As an effective physical method, cell squeezing technology based on microfluidics plays an increasingly promising role in intracellular delivery. To deepen our understanding of microfluidic chip design and optimization, it is essential to explore the underlying physics required in the generation of the appropriate tension for gating capsule membrane. In this investigation, an immersed finite element method (IFEM) has been adopted to simulate the interaction between capsule and fluid fields in microchannel with variable section. Having obtained the numerical results, the gating region on the membrane can be determined by the non-uniform tension distribution based on the critical gating membrane tension during the capsule translocates the microchannel. In addition, the gating integral, which is defined to measure the degree of gating, shows that the setting of driven pressure might be crucial for the design and optimization of the system. The numerical results demonstrate that the occurrence of secondary peak in deformed energy after the capsule passes through the confined microchannel under certain flow condition might be ascribed to the elastic recovery of the membrane. To investigate the effects of initial orientations, the translocation of an ellipsoid capsule through the channel has also been simulated numerically, which indicates that both flow shear force and compressive force due to the constrained solid wall have significant effects on membrane gating. Therefore, to improve the gating efficiency of capsule membrane, it is necessary to optimize various factors to achieve the balance among the compressive force, shear force and the translocation time.

作为一种有效的物理方法，基于微流控技术的细胞挤压技术在细胞内传递中发挥着越来越有希望的作用。为了加深我们对微流控芯片设计和优化的理解，必须探索为门控胶囊膜产生适当张力所需要的基本物理原理。在这项研究中，采用了一种浸入式有限元方法（IFEM）来模拟可变截面微通道中胶囊与流场之间的相互作用。已经获得了数值结果，可以基于胶囊移位微通道期间的临界门控膜张力，通过不均匀的张力分布来确定膜上的门控区域。此外，门控积分是用来测量门控程度的，表明驱动压力的设置对于系统的设计和优化可能至关重要。数值结果表明，在一定的流动条件下，胶囊通过受限的微通道后，变形能量中出现次高峰的原因可能是膜的弹性回复。为了研究初始取向的影响，还对椭圆形胶囊通过通道的移位进行了数值模拟，这表明由于固体壁受约束而产生的流动剪切力和压缩力均对膜门控具有显着影响。因此，为了提高胶囊膜的选通效率，需要优化各种因素以实现压缩力，剪切力和移位时间之间的平衡。