Redox-Responsive Cleavable Polymeric Brush Coated Magnetic Nanoparticles: Fabrication and Post-Polymerization Modification for Cellular Targeting

Polymer brush-coated magnetic nanoparticles find applications in areas from diagnostics to drug delivery. Generally, the brushes are irreversibly tethered onto the nanoparticle surface through robust chemical linkages to withstand diverse environments. The ability to trigger the release of the polymer brushes from the nanoparticle surface once they reach the intracellular environment would be a useful attribute. In this study, we report polymer brushes that undergo release from the nanoparticle surface in a redox-responsive fashion. Furthermore, cleaving the polymer brush also enables precise determination of their molecular weight. Also, we show that fluorescently labeled polymer brushes undergo chain-end functionalization using maleimide-containing dye and peptides. Installing integrin-targeting peptides onto the surface enhances their cellular internalization. One could envision that the redox-responsive polymer brush-coated magnetic nanoparticles disclosed here would be an attractive platform for applications where intracellular cleavage of polymeric chains would enhance their performance.