Multi-stimuli-responsive magnetic assemblies as tunable releasing carriers

A novel approach has been developed to prepare the magnetic micelles. Polyethylene glycol (PEG) and poly(N-isopropylacrylamide) (PNIPAM) are firstly attached on the surface of the magnetic nanoparticle via the host-guest inclusion between ferrocene groups (Fc) and beta-cyclodextrin (beta-CD). Then the resulting MNPs became amphiphilic in water above the LCST of PNIPAM and self-assembled into magnetomicelles with a size of 250 nm. These hybrid micelles show high loading capacity for anticancer drug (DOX) and high saturation magnetization simultaneously. Furthermore, these micelles could disassemble under the effects of oxidant or temperature, providing an opportunity to fine-tune the release properties of the encapsulated drug in response to temperature, H2O2 or pH independently, or a combined effect of multiple stimuli. Taking other advantages of magnetic carriers, such as high sensitivity to the external magnetic field, contrast effect to magnetic resonance, and magnetic hyperthermia, the micelles developed by this study show great potential application in cancer treatment.