Yin Haijing, Zhang Buchang, Yu Haizhu, Zhu Lin, Feng Yan, Zhu Manzhou, Guo Qingxiang, Meng Xiangming
†Department of Chemistry, Anhui University, Hefei, Anhui, China 230601.
‡Institute of Health Sciences, Anhui University, Hefei, Anhui, China 230601.
J Org Chem. 2015 May 1;80(9):4306-12. doi: 10.1021/jo502775t. Epub 2015 Apr 13.
Two novel water-soluble coumarin-based compounds (OC7, NC7) were designed and synthesized as two-photon fluorescent probes for biological Mg(2+) detection. The compounds feature a β-keto acid as a high selective binding site for Mg(2+) and the coumarin framework as the two-photon fluorophore. OC7 and NC7 show significant "off-on" detecting signals (9.05-fold and 23.8-fold fluorescence enhancement) and lower detection limits compared with previous reported two-photon fluorescent probes for Mg(2+). Moreover, OC7-Mg(2+) and NC7-Mg(2+) exhibit large two-photon absorption cross sections (340 and 615 GM) at the near-infrared wavelengths (740 and 860 nm), which indicates that the probes are very suitable for detection of Mg(2+) in vivo. Both OC7 and NC7 are pH-insensitive and of low cytotoxicity and can be applied to image intracellular Mg(2+) under two-photon microscopy (TPM). Our results provide a strategy to modify the coumarin fluorophore to get better two-photon fluorescent properties. And the results also suggest that electronic density of β-keto acid plays a very important role in the recognition of Mg(2+).
设计并合成了两种新型的基于香豆素的水溶性化合物（OC7、NC7），作为用于生物镁离子（Mg²⁺）检测的双光子荧光探针。这些化合物以β-酮酸作为Mg²⁺的高选择性结合位点，以香豆素骨架作为双光子荧光团。与先前报道的用于Mg²⁺的双光子荧光探针相比，OC7和NC7显示出显著的“关-开”检测信号（荧光增强9.05倍和23.8倍）以及更低的检测限。此外，OC7-Mg²⁺和NC7-Mg²⁺在近红外波长（740和860 nm）处表现出较大的双光子吸收截面（340和615 GM），这表明这些探针非常适合于体内Mg²⁺的检测。OC7和NC7均对pH不敏感且细胞毒性低，可应用于双光子显微镜（TPM）下的细胞内Mg²⁺成像。我们的结果提供了一种修饰香豆素荧光团以获得更好双光子荧光性质的策略。结果还表明，β-酮酸的电子密度在Mg²⁺的识别中起着非常重要的作用。
