Preparo e ensaio antimicrobiano de biopolímero formado por membrana de celulose bacteriana associada a nanopartículas de dióxido de titânio

Abstract

The high interest in nanotechnology has contributed to the advancement in the research of cellulosic nanomaterials. Bacterial cellulose (CB) is an extracellular polysaccharide, secreted by certain species of bacteria, such as Gluconacetobacter xylinus, which has interesting properties such as biocompatibility, biodegradability, high purity, fiber resistance and water retention, with several applications in areas of health, food, cosmetics, electronics, textiles, among others. The titanium dioxide nanocomposites (NPs-TiO2) have several properties such as chemical stability, great catalytic activity, and have antimicrobial properties with the possibility of incorporation into polymers for the generation of new materials with new properties. However, studies with NPs-TiO2 integrated with cellulose produced by bacteria are scarce. This project aims to prepare and test the antimicrobial activity of a biopolymer formed by bacterial cellulose membrane aggregated to titanium dioxide nanocomposites. In this regard, bacterial cellulose membranes were produced using Gluconacetobacter xylinus in medium containing glycerol as the main source of carbon, followed by the incorporation of titanium dioxide (TiO2) nanoparticles in an ultrasonic bath and subsequent antimicrobial assay against Escherichia coli bacteria with liquid activation in ultraviolet light (UV) chamber and Escherichia coli and Staphylococcus aureus without photoactivation in solid medium. The presence and incorporation of TiO2 particles in the membranes was confirmed by FTIR spectroscopy. Thus, due to the non-bactericidal nature of pure biopolymers, the functionalization of the cellulose membrane with titanium dioxide nanocomposites was evaluated, with inhibition of microbial growth for CB-TiO2 in the absence (68.0% inhibition) and, mainly, in the presence of UV-A radiation (98.5% inhibition).