Brownian fluctuations and hydrodynamics of a microhelix near a solid wall
Brownian fluctuations and hydrodynamics of a microhelix near a solid wall
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DOI：
10.1038/s41598-020-61451-y
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发表时间：
2020-03-12
影响因子：
4.6
通讯作者：
Di Leonardo, Roberto
中科院分区：
文献类型：
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作者：
Bianchi, Silvio;Sosa, Viridiana Carmona;Di Leonardo, Roberto
我们结合双光子光刻和光镊来研究微加工螺旋的布朗波动和螺旋桨特性。通过对均方位移和时间相关函数的分析，我们恢复了完整迁移率张量的分量。我们发现布朗运动显示了角度波动和平移波动之间的相关性，从中我们可以直接测量负责产生推力的流体动力耦合系数。通过改变微螺旋与无滑移边界的距离，我们可以系统地测量附近壁对阻力矩阵的影响。我们的结果表明，当附近存在无滑移边界时，旋转螺旋移动得更快，这为合成微型游泳器和生物微型游泳器在有限几何形状中的推力增强提供了定量见解。
We combine two-photon lithography and optical tweezers to investigate the Brownian fluctuations and propeller characteristics of a microfabricated helix. From the analysis of mean squared displacements and time correlation functions we recover the components of the full mobility tensor. We find that Brownian motion displays correlations between angular and translational fluctuations from which we can directly measure the hydrodynamic coupling coefficient that is responsible for thrust generation. By varying the distance of the microhelices from a no-slip boundary we can systematically measure the effects of a nearby wall on the resistance matrix. Our results indicate that a rotated helix moves faster when a nearby no-slip boundary is present, providing a quantitative insight on thrust enhancement in confined geometries for both synthetic and biological microswimmers.