Synthesis, Magneto-structural Properties and Colloidal Stability Studies of Ni0.3Zn0.7Fe2O4 Nanoparticles Coated with Pluronic P123 Block Copolymer for Potential Biomedical Applications

Spinel Ni0.3Zn0.7Fe2O4 (NZFO) magnetic nanoparticles was prepared by the low temperature auto-combustion method using a glycine fuel-rich composition without any further heat treatment at high temperature. Subsequently, the synthesized MNPs were coated with Pluronic P123 (PP123) after its surface was functionalized with oleic acid (OA). The effect of the coatings on the morphology, structural and magnetic properties of NZFO nanoparticles was studied using powder X-ray diffraction (XRD), Fourier transform infrared, thermogravimetric analysis, field emission scanning electron microscopy (FE-SEM) and vibrating sample magnetometer (VSM). The colloidal behaviour of coated MNPs in physiological saline medium like water or phosphate buffer saline (PBS) was also studied by zeta potential measurements. XRD results showed the formation of cubic spinel crystalline phase with and without OA–PP123 coatings. Also, after OA–PP123 coating, the crystallite size (from Scherrer formula) decreases from 55 to 53 nm. However, an enlargement in the particle size and a reduction in agglomeration were observed from FE-SEM results when the nanoparticles were coated with OA–PP123. VSM measurements showed ferromagnetic behaviour at room temperature before and after coating. The colloidal stability study of the coated sample revealed a considerable high zeta potential value at physiological pH (7.4) highlighting its potential biomedical applications.