Estudo da interação entre nanopartículas de ouro com LTriptofano e organilcalcogênicos

Abstract

Nanomaterials have been the subject of increasing interest due to their wide range of applications and commonly used for the production of biomarkers and hybrid materials in various areas of expertise. Therefore, the search for functionalizing molecules that can enhance the physical, chemical and / or biological these materials and techniques to assist in the characterization of the compounds formed are necessary. Thus, the present study sought through spectroscopic absorption and fluorescence; evaluate the behavior of the amino acid L Tryptophan and organocalcogênios in the presence of different concentrations and diameters of gold nanoparticles. For the analysis, concerning the interactions between the amino acid and gold nanoparticles observed suppression of fluorescence intensity, increasing the absorbance of the indole groups and the appearance of a second peak wavelength band of 520 nm derived of the plasmon resonance. Since this effect was proportional to the concentration of gold nanoparticles in solution. As for organilcalcogênios, first, held its characterization, it was possible to detect the presence of the main vibrations of molecules by infrared spectroscopy, molecular modeling and Raman spectroscopy. The latter was also used to investigate the presence of nanoparticles in order that the measurements were performed in solution and can be viewed the rise of a band in the region of 300 cm-1, where the disclosure of the functionalization process because this region is derived from chalcogenides gold vibrations. As for fluorescence and absorption of organilcalcogênios analysis, the results are satisfactory, it can be seen a difference in both emission spectra when the absorption, demonstrating the interaction of the nanoparticles with the environment. The fluorescence (p-Cl(C6H4Se))2 and L tryptophan in the presence of the nanoparticles demonstrated that the interactions cause the same suppression effect of fluorescence intensities. This effect promoted by photoinduced electron transfer process of the present organic groups of the aforementioned molecules to the metal surfaces, and different from (C6H5Te)2, which showed an increased effect on the fluorescence intensity after the interaction with the surface of metal. This fact is associated with the transfer effect of plasmon energy present in the nanoparticles to the molecules of (C6H5Te)2.