Atividade antibacteriana de magnetita (Fe3O4) isolada e associada a campos eletromagnéticos sobre Escherichia coli DH5a pVAX-1 (resistente à canamicina)

Abstract

Due to the increase in bacterial resistance in recent years, research and development of alternative antibacterial therapies has become necessary and, in this sense, the use of magnetic fields has been explored as it is a non-pharmacological therapy and, therefore, probably exempt of the molecular effects of the resistance phenomenon. At the same time, nanoparticles with magnetic properties, especially magnetite (Fe3O4), are still little explored in terms of their antibacterial potential. In this context, the present work evaluated the intrinsic antibacterial properties of magnetite nanoparticles, synthesized by high-energy milling, and their association with a variable external magnetic field of 70 mT at 10 Hz on Escherichia coli DH5α pVAX-1. After synthesis, the nanoparticles were characterized as to their composition and primary size, by X-ray diffraction (XRD); as to its hydrodynamic size, by dynamic light scattering (DLS) and as to its surface charge, by zeta potential. Subsequently, in vitro assays were performed, in which alterations in the bacterial inhibition curve were investigated; in bacterial morphology, using microscopy (SEM), and in bacterial surface load, using zeta potential. The association between the antibiotic kanamycin and magnetite was also evaluated regarding the potentiated effect between the substances. Exposure to isolated magnetite, or combined to a magnetic field, generated significant bacteriostatic effects, in addition to morphological changes in the bacterial surface and an increase in the zeta potential of the suspension. The use of magnetite nanoparticles also potentiated the inhibitory effect of the antibiotic kanamycin, pointing to a second option for use as an adjunct to antibiotic therapy. The results presented reveal important antimicrobial potential and additional in vivo tests are needed to prove the importance of the effects observed in a biological system.