A Highly Selective Colorimetric Sensor for Cysteine Detection

• Autor(a) principal: Peng,Mengjiao
• Data de Publicação: 2020
• Outros Autores: Wang,Hui, Gibson,Gregory L., Shang,Hua, Yang,Jianmin, Chen,Yan, Lu,Yin
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532020000200305
• topic: fluorescent sensor; cysteine detection; colorimetric; high selectivity

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 CuII ion from the non-fluorescent a-CuII 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 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-CuII 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.