A novel pH-responsive probe based on an imidazo[1,2-a]indole fluorophore architecture is reported. The probe was highly selective to strongly acidic pH (pK_a = 3.56) with high sensitivity and a fast response time (within 30 s). The probe did not demonstrate any fluorescence changes in the presence of interfering metal ions, and it featured excellent reversibility under strongly acidic conditions. The mechanism of detection of the probe was determined to be based on intramolecular charge transfer (ICT) at different pH. The probe was also able to be used for imaging for detecting acidic pH in Saccharomyces cerevisiae.

中文翻译：

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基于咪唑并[1,2-a]吲哚荧光团的新型pH响应荧光探针的制备及其在酿酒酵母极低pH检测中的应用

报道了一种基于咪唑并[1,2-a]吲哚荧光团结构的新型 pH 响应探针。该探针对强酸性 pH (p Ka = 3.56) 具有高度选择性，具有_高灵敏度和快速响应时间（30 秒内）。该探针在存在干扰金属离子的情况下没有表现出任何荧光变化，并且在强酸性条件下具有出色的可逆性。探针的检测机制被确定为基于不同pH下的分子内电荷转移（ICT）。该探针还能够用于成像以检测酿酒酵母中的酸性 pH 值。