Copper ion plays an important role in many biological processes in human body. H₂S is considered as the third gasses transmitter after carbon monoxide and nitric oxide. Here a novel ICT-based fluorescent ON-OFF-ON probe for Cu²⁺ and H₂S detection was developed. Selectivity and sensitivity of probe was confirmed in aqueous Tris-HCl buffer (10 mM, pH 7.4, containing 90% acetonitrile). Probe DF-CU shows high selectivity over other analytes. The degree of fluorescence quenching is linearly associated with the concentration of Cu²⁺ (R² = 0.9919). The limit of detection (LOD, calculated according to the 3σ/slope) for Cu²⁺ was 6.4 μM. Probe can work in almost all pH. The probe shows a very fast response to Cu²⁺ (within 10 s). Its response to copper ion could be reversed by H₂S. The complex of probe with Cu²⁺ could be used for H₂S detection. Furthermore, this ON-OFF-ON fluorescent probe successfully applied in the living cells for the detection of Cu²⁺ and H₂S.

中文翻译：

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基于香豆素的可逆荧光探针，用于选择性检测活细胞中的 Cu2+。

铜离子在人体内的许多生物过程中起着重要作用。H ₂ S被认为是继一氧化碳和一氧化氮之后的第三种气体传递体。这里开发了一种用于 Cu ²⁺和 H ₂ S 检测的新型基于 ICT 的荧光 ON-OFF-ON 探针。在水性 Tris-HCl 缓冲液（10 mM，pH 7.4，含有 90% 乙腈）中确认探针的选择性和灵敏度。探针 DF-CU 显示出比其他分析物高的选择性。荧光猝灭的程度与Cu ²⁺的浓度呈线性相关(R ²  = 0.9919)。^{Cu 2+}的检出限（LOD，按3σ/斜率计算）为 6.4 μM。探头几乎可以在所有 pH 值下工作。^{该探针对 Cu 2+}显示出非常快的响应（10 秒内）。其对铜离子的响应可被H ₂ S逆转。探针与Cu ²⁺的络合物可用于H ₂ S的检测。此外，该ON-OFF-ON荧光探针成功应用于活细胞中检测Cu ²⁺和H ₂ S。