Micelle-like\nNanoparticles for Drug Delivery and Magnetically\nEnhanced Tumor Chemotherapy

Using the coordination bonds between transition metal\natoms and\nelectron-rich functional groups, we synthesized two kinds of micelle-like\nnanoparticles. Using magnetic Fe<sub>3</sub>O<sub>4</sub> as the core,\npoly(methyl methacrylate) (PMMA) and poly(acrylic acid) (PAA) brushes\nwere grafted via activators regenerated by electron transfer for atom\ntransfer radical polymerization (ARGET-ATRP), which formed micelle-like\nmagnetic nanoparticles Fe<sub>3</sub>O<sub>4</sub>/PAA–PMMA\nwith a hydrophobic outer layer and Fe<sub>3</sub>O<sub>4</sub>/PMMA–PAA\nwith a hydrophilic outer layer. Both the micelle-like nanoparticles\nhad amphiphilic properties and can be used to load hydrophilic or\nhydrophobic drugs. Even loaded with hydrophobic drugs, the micelle-like\nnanoparticles can still be dispersed in aqueous solution, and Fe<sub>3</sub>O<sub>4</sub>/PAA–PMMA had a higher loading content.\nAs the drug carrier, these two micelle-like nanoparticles can be used\nfor magnetically targeted drug delivery and magnetic resonance imaging\ndue to superparamagnetic Fe<sub>3</sub>O<sub>4</sub>. In addition,\ndue to the magnetic retention effect, the drug-loaded micelle-like\nnanoparticles remained at the tumor site, increasing the local drug\nconcentration. At the same time, the drug-loaded micelle-like nanoparticles\ngenerated a magnetocaloric effect under the alternating magnetic field,\nwhich not only killed tumor cells by magnetic hyperthermia but also\npromoted the rapid release of drugs at the tumor site. In general,\nmagnetically enhanced chemotherapy showed the best therapeutic effect\non tumors.