The process by which wounds are repaired is more complex than was previously thought, reports a paper published online this week in Nature Physics. These findings motivate new strategies for assisted wound repair and provide insight into our understanding of how the spatial distribution and migration of cells enables tissue development.

Wound repair is initiated by cells that crawl towards the injury site, with later stages of the process relying on the contraction of a cable-like ring of biopolymers. This ring is thought to aid cell migration by drawing in like a purse-string to pull cells together over the damaged site.

Xavier Trepart and colleagues use traction force measurements - measurements of the force a cell exerts on its surroundings - to look at the physical forces involved as cells move towards the injury site. They suggest that in the second phase of healing, the biopolymer ring transmits a contractile force to its surroundings. This force compresses the extracellular environment, and steers the migrating cells towards the injury site.