Investigating the Effects of Laser Induced Cavitation Bubbles and Fast Calcium Influx in Wound Healing

A major challenge in biology and medicine is understanding the mechanisms of epithelial wound healing, i.e., identifying how an epithelial tissue repairs a wound through coordinated and patterned changes in cellular behavior. A key question is how the patterns of cell behavior relate to the patterns of cellular damage around a wound. To investigate this relationship, we make laser wounds in the notal epithelium of Drosophila pupae. Laser ablation makes a controlled and reproducible pattern of cellular damage via both plasma generation at the focus and a rapidly expanding and collapsing cavitation bubble, which applies shear stress that damages the plasma membrane of surrounding cells. The subcellular location of this damage can be tracked using the patterns of rapid calcium influx on millisecond time scales. We can also use fluorescent cell surface markers to track rapid displacements across the field of cells. Combining the displacement fields and patterns of fast calcium influx, we can relate shear-stress to damage around the wound and on to the pattern of cell behaviors observed on longer time scales.