Gold nanoparticles doped metal-organic frameworks as near-infrared light-enhanced cascade nanozyme against hypoxic tumors

We report gold nanoparticles (AuNPs) doped iron-based metal-organic frameworks (GIM) which displays near-infrared light (NIR)-enhanced cascade nanozyme against hypoxic tumors. Due to the strong protein adsorption-induced surface passivation, AuNPs suffer from the loss of glucose oxidase (GOx) activity. However, GIM could protect the GOx-like activity of AuNPs with the satisfactory shield capability. In addition, GIM exhibited excellent photothermal conversion ability and unique NIR light-enhanced GOx-like activity, which could efficiently increase the endogenous H₂O₂ production. Meanwhile, as the produced H₂O₂ is converted by GIM into O₂ and highly toxic ⋅OH. Thus, GIM-catalyzed cascade reactions with NIR light irradiation not only offer the O₂ but also promote the reactive oxygen species (ROS) generation at tumor sites. The produced O₂ could be further applied to AuNPs catalytic oxidation of glucose and relieve hypoxic condition of tumor microenvironment (TME). As a proof-of-concept study, GIM demonstrates the admirable tumor ablation under NIR irradiation in vivo.