Phyto-mediated synthesis of Ni-Fe bimetallic nanoparticles using Abrus precatorius for antioxidant, antimicrobial and photocatalytic dye degradation applications.

The development of sustainable nanomaterials through green synthesis has emerged as a promising strategy for biomedical and environmental applications. In this study, bimetallic Ni-Fe nanoparticles (NPs) were synthesized via an eco-friendly approach using aqueous seed extract of Abrus precatorius as a natural reducing and stabilizing agent. The UV-visible spectroscopy confirmed nanoparticle formation with characteristic absorption peaks at 257 and 278 nm. The FTIR analysis revealed the involvement of hydroxyl, carbonyl and phenolic functional groups in nanoparticle stabilization, while SEM and DLS analyses demonstrated predominantly cuboidal morphology with an average hydrodynamic diameter of 308 nm (PDI = 0.347). The green-synthesized Ni-Fe NPs exhibited significant dose-dependent antioxidant activity, showing 37% DPPH scavenging, 34% hydrogen peroxide scavenging and 45% hydroxyl radical inhibition at 250 µg/mL, along with a FRAP absorbance of 0.22. Broad-spectrum antimicrobial activity was observed against Gram-positive (Staphylococcus aureus, Bacillus subtilis), Gram-negative (Escherichia coli, Klebsiella pneumoniae) and fungal (Aspergillus niger) strains. Furthermore, photocatalytic studies demonstrated efficient degradation of methyl orange dye, achieving 43% degradation after 6 h under solar irradiation at 125 µg/mL. The multifunctional performance of these green-synthesized Ni-Fe NPs highlight their potential for integrated biomedical and environmental remediation applications.