Embryos are growing organisms with highly heterogeneous properties in space and time. Understanding the mechanical properties is a crucial prerequisite for the investigation of morphogenesis. During the last 10 years, new techniques have been developed to evaluate the mechanical properties of biological tissues in vivo. To address this need, we employed a new instrument that, via the combination of micro‐indentation with Optical Coherence Tomography (OCT), allows us to determine both, the spatial distribution of mechanical properties of chick embryos, and the structural changes in real‐time. We report here the stiffness measurements on the live chicken embryo, from the mesenchymal tailbud to the epithelialized somites. The storage modulus of the mesoderm increases from (176 ± 18) Pa in the tail to (716 ± 117) Pa in the somitic region (mean ± SEM, n = 12). The midline has a mean storage modulus of (947 ± 111) Pa in the caudal (PSM) presomitic mesoderm (mean ± SEM, n = 12), indicating a stiff rod along the body axis, which thereby mechanically supports the surrounding tissue. The difference in stiffness between midline and presomitic mesoderm decreases as the mesoderm forms somites. This study provides an efficient method for the biomechanical characterization of soft biological tissues in vivo and shows that the mechanical properties strongly relate to different morphological features of the investigated regions.

中文翻译：

---

光学相干断层扫描辅助显微压痕对鸡胚中胚层的体内表征


胚胎是正在生长的生物体，在空间和时间上具有高度异质性。了解力学性能是研究形态发生的重要先决条件。在过去的十年中，已经开发出新技术来评估体内生物组织的机械性能。为了满足这一需求，我们采用了一种新仪器，通过将微压痕与光学相干断层扫描 (OCT) 相结合，使我们能够确定鸡胚胎机械性能的空间分布以及真实胚胎的结构变化。时间。我们在此报告活鸡胚胎从间充质尾芽到上皮体节的硬度测量。中胚层的储能模量从尾部的（176±18）Pa增加到体节区域的（716±117）Pa（平均值±SEM，n = 12）。尾部 (PSM) 前体中胚层中线的平均储能模量为 (947 ± 111) Pa（平均值 ± SEM，n = 12），表明沿身体轴有一根坚硬的杆，从而机械地支撑周围组织。随着中胚层形成体节，中线和体前中胚层之间的硬度差异减小。这项研究为体内软生物组织的生物力学表征提供了一种有效的方法，并表明机械性能与研究区域的不同形态特征密切相关。