Strongly emissive individual DNA-encapsulated Ag nanoclusters as single-molecule fluorophores
Strongly emissive individual DNA-encapsulated Ag nanoclusters as single-molecule fluorophores
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DOI：
10.1073/pnas.0610677104
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发表时间：
2007-07-31
影响因子：
11.1
通讯作者：
Dickson, Robert M.
中科院分区：
文献类型：
--
作者：
Vosch, Tom;Antoku, Yasuko;Dickson, Robert M.
本文提出的水溶性、近红外发射DNA包封的银纳米团簇在单分子和本体水平上表现出极其明亮且光稳定的发射。光物理学已经通过强度依赖相关分析阐明，并且表明银的重原子效应在被氧猝灭之前迅速减少激发的暗能级，从而赋予很大的光稳定性、非常高的单分子发射速率，并且在实验相关的时间尺度（0.1至> 1，000 ms）上基本上没有闪烁。从这些生物相容性物质中观察到强反聚束，其在光漂白之前发射> 10（9）光子。显著的暗态量子产率甚至使得能够仅用单个检测器将来自发射态的聚束观察为自相关曲线中的下降，因为暗态阻止了来自发射能级的发射。这些物种代表了现有染料的显着改进，非幂律闪烁动力学表明，这些非常小的物种可能是更大和强间歇性半导体量子点的替代品。
The water-soluble, near-IR-emitting DNA-encapsulated silver nanocluster presented herein exhibits extremely bright and photostable emission on the single-molecule and bulk levels. The photophysics have been elucidated by intensity-dependent correlation analysis and suggest a heavy atom effect of silver that rapidly depopulates an excited dark level before quenching by oxygen, thereby conferring great photostability, very high single-molecule emission rates, and essentially no blinking on experimentally relevant time scales (0.1 to > 1,000 ms). Strong antibunching is observed from these biocompatible species, which emit > 10(9) photons before photobleaching. The significant dark-state quantum yield even enables bunching from the emissive state to be observed as a dip in the autocorrelation curve with only a single detector as the dark state precludes emission from the emissive level. These species represent significant improvements over existing dyes, and the nonpower law blinking kinetics suggest that these very small species may be alternatives to much larger and strongly intermittent semiconductor quantum dots.