Catalase-imprinted Fe₃O₄/Fe@fibrous SiO₂/polydopamine nanoparticles: An integrated nanoplatform of magnetic targeting, magnetic resonance imaging, and dual-mode cancer therapy

Recent advances in the research on the molecular mechanism of cell death and methods for preparation of nanomaterials make the integration of various therapeutic approaches, targeting, and imaging modes into a single nanoscale complex a new trend for the development of future nanotherapeutics. Hence, a novel ellipsoidal composite nanoplatform composed of a magnetic Fe₃O₄/Fe nanorod core (~120 nm) enwrapped by a catalase (CAT)-imprinted fibrous SiO₂/ polydopamine (F-SiO₂/PDA) shell with thickness 70 nm was prepared in this work. In vitro experiments showed that the Fe₃O₄/Fe@F-SiO₂/PDA nanoparticles can selectively inhibit the bioactivity of CAT in tumor cells by the molecular imprinting technique. As a result, the H₂O₂ level in tumor cells was elevated dramatically. At the same time, the Fe₃O₄/Fe core released Fe ions to catalyze the conversion of H₂O₂ to ·OH in tumor cells. Eventually, the concentration of ·OH in tumor cells rapidly rose to a lethal level thus triggering apoptosis. Combined with the remarkable near-infrared light (NIR) photothermal effect of the CAT- imprinted PDA layer, the Fe₃O₄/Fe@F-SiO₂/PDA nanoparticles can effectively kill MCF-7, HeLa, and 293T tumor cells but are not toxic to nontumor cells. Furthermore, these nanoparticles show good capacity for magnetic targeting and suitability for magnetic resonance imaging (MRI). Therefore, the integrated multifunctional nanoplatform opens up new possibilities for high-efficiency visual targeted nonchemo therapy for cancer.