Optical assembling dynamics of individual polymer nanospheres investigated by single-particle fluorescence detection
Optical assembling dynamics of individual polymer nanospheres investigated by single-particle fluorescence detection
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DOI：
10.1103/physreve.70.061410
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发表时间：
2004-12-01
影响因子：
2.4
通讯作者：
Masuhara, H
中科院分区：
文献类型：
--
作者：
Hosokawa, C;Yoshikawa, H;Masuhara, H
当激光束聚焦到胶体纳米颗粒悬浮液中时，由于光学梯度力，许多纳米颗粒可以被限制在焦点中。为了揭示聚合物纳米粒子的组装动力学，通过分析纳米粒子荧光强度随时间的变化来研究聚合物纳米粒子的组装过程。在100 nm大小的颗粒的稀悬浮液中，观察到对应于被捕获的单个纳米颗粒的荧光强度的逐步增加。统计分析表明，纳米粒子的初始组装速率与激光功率和颗粒悬浮液浓度成正比，正如扩散方程所预期的那样。在40 nm大小的颗粒悬浮液中，获得了荧光强度的闪烁曲线，其中2-3个颗粒同时被捕获，然后逃离焦点。通过统计分析和二维Monte Carlo模拟，认为这种聚集现象是由光阱辅助的团簇形成引起的。
When a laser beam is focused into colloidal nanoparticle suspensions, a number of nanoparticles can be confined in the focal spot due to an optical gradient force. To reveal the assembling dynamics of polymer nanoparticles, the assembling process was investigated by analyzing the time evolution of the fluorescence intensity of the nanoparticles. In a dilute suspension of 100-nm-sized particles, a stepwise increase of the fluorescence intensity corresponding to a trapped single nanoparticle was observed. Statistical analysis revealed that the initial assembling rate of nanoparticles was proportional to the laser power and concentration of particle suspensions as expected from the diffusion equation. In 40-nm-sized particle suspensions, blinking profiles of fluorescence intensity were obtained, in which 2-3 particles were simultaneously trapped and then escaped from the focal point. It is considered from statistical analyses and two-dimensional Monte Carlo simulations that this assembling phenomenon is attributable to cluster formation assisted by optical trapping.