Antimicrobial activity of metal oxide nanoparticles against Gram-positive and Gram-negative bacteria: a comparative study

Figures & data

Figure 1 X-ray diffraction spectra of ZnO, CuO, and Fe₂O₃ nanoparticles.

Figure 2 Transmission electron microscopy images of (A) ZnO, (B) CuO, and (C) Fe₂O₃ nanoparticles and histogram of particle-size distribution for different metal oxide nanoparticles.

Figure 3 Fourier-transform infrared spectra of ZnO, CuO, and Fe₂O₃ nanoparticles.

Figure 4 Zone of inhibition produced by different metal oxide nanoparticles against both Gram-positive and Gram-negative bacterial strains. Antibacterial activity of (A) ZnO; (B) CuO; and (C) Fe₂O₃ of bacterial strains (a), Escherichia coli, (b) Staphylococcus aureus, (c) Pseudomonas aeruginosa, and (d) Bacillus subtilis.

Figure 5 Bar graphs showing zone of inhibition introduced by different metal oxides against various microorganisms.

Table 1 Minimum bactericidal concentration (MBC) of different metal oxide nanoparticles against Gram-negative and Gram-positive bacteria

Nanoparticles	MBC values (μg/mL)
	Escherichia coli	Pseudomonas aeruginosa	Staphylococcus aureus	Baccillus subtilis
ZnO	18 ± 0.5	14 ± 0.6	16 ± 0.2	12 ± 0.5
CuO	25 ± 0.3	28 ± 0.5	22 ± 0.5	20 ± 0.7
Fe2O3	65 ± 1.5	120 ± 2.3	80 ± 1.5	78 ± 1.4
Tetracycline*	30 ± 0.4	30 ± 1.2	28 ± 1.2	25 ± 1.5

Notes: Values are mean of three replicates;

* standard antibiotic.