Sheathless particle focusing in a microfluidic chamber by using the thermoplasmonic Marangoni effect
Sheathless particle focusing in a microfluidic chamber by using the thermoplasmonic Marangoni effect
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DOI：
10.1063/1.4942601
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发表时间：
2016-02-15
影响因子：
4
通讯作者：
Suzuki, Motofumi
中科院分区：
文献类型：
--
作者：
Namura, Kyoko;Nakajima, Kaoru;Suzuki, Motofumi
我们在50微米厚的水室中对微泡周围的Marangoni流动模式进行了实验研究，发现了一种能够实现无护套粒子聚焦的过渡流模式。在金纳米岛薄膜上，激光光斑周围热塑性诱导出温度梯度，微泡周围产生Marangoni流，驱动分散在水中的亚微米粒子。当激光光斑稍微偏离气泡中心时，颗粒被下面的气泡连续收集并向一个方向泄漏，形成聚焦的粒子流。粒子聚焦Marangoni流的产生归因于燃烧室垂直方向和水平方向温度梯度的适当平衡，这是由激光光斑相对于气泡中心的位置控制的。用激光功率在时间上控制这种流动模式，会导致气泡下面的气泡周期性地发射出团簇粒子。这种具有热浆Marangoni流的颗粒处理方法可用于提高在微流体室中发生的反应或传感过程的效率。(C)2016 AIP出版有限责任公司。
We experimentally investigated the modes of the Marangoni flow around a microbubble in a 50-mu m-thick water chamber and found a transition flow mode that enables sheathless particle focusing. A temperature gradient was thermoplasmonically induced around the laser spot on a gold nanoisland film, and Marangoni flows were generated around the microbubble to drive submicron particles dispersed in the water. When the laser spot was slightly displaced from the bubble center, the particles were continuously collected by the bubble underneath and leaked in one direction to form a focused particle stream. The generation of the particle-focusing Marangoni flow was attributed to the appropriate balance of the temperature gradient in the perpendicular and horizontal directions of the chamber, which was controlled by the laser spot position against the bubble center. Temporally controlling this flow mode with laser power caused the periodic emission of clustered particles from the bubble underneath. This particle handling method with a thermoplasmonic Marangoni flow can be useful for improving the efficiency of reaction or sensing processes that take place in a microfluidic chamber. (C) 2016 AIP Publishing LLC.