Single-atom catalysts (SACs) have attracted extensive attention in the catalysis field because of their remarkable catalytic activity, gratifying stability, excellent selectivity, and 100% atom utilization. With atomically dispersed metal active sites, Fe-N-C SACs can mimic oxidase by activating O-2 into reactive oxygen species, O-2(-)center dot radicals. Taking advantages of this property, single-atom nanozymes (SAzymes) can become a great impetus to develop novel biosensors. Herein, the performance of Fe-N-C SACs as oxidase-like nanozymes is explored. Besides, the Fe-N-C SAzymes are applied ...