Phytogenic fabrication of iron oxide nanoparticles and evaluation of their in vitro antibacterial and cytotoxic activity

Several metal-based nanoparticles (NPs) have been found to be toxic and are known to exert adverse health outcomes with irreversible side effects. This highlights the need to discover effective, stable, and biocompatible therapeutic components using natural sources. Here, a hexane extract of Nigella sativa seeds was used to synthesize iron oxide NPs (NS-IONPs) embedded with N. sativa phytoconstituents. The extract acted as a reducing agent that restricted the size of the NS-IONPs to 5–6 nm, signifying the potential to be cleared through the renal system. The fabricated NS-IONPs had a prominent effect on pathogenic gram-negative bacteria, E. coli (19.3 mm) and Salmonella typhi (14.2 mm) and lung cancer cells (lowest IC₅₀of 18.75 µg/mL) mainly by binding to the phospholipid components of the cell membrane. This resulted in cell shrinkage and further inhibited cell growth. Transmission electron microscopy analyses revealed that the mechanisms of cellular NP uptake varied depending on the cell type. Accumulation of NS-IONPs inside the cell increased BAX expression and arrested the cells at the G0/G1 phase, thereby conspicuously extending the G0 phase to initiate necrosis. Thus, these finding suggest that the synthesized NS-IONPs exhibited high antibacterial activity and effective cytotoxicity against cancer cell lines A549 and HCT116 compared to IONPs. The innovation of the current study is that the biogenic fabrication of IONPs is simple and cost effective results in stable nanomaterial, NS-IONPs with potential antibacterial and anticancer activity, which can be explored furthermore for various biomedical applications.