Design, synthesis, characterization and biological evaluation of cobalt-ferrite nanoparticles for biomedical applications

Cobalt-Ferrite nanoparticles (CF NPs) are increasingly used in biomedical applications due to their unique magnetic properties and biocompatibility. In this study, CF NPs were synthesized via co-precipitation, both in the presence and absence of oleic acid (OA) as a surfactant. Plackett-Burman Design was employed to study the influence of reaction conditions on the particle size distribution of bare and OA-coated CF NPs. Representative bare and OA-coated CF NP samples were characterized for morphology, composition, thermal stability, and optical and magnetic properties using TEM, XRD, FTIR, TGA, UV–Vis, and VSM. The highest saturation magnetization value (∼44 emu/g) was observed for bare CF NPs of smaller sizes. MTT assay results indicated that none of the tested samples showed significant cytotoxicity at the concentrations tested (1, 10, and 100 µg/mL), except for the bare CF NPs, which reduced viability of A549 cells to approximately 50 % following 72-hour exposure at 100 µg/mL. Following incubation in a cell culture medium for 48 h, proteins bound to the surface of CF NPs were analyzed using SDS-PAGE, revealing bovine serum albumin, apolipoprotein A-I and fibronectin as the most abundant proteins across samples. Overall, OA-coating slightly improved colloidal stability and reduced cytotoxicity, without significantly compromising the magnetic or protein-binding properties.