Xu Tian-Liang, Qin Chao-Ran, Tang Bin, Gao Jin-Cheng, Zhou Jiankang, Chen Kang, Zhang Tian Hui, Tian Wen-de
Center for Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University, Suzhou 215006, China.
School of Optoelectronic Science and Engineering, Soochow University, Suzhou 215006, China.
J Chem Phys. 2024 Aug 14;161(6). doi: 10.1063/5.0217158.
It has been supposed that the interplay of elasticity and activity plays a key role in triggering the non-equilibrium behaviors in biological systems. However, the experimental model system is missing to investigate the spatiotemporally dynamical phenomena. Here, a model system of an active chain, where active eccentric-disks are linked by a spring, is designed to study the interplay of activity, elasticity, and friction. Individual active chain exhibits longitudinal and transverse motions; however, it starts to self-rotate when pinning one end and self-beat when clamping one end. In addition, our eccentric-disk model can qualitatively reproduce such behaviors and explain the unusual self-rotation of the first disk around its geometric center. Furthermore, the structure and dynamics of long chains were studied via simulations without steric interactions. It was found that a hairpin conformation emerges in free motion, while in the constrained motions, the rotational and beating frequencies scale with the flexure number (the ratio of self-propelling force to bending rigidity), χ, as ∼(χ)4/3. Scaling analysis suggests that it results from the balance between activity and energy dissipation. Our findings show that topological constraints play a vital role in non-equilibrium synergy behaviors.
人们认为，弹性与活性之间的相互作用在触发生物系统中的非平衡行为方面起着关键作用。然而，用于研究时空动力学现象的实验模型系统尚不存在。在此，设计了一个由弹簧连接活性偏心盘的活性链模型系统，以研究活性、弹性和摩擦力之间的相互作用。单个活性链表现出纵向和横向运动；然而，当固定一端时它会开始自转，而当夹住一端时它会自振。此外，我们的偏心盘模型能够定性地重现此类行为，并解释第一个圆盘围绕其几何中心的异常自转现象。此外，通过无空间相互作用的模拟研究了长链的结构和动力学。研究发现，在自由运动中会出现发夹构象，而在受限运动中，旋转频率和自振频率与弯曲数（自推进力与弯曲刚度之比）χ的关系为~(χ)4/3 。标度分析表明，这是由活性与能量耗散之间的平衡导致的。我们的研究结果表明，拓扑约束在非平衡协同行为中起着至关重要的作用。
