Molecular rotor measures viscosity of live cells via fluorescence lifetime imaging
Molecular rotor measures viscosity of live cells via fluorescence lifetime imaging
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DOI：
10.1021/ja800570d
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发表时间：
2008-05-28
影响因子：
15
通讯作者：
Suhling, Klaus
中科院分区：
文献类型：
--
作者：
Kuimova, Marina K.;Yahioglu, Gokhan;Suhling, Klaus
4,4'-二氟-4-硼-5-（对氧烷基）苯基-3a，4a-diaza-s-indacene(1)的荧光强度和寿命与介质粘度有很强的相关性，这是由于5-苯基的粘度依赖扭转，从而使其进入暗非发射激发态。我们提出了一种灵敏和通用的方法来测量局部微粘度在生物系统中，基于荧光寿命的测定1。用1孵育的活细胞进行荧光寿命成像（FLIM）显示，分子转子的细胞内寿命为1.6 +/- 0.2 ns，对应于细胞内黏度约为140 cP。细胞中1的时间分辨荧光各向异性证实了荧光团的不显著结合。本研究得到的黏度值比水和细胞质的黏度值高得多。细胞内腔室的高粘度可能在重要的细胞内过程中起重要作用，包括活性氧的扩散速率，导致程序性细胞破坏。
The fluorescence intensity and lifetime of the 4,4'-difluoro-4-bora-5-(p-oxoalkyl)phenyl-3a,4a-diaza-s-indacene (1) show a strong correlation with the viscosity of the medium due to the viscosity-dependent twisting of the 5-phenyl group, which gives access to the dark nonemissive excited state. We propose a sensitive and versatile method for measuring the local microviscosity in biological systems, based on the determination of the fluorescence lifetime of 1. Fluorescence lifetime imaging (FLIM) performed on live cells incubated with 1 demonstrates the distinct intracellular lifetime of the molecular rotor of 1.6 +/- 0.2 ns corresponding to the intracellular viscosity of ca. 140 cP. Time-resolved fluorescence anisotropy of 1 in cells confirms insignificant binding of the fluorophore. The viscosity value obtained in the present study is considerably higher than that of water and of cellular cytoplasm. The high viscosity of intracellular compartments is likely to play an important role in vital intracellular processes, including the rate of diffusion of reactive oxygen species, causing programmed cell destruction.