Fe-Ni dual-single atoms nanozyme with high peroxidase-like activity for sensitive colorimetric and fluorometric dual-mode detection of cholesterol

Cholesterol is widely existed in nerve myelin sheath and various membrane structures, whose abnormal level would deteriorate human cells or even cause diseases. Herein, Fe-Ni dual-single-atom nanozyme was efficiently incorporated into N-doped carbon nanosheets (FeNi DSAs/N-CSs) by a simple calcination method. Its nanozyme activity and the catalytic mechanism were investigated in details. The FeNi DSAs/N-CSs nanozyme showed superior peroxidase-like property, which was applied for the dual-mode determination of hydrogen peroxide (H2O2) and cholesterol. The colorimetric/fluorometric assays of H2O2 displayed the linear ranges of 1 - 50mM and 5-40mM with low limit of detection 0.45mM and 3.33mM, respectively. In parallel, there exhibited the linear ranges of 0.5 - 5.0mM and 0.25-5.0mM for the colorimetric/fluorometric analysis of cholesterol, coupled with the limits of detection down to 0.19mM and 0.044mM, respectively. This work provided a rapid, cost-effectiveness and simple colorimetric/fluorometric method for sensitive dual-mode detection of cholesterol in human serum samples. [Display omitted] •The FeNi DSAs/N-CSs were fabricated by a simple pyrolysis strategy.•The FeNi DSAs/N-CSs showed superior intrinsic peroxidase-like activity.•The catalysis of nanozymes was due to the generated hydroxyl radicals from decomposition of self-generated H2O2.•The high nanozyme activity resulted from the synergistic catalytic effects of dual-single atoms.•FeNi DSAs/N-CSs nanozyme was used for the sensitive colorimetric/fluorometric assays for cholesterol.