Surface modifications of superparamagnetic iron oxide nanoparticles with citric acid, selenium, and silver combining with polymer blend as antibacterial agent

Antibiotic resistance is a growing global health crisis. This study introduces a novel nanocomposite material incorporating superparamagnetic iron oxide nanoparticles (SPION), citric acid (CA), selenium (Se), silver (Ag), and a polymer matrix (M8) consisting of polyethylene glycol, polyvinylpyrrolidone, chitosan, and polyvinyl alcohol. The novel materials were used to inhibit Pseudomonas aeruginosa (PA), Staphylococcus aureus (SA), and Salmonella enterica (SE). The optimal molar ratio of SPION:CA: CSPION:Se: CSPION/Se/Ag was 1:2:0.5, yielding nanoparticles with an average size of 15.09 ± 2.95 nm (FE-SEM) and a saturation magnetization of 21.51 emu/g (VSM). XRD confirmed the coexistence of Fe₃O₄, Se, and Ag crystalline phases, while FTIR revealed ionic and hydrogen bonding interactions between the polymers, citric acid, and metal nanoparticles. EDS analysis validated the successful incorporation of Se (7.06 wt%) and Ag (22.00 wt%). At this ratio, the inhibition percentage against PA, SA, and SE (using the minimum inhibitory concentration method) at 50% dilution is 99.99 ± 0.52%, 99.31 ± 2.74%, and 47.41 ± 3.69%, respectively. The superior performance is attributed to synergistic effects between SPION, Se, Ag, and the polymer blend, offering a promising approach for combating antibiotic-resistant bacteria.