One-pot synthesis of porous Fe3O4 shell/silver core nanocomposites used as recyclable magnetic antibacterial agents

• The porous Fe3O4 shell/silver core nanocomposites have been successfully prepared via a simple one-pot hydrothermal method.
• The as-prepared Ag@Fe3O4 nanocomposites exhibit high antibacterial activity against both Gram-positive and Gram-negative bacteria.
• The porous Fe3O4 shell/silver core nanocomposites show a stronger antibacterial ability than the solid Fe3O4 shell/silver core nanocomposites.
• The recovery nanocomposites still have antibacterial activity and can be reused.

Porous Fe3O4 shell/silver core nanocomposites featuring sustainable and recyclable antibacterial activity have been successfully prepared via a facile one-pot hydrothermal method. The unique structural feature of the Ag@Fe3O4 nanocomposites with Ag embedded in porous Fe3O4 shell endows them with the ability of sustained-release of silver ions. Their antimicrobial activity studies were investigated on both Gram negative Escherichia coli and Gram positive Bacillus subtilis, which demonstrate that the nanocomposites are highly toxic to microorganisms and exhibit sustainable antibacterial activity. Besides, the Ag@Fe3O4 nanocomposites can be separated easily from the medium by a small magnet, which provided an effective way to eliminate the residual nanosilver from the surroundings. We finally demonstrate that the recovered nanocomposites exhibit recyclable antibacterial activity, acting as an ideal long-acting antibacterial agent.