Study of the influence of the shape and size of the ZnO nanoparticles synthesized from different precursors on the antibacterial activity

Three different shapes of ZnO nanoparticles were synthesized using three different precursors. The synthesized samples have been characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM). The XRD measurements reveal that the prepared nanomaterials have a hexagonal wurtzite structure. TEM observations showed that the form and the size of nanoparticles depend on the precursor used to prepare ZnO. The antibacterial activities of the different prepared ZnO nanoparticles were tested against Staphilococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacteria. The results obtained have shown that the antibacterial activities depend on the concentration, shape (agglomerates, hexagonal microrods and hexagonal nanoparticles) and crystallite size of ZnO particles. The minimum concentration of ZnO nanoparticles that inhibits the growth Staphilococcus aureus or Escherichia coli (0.015 mg/ml) is very lower than those reported by many authors indicating that the ZnO nanoparticles agglomerates act efficiently even at very low concentrations and with the same sensitivity against the two types of bacteria.