Preparation and characterization of novel water-based biodegradable polyurethane nanoparticles encapsulating superparamagnetic iron oxide and hydrophobic drugs

Abstract

Superparamagnetic iron oxide nanoparticles (SPIO NPs) are widely used in magnetic resonance imaging and magnetic hyperthermia. In this study, we used the self-assembly behavior of biodegradable polyurethane nanoparticles (PU NPs) in water to encapsulate SPIO NPs (SPIO–PU NPs) or hydrophobic model drugs (drug–PU NPs) by an in situ method. PU NPs and SPIO–PU NPs were characterized by dynamic light scattering, transmission electron microscopy, infrared spectroscopy, and thermogravimetric analysis. The superparamagnetic property and magnetic heating ability of SPIO–PU NPs were assessed. PU NPs had no significant cytotoxicity and could be taken up by cells. SPIO–PU NPs were highly efficient in labeling cancer cells with cellular uptake of ∼16 pg iron per cell on average. Hydrophobic drugs were entrapped in PU NPs effectively and showed a sustained release profile. Upon heating, the release of drug was accelerated. This proof-of-concept study demonstrated a novel way to encapsulate SPIO and hydrophobic drugs in PU NPs with smart designs for potential applications in cancer diagnostics, hyperthermia, and chemotherapy.