospheres. A Raman, Surface Enhanced Raman Scattering and Theoretical Study Artículo de revista Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy, 134 , pp. 251-256, 2015, ISSN: 1386-1425. Resumen | Enlaces | BibTeX | Etiquetas: alzheimer-disease, anti-aggregation approximations, assemblies, beta-amyloid, calculations, clpffd extended hartree-fock htickel molecular-orbital nanoparticles, of peptide peptide, protein, sers, silver, spectroscopy, stability theories, theory type @article{RN262, title = {Interaction of the Clpffd Peptide with Gold Nanospheres. A Raman, Surface Enhanced Raman Scattering and Theoretical Study}, author = { A.M. Vera and J.J. Carcamo and A.E. Aliaga and J.S. Gomez-Jeria and M.J. Kogan and M. Campos-Vallette}, url = {/brokenurl#<Go to ISI>://WOS:000342718700034}, doi = {10.1016/j.saa.2014.06.116}, issn = {1386-1425}, year = {2015}, date = {2015-01-01}, journal = {Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy}, volume = {134}, pages = {251-256}, publisher = {2014 Elsevier B.V.}, abstract = {In a previous work we demonstrated that toxic aggregates of the protein beta-amyloid (ATA beta) involved in the Alzheimer's disease (AD) can be destabilized upon electromagnetic irradiation of the peptide Cys-Leu-Pro-Phe-Phe-Asp (CLPFFD) adsorbed on gold nanospheres (AuNSs). For a selective recognition of the therapeutic target (i.e. ATA beta) of AD by the conjugates peptide-nanoparticle it is relevant to understand how the interaction between attached ligands and nanoparticles occurs. In this work a surface enhanced Raman scattering spectroscopy (SERS) study of the interactions of CLPFFD with AuNSs of 10 nm average diameter was carried out. The SERS data suggest that phenylalanine displays its aromatic ring coplanar to the surface which is supported by theoretical data obtained from molecular mechanics (MM) and Extended Huckel Theory (EHT) calculations.}, keywords = {alzheimer-disease, anti-aggregation approximations, assemblies, beta-amyloid, calculations, clpffd extended hartree-fock htickel molecular-orbital nanoparticles, of peptide peptide, protein, sers, silver, spectroscopy, stability theories, theory type}, pubstate = {published}, tppubtype = {article} } In a previous work we demonstrated that toxic aggregates of the protein beta-amyloid (ATA beta) involved in the Alzheimer's disease (AD) can be destabilized upon electromagnetic irradiation of the peptide Cys-Leu-Pro-Phe-Phe-Asp (CLPFFD) adsorbed on gold nanospheres (AuNSs). For a selective recognition of the therapeutic target (i.e. ATA beta) of AD by the conjugates peptide-nanoparticle it is relevant to understand how the interaction between attached ligands and nanoparticles occurs. In this work a surface enhanced Raman scattering spectroscopy (SERS) study of the interactions of CLPFFD with AuNSs of 10 nm average diameter was carried out. The SERS data suggest that phenylalanine displays its aromatic ring coplanar to the surface which is supported by theoretical data obtained from molecular mechanics (MM) and Extended Huckel Theory (EHT) calculations. |
2011 |
Diaz-Fleming, G; Celis, F; Campos-Vallette, M; Aliaga, A E; Escobar, M; Koch, R Raman, Infrared, Sers and Theoretical Study of 3-(1-Phenylpropan-2-Ylamino) Propanenitrile, Fenproporex Artículo de revista Journal of Raman Spectroscopy, 42 (7), pp. 1497-1504, 2011, ISSN: 0377-0486. Resumen | Enlaces | BibTeX | Etiquetas: calculations, density-functional dft elements, fenproporex, gold, infrared, raman, scattering, sers, silver, spectroscopy, surface-enhanced temperature theory @article{RN41f, title = {Raman, Infrared, Sers and Theoretical Study of 3-(1-Phenylpropan-2-Ylamino) Propanenitrile, Fenproporex}, author = { G. Diaz-Fleming and F. Celis and M. Campos-Vallette and A.E. Aliaga and M. Escobar and R. Koch}, url = {/brokenurl#<Go to ISI>://WOS:000293001000003}, doi = {10.1002/jrs.2882}, issn = {0377-0486}, year = {2011}, date = {2011-01-01}, journal = {Journal of Raman Spectroscopy}, volume = {42}, number = {7}, pages = {1497-1504}, publisher = {2011 John Wiley & Sons, Ltd.