Ultrasmall iridium-encapsulated porphyrin metal-organic frameworks for enhanced photodynamic/catalytic therapy by producing reactive oxygen species storm.

Transition metal-coordinated porphyrin metal-organic frameworks (MOFs) were perspective in photodynamic therapy (PDT) and catalytic therapy. However, the tumor hypoxia and the insufficient endogenous hydrogen peroxide (H ₂ O ₂ ) seriously limited their efficacies. Herein, by encapsulating ultrasmall iridium (Ir) and modifying glucose oxidase (GOx), an iron-coordinated porphyrin MOF (Fe-MOF) nanoplatform (Fe-MOF@Ir/GOx) was designed to strengthen PDT/catalytic therapy by producing reactive oxygen species (ROS) storm. In this nanoplatform, Fe-MOF showed glutathione (GSH)-responsive degradation, by which porphyrin, GOx and ultrasmall Ir were released. Moreover, ultrasmall Ir possessed dual-activities of catalase (CAT)-like and peroxidase (POD)-like, which provided sufficient oxygen (O ₂ ) to enhance PDT efficacy, and hydroxyl radical (·OH) production was also improved by combining Fenton reaction of Fe ²⁺ . Further, GOx catalyzed endogenous glucose produced H ₂ O ₂ , also reduced pH value, which accelerated Fenton reaction and resulted in generation of ROS storm. Therefore, the developed Fe-MOF@Ir/GOx nanoplatform demonstrated enhanced PDT/catalytic therapy by producing ROS storm, and also provided a promising strategy to promote degradation/metabolism of inorganic nanoplatforms.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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