In vitro assessment of antibacterial properties and cytotoxicity of Al2O3-Ag nanopowders

The present paper describes an in vitro assessment of the antibacterial properties and cytotoxic activity on mammalian cells of silver nanoparticles incorporated into an aluminium nano-oxide substrate produced by the thermal decomposition-reduction method. The Al2O3-Ag nanopowders show good bactericidal and fungicidal properties. An Al2O3-Ag (12.55 wt-%) specimen at the concentration of 50 mg mL(-1) reduced considerably the populations of Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus and Bacillus subtilis species, whereas the same nanopowder in a concentration of 90 mg mL(-1) inhibited significantly the growth of P. aeruginosa, E. coli, S. aureus and Candida albicans and also significantly limited the number of B. subtilis. The Al2O3-Ag nanoparticles also showed no cytotoxic effects on the three selected cell lines, i.e. L929, BJ and HeLa, and the cells remained >75% viability, as measured by MTT assay, and >102% viability, obtained by EZ4U assay, relative to control at concentration as high as 200 mu g mL(-1).