Opto-thermophoretic separation and trapping of plasmonic nanoparticles
Opto-thermophoretic separation and trapping of plasmonic nanoparticles
复制标题
DOI：
10.1039/c9nr05052c
复制
发表时间：
2019-11-28
期刊：
影响因子：
6.7
通讯作者：
Miyasaka, Hiroshi
中科院分区：
文献类型：
--
作者：
Setoura, Kenji;Tsuji, Tetsuro;Miyasaka, Hiroshi
光镊是捕获、传输和分析稀浓度下单个纳米物体的强大工具。然而，在具有各种材料的密集目标环境中操纵孤立的单个纳米物体仍然具有挑战性，例如活细胞和纳米胶体的混合物。在目前的工作中，我们已经成功地选择性地捕获了一些特定尺寸的金纳米壳，并完全清除了其他人，只有通过用聚焦的近红外连续波（CW）激光照射金纳米壳的致密胶体悬浮液。这是通过光学梯度力和热泳力之间的相互作用实现的：当梯度力将目标捕获在焦点处时，热泳力将其他目标从焦点处推出。被困目标和分离的其他人之间的距离大于20 μ m，使我们能够测量等离子体散射光谱的被困目标在一个单一的纳米粒子的水平。本方法为操纵和分析目标和各种材料的密集混合物中的单个纳米物体铺平了道路。
Optical tweezers are powerful tools to trap, transport, and analyse individual nano-objects at dilute concentrations. However, it is still challenging to manipulate isolated single nano-objects in dense target environments with various kinds of materials, such as in living cells and mixtures of nanocolloids. In the present work, we have succeeded in the selective trapping of a few gold nanoshells with specific sizes and sweeping others out completely, only by irradiating the dense colloidal suspension of gold nanoshells with a focused near infrared continuous-wave (CW) laser. This was achieved by an interplay between optical gradient- and thermophoretic forces: while the gradient force traps the targets at the focal spot, the thermophoretic force pushes others out from the focal spot. The distance between the trapped targets and the separated others was longer than 20 mu m, allowing us to measure plasmonic scattering spectra of the trapped targets at a single-nanoparticle level. The present method paves a way for manipulating and analysing single nano-objects in dense mixtures of targets and various kinds of materials.