Antibacterial activity investigation of magnetic metal nanoparticles decorated ionic liquids

Magnetic structures were prepared with co-precipitation method. Surface of Fe3O4 was modified with BMIM[NTf2] ionic liquid. The samples became antibacterial by loading metal nanoparticles (Au, Ag, Cu) and denoted as X/IL/Fe3O4 (X=Ag, Au, Cu). X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), thermal gravimetric analysis (TGA), Atomic absorption spectroscopy (AAS), Fourier transform infrared (FTIR) and vibration sample magnetometer (VSM) technics were applied for catalysts characterization. Modified nanocomposites were used for inactivation of Escherichia coli as the gram negative and Staphylococcus aureus as the gram positive of bacteria. Transmition electron micrscopy (TEM) images indicated that highest bacteria cell walls destruction is achieved when the surface of the magnetic nanoparticle is coated with Au particles. Ionic liquid with forming hydrogen bond with cell wall create a channel that metal ions transfer to outer layer of bacteria. Ionic liquid by hydrogen bonding interactions absorb the bacteria to the composite surface and facilitate the ion transfer and bacteria wall destroying. Minimum inhibitory concentration (MIC) study approved the positive effect of Ionic liquid for better antibacterial activity.