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A hydroxyphenylquinazolinone-based fluorescent probe DAP-1 with a large Stokes shift (162 nm) was firstly developed for detection of cysteine. The probe DAP-1 with two acrylate as highly Cys-selective sites was designed based on the combination of excited state intramolecular proton transfer (ESIPT) and aggregation-induced emission (AIE) mechanism. Upon the treatment with cysteine, DAP-1 displayed a strong fluorescence enhancement (65-fold). The limit of detection obtained from fluorescent titration was as low as 0.03 μM. DAP-1 could detect cysteine with high selectivity and sensitivity. Significantly, DAP-1 could be used to detect cysteine in living cells. [ABSTRACT FROM AUTHOR]

A novel 4′-hydroxybiphenyl-4-carbonitrile-based fluorescent probe, 1 , for selective detection of cystein (Cys) over homocystein (Hcy) and glutathione (GSH) was developed. This probe had simple structure and could be easily synthesized with good yield from commercially available materials. Moreover, probe 1 showed a remarkable large Stokes shift (180 nm) and displayed a rapid (5 min) and highly sensitive response (the detection limit was 0.15 μM) for Cys with fluorescence turn-on signal changes (142-fold fluorescence enhancement). Importantly, probe 1 could be used to detect and image both exogenous and endogenous Cys in living A549 cells. [ABSTRACT FROM AUTHOR]