Utilização de Pluronic F127 funcionalizado na obtenção de nanopartículas de prata com ação antibacteriana

Abstract

The emergence of multiresistant bacteria has become a challenge for contemporary medicine as these have caused a growing in cases of infectious diseases. Nanotechnology brings new possibilities in effectively combating bacteria that are resistant to conventional antibiotics, and one of the most promising systems are the silver nanoparticles that can be associated with polymers for biomedical use. The aim of this work was evaluate the potentialities of Pluronic F127 functionalized with amino acids in obtaining and stabilizing of silver metallic nanoparticles (AgNps). The amino acids glycine, L-Alanine and DL-Alanine were used in the esterification reaction of the PEO groups present in the polymer chain. The esterified polymers were used in the reduction of Ag+ ions and in the stabilization of the nanoparticles by hydrothermal route using a solution of AgNO3 as the source of Ag+ ions, and Pluronic esterified as both reducing e stabilizing agent. AgNps were also obtained by photosensitization under the incidence of UV light (365 nm). Kinetic studies were performed for the photosensitization route in order to understand the influence of the polymer to the size, shape and distribution of AgNps. The functionalization was characterized by Fourier transform infrared spectroscopy (FT-IR) and the nanoparticles obtained were characterized by Ultravioletvisible absorption spectroscopy (UV-Vis spectroscopy), and transmission electron microscopy (TEM). FT-IR analysis suggested that the esterification occurred. The UVVis and TEM analyzes showed that the AgNps obtained by the hydrothermal route are predominantly spherical, whereas those obtained by photosensitization give rise to rods and prisms. Kinetic studies show that alanine and glycine form particles with different velocities and the different enantiomers (L and DL) influence the size and shape of AgNps. The nanoparticles obtained by the two routes had their bactericidal efficiency tested against S. aureus by the well diffusion method. The nanoparticles by photosensitization obtained with the polymer functionalized with DL-Alanine proved to be the most efficient against S. aureus.