Propriedades espectroscópicas da ação antimicrobiana do peptídeo polycerradin

Abstract

The spectroscopy is a technique based on light-matter interaction, which provides information about the composition and structure of molecules. For this reason, it is used in various fields of science, including the biology. There are various types of spectroscopy, based on different physical phenomena, however, in this article, we had addressed only two types: Raman and photoluminescence. Raman spectroscopy consists in the analysis of the inelastic scattering of radiation by focusing on a molecule. The light-matter interaction in this case results in a molecular vibrational energy change. On the other hand, the photoluminescence spectroscopy analyzes the radiation emitted by molecules due to electronic transitions induced by absorption of a photon. This study addresses the application of both techniques in the problem of combating pathogenic microorganisms. Some fungi and bacteria are causative of serious diseases and, therefore, the enhancement of efficiency in identifying and combating these microorganisms is of great interest to public health. This work aimed the application of Raman spectroscopy and photoluminescence to the identification of three pathogenic microorganisms and changes in the spectra emitted by them by adding an antimicrobial agent. In this study a novel peptide with antifungal and antibiotic action was used, called polycerradin, with biological activity demonstrated by agar diffusion tests. The spectra obtained by the Raman scattering technique were not conclusive, since there was photoluminescence emission concomitantly. However, the photoluminescence spectra showed a significant decrease in peak intensity at 695 nm when the ELP was added, for all three microorganisms studied. These results demonstrate, therefore, the great potential application of photoluminescence spectroscopy not only for the identification of microorganisms as well as for determination of the inhibition and/or killing of the same by adding an antimicrobial agent. As a future prospect, we aim to develop a biosensor based on photoluminescence technique, to be used in the identification and monitoring of micro-organisms. This biosensor could be applied in various areas such as medical, food industry, sanitary, among others.