Fe2O3-type iron oxide nanoparticles from Aerva lanata leaf extract exhibit antibiofilm, discriminatory toxicity in cancer cells, and theranostic against oxidative stress in zebrafish

• Phytogenic Fe NPs were crystalline, stable (-27 mV), and nanosized (30 – 40 nm) • Fe NPs exhibited a dose-dependent effect on biofilm damage by ROS-mediated oxidative stress • Fe NPs exhibited discriminatorily cytotoxicity in MDA-MB-231 cancer cells related to HEK-293 normal cells • Fe NPs showed theragnostic potential against H2O2-induced oxidative stress at 30 µg/mL in zebrafish embryos In the study, phytosynthesized iron oxide nanoparticles (Fe NPs) from Aerva lanata leaf extract. The phytosynthesized Fe NPs were characterized and assessed for multi-biofunctional features such as antioxidant, antibiofilm, and theranostic against oxidative stress in zebrafish embryos. UV-vis spectroscopy confirmed the phytosynthesis of Fe NPs and found λ max 390 nm. Fourier transform infrared spectroscopy (FTIR) revealed the role of A. lanata leaf extract in the synthesis of Fe NPs. Fe NPs exhibited crystalline in nature, stable (-27 mV zeta potential), and 91.8 d.nm. X-ray crystallography (XRD) revealed that Fe NPs were crystalline with a 26 nm size. The EC 50 value (concentration required to scavenge 50% of free radicals) of Fe NPs in ABTS and DPPH assay was 76.21 ± 1.39 and 81.53 ± 3.07 µg/mL, respectively. Fe NPs exhibited potential antibacterial activity against B. subtilis, E. coli, K. pneumoniae , and S. aureus by micro-well dilution technique. Fe NPs exhibited a dose-dependent effect on biofilm damage and reactive oxygen species (ROS)-mediated oxidative stress in bacteria. The live/dead assay revealed that Fe NPs-induced bacterial death by compromising the membrane integrity. The MTT cell viability assay and morphological observations revealed that Fe NPs discriminatorily induced cytotoxicity in MDA-MB-231 cancer cells (human breast cancer cell line) related to HEK-293 normal cells (human embryonic kidney cells). The IC 50 value of Fe NPs (concentration required to reduce 50% of cell viability) against MDA-MB-231 and HEK-293 cells was observed as 158.29 ± 4.78 and 187.08 ± 5.64 µg/mL, respectively. Fe NPs highly escalated the ROS and caspase-3 levels in cancer cells related to normal cells. Moreover, this is the first report to reveal the unique theranostic potential of A. lanata leaf extract-mediated synthesized Fe NPs against oxidative stress. They demonstrated that Fe NPs were highly selective in inducing oxidative-stress-mediated apoptosis in cancer cells. Fe NPs were found biocompatible up to 50 µg/mL in zebrafish embryos at 24, 48, 72, and 96 hours post fertilization (hpf). Moreover, Fe NPs showed amelioration potential against hydrogen peroxide-induced oxidative stress at 30 µg/mL. Thus, phytogenic Fe NPs may help reduce the biofilm formation of multidrug-resistant bacteria, a major problem today. Moreover, phytogenic Fe NPs are highly helpful in overcoming oxidative stress-mediated disorders like cancer, neurodegenerative, diabetes, inflammation, cardiovascular diseases, etc.