Synthesis of catalytically active peroxidase-like Fe-doped carbon dots and application in ratiometric fluorescence detection of hydrogen peroxide and glucose

摘要

In this study, we have presented a novel strategy to fabricate fluorescent Fe-doped carbon dots (Fe-CDs) by one-step hydrothermal carbonization, using methylthymol blue sodium salt (MTB) and FeCl3 center dot 6H(2)O as precursors. Multiple techniques were employed to characterize the properties of the obtained Fe-CDs. Importantly, the intrinsic peroxidase-like activity of the Fe-CDs was explored. Through catalyzing the oxidization of o-phenylenediamine (OPD) by hydrogen peroxide (H2O2), the Fe-CDs exhibited a superior catalytic performance over horseradish peroxidase (HRP) attributed to the doped Fe elements in the Fe-CDs. By the combination of favorable fluorescence properties and excellent catalytic activities, Fe-CD based ratiometric fluorescence sensing systems toward H2O2 and glucose have been designed in view of the inner filter effect (IFE) between Fe-CDs and 2,3-diaminophenazine (DAP, the oxidation product of OPD). Such responses can be used for well quantifying H2O2 and glucose in the ranges of 0-133 mu M and 0-300 mu M with detection limits of 0.47 and 2.5 mu M (S/N = 3), respectively. The proposed sensing system has been successfully used for the assay of glucose in human serum samples, indicating great promise as a practical platform for blood glucose sensing.