Time-Resolved Fluorescence Anisotropy of a Molecular Rotor Resolves Microscopic Viscosity Parameters in Complex Environments.
Time-Resolved Fluorescence Anisotropy of a Molecular Rotor Resolves Microscopic Viscosity Parameters in Complex Environments.
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DOI：
10.1002/smll.201907139
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发表时间：
2020-05
期刊：
影响因子：
13.3
通讯作者：
I. E. Steinmark;P. Chung;Robert M. Ziolek;Bethan Cornell;Paul E. Smith;J. Levitt;C. Tregidgo;
中科院分区：
文献类型：
--
作者：
I. E. Steinmark;P. Chung;Robert M. Ziolek;Bethan Cornell;Paul E. Smith;J. Levitt;C. Tregidgo;
了解复杂环境中的粘度仍然是一个很大程度上悬而未决的问题，尽管它在确定体内反应速率的重要性。在这里，时间分辨荧光各向异性成像（TR-FAIM）与荧光分子转子（FMR）相结合，同时确定两个非等效的粘度相关的参数在复杂的非均质环境。参数，FMR旋转相关时间和寿命，从荧光各向异性衰减，这在异质环境中表现出下降和上升的行为，由于多个染料种群提取。这种衰变在人工构建的脂肪体和活细胞脂滴细胞器中都有发现。分子动力学模拟用于分配每个人口的脂质系统内的纳米环境。粘性较小的群体对应于显示出相对于脂质膜法线平均25°倾斜的状态，并且粘性较大的群体对应于显示出平均55°倾斜的状态。这种结合实验和模拟的方法，使复杂的生物系统中的粘性纳米环境内的FMR探针行为的全面描述。
Understanding viscosity in complex environments remains a largely unanswered question despite its importance in determining reaction rates in vivo. Here, time-resolved fluorescence anisotropy imaging (TR-FAIM) is combined with fluorescent molecular rotors (FMRs) to simultaneously determine two non-equivalent viscosity-related parameters in complex heterogeneous environments. The parameters, FMR rotational correlation time and lifetime, are extracted from fluorescence anisotropy decays, which in heterogeneous environments show dip-and-rise behavior due to multiple dye populations. Decays of this kind are found both in artificially constructed adiposomes and in live cell lipid droplet organelles. Molecular dynamics simulations are used to assign each population to nano-environments within the lipid systems. The less viscous population corresponds to the state showing an average 25° tilt to the lipid membrane normal, and the more viscous population to the state showing an average 55° tilt. This combined experimental and simulation approach enables a comprehensive description of the FMR probe behavior within viscous nano-environments in complex, biological systems.