Reprinted from Environmental Health News
BOSTON—Standing at a lab bench, Tanya Shirman eyes her creation: a tiny glass vial filled with an iridescent, sand-like material.
Holding it between her thumb and forefinger, she gives the vial a gentle shake, and the material inside turns from shimmering blues to greens.
"This is what happens in butterfly wings," the petite Shirman, lifting her voice over the roar of a lab fume hood, told EHN. "The spectrum of colors changes from the structures in the wings at the nanoscale," that is, a scale hundreds of thousands of times smaller than the head of a pin.
Shirman, vice president of materials design at the Boston-based startup Metalmark Innovations, is referring to the concept of structural color found in nature—such as in butterfly wings, bird feathers, beetles, berries, and the sky.
In a butterfly's wings, for example, chitin—a complex carbohydrate that forms the outer shell of arthropods, insects, crustaceans, fungi and some algae—is ordered in ways that reflect or refract the light, like tiny prisms. These same microscopic structures that bring beauty to a butterfly also provide strength, lightness, and water repellency. It's this efficient design that has captured the imagination of Metalmark's founders and inspired their invention: indoor air purification systems that destroy, rather than trap, volatile organic compounds, viruses, and ultrafine particles.
Note: Metalmark Innovations was a finalist for the 2020 Ray of Hope Prize, awarded by the Biomimicry Institute and the Ray C. Anderson Foundation. Additionally three other finalist teams are highlighted in this article: Werewool, spotLESS Materials and Cypris Materials.