Antibacterial activity of Ag⁺ion-containing silver nanoparticles prepared using the alcohol reduction method

The reduction of Ag⁺ions in presence of ethyl alcohol as reducer and polymeric protective agent poly(N-vinylpyrrolidone) (PVP) occurs at 70 °C. When no other additives are present in the system, the slow reduction leads to silver nanoparticles being obtained. When the reduction is performed in the presence of higher PVP contents, the mean diameter of the silver ion-containing Ag nanoparticles decreased and a narrow particle size distribution was obtained. The antimicrobial activities of silver ions and Ag⁺ion-containing silver nanoparticles against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) were investigated. These particles exhibited bactericidal activity against E. coli and S. aureus, with the silver ion-containing Ag nanoparticles having greater bactericidal activity against E. coli compared with S. aureus.