Data from: Spermatozoa scattering by a microchannel feature: an elastohydrodynamic model

Sperm traverse their microenvironment through viscous fluid by propagating flagellar waves; the waveform emerges as a consequence of elastic structure, internal active moments, and low Reynolds number fluid dynamics. Engineered microchannels have recently been proposed as a method of sorting and manipulating motile cells; the interaction of cells with these artificial environments therefore warrants investigation. A numerical method is presented for the large-amplitude elastohydrodynamic interaction of active swimmers with domain features. This method is employed to examine hydrodynamic scattering by a model microchannel backstep feature. Scattering is shown to depend on backstep height and the relative strength of viscous and elastic forces in the flagellum. In a `high viscosity' parameter regime corresponding to human sperm in cervical mucus analogue, this hydrodynamic contribution to scattering is comparable in magnitude to recent data on contact effects, being of the order of 5-10°. Scattering can be positive or negative depending on the relative strength of viscous and elastic effects, emphasising the importance of viscosity on the interaction of sperm with their microenvironment. The modulation of scattering angle by viscosity is associated with variations in flagellar asymmetry induced by the elastohydrodynamic interaction with the boundary feature.精子通过传播鞭毛（flagellum）波，在粘性流体中穿行于自身的微环境；其波形源于弹性结构、内部主动力矩以及低雷诺数（low Reynolds number）流体动力学的共同作用。近年来，工程化微通道（microchannel）被提出可用于分选和操控活动细胞，因此细胞与这类人工微环境的相互作用值得深入研究。本文提出了一种数值方法，用于分析主动泳动体与流场域特征之间的大振幅弹性流体动力学相互作用。该方法被用于研究模型微通道阶跃结构引发的流体动力学散射现象。研究表明，散射程度取决于阶跃高度以及鞭毛内粘性力与弹性力的相对强度。在对应人类精子处于宫颈黏液模拟环境的"高粘性"参数区间内，流体动力学对散射的贡献量级与近期关于接触效应的研究数据相当，约为5至10°。散射可呈现正或负两种方向，具体取决于粘性效应与弹性效应的相对强度，这凸显了粘性在精子与其微环境相互作用中的重要性。粘性对散射角的调控作用，与边界特征引发的弹性流体动力学相互作用所导致的鞭毛不对称性变化密切相关。