A cobalt-doped iron oxide nanozyme as a highly active peroxidase for renal tumor catalytic therapy

摘要

The Fe _(3) O _(4) nanozyme, the first reported nanozyme with intrinsic peroxidase-like activity, has been successfully employed for various diagnostic applications. However, only a few studies have been reported on the therapeutic applications of the Fe _(3) O _(4) nanozyme partly due to its low affinity to the substrate H _(2) O _(2) . Herein, we report a new strategy for improving the peroxidase-like activity and affinity of the Fe _(3) O _(4) nanozyme to H _(2) O _(2) to generate reactive oxygen species (ROS) for kidney tumor catalytic therapy. We showed that cobalt-doped Fe _(3) O _(4) (Co@Fe _(3) O _(4) ) nanozymes possessed stronger peroxidase activity and a 100-fold higher affinity to H _(2) O _(2) than the Fe _(3) O _(4) nanozymes. The lysosome localization properties of Co@Fe _(3) O _(4) enable Co@Fe _(3) O _(4) to catalyze the decomposition of H _(2) O _(2) at ultralow doses for the generation of ROS bursts to effectively kill human renal tumor cells both in vitro and in vivo . Moreover, our study provides the first evidence that the Co@Fe _(3) O _(4) nanozyme is a powerful nanozyme for the generation of ROS bursts upon the addition of H _(2) O _(2) at ultralow doses, presenting a potential novel avenue for tumor nanozyme catalytic therapy.