Green synthesis of ZnO nanoparticles with Veronica multifida and their antibiofilm activity.

In the present study, Veronica multifida leaf extract and zinc acetate dihydrate were utilized to synthesize zinc oxide (ZnO) nanoparticles (NPs) eco-friendly and cost-effectively under different physical conditions. Soxhlet extractor was used for the preparation of aqueous plant extract. UV-Vis (ultraviolet-visible) spectrophotometer, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscope (TEM) were used to characterize the ZnO NPs. UV-Vis spectrophotometer in the range of 200-800 nm was used to get information about the formation of ZnO NPs at different pH and temperatures. FTIR spectrum revealed the presence of functional groups in ZnO NPs. XRD, scanning electron microscope, and TEM analyses confirmed the crystal structure and average size of ZnO NPs. The antimicrobial activities of ZnO NPs were tested on microorganisms, that is, Escherichia coli ATCC 43895, Staphylococcus aureus ATCC 29213, Bacillus subtilis, Bacillus licheniformis, Pseudomonas aeruginosa, and Salmonella typhimurium. Moreover, antibiofilm activity of ZnO NPs was performed against P. aeruginosa and S. aureus ATCC 29213. ZnO NPs have shown effective antimicrobial and antibiofilm activities against tested microorganisms. The results elucidated that eco-friendly and cost-effectively produced ZnO NPs could be used as coating materials and in a wide range of industrial applications, such as pharmaceutical industries and cosmetics.