Phyco-fabrication of iron oxide nanoparticles using Chlorella vulgaris: Antibacterial potential and antioxidant activity

Green microalgae are being used in innovative ways to synthesize nanoparticles and molecules that are viable for commercial applications. Recent advances in the eco-friendly biological generation of Fe2O3 NPs have significantly improved both their biological applicability and quality. In this study, Fe2O3 NPs were synthesized using Chlorella vulgaris (BUACC06) extract as a strong reducing and capping agent, and their formation was monitored by UV-visible spectroscopy, observing a characteristic peak at 416 nm. Subsequently, the synthesized Fe2O3 NPs were characterized for their shape, size, charge, crystallinity, purity, and functional groups using SEM, TEM, Zeta potential, XRD, EDX, and FT-IR analysis. Magnetic properties were also characterized through coercivity and magnetization measurements. The antimicrobial activity of the phyco-fabricated Fe2O3 NPs was evaluated against four Gram-positive and Gram-negative bacterial strains. Among them, Bacillus subtilis was found to be the most susceptible (ZOI: 18 mm), while Escherichia coli and Staphylococcus aureus showed the least susceptibility (ZOI: 16 mm). Furthermore, the antioxidant capacity of the phyco-fabricated Fe2O3 NPs was assessed through DPPH assays, yielding an IC50 of 19.76 μg mL-1. Their biocompatibility and protective effects on 3T3 and C6 cells were also assessed at different concentrations. In conclusion, our study revealed great biological potential of the phyco-fabricated Fe2O3 NPs, suggesting their promise for future in vitro and in vivo therapeutic studies.