Artificial melanin particles: new building blocks for biomimetic structural coloration

Melanin, a black component of human hair, plays an important role in bright structural colorations in nature. For example, the beautiful and highly visible colorations of peacock feathers are achieved by periodic structures formed by melanin granules that have light absorbing capabilities. In recent years, polydopamine, which is easily obtained by the self-oxidative polymerization of dopamine, has attracted attention as a mimic of natural melanin. This focus review provides an overview of our recent research on structural color materials created using polydopamine-based artificial melanin particles and research trends in this area. Melanin, a black component of human hair, plays an important role in bright structural colorations in nature. Polydopamine-based artificial melanin particles, inspired by natural melanin and its important role in structural coloration, were used to produce bright structural colors by controlling light reflection and absorption. A variety of structural coloration characteristics have become possible through our investigations of the assembly structure, composition, shape, and application of artificial melanin particles.