Potent dual-mode hyperthermia and chemodynamic therapy triggered by smart magnetic ring-shaped nanozymes under switchable T1–T2 MRI navigation

• The multi-stimuli responsive nanozyme platform integrates a single hollow nanoring Fe 3 O 4 @MnO 2 @PDA that combines magnetothermal, photothermal, and chemodynamic therapy for enhanced tumor treatment. • Magnetic hyperthermia and photothermal therapy synergistically elevate tumor temperatures, achieving superior ablation when compared to single-mode hyperthermia. • The MnO 2 shell of the nanozyme platform decomposes under the tumor microenvironment, releasing Mn 2+ ions that generate hydroxyl radicals, thereby intensifying CDT with minimal off-target toxicity. • The Fe 3 O 4 core and MnO 2 shell of the nanozyme platform enable dual-modal MRI contrast enhancement, providing both T 2- weighted and T 1 -weighted MRI contrast, which improves tumor visualization and treatment monitoring. • In vivo validation with tumor-bearing mice demonstrated significant tumor reduction, along with excellent biocompatibility, minimal systemic toxicity, and efficient renal clearance, confirming the clinical translational potential of the nanozyme platform. Emerging nanotechnologies in cancer therapy increasingly highlight the importance of integrating therapeutic and diagnostic functions into a single platform for enhanced efficacy and real-time monitoring. Here, we present a vortex‐shaped nanoring Fe 3 O 4 @MnO 2 @PDA (polydopamine) engineered for dual‐mode T 1 – T 2 magnetic resonance imaging (MRI)‐guided, dual‐thermal, and Fenton‐like chemodynamic therapy (CDT). The ring‐shaped nano Fe 3 O 4 core provides magnetothermal hyperthermia, while the MnO 2 layer, acting as a responsive nanozyme, catalyzes endogenous H 2 O 2 to generate oxygen and bolster CDT. Meanwhile, the PDA coating efficiently absorbs near‐infrared light, amplifying photothermal effects for tumor ablation. Under dual‐heating conditions, the temperature rise rate (2.05–2.92 times) and final equilibrium temperatures (1.57–2.27 times) exceed those of single‐mode heating, underscoring a robust synergistic effect. Additionally, due to the shell’s shielding effect weakening T 2 signals and the tumor microenvironment enhancing T 1 relaxation, the T 1 (5.75 Mm −1 s −1 ) to T 2 (91.56 mM −1 s −1 ) ratio is optimized specifically at tumor sites, thus achieving effective dual‐modal MRI contrast. Moreover, the smart MnO 2 design not only furnishes dynamic imaging enhancements but also enables environment‐triggered Mn 2+ release, offering further diagnostic and therapeutic benefits. In vitro and in vivo evaluations confirm significant tumor suppression with minimal systemic toxicity. These findings position nanoring Fe 3 O 4 @MnO 2 @PDA as a promising dual‐mode MRI‐guided, dual‐thermal, and chemodynamic platform for advanced cancer therapy.