Synthesis, characterizations, and antibacterial properties of PbMoO4 nanocrystals

This study reports the synthesis and characterization of PbMoO4 nanocrystals and the antibacterial properties and modulation of their antibiotic activity. Lead molybdate nanocrystals were obtained through the conventional hydrothermal method, and the structural, vibrational and morphological properties of the sample were determined using X-ray diffraction, Raman and infrared spectroscopy, and scanning electron microscopy images. The obtained samples present scheelite-type tetragonal structure (space group I41/a) without secondary phases, and the Raman spectrum shows the formation of PbMoO4 structurally ordered at short-range, confirming the quality of the samples. The antibacterial and antibiotic-modulation activities were performed in triplicate using the microdilution method. The minimum inhibitory concentration (MIC) of antibiotics alone or in association with PbMoO4, were demonstrated using geometric mean. When assayed directly, the PbMoO4 presented a MIC ≥ 1024 μg/mL against all bacterial strains tested. When in association with the gentamicin against Staphylococcus aureus, a synergism was observed reducing 37.5% the MIC. However, in the assays against the Gram-negative strains was observed that the presence of lead affected the effect of the antibiotic, leading to an antagonism.