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Updated: Feb 13, 2026

Direct Detection of Isolevuglandins in Tissues Using a D11 scFv-Alkaline Phosphatase Fusion Protein and Immunofluorescence
Published on: July 5, 2021
A dual-mode biosensor for alkaline phosphatase detection based on DCIP and Eu3+-calcein
Bingyu Fu1,2,3, Yanru Shao1, Zhixiong Zheng1
1College of Life Science, Yangtze University, Jingzhou, Hubei, 434025, China. xuqi@yangtzeu.edu.cn.
None:
In this study, a simple and sensitive dual-mode biosensor was designed based on the color of 2,6-dichloroindiphenol (DCIP) and the fluorescence of calcein. The target alkaline phosphatase (ALP) can catalyze the dephosphorylation of L-ascorbic acid-2-phosphate (AAP) to form ascorbic acid (AA) and phosphate ions. The reducing properties of AA can reduce DCIP from blue to colorless. Meanwhile, phosphate ions can chelate with europium ions (Eu3+) to restore the fluorescence of Eu3+-calcein. In colorimetric mode, the linear detection range for ALP was 1.56-50 U L-1, with a limit of detection (LOD) of 0.27 U L-1. In fluorescence mode, the linear detection range was 0.78-25 U L-1 and LOD was 0.23 U L-1. Besides, the selectivity of this dual-mode for ALP was excellent and the recovery rates in serum samples were also satisfactory.
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