High-selective two-site fluorescent probe for Cys/SO 2 detection and cell imaging.

A fluorescent probe has been designed using cyanine phenothiazine and 7-nitro-1,2,3-benzoxadiazole (NBD) for selective detection of Cys-SO ₂ components. The probe utilizes the NBD structure to achieve specificity towards Cys and employs a reaction mechanism between the double bond of cyanine and phenothiazine with SO ₃ ^2- to achieve selectivity towards SO ₂ . Importantly, the NBPI phenothiazine structure incorporates a large C-O bond energy attached to NBD, effectively eliminating interference from Hcy and ensuring highly selective response to Cys. The optimized design of the probe enables excellent linearity and extremely low detection limits for Cys-SO ₂ components in vitro experiments. The probe NBPI allows separate detection of Cys-SO ₂ in the presence of both components. Furthermore, the probe NBPI demonstrated successful imaging of endogenous and exogenous Cys and SO ₂ in cell studies.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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