Clifford John N, Bell Toby D M, Tinnefeld Philip, Heilemann Mike, Melnikov Sergey M, Hotta Jun-ichi, Sliwa Michel, Dedecker Peter, Sauer Markus, Hofkens Johan, Yeow Edwin K L
J Phys Chem B. 2007 Jun 28;111(25):6987-91. doi: 10.1021/jp072864d. Epub 2007 May 26.
The single-molecule fluorescence blinking behavior of the organic dye Atto647N in various polymer matrixes such as Zeonex, PVK, and PVA as well as aqueous media was investigated. Fluorescence blinking with off-times in the millisecond to second time range is assigned to dye radical ions formed by photoinduced electron transfer reactions from or to the environment. In Zeonex and PVK, the measured off-time distributions show power law dependence, whereas, in PVA, no such dependence is observed. Rather, in this polymer, off-time distributions can be best fitted to monoexponential or stretched exponential functions. Furthermore, treatment of PVA samples to mild heating and low pressure greatly reduces the frequency of blinking events. We tentatively ascribe this to the removal of water pockets within the polymer film itself. Measurements of the dye immobilized in water in the presence of methylviologen, a strongly oxidizing agent, reveal simple exponential on- and off-time distributions. Thus, our data suggest that the blinking behavior of single organic molecules is sensitive to their immediate environment and, moreover, that fluorescence blinking on- and off-time distributions do not inherently and uniquely obey a power law.
研究了有机染料Atto647N在各种聚合物基质（如Zeonex、PVK和PVA）以及水性介质中的单分子荧光闪烁行为。荧光闪烁的关断时间在毫秒到秒的范围内，这归因于由光诱导电子转移反应从环境或向环境形成的染料自由基离子。在Zeonex和PVK中，测得的关断时间分布显示出幂律依赖性，而在PVA中未观察到这种依赖性。相反，在这种聚合物中，关断时间分布可以最好地拟合为单指数或拉伸指数函数。此外，对PVA样品进行温和加热和低压处理可大大降低闪烁事件的频率。我们初步将此归因于聚合物膜本身内水囊的去除。在强氧化剂甲基紫精存在下对固定在水中的染料进行测量，揭示了简单的指数开启和关断时间分布。因此，我们的数据表明，单个有机分子的闪烁行为对其直接环境敏感，而且，荧光闪烁的开启和关断时间分布并非固有且唯一地服从幂律。
