Fabrication of new Fe₃O₄/PVA/(C₆H₇O₆Na)_n nanohybrid ferrogels for antibacterial applications

New Fe₃O₄/polyvinyl alcohol (PVA)/sodium alginate (C₆H₇O₆Na)_n nanohybrid ferrogels for antibacterial applications were fabricated. The crystal and molecular structures along with optical and magnetic properties of the prepared samples were characterized. The antibacterial activity of the ferrogels against Bacillus subtilis and Escherichia coli was investigated using the agar dilution method. X-ray diffraction analysis showed that the Fe₃O₄/PVA comprised a PVA amorphous phase and a spinel-structured Fe₃O₄ crystalline phase. The Fe₃O₄/PVA crystallite size was 7.5-9.9 nm and the scanning electron micrographs showed that the Fe₃O₄/PVA agglomerated. The ferrogels were superparamagnetic with saturation magnetizations from 14.8 × 10⁻³ to 82.1 × 10⁻³ emu/g. The absorption of the ferrogels showed a bathochromic effect, accompanied by an increase in the bandgap from 2.09 to 2.18 eV with increasing Fe₃O₄ content in the ferrogels. The ferrogels demonstrated new potency as antibacterial agents against B. subtilis and E. coli, where their antibacterial performance increased with increasing Fe₃O₄ content.