Core-interlayer-shell Fe3O4@mSiO2@lipid-PEG-methotrexate nanoparticle for multimodal imaging and multistage targeted chemo-photodynamic therapy.

Multimodal imaging-guided multistage targeted synergistic combination therapy possesses many advantages including increased tumoricidal effect, reduced toxicity, and retarded drug resistance. Herein, we have elaborately developed a core-interlayer-shell structure Fe3O4@mSiO2@lipid-PEG-methotrexatenanoparticle(FMLM), in which the Fe3O4 core could be used for magnet-stimulate-response drug release, magnetic resonance imaging, and early-phase magnet targeting ability; the mSiO2 layer could encapsulate anticancer drug doxorubicin (Dox) for chemotherapy; and the protective shell of lipid-PEG and lipid-PEG-methotrexate offered later-phase specific cellular targeting ability, good water dispersibility, and loading of photosensitizer zinc phthalocyanine (ZnPc) for simultaneous near-infrared fluorescence imaging and photodynamic therapy. Both in vitro and in vivo studies indicated that the both Dox and ZnPc-loaded FMLM (Dox/ZnPc-FMLM) exhibited the enhanced tumor accumulation, increased cellular uptake, improved anticancer activity, and weaked side effects compared with Dox/ZnPc-Fe3O4@mSiO2@lipid-PEG nanoparticle (Dox/ZnPc-FML) and free drug. For the first time, magnet targeting cooperative with methotrexate macromolecular prodrug targeting is successfully exploited to develop a promising versatile theranostic nanoplatform for dual-modal fluorescence and magnetic resonance imaging-guided combined chemo-photodynamic cancer therapy.