Tumor-Targeting Multifunctional Rattle-Type Theranostic Nanoparticles for MRI/NIRF Bimodal Imaging and Delivery of Hydrophobic Drugs

The development of theranostic systems capable of diagnosis, therapy, and target specificity is considerably significant for accomplishing personalized medicine. Here, a multifunctional rattle-type nanoparticle (MRTN) as an effective biological bimodal imaging and tumor-targeting delivery system is fabricated, and an enhanced loading ability of hydrophobic anticancer drug (paclitaxel) is also realized. The rattle structure with hydrophobic Fe 3 O 4 as the inner core and mesoporous silica as the shell is obtained by one-step templates removal process, and the size of interstitial hollow space can be easily adjusted. The Fe 3 O 4 core with hydrophobic poly(tert-butyl acrylate) (PTBA) chains on the surface is not only used as a magnetic resonance imaging (MRI) agent, but contributes to improving hydrophobic drug loading amount. Transferrin (Tf) and a near-infrared fluorescent dye (Cy 7) are successfully modified on the surface of the nanorattle to increase the ability of near-infrared fluorescence (NIRF) imaging and tumor-targeting specificity. In vivo studies show the selective accumulation of MRTN in tumor tissues by Tf-receptor-mediated endocytosis. More importantly, paclitaxel-loaded MRTN shows sustained release character and higher cytotoxicity than the free paclitaxel. This theranostic nanoparticle as an effective MRI/NIRF bimodal imaging probe and drug delivery system shows great potential in cancer diagnosis and therapy.