Bactericidal Activity Study of ZrO2-Ag2O 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 ZrO2-Ag2O nanoparticles by sol-gel method. The nanoparticles were analyzed and tested for their antibacterial activity against gram-positive bacteria ofBacillus subtilis,Streptococcus mutans,Staphylococcus aureus, and gram-negative ofEscherichia coli,Pseudomonas aeruginosa,andKlebsiella oxytoca. X-ray diffraction showed the monoclinic ZrO2, cubic Ag2O, and peaks corresponding to ZrO(2)and Ag2O in their mixed samples. Scanning electron microscopy showed spherically shaped nanoparticles while dynamic light scattering analysis showed ZrO2(76 nm), Ag2O (50 nm), and ZrO2-Ag2O 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 Ag2O at 580 cm(-1), while ZrO2-Ag2O samples showed bands at 760 cm(-1). The screening by agar diffusion assay revealed a pronounced increase in the antibacterial activity of ZrO2-Ag2O against all the tested bacteria when compared with the pure ZrO(2)and Ag2O. The improved antibacterial activity of ZrO2-Ag2O largely results from the chemical stability conferred on it by the ZrO(2)as observed from the zeta potential measurement.