Analytical Sciences

A Graphene Quantum Dots-Enzyme Hybrid System for the Fluorescence Assay of Alkaline Phosphatase Activity and Inhibitor Screening

Hui HUANG,*,** Bingdi WANG,*,** Meng CHEN,* Wenjing ZHANG,* Yongxin Li,*** and Zhenning LIU**

*College of Food Science and Engineering, Jilin University, Changchun 130025, China
**Key Laboratory of Bionic Engineering (Ministry of Education), College of Biological and Agricultural Engineering, Jilin University, Changchun 130022, China
***State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China

A graphene quantum dots (GQDs) and horse radish peroxidase (HRP) hybrid system was designed for the sensing of alkaline phosphatase (ALP) activity and inhibitor screening. We found that the photoluminescence (PL) intensity of GQDs could be quenched efficiently in the presence of phenol, H₂O₂ and HRP. Moreover, ALP could hydrolyze disodium phenyl phosphate (DPP) to produce phenol, and also could result in the photoluminescence quenching of GQDs. The decrease in the PL intensity was linear to the activity of ALP in the concentration range of 0.02 – 0.8 U/L, with a detection limit of 0.008 U/L. The proposed GQDs/HRP hybrid system was successfully applied to ALP determination in human serum samples. The inhibition study was further analyzed, and Na₃VO₄ (as an ALP inhibitor) showed a clear inhibition effect. The results suggest that the GQDs/HRP hybrid system has good potential applications for the assay of ALP activity and inhibitors screening in related biochemical fields.

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