Imaging Single Molecular Machines Attached with Two BODIPY Dyes at the Air-Solid Interface: High Probability of Single-Step-Like Photobleaching and Nonscaling Intensity
Imaging Single Molecular Machines Attached with Two BODIPY Dyes at the Air-Solid Interface: High Probability of Single-Step-Like Photobleaching and Nonscaling Intensity
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DOI：
10.1021/acs.jpcc.6b07518
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发表时间：
2016-11-24
影响因子：
3.7
通讯作者：
Wang, Gufeng
中科院分区：
文献类型：
--
作者：
Jin, Tao;Garcia-Lopez, Victor;Wang, Gufeng
单分子荧光显微镜（SMFM）是一种在环境条件下监测单分子机器行为的强大技术。为了提高荧光强度和光稳定性，一种策略是将多种染料连接到同一个单分子机器上。然而，目前尚不清楚当多种染料在它们之间的距离接近2nm的范围内被压缩到同一分子中时，染料的荧光性质将如何变化。在这项研究中，我们研究了两种类型的单分子机器，每一个配备了两个BODIPY染料具有不同的距离的光物理。我们发现，在空气玻璃界面处，与两种染料连接的单分子具有很高的倾向，显示出类似单步的光漂白，使它们看起来像一个单一的染料。我们建议，产品的第一次光漂白事件，可能是一个超氧阴离子自由基，参与破坏相邻的染料。此外，双染料系统的荧光强度不与所连接的染料的数量成比例。非标度荧光强度可以通过分子内荧光共振能量转移（FRET）或/和单线态三重态湮灭过程使用自猝灭模型来解释。该研究揭示了单分子与两种染料连接的荧光性质，为设计荧光标记的纳米机器分子提供了新的思路。
Single-molecule fluorescence microscopy (SMFM) is a powerful technique in monitoring single molecular machine actions at ambient conditions. To improve the fluorescence intensity and photostability, one strategy is to attach multiple dyes to the same single molecular machine. However, it is unclear how the fluorescence property of the dyes will change when multiple dyes are compacted into the same molecule within a distance between them of similar to 2 nm. In this study, we investigated the photophysics of two types of single molecular machines that are each equipped with two BODIPY dyes with different distances. We found that at the air glass interface, single molecules attached with two dyes have a high tendency to show a single-step-like photobleaching, making them to appear like a single dye. We propose that the product of the first photobleaching event, possibly a superoxide anion radical, is involved in the destruction of the neighboring dye. In addition, the fluorescence intensity of the two-dye system does not scale with the number of dyes attached. The nonscaling fluorescence intensity can be explained using a self-quenching model through an intramolecular fluorescence resonance energy transfer (FRET) or/and singlet triplet annihilation process. This study discloses the fluorescence property of single molecules attached with two dyes and sheds new light on designing fluorescently tagged nanomachine molecules.