Hydrodynamics of Sperm Cells near Surfaces
Hydrodynamics of Sperm Cells near Surfaces
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DOI：
10.1016/j.bpj.2010.05.015
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发表时间：
2010-08-18
影响因子：
3.4
通讯作者：
Gompper, Gerhard
中科院分区：
文献类型：
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作者：
Elgeti, Jens;Kaupp, U. Benjamin;Gompper, Gerhard
精子由一条积极跳动的尾巴推动，并表现出各种各样的游泳模式。当精子被限制在两堵平行的墙之间时，它们要么绕圈游动，要么沿着靠近墙的曲线轨迹游动。我们采用中尺度流体力学模拟结合机械精子模型来研究靠近墙壁的游动行为。模拟结果表明，由于鞭毛跳动产生的流体动力流场，精子在鞭毛壁处被捕获。圆形轨迹是由精子形状的手性不对称决定的。对于强（弱）手性，精子以紧密（宽）的圆圈游动，鞭毛的跳动面垂直（平行）于鞭毛壁。为了比较，我们还进行了基于鞭毛局部各向异性摩擦的模拟。在这种阻力近似下，也得到了表面粘附和圆形游动模式。然而，现在的粘附机制是由于空间排斥力，并且拍打平面的方向是不同的。我们的模型提供了一个理论框架来解释精子在墙附近和远离墙的几种不同的游泳行为。此外，该模型还提出了一种机制，即精子通过改变形状在化学梯度中导航。
Sperm are propelled by an actively beating tail, and display a wide variety of swimming patterns. When confined between two parallel walls, sperm swim either in circles or on curvilinear trajectories close to the walls. We employ mesoscale hydrodynamics simulations in combination with a mechanical sperm model to study the swimming behavior near walls. The simulations show that sperm become captured at the wall due to the hydrodynamic flow fields which are generated by the flagellar beat. The circular trajectories are determined by the chiral asymmetry of the sperm shape. For strong (weak) chirality, sperm swim in tight (wide) circles, with the beating plane of the flagellum oriented perpendicular (parallel) to the wall. For comparison, we also perform simulations based on a local anisotropic friction of the flagellum. In this resistive force approximation, surface adhesion and circular swimming patterns are obtained as well. However, the adhesion mechanism is now due to steric repulsion, and the orientation of the beating plane is different. Our model provides a theoretical framework that explains several distinct swimming behaviors of sperm near and far from a wall. Moreover, the model suggests a mechanism by which sperm navigate in a chemical gradient via a change of their shape.