Specific enzymatic synthesis of 2,3-diaminophenazine and copper nanoclusters used for dual-emission ratiometric and naked-eye visual fluorescence sensing of choline

This work demonstrates a novel, facile and efficient biosensor for dual-emission ratiometric and visual fluorescence detection of choline. Copper nanoclusters (CuNCs) were prepared by using N 2 H 4 ·H 2 O as the reducing agent and lysozyme as the stabilizer, based on an ambient hydrothermal method....

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Bibliographic Details
Published in:New journal of chemistry 2018, Vol.42 (21), p.17323-17330
Main Authors: Bu, Xiangning, Fu, Yongxin, Jin, Hui, Gui, Rijun
Format: Article
Language:English
Subjects:
Biosensors
Choline
Copper
Emission
Fluorescence
Hydrogen peroxide
Lysozyme
Nanoclusters
Oxidase
Oxidation
Peroxidase
Phenylenediamine
Reducing agents
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Summary:This work demonstrates a novel, facile and efficient biosensor for dual-emission ratiometric and visual fluorescence detection of choline. Copper nanoclusters (CuNCs) were prepared by using N 2 H 4 ·H 2 O as the reducing agent and lysozyme as the stabilizer, based on an ambient hydrothermal method. The prepared CuNCs were blue-emitting and showed an emission peak centered at 440 nm. In the mixture system consisting of CuNCs, choline oxidase, horseradish peroxidase (HRP) and o -phenylenediamine (OPD), the added choline was catalyzed by choline oxidase to generate H 2 O 2 . OPD was oxidized by H 2 O 2 and HRP to generate 2,3-diaminophenazine (DAP). As the oxidation product of OPD, DAP emitted a fluorescence peaked at 550 nm and the fluorescence exhibited a regular enhancement with the increase of the choline concentration. Meanwhile, the fluorescence of the CuNCs was reduced by DAP due to an internal filtration effect-induced fluorescence quenching. There is an optimal linear relationship ( r = 0.9992) between the ratiometric fluorescence intensity ( I DAP / I CuNCs , I 550 / I 440 ) and the choline concentration in the range of 0.1–80 μM, with a low limit of detection of 25 nM. The response of I DAP / I CuNCs to choline was sensitive and selective over potential interferents existing in real samples. This developed sensor enabled the naked-eye visual detection of choline in aqueous solutions and on immersed filter papers. In human serum and liquid milk samples, this sensor showed a superior performance for choline detection.
ISSN:1144-0546
1369-9261
DOI:10.1039/C8NJ03927E