A Highly Selective Colorimetric Sensor for Cysteine Detection

Mengjiao Peng, Hui Wang, Gregory Gibson, Hua Shang, Jianmin Yang, Yan Chen, Yin Lu
2019 Journal of the Brazilian Chemical Society  
Introducing a hybrid xanthene as a fluorophore, an 'ensemble'-based fluorescent sensor (E)-2-(6-(diethylamino)-2-((2-hydroxyphenylimino)methyl)-3-oxo-3H-xanthen-9-yl)benzoic acid (a) was designed and synthesised for detection of cysteine. Cysteine can release Cu II ion from the non-fluorescent a-Cu II complex. Then hydrolytic cleavage of Schiff base a produces a pink fluorescent compound 2-(6-(diethylamino)-2-formyl-3-oxo-3H-xanthen-9-yl)benzoic acid (2). We call this process a fluorescence
more » ... a fluorescence off-on change. An obvious color change from purple a to pink 2 can be easily observed by the naked-eye. The calibration curve showed that the fluorescence intensity at 560 nm linearly increased over the cysteine concentration range of 0.379-100 μmol L -1 with a limit of detection of 0.379 μmol L -1 . Sensor a-Cu II displayed excellent selectivity for cysteine, even homocysteine and glutathione did not show influence. The sensor was also used for detecting cysteine in human breast adenocarcinoma cells, which illustrates the practical value. Overall, the sensor appears to be useful for rapid, convenient and selective cysteine detection in living tissues.
doi:10.21577/0103-5053.20190177 fatcat:6cp7exi7hngxdolzxm2wx27mhi