BACKGROUND Gravity, especially hypergravity, can affect the morphology of membranes, and further influence most biological processes. Since vesicle structures are relatively simple, the vesicle can be treated as a vital model to study the mechanical properties of membranes in most cases. Basic research on membrane tension has become a vital research topic in cellular biomechanics. METHODS In this study, a new vesicle model is proposed to quantitatively investigate the response of membrane tension to gravity. In the model, the aqueous lumen inside the vesicle is represented by water, and the vesicle membrane is simplified as a closed, thin, linear elastic shell. Then, the corresponding static equilibrium differential equations of membrane tension are established, and the analytical expression is obtained by the semi-inverse method. The model parameters of the equations are accurately obtained by fitting the reported data, and the values calculated by the model agree well with the reported results. RESULTS The results are as follows: First, both the pseudo-ellipsoidal cap and the pseudo-spherical cap can be used to describe the deformed vesicle model; however, the former can better represent the deformation of the vesicle model because the variance of the pseudo-ellipsoidal cap is smaller. Second, the value of membrane tension is no longer a constant for both models. Interestingly, it varies with the vesicle height under the action of gravity. The closer it is to the substrate, the greater the membrane tension. Finally, the inclination between the tangent and the radial lines at a certain point is nearly proportional to the radius of the cross section in both models. CONCLUSION These findings may be helpful to study the vesicle model spreading more accurately by taking into account the influence of gravity because it could affect the distribution of membrane tension. Furthermore, it may also provide some guidance for cell spreading and may have some implications for membrane tension-related mechanobiology studies, especially in the hypergravity conditions.

中文翻译：

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在近似细胞模型中膜张力对重力的响应。

背景技术重力，特别是超重力，可以影响膜的形态，并进一步影响大多数生物过程。由于囊泡结构相对简单，因此在大多数情况下，囊泡可以作为研究膜的机械性能的重要模型。膜张力的基础研究已成为细胞生物力学中至关重要的研究课题。方法在这项研究中，提出了一种新的囊泡模型来定量研究膜张力对重力的响应。在该模型中，囊泡内部的水腔由水表示，囊泡膜简化为封闭的，薄的线性弹性壳。然后，建立了相应的膜张力静平衡微分方程，并通过半逆法得到了解析表达式。通过拟合报告的数据可以准确地获得方程的模型参数，并且模型计算的值与报告的结果非常吻合。结果结果如下：首先，伪椭圆形帽和伪球形帽都可以用来描述变形的囊泡模型。然而，前者可以更好地表示囊泡模型的变形，因为伪椭圆形帽的方差较小。其次，两个模型的膜张力值不再是常数。有趣的是，它在重力作用下随囊泡高度而变化。距基材越近，膜张力越大。最后，在两个模型中，切线和径向线之间在某个点处的倾斜度几乎与横截面的半径成比例。结论这些发现可能有助于研究囊泡模型，通过考虑重力的影响来更精确地扩散，因为它可能会影响膜张力的分布。此外，它还可以为细胞扩散提供一些指导，并可能对膜张力相关的力学生物学研究产生某些影响，尤其是在超重力条件下。