Sorting and separation of microparticles by surface properties using liquid crystal-enabled electro-osmosis
Sorting and separation of microparticles by surface properties using liquid crystal-enabled electro-osmosis
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DOI：
10.1080/02678292.2018.1481539
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发表时间：
2018-06
期刊：
影响因子：
2.2
通讯作者：
C. Peng;T. Turiv;Yubing Guo;Q. Wei;O. Lavrentovich
中科院分区：
文献类型：
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作者：
C. Peng;T. Turiv;Yubing Guo;Q. Wei;O. Lavrentovich
微粒的分选与分离是一个具有跨学科性质的挑战性问题。现有的技术可以通过微粒的体积特性来区分它们，如大小、密度、电极化率等。下一个挑战是分离出具有相同体积特性的粒子，这些粒子仅在细微的表面特征（如配体的功能化）上有所不同。在这项工作中，我们提出了一种分类和分离表面性质不同的颗粒和液滴的技术。作为色散介质，我们使用向列液晶（LC）而不是各向同性流体，这使我们能够通过分散粒子周围LC顺序的明显扰动来放大表面性质的差异。这些粒子被放置在受交变电场作用的分子取向空间扭曲的LC电池中。分子取向的梯度有两个作用。首先，这些预先施加的梯度和粒子周围的扭曲之间的弹性相互作用将具有不同表面特性的粒子在空间中分开。其次，这些预先施加的图案产生电渗透流，由电场驱动，将分类的颗粒输送到不同的位置，从而分离它们。所展示的独特的分选和分离能力为芯片实验室，细胞分选和生物传感应用提供了机会。图形抽象
ABSTRACT Sorting and separation of microparticles is a challenging problem of interdisciplinary nature. Existing technologies can differentiate microparticles by their bulk properties, such as size, density, electric polarisability, etc. The next level of challenge is to separate particles that show identical bulk properties and differ only in subtle surface features, such as functionalisation with ligands. In this work, we propose a technique to sort and separate particles and fluid droplets that differ in surface properties. As a dispersive medium, we use a nematic liquid crystal (LC) rather than an isotropic fluid, which allows us to amplify the difference in surface properties through distinct perturbations of LC order around the dispersed particles. The particles are placed in an LC cell with spatially distorted molecular orientation subject to an alternating current electric field. The gradients of the molecular orientation perform two functions. First, elastic interactions between these pre-imposed gradients and distortions around the particles separate the particles with different surface properties in space. Second, these pre-imposed patterns create electro-osmotic flows powered by the electric field that transport the sorted particles to different locations thus separating them. The demonstrated unique sorting and separation capability opens opportunities in lab-on-a-chip, cell sorting and bio-sensing applications. GRAPHICAL ABSTRACT