Recently, researchers with Institute of Solid State Physics, Hefei Institutes of Physical Science constructed a dual-response ratiometric fluorescent sensor for visual and colorimetric detection of tetracycline.

Antibiotics play an important role in human health protecting. However, everything has its two sides and so do antibiotics since its abuse may put humans at risk. And long-term consumption of foods with antibiotic residues will increase human body’s resistance of bacteria as well as the risk of developing chronic diseases.

To tackle the problem, scientists have been trying to work out a fast, simple, real-time and visual method to detect antibiotics. The dual-response ratiometric fluorescent sensor has been taken into their consideration for it has advantages in real-time antibiotic detection. Only with the help of ultraviolet lamp rather than large-scale experimental equipment, can it present visual multi-color changes. In addition, compared with the single-color fluorescent probe, the dual-response ratiometric fluorescent sensor could eliminate the fluorescence intensity fluctuation caused by external factors such as external environment and instrument efficiency through self-calibration, then improving the accuracy of detection.

The team based on dual-response fluorescent quantum dot ratiometric sensor to achieve visual quantitative detection of tetracycline (TC).

In the work, the team tried to provide a dual-response visual detection strategy for wide-chromaticity of TC through the functional modification of water-soluble cadmium telluride quantum dots (CdTe QDs) by europium ions (Eu³⁺ ), the specific recognition of TC by Eu³⁺ and the enhanced fluorescence of Eu³⁺ caused by the charge transfer of CdTe QDs.

When the target detection substance TC was added, the probe fluorescence changed from green to yellow, and finally to red. The fluorescence intensity ratio I ₆₁₆/I₅₁₂ of the Eu/CdTe QDs sensor at 616 nm and 512 nm had a good linear relationship with the TC concentration in the range of 0-80 μM, and its detection limit (LOD) reached 2.2 nM.

The sensor was successfully used for rapid on-site detection of tap water samples and milk samples showing the wide applicability in pursuing the concepts simple, rapid, visual, and real-time for food safety and environmental protection.

This work was financially supported by National Natural Science Foundation of China (Nos, 21876175, 21605144, 21806168), National Basic Research Program of China (2015CB932002) and Key Research and Development Program of Anhui Province (1804a07020103).

Link to the paper: A dual-response ratiometric fluorescent sensor by europium-doped CdTe quantum dots for visual and colorimetric detection of tetracycline

Schematic diagram of visual detection of tetracycline based on dual-response quantum dot ratiometric fluorescent sensor. (Image by HAN Shuai)

Contact:

ZHOU Shu

Hefei Institutes of Physical Science (http://english.hf.cas.cn/)

Email: zhous@hfcas.ac.cn