It might have taken billions of years, but nature, for the most part, has been very successful at solving many of the problems we find ourselves confronting today. It's a realization that has taken some time to sink in, but which has now grown into a discipline called biomimicry. Biomimicry is all about learning from nature; studying nature's designs and emulating these to solve human challenges. Which is how we ended up with products like Velcro and self-cleaning coatings.
One of the more intriguing capabilities in nature is, however, the number of biological systems that are able to self heal. Scientists, spurred on by the potential economic benefits of materials that would be able to repair themselves - longer lifetime, lower maintenance costs and more efficiency - have worked to develop self-healing systems for various materials, including plastics. And with success: various polymers are now available which have the intrinsic ability to repair damage caused by usage over time. Up until now, however, composites, were a whole different ballgame. But once again, nature showed the way.
The most common type of damage occurring in fiber-reinforced composites is delamination. Internal delamination damage in composites is not only difficult to detect, it is nearly impossible to repair by conventional methods. It is a problem that has been a significant factor limiting more widespread use of these materials, as a small, internal crack can quickly develop into irreversible damage.