Impact of different magnetic materials added to silver-magnetite nanoparticles on the structural, magnetic and antimicrobial properties.

Different magnetic materials of spinel copper and cobalt nanoferrites added to silver-magnetite nanoparticles were fabricated by a facile, low cost, and rapid auto-combustion method to form a nanocomposite. X-ray diffraction patterns and atomic force microscopy were studied for the investigated samples and confirmed their nanosize range. Adding cobalt nanoferrite to silver-magnetite (CoAF) yielded a more pronounced effect in the magnetic measurements than adding copper nanoferrite (CuAF). This result was attributed to the much higher coercivity H c and saturation magnetization M s (5.7-fold and 2.8-fold, respectively) of CoAF than CuAF; accordingly, the CoAF nanocomposite can be applied to a permanent magnet. Next, the operating frequencies of the nanocomposites were calculated from the magnetic measurements. The CoAF and CuAF nanocomposites were applicable in the microwave super-high-frequency C-band and the microwave super-high-frequency S-band, respectively. Both nanocomposites were ineffective against the tested fungi but showed strong antimicrobial activities against the tested Gram-positive and Gram-negative bacteria. Thus, CoAF and CuAF nanocomposites are potential antibacterial nanomaterials for biomedical applications.