Carbon dots doped with nitrogen and sulfur and loaded with copper(II) as a “turn-on” fluorescent probe for cystein, glutathione and homocysteine

• Published in: Mikrochimica acta (1966) 2016-04, Vol.183 (4), p.1409-1416
• Main Authors: Guo, Ying, Yang, Lianli, Li, Wuwu, Wang, Xiaofang, Shang, Yonghui, Li, Baoxin
• Format: Article
• Language: English
• Subjects: Alfalfa; Analytical Chemistry; Carbon dots; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Copper; Copper compounds; Fluorescence; Garlic; Glutathione; Homocysteine; Investigations; Microengineering; Nanochemistry; Nanotechnology; Nitrogen; Original Paper; Quenching; Sulfur; Thiols
• ISSN: 0026-3672; 1436-5073
• DOI: 10.1007/s00604-016-1779-6

We report on the synthesis of fluorescent carbon dots doped with nitrogen and sulfur (N,S-CDs) via a hydrothermal process in pure water and starting from a mixture of alfalfa and garlic. Compared to N-doped CDs, the N,S-CDs exhibit a high fluorescence quantum yield (10 %) and a more longwave emission maximum (at 481 nm). The results also pave the way to tune the luminescence of CDs. The fluorescence of the N,S-CDs is quenched by Cu(II) ions but is recovered by addition of any of the biothiols cystein, glutathione or homocysteine. This turn-on effect was exploited to design a method for the quantification of these thiols in concentrations as low as 86 nM. The method was successfully applied to the determination of Cys in (spiked) human serum samples. Graphical Abstact Carbon dots doped with nitrogen and sulfur and loaded with copper(II) as a “turn-on” fluorescent probe for cystein, glutathione and homocysteine. Nitrogen and sulfur co-doped carbon dots with blue-green fluorescence are synthesized by one-step hydrothermal treatment of hybrid plant (alfalfa and garlic), and demonstrated as environmentally-friendly fluorescence probes for the sensing of biothiols with high sensitivity and selectivity.