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In this work, a tumor microenvironment (TME)-responsive biodegradable MnSiO 3 @Fe 3 O 4 nanoplatform for dual-mode magnetic resonance imaging (MRI)-guided combinatorial cancer therapy was constructed. Fe 3 O 4 nanoparticles decorated on the surface of MnSiO 3 could effectively obstruct the pores of MnSiO 3 and reduce the leakage of anticancer drugs under physiological conditions. The structure of the nanoplatform was broken under the weakly acidic and high-concentration glutathione conditions in the TME, resulting in the separation of the Fe 3 O 4 nanoparticles from the nanoplatform and rapid drug release. In addition, the exfoliated Fe 3 O 4 and released Mn 2+ can help reduce the interference between their T 1 and T 2 contrast abilities, resulting in dual-mode MRI contrast enhancement. Furthermore, during the exfoliation process of the Fe 3 O 4 nanocrystals, the catalytic activity of the Fe 3 O 4 nanocrystals toward a Fenton-like reaction within cancer cells could be improved because of the increase in specific surface area, which led to the generation of highly toxic hydroxyl radicals and induced HeLa cell apoptosis. The nanoplatform also displayed excellent T 1 -T 2 dual-mode MRI contrast enhancement and anticancer activity in vivo with reduced systemic toxicity. Thus, this multifunctional nanoplatform could be a potential nanotheranostic for dual-mode MRI-guided combinatorial cancer therapy., (Copyright © 2018 Elsevier Ltd. All rights reserved.)