Synthesis of Fe3O4/Ag nanohybrid ferrofluids and their applications as antimicrobial and antifibrotic agents

To date, the search for creating stable ferrofluids with excellent properties for biomedical application is one of the challenging scientific and practical investigations. In this study, novel Fe₃O₄/Ag nanohybrid ferrofluids from iron sand were synthesized using a double-layer method. The Fe₃O₄/Ag nanocomposites exhibited stable crystallite sizes of 11.8 12.1 nm and 36.8-37.2 nm for Fe₃O₄ and Ag, respectively. The lattice parameters of the spinel structure Fe₃O₄ and face-centered cubic Ag were respectively 8.344 Å and 4.091 Å. With increasing Ag amount, the crystallite phase of Ag in the nanocomposites increased from 40.2% to 77.2%. The XPS results confirmed that Fe₃O₄/Ag nanocomposites were successfully prepared, where Fe₃O₄ mixed well with Ag via strong ionic bonding. The FTIR results confirmed the presence of Fe₃O₄/Ag, oleic acid, and dimethyl sulfoxide as the filler, first layer, and second layer, respectively. The as-prepared ferrofluids exhibited superparamagnetic behavior, where the saturation magnetization decreased with increasing Ag content. The Fe₃O₄/Ag nanohybrid ferrofluids exhibited excellent antimicrobial performance against <i>Bacillus subtilis</i>, <i>Staphylococcus aureus</i>, <i>Escherichia coli</i>, and <i>Candida albicans</i>. More importantly, the Fe₃O₄/Ag nanohybrid ferrofluids decreased the progression of liver fibrosis-related inflammation and fibrogenic activity on hepatic stellate cells.