Functional responsive superparamagnetic core/shell nanoparticles and their drug release properties

Abstract

The preparation of responsive superparamagnetic iron oxide (SPIO) nanoparticles (NPs), able to carry the anticancer drug doxorubicin (DOX) and to release it in physiological media at the physiological temperature, is one of the major challenges in nanomedicine. In this work, two families of NPs were synthesized. The first one consists of superparamagnetic Fe₃O₄ NPs functionalized via covalent grafting by a biocompatible responsive copolymer based on 2-(2-methoxy)ethyl methacrylate (MEO₂MA) and oligo(ethylene glycol) methacrylate (OEGMA). The second one consists of the same core/shell NPs but folic acid, a biological cancer targeting molecule, was grafted at the polymer chain end. The core/shell NPs were fully characterized by the combination of spectroscopic and microscopic techniques. The influence of the polymer chain structure in water and in physiological media was studied. We demonstrate that the magnetic properties of the NPs were only influenced by the amount of the grafted polymer and no influence of NP aggregation was evidenced. Indeed, the derived nanostructured materials displayed a combination of the physical properties of the core and the macromolecular behavior of the shell. The drug release experiments confirmed that DOX was largely released above the co-polymer LCST due to the presence of DOX. The nanomaterials developed in this work have high potential as multi-modal cancer therapy tools.