RESUMO
In this work, was studied the adsorption and orientation of three dipyridinic derivatives 9,10-bis-((E)-2-(pyridin-4-yl)vinyl)anthracene (DPAC), 1,4-bis-((E)-2-(pyridin-4-yl)vinyl)naphthalene (DPNA-T) and 2,6-bis-((E)-2-(pyridin-4-yl)vinyl)naphthalene (DPNA-L) on gold nanoparticles, using Surface Enhanced Raman Scattering (SERS). Systematic modification in the shapes of the bifunctional systems (Cross-shape, T-shape and Linear-shape) shows changes significant in the preferential orientation of these analytes on the nanostructured gold surface. Additional data from UV-vis measurements and TEM images are in agreement with the Reaction Limited Colloid Aggregation (RLCA) mechanisms for DPAC and DPNA-T and Diffusion Limited Colloid Aggregation (DLCA) mechanisms for DPNA-L, showing that for the same analyte concentration, the aggregation mechanism depends on the molecular shape. These results allow us to rationalize the fundamental aspects involved in the development of devices based on plasmonic resonance with potential applications in the field of molecular electronics.
Assuntos
Ouro , Nanopartículas Metálicas , Adsorção , Coloides , Análise Espectral RamanRESUMO
Infrared and Raman spectra of O,O-dimethyl S-methylcarbamoylmethylphosphorodithioate, dimethoate, have been recorded. Density functional theory, DFT, with the B3LYP functional was used for the optimization of the ground state geometry and simulation of the infrared and Raman spectra of this molecule. Calculated geometrical parameters fit very well with the experimental ones. Based on the recorded data, the DFT results and a normal coordinate analysis based on a scaled quantum mechanical (SQM) force field approach, a complete vibrational assignment was made for the first time.
Assuntos
Dimetoato/química , Inseticidas/química , Compostos Organotiofosforados/química , Modelos Moleculares , Teoria Quântica , Espectrofotometria Infravermelho , Análise Espectral RamanRESUMO
The Raman spectra (1800-200 cm(-1)) of isolated dried collagen types I and III were recorded at different times after shockwave (SW) application in aqueous media. SWs were applied in a single session. One week after the SW application the vibrational data analysis indicates changes in the conformation of the collagens; orientational changes are also inferred. During the next three weeks collagens tended to recover the conformation and orientation existing before SW application.
Assuntos
Colágeno/química , Ondas de Choque de Alta Energia , Análise Espectral Raman/métodos , Animais , Bovinos , Ratos , Fatores de Tempo , VibraçãoRESUMO
Hemocyanin, the oxygen transporter metallo-glycoprotein from mollusks, shows strong relationship between its notable structural features and intrinsic immunomodulatory effects. Here we investigated the individual contribution of CCHA and CCHB subunits from Concholepas hemocyanin (CCH) to in vivo humoral immune response and their pre-clinical evaluation as immunotherapeutic agent in a mice bladder cancer model, in relation to their biochemical properties. To this end, subunits were purified and well characterized. Homogeneous subunits were obtained by anionic exchange chromatography, and its purity assessed by electrophoretic and immunochemical methods. While each CCH subunit contains eight functional units showing partial cross reaction, the vibrational spectral analysis showed several spectral differences, suggesting structural differences between them. In addition, we demonstrated differences in the carbohydrate content: CCHA had a 3.6% w/w sugar with both N- and O-linked moieties. In turn, CCHB had a 2.5% w/w sugar with N-linked, while O-linked moieties were nearly absent. Considering these differences, it was not possible to predict a priori whether the immunogenic and immunotherapeutic properties of subunits might be similar. Surprisingly, both subunits by itself induced a humoral response, and showed an antitumor effect in the bladder carcinoma cell line MBT-2. However, when immunologic parameters were analyzed, CCHA showed better efficiency than CCHB. No allergic reactions or any toxic effects were observed in mice treated with CCHA, sustaining its potential therapeutic use. Our study supports that CCHA subunit accounts for the most important features involved in the immunogenicity of CCH, such as better hydrophilicity and higher content of carbohydrates.
