Car crashes, battle wounds, and surgeries can leave people with gaping holes in soft tissue that are often too large for their bodies to repair. Now, researchers have developed a nanofiber-reinforced injectable gel that can rebuild missing muscle and connective tissues by serving as a scaffold and recruiting the body’s wound-healing cells. So far, the team has tested the material only in rats and rabbits. But if it performs as well in humans, it could give reconstructive surgeons a fast and easy way to help patients regenerate lost tissues without scarring or deformity.