Enhanced antibacterial activities of zirconia nanoparticles modified with yttrium oxide and alumina

Antibacterial activities of ZrO2, binary mixture (ZrO2+ Y2O3),and triple mixture (ZrO2 + Y2O3 + Al2O3) were studied against pathogenic bacterial strains, Escherichia coli and Staphylococcus aureus. The study also revealed the bacterial biofilm inhibition and biocompatibility of ZrO2 + Y2O3 + Al2O3. The triple mixture, composed of zirconium dioxide, yttrium trioxide, and aluminum trioxide (ZrO2 + Y2O3 + Al2O3), exhibited highest anti-bacterial effects against Staphylococcus aureus as compared with the Escherichia coli, with inhibition zone diameters of 27.33 mm and 22.66 mm, respectively. The binary mixture (ZrO2 + Y2O3) was comparable with the triple mixture in their antibacterial effects with the inhibition zone diameters of 24.66 mm and 21 mm as against Staphylococcus aureus, and Escherichia coli, respectively. Finally, the ZrO2 alone showed the lowest antibacterial effects. Furthermore, after 24 h of incubation at 37 °C, the three composites were also evaluated for the potential anti-adherence for the microbial biofilm in Streptococcus mutans. The results showed the adhesion process was decreased with increasing the concentrations of the triple mixture. Moreover, the in vitro biocompatibility evaluations in Rat Embryonic Fibroblast (REF) cells showed that the nanoparticles possessed low cytotoxicity, and indicated good biocompatibility. Hence, it was inferred that the synthesized Zirconia–Yttria triple mixture system can be useful for biomedical applications, especially in the field of dental implant techniques.