Size Attenuated Copper Doped Zirconia Nanoparticles Enhances In Vitro Antimicrobial Properties

Biofilm formation hinders the activity of antimicrobial drugs at the site of infections and any agent that can act on both Gram-positive and Gram-negative bacteria by inhibiting the bacterial growth and rupturing the biofilm is needed to manage infection. In the present study, we have synthesized zirconia nanoparticles (ZrO₂ NPs) and copper doped zirconia nanoparticles (Cu-ZrO₂ NPs) and characterized them using dynamic light scattering, X-ray diffractometry, and scanning electron microscopy (SEM). The size of the Cu-ZrO₂ NPs drastically reduced compared to ZrO₂ NPs, and the antimicrobial activity was studied against Gram-positive bacteria (Lactobacillus sp.) and Gram-negative bacteria (Pseudomonas aeruginosa), respectively. The synthesized Cu-ZrO₂ NPs showed superior inhibitory action against Lactobacillus sp. compared to ZrO₂ NPs, due to the negatively charged cell wall of Lactobacillus sp., which could attract readily the positively charged Cu-ZrO₂ NPs, thereby inhibiting its activity. The biocompatibility was tested using XTT assay in FL cells, and the results demonstrated that Cu-ZrO₂ NPs were nontoxic to mammalian cells. Hence, it could be proposed that the synthesized Cu-ZrO₂ NPs possess possible biomedical applications and can be used as antibacterial agents without causing toxicity in mammalian cells.