A facile approach to fabricate self-assembled magnetic nanotheranostics for drug delivery and imaging

Superparamagnetic iron oxide (SPIO) nanoparticles were extensively employed for theranostic applications, due to their good biocompatibility and excellent magnetic resonance imaging (MRI) properties. However, these particles typically require surface modification due to their hydrophobic surfaces caused by the oil-phase surfactants used in the fabrication and the drug loading on their surface is usually limited. Here, we provided a novel and facile approach to conveniently perform surface modification of SPIO while simultaneously loading a large amount of drug. By synthesizing an amphiphilic irinotecan-based compound, which hydrophobic tail enabled to insert into the SPIOs assembly, an excellent SPIO-based theranostic nanomedicine (SPIO@IR) was formed. The SPIO@IR can not only extensively improve the drug efficacy, but also enable to visualize themselves by MRI in the biological system.