A copper response fluorescent probe for selective detection of GSH based on Nitrogen-doped carbon dots

A desirable ratiometric fluorescent probe (Nd-CDs) was applied to GSH detection, drug detection in real samples with tomato, blood serum and cell lysate leaves samples. • The double-emitting Nd-CDs were synthesized via facile hydrothermal approach with natural precursors. • A copper-responsive “off-on” based on Nd-CDs fluorescence probe to detect GSH. • Nd-CDs has been successfully detected with GSH in different real samples. Glutathione (GSH) is a biological sulfide that participates in various physiological processes. The development of highly sensitive and selective fluorescence sensing analysis methods is of extraordinary significance. As a natural precursor, green tea and fragrans were used to synthesize double-emitting N-doped carbon dots (Nd-CDs). Aimed to detect GSH, an “dual switch” fluorescent probe was constructed with copper ions (Cu 2+ ). The nanoprobe exhibits outstanding specificity and a linear range spanning from 0.1 to 100 μM in relation to Cu 2+ , accompanied by a limit of detection (LOD) of 14.5 nM. Due to the dynamic quenching process, the emission at 505 nm showed a special “turn-off” fluorescence sensing, while that at 436 nm was significantly elevated. Furthermore, GSH exhibits a strong attraction to the surface of Cu 2+ , leading to the formation of aggregates due to the chelating effect, resulting in fluorescence recovery of Nd-CDs with the sensing assay achieved a broad linear range of 0.1–80 μM and LOD 23.9 nM. Ultimately, the Nd-CDs@Cu 2+ fluorescent probe was effectively utilized for the determination of GSH in tomato, blood serum and cell lysates, indicating the potential applicability of the nanoprobe.