Toxicological Effect of ZnO Nanoparticles Based on Bacteria

Abstract

Streptococcus agalactiae and Staphylococcus aureus are two pathogenetic agents of several infective diseases in humans. Biocidal effects and cellular internalization of ZnO nanoparticles (NPs) on two bacteria are reported, and ZnO NPs have a good bacteriostasis effect. ZnO NPs were synthesized in the EG aqueous system through the hydrolysis of ionic Zn2+ salts. Particle size and shape were controlled by the addition of the various surfactants. Bactericidal tests were performed in an ordinary broth medium on solid agar plates and in liquid systems with different concentrations of ZnO NPs. The biocidal action of ZnO materials was studied by transmission electron microscopy of bacteria ultrathin sections. The results confirmed that bactericidal cells were damaged after ZnO NPs contacted with them, showing both gram-negative membrane and gram-positive membrane disorganization. The surface modification of ZnO NPs causes an increase in membrane permeability and the cellular internalization of these NPs whereas there is a ZnO NP structure change inside the cells.

Damage of lipopolysaccharides in outer cell membrane and production of ROS-mediated stress within bacteria makes nano zinc oxide a bactericidal agent

“…Low-cost precursors ease synthetic procedure, short span of time scale along with biocompatible reactants allowed this reaction to be called as 'green'. Importantly, hexagonal structure of ZNP with (101) plane, the highest intense one, confirmed the growth along [0001] direction which might have impact on bacterial system (Huang et al 2008). Several studies have suggested, two possible mechanisms could be involved in the interaction between nanoparticles and bacteria-(a) the production of increased levels of ROS, mostly hydroxyl radicals and singlet oxygen (Ostrovsky et al 2009) and (b) deposition of the nanoparticles on the surface of bacteria or accumulation of nanoparticles either in the cytoplasm or in the periplasmic From our experimental results, we speculated that ZNP is first bound with hydrophilic counterpart of LPS resulting in some sort of deformation within OM.…”

Zinc oxide nanoparticle-coated films: fabrication, characterization, and antibacterial properties

“…The unique physico-chemical properties of ZnO NPs have made them one of the most commercialized nanomaterials used in a variety of applications such as sunscreen products and textiles (Stoimenov et al 2002;Huang et al 2008, Jones et al 2008Akhavan et al 2009). ZnO NPs show activity as antibacterial materials against both Gram-positive and Gram-negative bacteria, including spores.…”

Cerium oxide and iron oxide nanoparticles abolish the antibacterial activity of ciprofloxacin against gram positive and gram negative biofilm bacteria

“…Moreover, antibacterial nanoparticles influence several structures and biological pathways found in a wide range of pathogenic bacteria. This makes it harder for bacteria to develop resistance against nanoparticles (Nel et al 2009;Huang et al 2008;Pal et al 2007). …”