Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, Hunan University, Changsha 410082, China.
Talanta. 2013 Dec 15;117:326-32. doi: 10.1016/j.talanta.2013.09.033. Epub 2013 Sep 25.
Development of fluorescent probes for Hg(2+) has become a hot topic in modern chemical research due to its high toxicity. In this paper, we for the first time report the synthesis and application of a thioether spirocyclic rhodamine B derivative (TR) as an efficient fluorescent probe for Hg(2+). TR was synthesized using a simple procedure under mild condition. By employing a thioether spirocycle instead of classic spirolactam as recognition unit, our proposed probe TR is acidity-insensitive, and exhibits a pH-independent and ultrasensitive response to Hg(2+). The probe works well within a wide pH range from 3.5 to 11.5, and exhibits a 350-fold fluorescence enhancement upon 0.5 equiv of Hg(2+) triggered, with a detection limit of 2.5 nM estimated for Hg(2+). In virtue of the strong thiophilic characteristic of Hg(2+), the response of the probe to Hg(2+) is instantaneous and highly selective, which make it favorable for cellular Hg(2+) imaging applications. It has been preliminarily used for highly sensitive monitoring of Hg(2+) level in living cells with satisfying resolution, demonstrating its value of the practical applications in biological systems.
由于汞（Hg(2+)）具有高毒性，因此开发用于检测 Hg(2+)的荧光探针成为现代化学研究的热门课题。在本文中，我们首次报道了一种硫醚螺环罗丹明 B 衍生物（TR）的合成及其作为高效荧光探针用于检测 Hg(2+)的应用。TR 是在温和条件下通过简单的步骤合成的。与经典的螺内酰胺相比，我们所提出的探针 TR 采用硫醚螺环作为识别单元，对酸度不敏感，对 Hg(2+)具有 pH 独立的超灵敏响应。该探针在 pH 3.5 至 11.5 的较宽范围内工作良好，在 0.5 当量 Hg(2+)触发下荧光增强 350 倍，Hg(2+)的检测限估计为 2.5 nM。由于 Hg(2+)具有很强的亲硫性，探针对 Hg(2+)的响应是瞬时的和高度选择性的，这使其有利于细胞内 Hg(2+)成像应用。它已初步用于在活细胞中对 Hg(2+)水平进行高灵敏度监测，具有令人满意的分辨率，显示了其在生物系统中的实际应用价值。
