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.