A multifunctional mesoporous nanocontainer with an iron oxide core and a cyclodextrin gatekeeper for an efficient theranostic platform

We report on the dual function of a silica-iron oxide hybrid nanoparticle combined with a stimulus responsive gatekeeper on the surface. Multifunctional hybrid nanoparticles (Fe@Si-DOX-CD-PEG) composed of an Fe3O4 core, a mesoporous silica shell, and GSH-responsive CD gatekeepers are an excellent platform for anticancer drug delivery and MR imaging. In particular, the CD gatekeepers on the surface of the hybrid nanoparticle play a key role in accommodating anticancer drug molecules in the pore of the silica shell without premature release until CD gatekeepers are cleaved by GSH. We confirmed, from an in vitro study with the A549 cell line, that DOX was released from the internalized carriers due to GSH-mediated cleavage of the CD gatekeeper. Consequently, apoptotic and clonogenic death occurred in the cells treated with Fe@Si-DOX-CD-PEG. The accumulation of Fe@Si-DOX-CD-PEG in the tumors was detected by in vivo MR imaging. The growth of the tumor in vivo was effectively suppressed by the intravenously injected Fe@Si-DOX-CD-PEG. In addition, the results of the in vivo MR imaging reflected the in vivo inhibition of the cancer growth by Fe@Si-DOX-CD-PEG.