Fe2B magnetic nanoparticles: synthesis, optimization and cytotoxicity for potential biomedical applications

Abstract

Crystalline iron boride (Fe2B) nanoparticles were successfully synthesized with magnesiothermic reduction reactions triggered by mechanochemical synthesis (MCS) and purified using selective hy-drochloric (HCl) acid leaching. Various parameters of MCS were investigated in detail to optimize the synthesis conditions. First, Fe2O3/B/Mg powder mixtures were blended and milled for various durations (up to 8 h) using a high-energy ball mill until Fe2B formation was complete. For the milling optimization, two different ball-to-powder weight ratios (BPRs) were employed: 10/1 and 15/1. Different sizes of milling balls as MCS media were used to investigate their effects on the Fe2B formation. After the MCS experiments, powders were purified with a 4 M hydrochloric acid (HCl) solution to leach out the MgO by-product phase and to obtain pure Fe2B particles. Based on all the optimization studies, Fe2O3/B/Mg powders milled for 6 h using one 4 14.3 mm ball and five 4 12.4 mm balls with a 10/1 BPR and purified were selected as ideal products. Microstructural, thermal, rheological and magnetic properties were determined for the optimum Fe2B nanoparticles. This optimum batch comprising pure Fe2B nano-particles (with an average size of 35 nm) was tested for biocompatibility (up to 72 h with 200 mg/mL) and specific absorption rate (SAR up to 55 & DEG;C) to evaluate its use in biomedical applications. The dose and time-dependent cytotoxicity of poly (acrylic acid) coated Fe2B nanoparticles (PAA-Fe2B) were investi-gated with cancerous HeLa, MCF7, A549 and MDA-MB-231 and healthy Vero E6 cells. PAA-Fe2B nano-particles were found to be cytocompatible with Vero E6 cells, HeLa and MCF7 cancer cells. The SAR value of the Fe2B nanoparticles was determined as 9.15 W/g, so the synthesis mechanism and some properties of Fe2B nanoparticles were successfully proposed for possible biomedical applications.