Wormwood-mediated green synthesis of iron oxide nanoparticles for antioxidant and antibacterial activities

For the first time, iron oxide nanoparticles (IONPs) with exceptional long-term stability at pH 7.6 were prepared using an aqueous Wormwood leaf extract. This unprecedented stability is of great importance in biomedical applications. The size and morphology of the iron oxide nanoparticles were studied using transmission electron microscopy (TEM), X-ray diffraction (XRD), zeta potential, and dynamic light scattering (DLS). Fourier transform infrared (FTIR) was used to identify the active functional groups in the extract that stabilized the iron oxide nanoparticles. Ultraviolet-visible (UV-Vis) spectroscopy showed a peak centered at 295 nm, confirming the successful preparation of iron oxide nanoparticles, which have stability of more than half a year. In this work, the stability of colloidal iron oxide nanoparticles was studied at different pH levels and temperatures, with a tendency to agglomerate at pH levels above 8.9 and below 6.5. The iron oxide nanoparticles had a size of 33 ± 2.5 nm, as determined by DLS analysis results. Furthermore, the zeta potential showed a positive charge of 44.32 mV, indicating excellent stability. Transmission electron microscopy (TEM) images revealed a spherical shape and a small size (17 ± 7.4 nm). The antioxidant activities were studied, and the results were 88.6% and 94.2% at the highest concentration (500 μg/mL) for both IONPs and aqueous artemisia extract, respectively. Furthermore, the IONPs exhibited good antibacterial properties against Staphylococcus aureus and Acinetobacter baumannii at concentrations (10, 30, and 60 μg/mL), better than the aqueous Wormwood extract at (0.0035 g/mL). The MIC was 30 μg/mL.