Electromagnetic exposure and magnetic nanoparticle impact on some bacteria

In this paper an experimental study focused on the biological effects of low power density microwaves and magnetic colloidal nanoparticles was carried out based on the laboratory simulation of environment electromagnetic pollution and magnetic contamination. 2 Gram positive and 1 Gram negative strains were chosen for the investigation of cell density changes induced by the supply with ferrite colloidal nanoparticles or/and two hours exposure to 10.75 GHz electromagnetic waves of non-thermal level. The diminution of cell density was recorded in all experimental variants, the iron oxides particles being found to induce stronger negative influence on the microorganism growth than the non-thermal microwaves. This was evidenced both for Staphylococcus aureus and Bacillus subtilis and for Escherichia coli; however the amplitude of the effect depends on the bacteria species, being the highest in S. aureus and the lowest in E. coli. The magnetite and the cobalt ferrite nanoparticles induced the most significant effects in S. aureus and B. subtilis while zinc ferrite nanoparticles led to the most visible effect of cell density diminution in E. coli. The simultaneous action of microwaves and magnetic nanoparticles seemed to modulate the effect evidenced when only magnetic nanoparticles were administrated probably by disturbing their interference with bacteria cells.