A biodegradable MnSiO₃@Fe₃O₄ nanoplatform for dual-mode magnetic resonance imaging guided combinatorial cancer...

In this work, a tumor microenvironment (TME)-responsive biodegradable MnSiO₃@Fe₃O₄ nanoplatform for dual-mode magnetic resonance imaging (MRI)-guided combinatorial cancer therapy was constructed. Fe₃O₄ nanoparticles decorated on the surface of MnSiO₃ could effectively obstruct the pores of MnSiO₃ 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 Fe₃O₄ nanoparticles from the nanoplatform and rapid drug release. In addition, the exfoliated Fe₃O₄ and released Mn²⁺ can help reduce the interference between their T₁ and T₂ contrast abilities, resulting in dual-mode MRI contrast enhancement. Furthermore, during the exfoliation process of the Fe₃O₄ nanocrystals, the catalytic activity of the Fe₃O₄ 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 T₁-T₂ 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.