Ferromagnetic nickel (II) oxide (NiO) nanoparticles: biosynthesis, characterization and their antibacterial activities

In this study, ferromagnetic nickel (II) oxide (NiO) nanopowders were synthesized using Rosemary extract in pH 8.3. The resulting nanoparticles were almost spherical and had a uniform size distribution. Then, their minimum inhibitory concentration (MIC) on Streptococcus mutans that can make tooth decay was evaluated. Oral streptococci cause damage to the tooth enamel by the fermentation of sucrose and production of lactic acid; additionally, this bacterium uses sucrose to make dental plaque. According to the data, the MIC of nanoparticles was >= 500 mu g/ml; the presence of plant phenols in Rosemary extract improved the bacteriostatic properties of NiO nanoparticles, because of its antioxidant properties. Due to the suitable antibacterial properties of nickel nanoparticles, nickel composite alloys can be proposed in the manufacture of dental amalgam. [GRAPHICS] .