Department of Mechanical Engineering, Shahrood University of Technology, Shahrood, Iran.
Sci Rep. 2021 Jan 26;11(1):2235. doi: 10.1038/s41598-021-81608-7.
One of the unresolved issues in physiology is how exactly myosin moves in a filament as the smallest responsible organ for contracting of a natural muscle. In this research, inspired by nature, a model is presented consisting of DPD (dissipative particle dynamics) particles driven by electro-osmotic flow (EOF) in micro channel that a thin movable impermeable polymer membrane has been attached across channel width, thus momentum of fluid can directly transfer to myosin stem. At the first, by validation of electro-osmotic flow in micro channel in different conditions with accuracy of less than 10 percentage error compared to analytical results, the DPD results have been developed to displacement of an impermeable polymer membrane in EOF. It has been shown that by the presence of electric field of 250 V/m and Zeta potential - 25 mV and the dimensionless ratio of the channel width to the thickness of the electric double layer or kH = 8, about 15% displacement in 8 s time will be obtained compared to channel width. The influential parameters on the displacement of the polymer membrane from DPD particles in EOF such as changes in electric field, ion concentration, zeta potential effect, polymer material and the amount of membrane elasticity have been investigated which in each cases, the radius of gyration and auto correlation velocity of different polymer membrane cases have been compared together. This simulation method in addition of probably helping understand natural myosin displacement mechanism, can be extended to design the contraction of an artificial muscle tissue close to nature.
在生理学中，一个悬而未决的问题是，作为天然肌肉收缩的最小责任器官，肌球蛋白在纤维中是如何运动的。在这项受自然启发的研究中，提出了一个模型，该模型由在微通道中驱动的 DPD（耗散粒子动力学）粒子组成，在微通道中，一个薄的可移动不可渗透的聚合物膜横跨通道宽度附着，从而流体的动量可以直接传递到肌球蛋白干上。首先，通过在不同条件下对微通道中的电渗流进行验证，与解析结果相比，误差小于 10%，从而将 DPD 结果发展为电渗流中不可渗透聚合物膜的位移。结果表明，在电场强度为 250 V/m 和 Zeta 电位为-25 mV 以及无量纲通道宽度与电双层厚度比 kH=8 的情况下，与通道宽度相比，将在 8 s 内获得约 15%的位移。研究了电渗流中聚合物膜从 DPD 粒子位移的影响参数，如电场变化、离子浓度、Zeta 电位效应、聚合物材料和膜弹性量等，在每种情况下，都比较了不同聚合物膜案例的转动半径和自动相关速度。这种模拟方法除了可能有助于理解天然肌球蛋白的位移机制外，还可以扩展到设计接近自然的人工肌肉组织的收缩。
