Avaliação do efeito antimicrobiano de nanopartículas em bactérias da periodontite crônica

Abstract

Periodontal disease is a common and localized inflammatory disease caused by bacterial infection associated with dental biofilm and several pathological conditions, such as inflammation of the gingiva, degeneration of the periodontal ligament, root cementum and loss of alveolar bone, characterizing periodontitis. Chronic Periodontitis is one of the manifestations of Periodontal Disease, it stands out for the high prevalence and incidence, and still remains, throughout the world, as a public health problem, affecting the quality of life of these people. It can be considered a disease of high complexity as to the nature of its etiology, different forms of classification, treatment and maintenance. The major bacteria found include Porphyromonas gingivalis, Tannerella forsythia, P. intermedia, C. rectus, E. corrodens, Fusobacterium. nucleatum, Aggregatibacter actinomycetemcomitans, P. micros, Treponema and Eubacterium species. Antimicrobials, by the inhibition of pathogenic microorganisms growth, are a prophylactic and therapeutic alternative for multiple diseases, as well as Chronic Periodontitis. The high capacity of developing resistance to antibiotics has steadily increased and its control is still a major challenge. Nanotechnology provides a new platform for developing important metal properties in the form of nanoparticles (NPs) with promising applications as antimicrobial agents. Since the last decade, silver NPs (Ag-NP) have demonstrated antimicrobial properties against gram-negative bacteria and gram-positive bacteria. In this work, the NPs of Ag and zinc oxide decorated with silver (ZnO-Ag- NP) were synthesized and analyzed for: I the final quality of NPs by X-ray Diffraction (XRD) and Transmission Electron Microscopy MET); II by determining the minimum inhibitory concentration (MIC), the antimicrobial potential on Fusobacterium nucleatum (ATCC 10953) and Porphyromonas gingivalis (ATCC 33277), in vitro for a period of 24 to 96 hours. The antimicrobial activity of Amoxicillin (AMX) and Metronidazole (MTZ) on the strains were evaluated in the same experimental conditions. DRX confirmed the synthesis of Ag-NPs in the face-centered cubic crystallographic phase and ZnO-Ag-NP in the Wurtzite hexagonal phase. MET images showed aspherical shape with an average size of about 2 nm (Ag-NP) and 8 nm (ZnO-Ag-NP) indicating the efficiency of the synthesis method to obtain colloidal suspensions. The CIM for Ag-NP (in the range of 32.4 to 4.05 and> 150 to 37.5 μg / mL) and ZnO-Ag-NP (> 150 to 37.5 and 150 μg / mL) F. nucleatum and P. gingivalis, respectively, point to the concentration-time dependent activity; with higher Ag-NP antimicrobial activity for the same exposure times, 24, 48, 72 and 96 hours. Comparatively, greater sensitivity of F. nucleatum than P. gingivalis to NPs is clearly observed. AMX (0.047 to 0.023 μg / mL) and MTZ (5.0 to 0.625 μg / mL) presented lower MIC values than NPs under microdilution test conditions under anaerobic conditions. The development of new drugs or nanomaterials is promising in the face of the propagation of bacterial resistance, since they have a low propensity to induce microbial resistance when compared to conventional antibiotics.