Abstract
It has been suggested that mechanical factors influence morphogenesis. In this study, we aim to reveal stress distribution in fresh Xenopus laevis embryos. To estimate the stress distribution, we have been developing methods to measure surface topography and stiffness distribution on a section of the embryo. When an elastic body having residual stress is cut, pops and dents appear on the cut surface according to the direction and magnitude of the residual stress. In reality, however, fresh embryo is very soft and sticky, and its contents flow out easily after being cut. Active contraction occurs in ～45 s after cutting. Thus, we need to develop methods to cut the embryo with minimal damage and to observe its surface topography and stiffness distribution immediately after cutting. We measured the surface topography by cutting embryos along their median line in Steinberg's solution and observing the cut surface with a 3D laser scanning microscope (VK-X105, Keyence). Stiffness distribution was measured based on Hertzian contact theory by spraying metal microspheres 100 μm in diameter on the cut surface and observing their indentation.
