Colloidal Stability of Aqueous Suspensions of Polymer-Coated Iron Oxide Nanorods: Implications for Biomedical Applications

Abstract

Iron oxide nanorods are considered to be very promising platforms for biomedical applications, such as magnetic hyperthermia, magnetic resonance imaging, or immunoassays based on magnetooptical effects. However, their efficient colloidal stabilization is challenging, and colloidal aggregation could lead to the total loss of their performance. This work is focused on the synthesis and colloidal stabilization of iron oxide nanorods of an average length and diameter, L × d = 31 × 6 nm, synthesized by the hydrolysis of iron(III) salt, followed by reduction of the obtained akaganeite to iron oxide in a microwave reactor. Synthesized nanorods exhibited a weak ferrimagnetic behavior with remnant magnetization MR ∼ 3 emu/g and saturation magnetization MS ∼ 13 emu/g. The nanorods were dispersed in water after adsorption on their surface of three different polymers: linear bisphosphonate–poly(ethylene glycol) (PEG) molecules (denoted as OPT), polymethacrylate backbone/PEG side chains comb polymer (denoted as PCP; w...