Micelle-like Nanoparticles for Drug Delivery and Magnetically Enhanced Tumor Chemotherapy.

Using the coordination bonds between transition metal atoms and electron-rich functional groups, we synthesized two kinds of micelle-like nanoparticles. Using magnetic Fe₃O₄ as the core, poly(methyl methacrylate) (PMMA) and poly(acrylic acid) (PAA) brushes were grafted via activators regenerated by electron transfer for atom transfer radical polymerization (ARGET-ATRP), which formed micelle-like magnetic nanoparticles Fe₃O₄/PAA-PMMA with a hydrophobic outer layer and Fe₃O₄/PMMA-PAA with a hydrophilic outer layer. Both the micelle-like nanoparticles had amphiphilic properties and can be used to load hydrophilic or hydrophobic drugs. Even loaded with hydrophobic drugs, the micelle-like nanoparticles can still be dispersed in aqueous solution, and Fe₃O₄/PAA-PMMA had a higher loading content. As the drug carrier, these two micelle-like nanoparticles can be used for magnetically targeted drug delivery and magnetic resonance imaging due to superparamagnetic Fe₃O₄. In addition, due to the magnetic retention effect, the drug-loaded micelle-like nanoparticles remained at the tumor site, increasing the local drug concentration. At the same time, the drug-loaded micelle-like nanoparticles generated a magnetocaloric effect under the alternating magnetic field, which not only killed tumor cells by magnetic hyperthermia but also promoted the rapid release of drugs at the tumor site. In general, magnetically enhanced chemotherapy showed the best therapeutic effect on tumors.