Biomimetic CoO@AuPt nanozyme responsive to multiple tumor microenvironmental clues for augmenting chemodynamic therapy

Chemodynamic therapy (CDT), an emerging therapeutic strategy, has been recently exploited for in situ treatment through Fenton or Fenton-like reactions to generate cytotoxic reactive oxygen species (ROS). However, current systems rely significantly on the high local oxygen levels and strongly acidic conditions (pH = 3.0-5.0). Simultaneously, the produced ROS can be rapidly consumed by intracellular glutathione (GSH) in the electron transport chain. Herein, an original and biomimetic CoO@AuPt nanocatalyst was prepared based on the assembly of Au and Pt nanoparticles (NPs) on the surface of hollow CoO nanocapsules. The as-synthesized nanozyme exhibits extremely high stability under physiological conditions, whereas it undergoes spontaneous disintegration in the unique tumor microenvironment (TME). Subsequently, the decomposition products can catalyze a cascade of biochemical reactions to produce abundant ROS without any external stimuli. Thus, the present nanoplatform can increase intracellular ROS levels through continuous supply of H2O2, relief of local hypoxia and depletion of GSH, which result in remarkable and specific tumor damage both in vitro and in vivo. The findings of this study highlight the promising potential of CoO@AuPt nanocatalyst as a TME-responsive CDT nanomagnet for highly efficient tumor therapy.