Comparative Assessment of Antimicrobial Efficiency of Ionic Silver, Silver Monoxide, and Metallic Silver Incorporated onto an Aluminum Oxide Nanopowder Carrier

Abstract

The present paper provides comparative assessment of antimicrobial efficiency of ionic silver (Ag + ), silver monoxide (Ag 2 O), and metallic silver (Ag) incorporated onto an aluminum oxide nanopowder carrier (Al 2 O 3 ). The deposition of Ag + ions, Ag 2 O nanoparticles, and Ag nanoparticles on an different phases of aluminum oxide nanopowder carrier was realized using consecutive stages of dry sol-gel method. The Al 2 O 3 -Ag + , Al 2 O 3 -Ag 2 O, and Al 2 O 3 -Ag nanopowders were widely characterized qualitatively and quantitatively by SEM, physical nitrogen sorption and XRD analyses. Results indicate that the Al 2 O 3 nanopowders added with Ag + , Ag 2 O, and Ag, apart from phase composition, were not differing considerably from one another in terms of their morphology and physical properties. However, nanopowders of Al 2 O 3 -Ag were more agglomerated than Al 2 O 3 -Ag 2 O and Al 2 O 3 -Ag + nanopowders. The antibacterial activity of the nanopowders was examined by the spread plate method using bacterial strains such as Escherichia coli, Sarcina lutea , and Bacillus subtilis . The best antibacterial properties against Sarcina lutea strain were achieved in the amorphous-Al 2 O 3 -Ag + and Al 2 O 3 -Ag 2 O nanopowders, whereas the worst antimicrobial activity against Bacillus subtilis and Escherichia coli was shown by the Al 2 O 3 -Ag + and Al 2 O 3 -Ag nanopowders. The observed increase of the antibacterial activity as the silver content was not however significant for Al 2 O 3 -Ag nanopowders. The results obtained in the present experiments show that the Al 2 O 3 -Ag + , Al 2 O 3 -Ag 2 O, and Al 2 O 3 -Ag nanopowders, possessing good bactericidal properties, can be produced by using consecutive stages of dry sol-gel method, and Al 2 O 3 nanopowder added with Ag 2 O is considered as the best raw material in the production of antiseptic materials.