Hypoxia-activated ROS burst liposomes boosted by local mild hyperthermia for photo/chemodynamic therapy.

Abstract Single reactive oxygen species (ROS)-mediated therapy, photodynamic therapy (PDT) or chemodynamic therapy (CDT) is severely hindered in hypoxic solid tumor. Herein, to address the urgent challenge, a hypoxia-activated ROS burst liposome has been fabricated to achieve synergistic PDT/CDT that is initiated by the structural dissociation of poly(metronidazole) liposome in hypoxic tumor microenvironment (TME). The therapeutic enhancement of our ROS-blasting treatment is simultaneously regulated by external light-initiated PDT and endogenous iron oxide nanoclusters-triggered CDT, which is synergistically boosted and amplified by localized mild hyperthermia under 808/660 nm coirradiation. More importantly, in vitro and in vivo experiments demonstrate that electron-affinic poly(aminoimidazole) product from hypoxia-responsive transition of poly(metronidazole) polymers could efficiently enhance hypoxic cell apoptosis and induce solid tumor ablation. Thus, this work offers a potential hypoxia-activated ROS burst-PDT/CDT strategy with a superior antitumor efficacy, highlighting a promising clinical application.