Zinc oxide microrods and nanorods: different antibacterial activity and their mode of action against Gram-positive bacteria

摘要: The development of antibiotic resistance among pathogenic bacteria combined with increased implant-associated infections have determined a great interest towards new bactericidal materials containing various organic and inorganic substances. Among them, zinc oxide (ZnO) derived received considerable attention due to their unique antibacterial, antifungal, UV filtering properties as well high catalytic photochemical activities. In the present work, we investigate antimicrobial against two Gram-positive (Staphylococcus aureus Bacillus subtilis) ZnO microrods (MRs) nanorods (NRs), produced in bulk quantities through simple inexpensive methods. We demonstrate that effect is strongly dependent on rod size dose. Scanning electron microscopy analysis revealed investigated microbial types interact differently ZnO-MRs NRs different morphology. This resulted outcomes reported by respective Colony Forming Unit (CFU) capabilities. Moreover, Fourier Transform Infrared (FT-IR) spectroscopy changes cell outer structures, i.e. membrane exopolysaccharides (EPS), interaction are responsible for mechanism without accumulation reactive oxygen species. was further strengthened survival observed case bacterial cells treated presence an osmotic support, like glycerol. addition, Inductively Coupled Plasma Mass Spectrometry (ICP-MS) showed reduced viability not strictly correlated ion release suspension. then concluded ZnO-NRs superior both S. B. subtilis at much lower doses when compared ZnO-MRs. mainly smaller diameter NRs, which promotes surface damaging protein alteration wall. Finally, lack toxicity versus aureus, validated vivo using nematode Caenorhabditis elegans host infection model, confirm promising exploitation biomedical applications.