Bactericidal Activity Study of ZrO(2)-Ag(2)O Nanoparticles

In view of the continuous resistance to antibacterial agents by bacteria and the existing problems of silver nanoparticles as an antibacterial agent, this study reports on the synthesis of pure zirconium oxide, silver oxide, and ZrO(2)-Ag(2)O nanoparticles by sol-gel method. The nanoparticles were analyzed and tested for their antibacterial activity against gram-positive bacteria of Bacillus subtilis, Streptococcus mutans, Staphylococcus aureus, and gram-negative of Escherichia coli, Pseudomonas aeruginosa, and Klebsiella oxytoca. X-ray diffraction showed the monoclinic ZrO(2), cubic Ag(2)O, and peaks corresponding to ZrO(2) and Ag(2)O in their mixed samples. Scanning electron microscopy showed spherically shaped nanoparticles while dynamic light scattering analysis showed ZrO(2) (76 nm), Ag(2)O (50 nm), and ZrO(2)-Ag(2)O samples between 14 and 42 nm. The Fourier Transformed Infrared spectroscopy spectra of ZrO(2) gave bands at 480 cm(−1) to 750 cm(−1) (M-O stretching) with Ag(2)O at 580 cm(−1), while ZrO(2)-Ag(2)O samples showed bands at 760 cm(−1). The screening by agar diffusion assay revealed a pronounced increase in the antibacterial activity of ZrO(2)-Ag(2)O against all the tested bacteria when compared with the pure ZrO(2) and Ag(2)O. The improved antibacterial activity of ZrO(2)-Ag(2)O largely results from the chemical stability conferred on it by the ZrO(2) as observed from the zeta potential measurement.