CO2-switchable drug release from magneto-polymeric nanohybrids

Abstract

CO₂-responsive well-defined core–shell–corona structure magnetic Fe₃O₄@SiO₂-poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) nanocarriers have been developed as efficient drug delivery systems. The hybrid magnetic nanoparticles (MNPs) demonstrated a sandwich structure and highly super-paramagnetic biocompatibility properties as well as gas-responsive behavior. We found that the hydrodynamic radius (R_h) of the magnetic hybrid nanoparticles could be adjusted by alternate CO₂/N₂ treatment driving a switchable volume transition from contraction to expansion because of the CO₂ responsiveness of PDMAEMA. The CO₂-triggered protonation of the polymer shell gives rise to an obvious zeta potential change of the nanoparticles. Importantly, the CO₂ induced reversible “on–off” transformation makes it possible to perform a dosage release of doxorubicin (DOX) in vitro in a time-controllable manner which is of great significance in controlled drug release. In the presence of CO₂, the drug release rate is significantly accelerated, while low drug release could be achieved by removal of CO₂ using N₂. Moreover, the in vitro cytotoxicity test indicated that the CO₂-responsive magnetic nanocarriers have good biocompatibility and could be safely used in living systems.