ROS generation strategy based on biomimetic nanosheets by self-assembly of nanozymes

Reactive oxygen species (ROS) play an important role in physiology and have been applied in tumor therapy. However, insufficient endogenous H2O2 and hypoxia in cancer cells can lead to limited ROS production and poor therapeutic efficacy. Herein, we develop a biomimetic nanosheet material based on the self-assembly of nanozymes that could supply H2O2 under acidic conditions and catalyze a cascade of intracellular biochemical reactions to produce ROS under both normoxic and hypoxic conditions without any external stimuli. In this system, the copper peroxide nanosheets (CPNS), which are pH-responsive, were prepared through coordination of H2O2 to Cu2+ and then modified using ultrafine Pt NPs to form CPNS@Pt. The CPNS could decompose under acidic conditions, allowing the simultaneous release of Fenton catalytic Cu2+ and H2O2 accompanied by a Fenton-type reaction between them. On the other hand, Pt NPs were also released. The released Pt NPs behave as an oxidase mimic and catalase mimic. In this way, the well-defined CPNS@Pt can not only relieve hypoxic conditions but also generate ROS to induce cell apoptosis, thereby paving the way for the development of a nanozyme with multienzyme activity as a therapeutic strategy.