The browning of fruit and healing in insects has inspired the development of a material that regenerates and 'heals' itself after being damaged.

Surface injuries in fruit and insects expose phenolic compounds, which are then oxidized, forming a protective surface. Haeshin Lee and his colleagues at the Korea Advanced Institute of Science and Technology in Daejeon, South Korea, created a solution containing a phenol compound and a polyamine. When catalysed by oxygen, the chemicals reacted much as they do in fruit and insects, forming a film at the surface. When parts of the film were peeled away, it 'healed' itself, a process the authors repeated 40 times without seeing any measurable loss of strength.

Unlike other self-healing materials, the film does not require external stimuli such as increased pressure or temperature to trigger healing.

Adv. Mater. http://doi.org/f3r9bw (2016)