The main goal of this research was to develop a non-toxic, economical, and environmentally friendly process to synthesize cobalt ferrite (CoFe 2 O 4 ) nanoparticles via a green sol-gel auto-combustion route. An aqueous extract from the flower of Cyathocline purpurea was used as a novel bioreducing and stabilizing agent, representing the first application of this plant in the preparation of CoFe 2 O 4 nanoparticles. The aim was to investigate the multifunctionality of the synthesized nanoparticles for potential applications in nanomedicine, water purification, and antimicrobial activity. The green synthesized CoFe 2 O 4 nanoparticles were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible (UV–Vis) spectroscopy, vibrating sample magnetometry (VSM), dynamic light scattering (DLS), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX). XRD evidenced the development of a cubic spinel structure with nanocrystalline properties, while FTIR ensured metal–oxygen vibrations and plant functional groups on the surface. DLS showed a high hydrodynamic diameter of ∼340 nm and a near- neutral zeta potential. SEM micrographs showed a quasi-spherical morphology, and VSM analysis revealed a soft ferromagnetic behavior with a saturation magnetization of ∼28 emu/g. Functionally, the nanoparticles degraded methylene blue by 97.88% under visible light after 120 min. Antioxidant analysis using the DPPH assay revealed a dose-dependent radical scavenging activity of 91.99% to 97.29%. The antibacterial activity against B. subtilis, P. aeruginosa, and E. coli showed a stronger inhibition, especially against gram-negative bacteria. The putative antibacterial effect included membrane disruption, metal ion-mediated DNA damage, and reactive oxygen species (ROS) production. This research illustrates a novel, environmentally friendly synthesis of CoFe 2 O 4 nanoparticles from the flower extract of Cyathocline purpurea with multifunctional performance for biomedical and environmental applications. • Green sol–gel auto-combustion of CoFe 2 O 4 using Cyathocline purpurea extract. • Phase-pure spinel nanoparticles with controlled size. • Strong magnetic properties for easy recovery and biomedical use. • High photocatalytic efficiency for dye degradation. • Improved biocompatibility due to plant-based synthesis. • Low-cost, sustainable, and scalable method.
Harde et al. (Fri,) studied this question.