Room-Temperature Detection of a Single Molecule's Absorption by Photothermal Contrast
Room-Temperature Detection of a Single Molecule's Absorption by Photothermal Contrast
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DOI：
10.1126/science.1195475
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发表时间：
2010-10-15
期刊：
影响因子：
56.9
通讯作者：
Orrit, M.
中科院分区：
文献类型：
--
作者：
Gaiduk, A.;Yorulmaz, M.;Orrit, M.
到目前为止，单分子成像主要依赖于荧光检测。我们成像单一的非荧光偶氮染料分子在室温下甘油的折射效应的热量，他们在强烈的光照下释放在他们的环境。这种光热技术提供了对比度的吸收对象，无论散射的缺陷或粗糙度，与一个信号-噪声比类似于10的单个分子在300毫秒的积分时间。在不存在氧气的情况下，即使在超过10分钟的照射后，也几乎没有观察到漂白事件。在用氧饱和的溶液中，平均漂白时间为1分钟的量级。吸收信号中没有观察到闪烁。在漂白步骤的基础上，我们获得了单个发色团的平均吸收截面为4埃（2）。
So far, single-molecule imaging has predominantly relied on fluorescence detection. We imaged single nonfluorescent azo dye molecules in room-temperature glycerol by the refractive effect of the heat that they release in their environment upon intense illumination. This photothermal technique provides contrast for the absorbing objects only, irrespective of scattering by defects or roughness, with a signal-to-noise ratio of similar to 10 for a single molecule in an integration time of 300 milliseconds. In the absence of oxygen, virtually no bleaching event was observed, even after more than 10 minutes of illumination. In a solution saturated with oxygen, the average bleaching time was of the order of 1 minute. No blinking was observed in the absorption signal. On the basis of bleaching steps, we obtained an average absorption cross section of 4 angstroms(2) for a single chromophore.