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Updated: Nov 5, 2025

Ratiometric Imaging of Extracellular pH in Dental Biofilms
Published on: March 9, 2016
Ratiometric fluorescence sensor based on europium-grafted ZnO quantum dots for visual and colorimetric detection of
Wen-Jie Wu1, Qi Zhao2, Rui Zhou1
1Henan Key Laboratory of Diamond Optoelectronic Materials and Devices, Key Laboratory of Material Physics, Ministry of Education, School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450001, China.
Abstract:
An europium functionalized ZnO quantum dots (QDs) ratiometric fluorescent nanoprobe is designed to establish a real time, on-site visual, and highly sensitive probe method for tetracycline (TC). The yellow-emitting ZnO QDs serves as the internal reference, while the Eu3+ chelated on the surface of ZnO QDs is used as the signal reporting unit. This nanoprobe exhibits rapid response, excellent selectivity, and high sensitivity with a detection limit of 4 nM in detecting the levels of TC. In addition, fluorescence of the nanoprobe can change from yellow to red as the concentration of TC increases. Thus, naked eye detection of TC was realized using the test paper processed by nanoprobe, followed by RGB value analysis function on the mobile phone APP.

