SÍNTESE, CARACTERIZAÇÃO E AVALIAÇÃO DO POTENCIAL DE NANOPARTÍCULAS DE ACETATO DE CELULOSE COMO AGENTE FOTOSSENSIBILIZADOR NA INATIVAÇÃO FOTODINÂMICA DE BACTÉRIAS S. AUREUS E E. COLI.

Abstract

Throughout history, humanity has faced a variety of diseases caused by bacterial infections. The discovery of antibiotics transformed modern medicine and significantly increased life expectancy. However, the improper and excessive use of these medications over the years has contributed to an alarming rise in bacterial resistance. One strategy that has proven effective in eradicating microorganisms is photodynamic inactivation (PDI). Given this, the present study aimed to synthesize and characterize cellulose acetate nanoparticles (CAt-NPs) using the organic compound THF as a solvent (CAt-NPs) and to evaluate their efficacy in the PDI process. The CAt-NPs were synthesized via the nanoprecipitation method and characterized by scanning electron microscopy (SEM), dynamic light scattering (DLS), Zeta potential, and FTIR. In the biological assays, strains of Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922) were used, divided into two groups: (I) irradiated group and (II) non-irradiated group. The internalization time of the NPs was 1 hour, followed by an exposure of 1.5 hours to blue LED light with a wavelength of 450 nm and an energy dose of 28.84 mW.cm⁻² for the irradiated group. The concentrations tested for PDI were 100 ppm, 250 ppm, 500 ppm, and 1000 ppm of CAt-NPs. Biological tests indicated that CAt-NPs exhibit bactericidal and bacteriostatic effects at the higher concentrations against E. coli bacteria, whereas no significant effects were observed against S. aureus at any concentration.