Composed of a melanin core and silica shell, the particles get their hues from tricks of light
Ming Xiao/Univ. of Akron
Tiny balls of melanin could someday paint the rainbow. They’re one of the key ingredients in a new way to craft a spectrum of structural colors — hues created when light interacts with special nanostructures.
Structural colors are a longer-lasting alternative to chemical pigments, which lose all pizazz when they break down. Examples of durable hues abound in nature. For instance, many bird feathers and butterfly wings get their brilliant colors in part from nanoscale texturing (SN: 6/11/16, p. 32). But finding a simple way to generate these complex structural colors — a technique that can be scaled up and used to create many different hues — has been a tricky task.
In the new study, researchers made nano-sized balls of melanin aggregate into clusters called supraballs. Melanin, the pigment that darkens skin, appears black in the individual