Intelligent Pore Switch of Hollow Mesoporous Organosilica Nanoparticles for High Contrast Magnetic Resonance Imaging and Tumor-Specific Chemotherapy

Hollow mesoporous organosilica nanoparticles (HMONs) are widely considered as a promising drug nanocarrier, but the loaded drugs can easily leak from HMONs, resulting in the considerably decreased drug loading capacity and increased biosafety risk. This study reports the smart use of core/shell Fe3O4/Gd2O3 (FG) hybrid nanoparticles as a gatekeeper to block the pores of HMONs, which can yield an unreported large loading content (up to 20.4%) of DOX. The conjugation of RGD dimer (R2) onto the DOX-loaded HMON with FG capping (D@HMON@FG@R2) allowed for active tumor-targeted delivery. The aggregated FG in D@HMON@FG@R2 could darken the normal tissue surrounding the tumor due to the high r(2) value (253.7 mM(-1) s(-1)) and high r(2)/r(1) ratio (19.13), and the intratumorally released FG as a result of reducibility-triggered HMON degradation could brighten the tumor because of the high r(1) value (20.1 mM(-1) s(-1)) and low r(2)/r(1) ratio (7.01), which contributed to high contrast magnetic resonance imaging (MRI) for guiding highly efficient tumor-specific DOX release and chemotherapy.

Automated summary

This study creatively utilized core/shell Fe3O4/Gd2O3 hybrid nanoparticles as gatekeepers for HMONs to achieve a large loading content of DOX, enabling active tumor-targeted drug delivery. The increased contrast provided by the modified nanoparticles in MRI guided highly efficient tumor-specific drug release and chemotherapy.