Magnetic nanoparticles covalently immobilized on cell surfaces for localized magnetic hyperthermia

Abstract

Herein we report the use of biorthogonal click chemistry as a tool to immobilize magnetic nanoparticles (MNPs) and to localize magnetic hyperthermia on living cell membranes. The incorporation of azide reporters on cell membranes based on metabolic glycoengineering allows the “click” attachment of cyclooctyne-functionalized MNPs on cell membranes through strain-promoted [3+2] azide-alkyne cycloaddition (SPAAC). Hydrophobic 12 nm iron oxide MNPs were synthesized following by thermal decomposition and transferred to water by coating with a fluorescent amphiphilic polymer – poly (maleic anhydride-alt-1-octadecene), PMAO-TAMRA. The MNPs were further functionalized step-wise with polyethyleneglycol (PEG) to increase colloidal stability and with a strained alkyne at different percentages of the total reactive groups of the MNPs. Gel electrophoresis, thermogravimetric analysis and ζ-potential measurements confirmed the successful functionalization of the MNPs. In addition, confocal microscopy results revealed an effective covalent immobilization of MNPs on MCF-7 cell membranes at a 50% strained alkyne-functionalization. We are currently investigating the MH behaviour of the immobilized MNPs.