The ability to migrate is a fundamental property of animal cells which is essential for development, homeostasis and disease progression. Migrating cells sense and respond to biochemical and mechanical cues by rapidly modifying their intrinsic repertoire of signalling molecules and by altering their force generating and transducing machinery. We have a wealth of information about the chemical cues and signalling responses that cells use during migration. Our understanding of the role of forces in cell migration is rapidly evolving but is still best understood in the context of cells migrating in 2D and 3D environments in vitro. Advances in live imaging of developing embryos combined with the use of experimental and theoretical tools to quantify and analyse forces in vivo, has begun to shed light on the role of mechanics in driving embryonic cell migration. In this review, we focus on the recent studies uncovering the physical basis of embryonic cell migration in vivo. We look at the physical basis of the classical steps of cell migration such as protrusion formation and cell body translocation and review the recent research on how these processes work in the complex 3D microenvironment of a developing organism.

迁移能力是动物细胞的基本特性，对发育、体内平衡和疾病进展至关重要。迁移细胞通过快速修改其内在的信号分子库并通过改变其力产生和转导机制来感知和响应生化和机械线索。我们有大量关于细胞在迁移过程中使用的化学线索和信号反应的信息。我们对力在细胞迁移中的作用的理解正在迅速发展，但在体外 2D 和 3D 环境中细胞迁移的背景下仍能得到最好的理解。结合使用实验和理论工具来量化和分析体内力的发育胚胎实时成像的进展，已经开始阐明力学在驱动胚胎细胞迁移中的作用。在这篇综述中，我们重点关注最近揭示胚胎细胞在体内迁移的物理基础的研究。我们着眼于细胞迁移的经典步骤（例如突起形成和细胞体易位）的物理基础，并回顾了最近关于这些过程如何在发育中的生物体的复杂 3D 微环境中发挥作用的研究。