Viscoelastic properties of the nematode Caenorhabditis elegans, a self-similar, shear-thinning worm
Viscoelastic properties of the nematode Caenorhabditis elegans, a self-similar, shear-thinning worm
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DOI：
10.1073/pnas.1219965110
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发表时间：
2013-03-19
影响因子：
11.1
通讯作者：
Dalnoki-Veress, Kari
中科院分区：
文献类型：
--
作者：
Backholm, Matilda;Ryu, William S.;Dalnoki-Veress, Kari
从精子到蛇，许多不同尺度的生物都有波动运动。这些生物体必须推离它们的外部环境，如粘性介质、沙粒或高摩擦表面;此外，它们还必须努力使自己的身体弯曲。要充分理解波动运动和一般的运动，需要描述动物本身的物质特性。本文以秀丽隐杆线虫为模型生物，进行了三点弯曲测量的微力学实验，研究了其材料特性。测量了不同发育阶段（包括dauer）的蠕虫，并探测了蠕虫沿着不同位置。从这些实验中，我们计算的粘弹性蜗杆，包括有效的弹簧常数和阻尼系数的弯曲。C.秀丽线虫通过沿着其身体传播正弦波来移动。虽然以前描述波动运动的粘弹方法使用Kelvin-Voigt模型，其中弹性和粘性分量并行连接，但我们的测量表明，弹性和粘性分量串联的麦克斯韦模型更合适。蠕虫的粘性成分被证明是一致的非牛顿，剪切稀化流体。我们发现，作为蠕虫的成熟，它被很好地描述为一个自相似的弹性物体的剪切变稀阻尼项和刚度，变得更小，因为一个接近尾巴。
Undulatory motion is common to many creatures across many scales, from sperm to snakes. These organisms must push off against their external environment, such as a viscous medium, grains of sand, or a high-friction surface; additionally they must work to bend their own body. A full understanding of undulatory motion, and locomotion in general, requires the characterization of the material properties of the animal itself. The material properties of the model organism Caenorhabditis elegans were studied with a micromechanical experiment used to carry out a three-point bending measurement of the worm. Worms at various developmental stages (including dauer) were measured and different positions along the worm were probed. From these experiments we calculated the viscoelastic properties of the worm, including the effective spring constant and damping coefficient of bending. C. elegans moves by propagating sinusoidal waves along its body. Whereas previous viscoelastic approaches to describe the undulatory motion have used a Kelvin-Voigt model, where the elastic and viscous components are connected in parallel, our measurements show that the Maxwell model, where the elastic and viscous components are in series, is more appropriate. The viscous component of the worm was shown to be consistent with a non-Newtonian, shear-thinning fluid. We find that as the worm matures it is well described as a self-similar elastic object with a shear-thinning damping term and a stiffness that becomes smaller as one approaches the tail.