The fabrication of ratiometric fluorescence sensor for tetracycline detection based on europium-doped polymer dots

The construction of an effective and sensitive sensing probe for tetracycline (TC) detection is meaningful and essential for the environment and food safety. Herein, an efficient ratiometric sensing platform of PDs/Eu³⁺ was developed through straightforward magnetic stirring of fluorescent polymer dots (PDs) and Eu³⁺. TC can cause blue fluorescence at 440 nm of PDs/Eu³⁺ to be quenched and red fluorescence emission at 617 nm increased by the internal filtration effect (IFE), static quenching and antenna effect (AE), which could be used as an ratiometric nanoprobe for the quantitative detection of TC with a lower limit of detection (LOD) of 15.1 nM. Additionally, real sample analysis of TC with higher accuracy and reliability demonstrated the practicability of the proposed sensor. Moreover, the combination of PDs/Eu³⁺-loaded carboxymethylcellulose (CMC) beads and smartphone offers practical value for convenient and visual detection of TC. Furthermore, owing to the stronger coordination between Al³⁺ and TC, the PDs/Eu³⁺-TC with red fluorescence emission returned to blue-green color emission after treating with Al³⁺. Thus a basic logic gate operation of "INHIBIT" and information storage were realized, indicating the great potential of information computing systems and displays.