Synthesis and antibacterial properties of magnetically recyclable nanoporous silver/Fe3O4 nanocomposites through one-step dealloying

Abstract

We present a facile one-step dealloying strategy to fabricate novel nanoporous silver (NPS)/Fe₃O₄ nanocomposites with tunable magnetism and excellent antibacterial ability. The NPS/Fe₃O₄ nanocomposites were obtained by chemically dealloying rapidly solidified Al–Ag–Fe precursors in a 20 wt% NaOH solution. The microstructure of the NPS/Fe₃O₄ nanocomposites has been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM) and high resolution TEM (HRTEM) with nanobeam-EDX (NB-EDX). In the nanocomposites, the NPS matrix exhibits an open bicontinuous interpenetrating ligament–channel structure, with ligament/channel sizes of 20–50 nm, and the embedded Fe₃O₄ particles are octahedral and several hundred nanometers in size. Through changing the Ag/Fe atomic ratio in the Al–Ag–Fe precursors, we can tune the magnetic properties of the NPS/Fe₃O₄ nanocomposites. Antibacterial tests demonstrate that the NPS/Fe₃O₄ nanocomposites show excellent antibacterial activities against E. coli K12 and the embedded Fe₃O₄ makes these materials magnetically recyclable. The present NPS/Fe₃O₄ nanocomposites are potential antibacterial materials with a magnetically recyclable property.