Physical Principles of Extracellular Matrix Generation in Multicellular Organisms

Many events in the development of higher organisms, from the formation of the gastrointestinal system and the spinal cord to the eye, involve geometrical and even topological rearrangements of tissues taking the form of laterally extended cell sheets and their accompanying extracellular matrix. Similar tissue folding occur at various points in the life cycles of the simplest multicellular organisms: green algae and sponges, the basalmost of animals. In these organisms, developmental transformations manifest the interplay between generation of an extracellular matrix and geometrical transformations of tissues, yet there has been little biophysical quantification of these processes nor a biomechanical understanding of them. We seek to understand physical principles that govern the shapes and elasticity of tissues in these simplest multicellular organisms, to understand evolutionary precedents for related processes in higher organisms, and to answer the question: How do cells make structures external to themselves in a robust and accurate manner? This research involves a synthesis of experimental and theoretical work, using advanced imaging, micromanipulation, and force measurements in concert with mathematical theory to quantify and explain developmental dynamics, to place these results within evolutionary scenarios, and to open up new areas at the biology/physics interface.