School of Molecular Sciences and ⊥Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University , Tempe, Arizona 85287, United States.
Department of Biochemistry, Molecular Biology and Biophysics, and §Department of Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States.
Anal Chem. 2016 Jun 7;88(11):5920-7. doi: 10.1021/acs.analchem.6b00837. Epub 2016 May 17.
Efficient separations of particles with micron and submicron dimensions are extremely useful in preparation and analysis of materials for nanotechnological and biological applications. Here, we demonstrate a nonintuitive, yet efficient, separation mechanism for μm and subμm colloidal particles and organelles, taking advantage of particle transport in a nonlinear post array in a microfluidic device under the periodic action of electrokinetic and dielectrophoretic forces. We reveal regimes in which deterministic particle migration opposite to the average applied force occurs for a larger particle, a typical signature of deterministic absolute negative mobility (dANM), whereas normal response is obtained for smaller particles. The coexistence of dANM and normal migration was characterized and optimized in numerical modeling and subsequently implemented in a microfluidic device demonstrating at least 2 orders of magnitude higher migration speeds as compared to previous ANM systems. We also induce dANM for mouse liver mitochondria and envision that the separation mechanisms described here provide size selectivity required in future separations of organelles, nanoparticles, and protein nanocrystals.
高效分离微米和亚微米尺寸的颗粒在纳米技术和生物应用材料的制备和分析中非常有用。在这里，我们展示了一种非直观但高效的微米和亚微米胶体颗粒和细胞器分离机制，利用在微流控装置中的非线性后列阵中在电动和介电泳力的周期性作用下的颗粒传输。我们揭示了对于较大颗粒，出现与平均施加力相反的确定性颗粒迁移的区域，这是确定性绝对负迁移率（dANM）的典型特征，而对于较小颗粒则获得正常响应。在数值建模中对 dANM 和正常迁移的共存进行了表征和优化，并随后在微流控装置中实现，与以前的 ANM 系统相比，迁移速度至少提高了 2 个数量级。我们还诱导了小鼠肝线粒体的 dANM，并设想这里描述的分离机制提供了未来细胞器、纳米颗粒和蛋白质纳米晶体分离所需的尺寸选择性。