}, abstract = {Infrared, Raman and surface-enhanced Raman scattering (SERS) spectra of 3-(1-phenylpropan-2-ylamino) propanenitrile (fenproporex) have been recorded. Density functional theory (DFT) with the B3LYP functional was used for optimizations of ground state geometries and simulation of Raman and SERS vibrational spectra of this molecule. Bands of the vibrational spectra were assigned in detail. The comparison of SERS spectra obtained by using colloidal silver and gold nanoparticles with the corresponding Raman spectrum reveals enhancement and shifts in bands, suggesting a possible partial charge-transfer mechanism in the SERS effect. Information about the orientation of fenproporex on the nanometer-sized metal structures is also obtained.}, keywords = {calculations, density-functional dft elements, fenproporex, gold, infrared, raman, scattering, sers, silver, spectroscopy, surface-enhanced temperature theory}, pubstate = {published}, tppubtype = {article} } Infrared, Raman and surface-enhanced Raman scattering (SERS) spectra of 3-(1-phenylpropan-2-ylamino) propanenitrile (fenproporex) have been recorded. Density functional theory (DFT) with the B3LYP functional was used for optimizations of ground state geometries and simulation of Raman and SERS vibrational spectra of this molecule. Bands of the vibrational spectra were assigned in detail. The comparison of SERS spectra obtained by using colloidal silver and gold nanoparticles with the corresponding Raman spectrum reveals enhancement and shifts in bands, suggesting a possible partial charge-transfer mechanism in the SERS effect. Information about the orientation of fenproporex on the nanometer-sized metal structures is also obtained. |
2018 |
Molecular Dynamics Characterization of Silver Colloidal Interfaces for Sers Applications. Gallic Acid Test Artículo de revista Journal of Raman Spectroscopy, 49 (2), pp. 256-261, 2018, ISSN: 0377-0486. |
2017 |
Optimization of Sample Treatment for the Identification of Anthraquinone Dyes by Surface-Enhanced Raman Spectroscopy Artículo de revista Analytical and Bioanalytical Chemistry, 409 (8), pp. 2221-2228, 2017, ISSN: 1618-2642. |
A Review of Raman, Surface-Enhanced Raman Scattering (Sers) and Related Spectroscopic Techniques Applied to Biomolecules in Biomaterials Artículo de revista Journal of the Chilean Chemical Society, 62 (3), pp. 3627-3632, 2017, ISSN: 0717-9707. |
2016 |
Fluorescence and Surface-Enhanced Vibrational Spectroscopies of Lawsone and Plumbagin Artículo de revista Spectroscopy Letters, 49 (5), pp. 326-335, 2016, ISSN: 0038-7010. |
Surface-Enhanced Raman Scattering and Theoretical Study of the Bilichromes Biliverdin and Bilirubin Artículo de revista Spectroscopy Letters, 49 (5), pp. 336-342, 2016, ISSN: 0038-7010. |
Surface-Enhanced Raman Scattering Activity of Negatively Charged Bio-Analytes from a Modified Silver Colloid Artículo de revista Spectroscopy Letters, 49 (1), pp. 11-18, 2016, ISSN: 0038-7010. |
Sers Spectrum of Gallic Acid Obtained from a Modified Silver Colloid Artículo de revista Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy, 163 , pp. 68-72, 2016, ISSN: 1386-1425. |
2015 |
Raman and Surface Enhanced Raman Signals of the Sensor 1-(4-Mercaptophenyl)-2,4,6-Triphenylpyridinium Perchlorate Artículo de revista Journal of the Chilean Chemical Society, 60 (2), pp. 2944-2948, 2015, ISSN: 0717-9707. |
Interaction of the Clpffd Peptide with Gold Nanospheres. A Raman, Surface Enhanced Raman Scattering and Theoretical Study Artículo de revista Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy, 134 , pp. 251-256, 2015, ISSN: 1386-1425. |
2011 |
Raman, Infrared, Sers and Theoretical Study of 3-(1-Phenylpropan-2-Ylamino) Propanenitrile, Fenproporex Artículo de revista Journal of Raman Spectroscopy, 42 (7), pp. 1497-1504, 2011, ISSN: 0377-0486. |