Density-Gradient-Free Microfluidic Centrifugation for Analytical and Preparative Separation of Nanoparticles
Density-Gradient-Free Microfluidic Centrifugation for Analytical and Preparative Separation of Nanoparticles
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DOI：
10.1021/nl404771g
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发表时间：
2014-05-01
期刊：
影响因子：
10.8
通讯作者：
Knowles, Tuomas P. J.
中科院分区：
文献类型：
--
作者：
Arosio, Paolo;Mueller, Thomas;Knowles, Tuomas P. J.
沉降和离心技术广泛应用于生物分子和胶体的分离，但需要存在受控的密度梯度以稳定操作。在这里，我们提出了一种方法来分离纳米粒子在自由溶液中没有梯度。我们使用微流体技术来产生垂直于沉积方向的对流。我们表明，流体动力学瑞利-泰勒不稳定性，这在传统的方法中，需要存在的密度梯度，可以抑制在微通道中的Poiffille流。我们通过展示纳米尺度上颗粒混合物的分离来说明这种方法的力量，纳米尺度的数量级小于传统惯性微流体方法分离的微米大小的物体。该技术表现出一系列有利的特征，包括分析时间短，样品体积小，分析物的有限稀释，与表面的有限相互作用以及通过调整系统的几何形状容易地调整分离范围的可能性。这些功能突出了无梯度微流控离心作为一个有吸引力的路线走向广泛的纳米级应用的潜力。
Sedimentation and centrifugation techniques are widely applied for the separation of biomolecules and colloids but require the presence of controlled density gradients for stable operation. Here we present an approach for separating nanoparticles in free solution without gradients. We use microfluidics to generate a convective flow perpendicular to the sedimentation direction. We show that the hydrodynamic Rayleigh-Taylor-like instability, which, in traditional methods, requires the presence of a density gradient, can be suppressed by the Poiseuille flow in the microchannel. We illustrate the power of this approach by demonstrating the separation of mixtures of particles on the nanometer scale, orders of magnitude smaller than the micrometer-sized objects separated by conventional inertial microfluidic approaches. This technique exhibits a series of favorable features including short analysis time, small sample volume, limited dilution of the analyte, limited interactions with surfaces as well as the possibility to tune easily the separation range by adjusting the geometry of the system. These features highlight the potential of gradient-free microfluidic centrifugation as an attractive route toward a broad range of nanoscale applications.