pH-Responsive Polymer-Stabilized ZIF-8 Nanocomposites for Fluorescence and Magnetic Resonance Dual-Modal Imaging-Guided Chemo-/Photodynamic Combinational Cancer Therapy

A multifunctional diagnosis and treatment integration platform is crucial in cancer treatments. Here, we show that by integrating Gd-doped silicon nanoparticles (Si-Gd NPs), chlorine e6 (Ce6), doxorubicin (DOX), zeolitic imidazolate framework-8 (ZIF-8), poly(2-(diethylamino)ethyl methacrylate) polymers (HOOC-PDMAEMA-SH), and folic acid-poly(ethylene glycol)-maleimide (MaL-PEG-FA) into one single nanoplatform by a self-assembly method, novel multifunctional MOFs (named FZIF-8/DOX-PD-FA) are synthesized with great biocompatibility and tumor targeting as well as pH responsiveness and no drug leakage for drug delivery. In the design, Si-Gd NPs and Ce6 embedded in the nanocomposites are used for magnetic resonance and fluorescence dual-modal imaging, respectively. DOX loaded by the FZIF-8/DOX-PD-FA porous structure is used for chemotherapy, while Ce6 is excited by near-infrared radiation (NIR) for photodynamic therapy. In addition, the pH-responsive ability of HOOC-PDMAEMA-SH to effectively prevent drug leakage is demonstrated by drug release studies in vitro. From the results of confocal microscopy imaging in vitro and fluorescence/magnetic resonance imaging in vivo, FZIF-8/DOX-PD-FA showed a targeting effect on MCF-7 cancer cells. More importantly, the results of treatment experiments on tumor-bearing mice showed that the tumor volume of the FZIF-8/DOX-PD-FA + NIR group is decreased the most compared to the original volume. Owing to the unique dual-modal imaging capability and excellent chemo-/photodynamic combinational cancer therapy effect, the present hybrid nanocarrier provides a new research platform for a new generation of theranostic nanoparticles.