Plasmon Heating Promotes Ligand Reorganization on Single Gold Nanorods
Plasmon Heating Promotes Ligand Reorganization on Single Gold Nanorods
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DOI：
10.1021/acs.jpclett.9b00079
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发表时间：
2019-03-21
影响因子：
5.7
通讯作者：
Willets, Katherine A.
中科院分区：
文献类型：
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作者：
Cheng, Xiaoyu;Anthony, Taryn P.;Willets, Katherine A.
利用单分子荧光显微镜跟踪单等离子体金纳米棒表面的动态配体重组。利用低pH负载法，通过金-硫醇键将荧光标记的DNA连接到金纳米棒上。从纳米棒表面的荧光标记中最初没有观察到荧光活性，我们将其归因于金属上DNA的塌陷几何形状。在几分钟的激光照射下，观察到荧光活性显著增加，这表明配体壳层从坍塌、淬灭的几何图形重组为竖直、有序的几何图形。配体的重组是由等离子体介导的光热加热促进的，这一点得到了使用外部热源的对照的验证，并通过光学和热扩散耦合模型进行了模拟。利用超分辨率图像重建，我们观察到在单粒子水平上发生配基重组的空间变化。结果表明，非均匀等离子体加热的可能性，这将隐藏在传统的系综平均测量。
Single-molecule fluorescence microscopy is used to follow dynamic ligand reorganization on the surface of single plasmonic gold nanorods. Fluorescently labeled DNA is attached to gold nanorods via a gold-thiol bond using a low-pH loading method. No fluorescence activity is initially observed from the fluorescent labels on the nanorod surface, which we attribute to a collapsed geometry of DNA on the metal. Upon several minutes of laser illumination, a marked increase in fluorescence activity is observed, suggesting that the ligand shell reorganizes from a collapsed, quenched geometry to an upright, ordered geometry. The ligand reorganization is facilitated by plasmon-mediated photothermal heating, as verified by controls using an external heat source and simulated by coupled optical and heat diffusion modeling. Using super-resolution image reconstruction, we observe spatial variations in which ligand reorganization occurs at the single-particle level. The results suggest the possibility of nonuniform plasmonic heating, which would be hidden with traditional ensemble-averaged measurements.