Construction of continuously enhanced fluorescent sensor for detection of glutathione in normal and cancer cells

In this paper, water-soluble cysteamine (CA)-capping CdSe quantum dots (CA-CdSe) could be used as a continuous fluorescent sensor. The CA-CdSe QDs can respond to Ag⁺ with a detection limit of 54.1 nM. Interestingly, CA-CdSe quantum dots combined with Ag⁺ to generate a new nano-fluorescence sensor-Ag⁺ modified CA-CdSe QDs (Ag⁺@CA-CdSe). Ag⁺@CA-CdSe can detect glutathione (GSH) with good sensitivity and anti-interference performance. The detection limit of Ag⁺@CA-CdSe fluorescenct sensor for GSH is as low as 0.74 μM. In addition, the novel nano-fluorescent sensor Ag⁺@CA-CdSe exhibited good cell permeability and was successfully applied to detect exogenous and endogenous GSH concentrations in cells. It could distinguish cancerous and normal cells by in vitro cell fluorescence imaging.