Models for Spatio-angular Self-organization in Cell Biology

In the past, models for population distributions have tended to dwell exclusively on spatial distribution and temporal dynamics. In nature, however, the relative orientations of individuals may have an important influence on their dynamics and interactions, increasing the level of complexity of corresponding biological phenomena. On the cellular level, a related in vitro phenomenon is the mutual contact and self-organization in mammalian cells such as fibroblasts on a surface (Elsdale & Bard 1972). When fibroblasts are grown in culture the following se­quence of events is observed. As cells come into contact they assume a bipolar morphology. Cell density increases as a result of cell division and clusters of cells become aligned in parallel arrays (cells remain in a monolayer if collagenase has been added to the culture). The patchwork of arrays that form is relatively sta­ble, though gradually the singularities in the alignment field annihilate each other so that finally all patches tend towards the same direction. The corresponding three-dimensional in vivo process plays an important role in morphogenesis.