Photo-induced tumor therapy using MnO₂/IrO₂-PVP nano-enzyme with TME-responsive behaviors

In this research, MnO₂/IrO₂ nanoplatform was one-step synthesized from the heat-induced oxidation-reduction between potassium permanganate and iridium chloride and modified with polyvinylpyrrolidone (PVP) on the surface to obtain MnO₂/IrO₂-PVP nanoparticles (MIP NPs) with excellent colloidal stability of biocompatibility. Then, the photosensitizer Chlorin e6 (Ce6) was loaded onto the surface of MIP NPs. The IrO₂ can efficiently transform the 808 nm near-infrared laser into heat with a photothermal conversion of 27.57 % for tumor photothermal therapy. Interestingly, the MnO₂ can not only react with the redundant H⁺ and realize the magnetic resonance imaging of the tumor but also catalytic the decomposition of H₂O₂ in the tumor to generate O₂ and relieve the hypoxia status of the tumor. The in-situ formed O₂ can promote the production of cancer cell-toxic singlet oxygens (¹O₂) under the irradiation of 660 nm laser and boost the tumor photodynamic therapy efficiency. Moreover, it was found that PVP can fall off from the MIP NPs to increase their accumulation in the tumor. Such a MIP/Ce6-based nanoplatform which plays the synergism with tumor microenvironment shows promising potential for the combined photo-therapy of the tumor.