A ratiometric fluorescence sensor for determination of choline based on gold nanoclusters and enzymatic reaction.

[Display omitted] • The enzymatic cascade increased the selectivity of the sensor and reduced the reaction time. • Gold nanoclusters were synthesized for internal calibration to improve the accuracy of the sensor. • The constructed ratiometric fluorescence sensor for choline detection has two linear ranges of 0.5–20 μM and 20–100 μM and low LOD of 0.27 μM. • The fluorescent sensor was successfully applied to the detection of choline in human serum. Choline (ChO) is a biomarker of many diseases. Its accurate and sensitive detection is of great significance for the diseases diagnosis. Gold nanoclusters with bovine serum albumin as template (BSA-AuNCs) were synthesized by microwave-assisted method. A ratiometric fluorescence sensor was constructed based on BSA-AuNCs and 2,3-diaminophenazine, which was the oxidation product of o-phenylenediamine. Combined with cascade enzymatic reaction, it was used for the detection of choline. In the detection system, choline oxidase improved the selectivity of detection, and the peroxidase-like activity of molybdenum disulfide nanosheets shortened the detection time. The linear ranges of choline detection by ratiometric fluorescence sensor were 0.5–20 μM and 20–100 μM. The detection limit was 0.27 μM. The ratiometric fluorescence sensor was easy to operate and had good selectivity. Compared with single signal sensor, it can effectively reduce the error interference such as environmental change, and the detection result was more accurate. [ABSTRACT FROM AUTHOR]