DNA-scaffold copper nanoclusters integrated into a cerium(III)-triggered Fenton-like reaction for the fluorometric and colorimetric enzymatic determination of glucose
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A fluorometric and colorimetric method are described for the determination of hydrogen peroxide and glucose by integrating copper nanoclusters (CuNCs) into a Fenton-like reaction. The mechanism mainly depends on the fast formation of long-strand DNA-templated CuNCs with strong red fluorescence (with excitation/emission maxima at 340/640 nm) in the absence of H2O2. The DNA can be cleaved into short-oligonucleotide fragments by hydroxy radicals as formed in the Ce(III)-triggered Fenton-like reaction in the presence of H2O2. As a result, short-strand DNA loses the ability as a template for the formation of CuNCs. This leads to a decrease of fluorescence. The colorimetric assay, in turn, is based on the oxidation of colorless Ce(III) ions to the distinctly yellow Ce(IV) ions (with an absorption maximum at 400 nm) by H2O2. Compared with those assays based on the use of enzyme mimics, this method does not require any chromogenic substrates such as ABTS and TMB. Based on the dual-signal readout platform, we successfully achieved the detection of H2O2 and glucose. LODs are as low as 0.266 μM and 2.92 μM. The methods were applied to the sensitive determination of glucose by using glucose oxidase (GOx) which catalyzes the oxidization of glucose to produce H2O2. The practical application was demonstrated by determination of glucose in human serum, with apparent recoveries of 98.4–101.9% and 99.1–105.6%, respectively. The concentration of glucose ranges from 1 to 500 μM and 50 to 600 μM based on the dual-signal readout platform, respectively. This fluorometric and colorimetric dual-mode strategy will pave a new avenue for constructing effective assays for H2O2-related analytes in biochemical and clinical applications.
KeywordsDNA-templated CuNCs Fenton-like reaction Dual-signal readout Glucose assay Enzymatic reaction Polythymine Glucose oxidase Hydroxyl radical Visual detection
The authors gratefully acknowledge the National Natural Science Foundation of China (Grant No. 21775087), Beijing Natural Science Foundation (Grant No. 2162010), and Scientific Research Project of Beijing Educational Committee (Grant No. KM201610028008), and Cross-Disciplinary Research Project of Capital Normal University.
Compliance with ethical standards
Conflict of interest
The authors declare no competing financial interest.
- 6.Chen S, Zheng H, Wang J, Hou J, He Q, Liu H, Xiong C, Kong X, Nie Z (2013) Carbon nanodots as a matrix for the analysis of low-molecular-weight molecules in both positive-and negative-ion matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and quantification of glucose and uric acid in real samples. Anal Chem 85:6646–6652CrossRefGoogle Scholar
- 19.Liu W, Ding F, Wang Y, Mao L, Liang R, Zou P, Wang X, Zhao Q, Rao H (2018) Fluorometric and colorimetric sensor array for discrimination of glucose using enzymatic-triggered dual-signal system consisting of Au@Ag nanoparticles and carbon nanodots. Sens Actuators B Chem 265:310–317CrossRefGoogle Scholar