Life in complex fluids: Swimming in polymers
Life in complex fluids: Swimming in polymers
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DOI：
10.1103/physrevfluids.7.110515
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发表时间：
2022-11-21
影响因子：
2.7
通讯作者：
Arratia, Paulo E.
中科院分区：
文献类型：
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作者：
Arratia, Paulo E.
许多微生物在复杂的流体中生活和进化。例如，宫颈粘液中的哺乳动物精子，潮湿土壤中的蠕虫(例如线虫)，以及我们胃壁中的细菌(例如幽门螺杆菌)。由于(生物)聚合物和/或固体的存在，这类流体通常对(剪切)应力表现出非线性响应，包括粘弹性和剪切速率相关的粘度。这些微生物与其流体环境之间的成功相互作用对许多生物过程的功能至关重要，包括人类繁殖、生态系统动力学以及疾病和感染的传播。这种相互作用通常是非线性的，可能导致许多意想不到的行为。在这里，我将讨论在描述、模拟和理解模型微生物在粘弹性和剪切稀释液中的游动行为方面的进展。将探索三种主要微生物：(I)线虫线虫，一种波动的游泳者；(Ii)绿藻C.reinhardtii，一种拖拉式游泳者；以及(Iii)细菌大肠杆菌，一种推进式游泳者。对人造微粒和游泳者的研究也将被讨论；这样的研究有助于将生物学与水动力效应分离。我们将主要通过实验来探索这些游泳者的步态、几何形状以及驱动和流体流变学行为之间的相互作用，并讨论这些结果与数值和分析预测的关系。
Many microorganisms live and evolve in complex fluids. Examples include mammalian spermatozoa in cervical mucus, worms (e.g., C. elegans) in wet soil, and bacteria (e.g., H. pylori) in our stomach lining. Due to the presence of (bio)polymers and/or solids, such fluids often display nonlinear response to (shear) stresses including viscoelasticity and shear-rate-dependent viscosity. The successful interaction between these microorganisms and their fluid environment is critical to the function of many biological processes includ-ing human reproduction, ecosystem dynamics, and the spread of disease and infection. This interaction is often nonlinear and can lead to many unexpected behaviors. Here, I will discuss developments in characterizing, modeling, and understanding the swimming behavior of model microorganism in viscoelastic and shear-thinning fluids. Three main microorganisms will be explored: (i) the nematode C. elegans, an undulatory swimmer; (ii) the green algae C. reinhardtii, a puller swimmer; and (iii) the bacterium E. coli, a pusher swimmer. Investigation with artificial particles and swimmers will also be discussed; such studies are helpful in decoupling the biology from hydrodynamic effects. We will explore the interactions between these swimmers' gaits, geometry, and actuation and fluid rheolog-ical behavior using mostly experiments, and discuss these results relative to numerical and analytical predictions.