Fe3O4-silica core-shell nanoporous particles for high-capacity pH-triggered drug delivery

We demonstrate a one-step procedure for the synthesis of Fe3O4-silica core-shell nanoparticles with hierarchically ultra-large pores independent of any post-treatment such as annealing and template-molecule removal. The nanoporous silica shells with available amine groups were functionalized by clickable linkers to produce pH-sensitive amides for regulating the release of an anti-cancer drug, doxorubicin (DOX). The loading amount of DOX reached up to 13.2 mg per 100 mg nanoparticles, 74.2% of which can be effectively released after 63 h at body temperature and pH 5 with decreased side effects. Such excellent features of these nanoparticles appear to arise from the integrated hierarchically ultra-large open-porosities and a homogeneous dispersibility in aqueous solution that has a great potential for their use as drug delivery systems.