Dumat Blaise, Chieffo Carolina
Laboratoire des biomolécules, LBM, Département de chimie, École normale supérieure, PSL University, Sorbonne Université, CNRS, 75005, Paris, France.
Chemistry. 2025 Feb 12;31(9):e202404077. doi: 10.1002/chem.202404077. Epub 2024 Dec 11.
Dipolar fluorescent molecular rotors (FMRs) are environmentally-sensitive fluorophores that can be used in bioimaging applications to sense local viscosity and polarity. Their sensitivity to viscosity can also be used for the fluorogenic labeling of biomolecules such as DNA or proteins. In particular, we have previously used FMRs to develop a series of tunable fluorogens targeting the self-labeling protein tag Halotag for wash-free protein imaging in live cells. Despite these very useful properties, FMRs typically display moderate molar absorption coefficients that limits their overall fluorescence brightness. Herein, we synthesized a series of three model hemicyanines based on a styrylindolenium scaffold and performed a detailed study of their photophysical properties in solvents with various polarity and viscosity. We show that with a strong julolidine electron-donating group it is possible to combine intense cyanine-like absorption with the high sensitivity to viscosity of FMRs. We use this property to develop a lysosomal pH sensor and two bright cell-impermeant fluorogens targeting HaloTag for imaging membrane proteins. We believe that this bright fluorogenic scaffold based on a simple chemical structure can be used in the future to build up a variety of probes and sensors with efficient photophysical properties.
偶极荧光分子转子（FMRs）是对环境敏感的荧光团，可用于生物成像应用中以检测局部粘度和极性。它们对粘度的敏感性还可用于对生物分子（如DNA或蛋白质）进行荧光标记。特别是，我们之前已使用FMRs开发了一系列可调节的荧光团，靶向自标记蛋白标签卤代标签，用于活细胞中的免洗蛋白成像。尽管具有这些非常有用的特性，但FMRs通常显示出中等的摩尔吸收系数，这限制了它们的整体荧光亮度。在此，我们基于苯乙烯基吲哚鎓支架合成了一系列三种模型半菁，并对它们在具有不同极性和粘度的溶剂中的光物理性质进行了详细研究。我们表明，通过一个强的呫吨啶供电子基团，可以将强烈的类似花青的吸收与FMRs对粘度的高敏感性结合起来。我们利用这一特性开发了一种溶酶体pH传感器以及两种靶向卤代标签的明亮的细胞不可渗透荧光团，用于成像膜蛋白。我们相信，这种基于简单化学结构的明亮荧光支架未来可用于构建各种具有高效光物理性质的探针和传感器。
