Antibacterial Ag–SiO2 composite films synthesized by pulsed laser deposition

• Ag–SiO2 composite films were produced by PLD method for the first time.
• The Ag:SiO2 ratio of the composite films can be nicely controlled.
• The resultant films exhibit high antibacterial effectivity.
• The present room temperature deposition can be applied on diverse substrates.

To prevent the deleterious effects of antibiotic overuse, alternative strategies against microbial pathogens become essential in clinic surgeries. Thereinto, antibacterial inorganic coating materials have stimulated great interest recently. In this work, Ag–SiO2 composite films have been synthesized at room temperature (RT) using pulsed laser deposition, and the ratio of Ag and SiO2 in the films can be strictly controlled by tuning the Ag:SiO2 ablated area ratio of the target. The resultant films exhibit pronounced antibacterial properties against both gram-negative Escherichia coli (E. coli) and gram-positive Staphylococcus aureus (S. aureus). It is revealed that all films obtained are highly effective against S. aureus even at a low Ag:SiO2 ratio, while those with a larger Ag:SiO2 ratio can inhibit E. Coli more efficiently. This RT gas-phase deposition of Ag–SiO2 composite films can be universally applied on diverse substrates and may have promising applications as antibacterial coatings in orthopedic and dental surgeries.