Assuntos
Antineoplásicos/imunologia , Carcinoma/tratamento farmacológico , Gastrópodes/química , Hemocianinas/imunologia , Neoplasias da Bexiga Urinária/tratamento farmacológico , Animais , Formação de Anticorpos , Antineoplásicos/química , Antineoplásicos/uso terapêutico , Carcinoma/imunologia , Linhagem Celular Tumoral , Reações Cruzadas/imunologia , Hemocianinas/química , Hemocianinas/uso terapêutico , Imunoterapia , Estimativa de Kaplan-Meier , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Subunidades Proteicas/química , Subunidades Proteicas/imunologia , Subunidades Proteicas/uso terapêutico , Neoplasias da Bexiga Urinária/imunologiaRESUMO
This paper reports a DFT modelling of SERS spectra for benzene and benzonitrile on the basis of a simple noncoordinate substrate-adsorbate model. Assignment of normal modes was obtained from internal force constants and potential energy distribution matrices and used to identify, according the SERS selection rules, the orientation of the optimized molecules on the metallic surface. Calculated band enhancements are in good agreement with experimental observations. The optimized geometry parameters of the molecule-Ag system, changes of HOMO-LUMO energies are discussed to give insight in the different SERS mechanisms for both molecules.
Assuntos
Derivados de Benzeno/química , Benzeno/química , Modelos Químicos , Nitrilas/química , Compostos Organometálicos/química , Teoria Quântica , Prata/química , Análise Espectral Raman/métodos , Propriedades de Superfície , TermodinâmicaRESUMO
The SERS modelling of o-, m-, and p-methoxybenzonitrile has been performed following the same methodology that in Part I. Optimized structure obtained from DFT calculations in a B3LYP-LANL2DZ level of calculation shows different tilted positions for the isomers under study. From correlations obtained by comparison of Raman and SERS spectra concerning geometrical parameters, frequency shifting, change in band intensity, and force constants is possible to give insight about the different effect of the metal surface on these molecules and the structural reasons of this behaviour. Frontier orbital analysis gives further information and reveals a ligand to metal charge transfer mechanism for all isomers, as well as its relative importance.
Assuntos
Anisóis/química , Modelos Químicos , Estrutura Molecular , Prata/química , Análise Espectral Raman , TermodinâmicaRESUMO
Thermodynamic constants (Cv> Cp and itf) and physical properties a, fis and v) of the n-CnF2n+2 compounds with n=4 to 8 were evaluted and estimated from correlations. The values are compared with those obtained for the corresponding molecules in the n-CnH2n+2 series and tfje results were found to be consistent with the published experimental data. The liquid structure or n-perfluorated compounds is discussed on the basis of these data.
Thermodynamic constants (Cv> Cp and itf) and physical properties a, fis and v) of the n-CnF2n+2 compounds with n=4 to 8 were evaluted and estimated from correlations. The values are compared with those obtained for the corresponding molecules in the n-CnH2n+2 series and tfje results were found to be consistent with the published experimental data. The liquid structure or n-perfluorated compounds is discussed on the basis of these data. Physical and thermodynamic properties; Number 4 to eight.
RESUMO
Thermodynamic constants (Cv> Cp and itf) and physical properties a, fis and v) of the n-CnF2n+2 compounds with n=4 to 8 were evaluted and estimated from correlations. The values are compared with those obtained for the corresponding molecules in the n-CnH2n+2 series and tfje results were found to be consistent with the published experimental data. The liquid structure or n-perfluorated compounds is discussed on the basis of these data.
Thermodynamic constants (Cv> Cp and itf) and physical properties a, fis and v) of the n-CnF2n+2 compounds with n=4 to 8 were evaluted and estimated from correlations. The values are compared with those obtained for the corresponding molecules in the n-CnH2n+2 series and tfje results were found to be consistent with the published experimental data. The liquid structure or n-perfluorated compounds is discussed on the basis of these data. Physical and thermodynamic properties; Number 4 to eight.