Fe Single-Atom Nanozymes for Real-Time Dual Monitoring of H2O2 Released from Living Cells

Excessive accumulation of hydrogen peroxide (H2O2) in the physiological pool can cause oxidative stress of cells and eventually lead to the occurrence of diseases. Therefore, accurate and real-time detection of H2O2 is of great significance for disease detection and prevention. In this study, an Fe single-atom nanozyme (Fe-SNC) with an Fe-N4 active center was synthesized, which showed excellent peroxidase-like activity in an acidic environment and amazing electrocatalytic activity in H2O2 reduction reaction. Based on this, we proposed a colorimetric and electrochemical dual-signal detection strategy to real-time monitor H2O2 secreted by living cells. Compared with single-signal response mode, double-signal response mode has higher precision and sensitivity. The results show that the detection range of the colorimetric analysis method is 3–1000 μM and the detection limit is 1.3 μM. The detection range of the electrochemical analysis method is 1–8127 μM, and the detection limit is 0.61 μM. We believe that the dual-signal detection strategy based on Fe-SNC not only provides a way for the ultra-sensitive detection of hydrogen peroxide but also has a broad application prospect in clinical diagnosis.