Bacteria and leukocytes employ donut-shaped transcellular holes in plasma membrane to cross the endothelial barrier. How these fused holes are regulated in a double-bilayer system is currently poorly understood. Here we use membrane physics to present a universal relationship that determines the geometry of the donut-shaped holes. Our study reveals that hole radius is determined by plasma membrane tension via a commonly used critical length scale $\sqrt{\kappa /\lambda }$ defined by flexural stiffness ($\kappa$) and in-plane tension ($\lambda$). This relationship suggests that the hole diameter increases with a reduction in membrane tension, a finding aligned with the experimental observations but in contrast with the main current model in the literature.

细菌和白细胞利用质膜中的甜甜圈形跨细胞孔穿过内皮屏障。这些融合的孔是如何在双双层系统中调节的，目前还知之甚少。在这里，我们使用膜物理学来呈现确定甜甜圈形孔几何形状的通用关系。我们的研究表明，孔半径是由质膜张力通过常用的临界长度尺度决定的$\sqrt{\kappa /\lambda }$ 由弯曲刚度定义 ($\kappa$) 和面内张力 ($\lambda$）。这种关系表明孔径随着膜张力的降低而增加，这一发现与实验观察一致，但与文献中的主要电流模型相反。