Biological growth and synthetic fabrication of structurally colored materials

Abstract

Nature’s light manipulation strategies—in particular those at the origin of bright iridescent colors—have fascinated humans for centuries. In recent decades, insights into the fundamental concepts and physics underlying biological light-matter interactions have enabled a cascade of attempts to copy nature’s optical strategies in synthetic structurally colored materials. However, despite rapid advances in bioinspired materials that emulate and exceed nature’s light manipulation abilities, we tend to create these materials via methods that have little in common with the processes used by biology. In this review, we compare the processes that enable the formation of biological photonic structures with the procedures employed by scientists and engineers to fabricate biologically inspired photonic materials. This comparison allows us to reflect upon the broader strategies employed in synthetic processes and to identify biological strategies which, if incorporated into the human palette of fabrication approaches, could significantly advance our abilities to control material structure in three dimensions across all relevant length scales.

Evolution of single gyroid photonic crystals in bird feathers

“…Simulations ( 15 ) suggest that the phase behavior of patchy particles with mutual short-range attraction and long-range repulsion can include a metastable single gyroid phase. Future research into in vivo and in vitro arrested phase separation of colloidal solutions of charged proteins or similar polymers may provide novel insights into synthetic self-assembly of ordered mesoporous phases, including the single gyroid ( 4 ).…”

“…Structural coloration is an important aspect of their appearance, and often functions in social and sexual signaling ( 3 ). Physicists and engineers are increasingly interested in animal structural coloration as a source of inspiration for mesoscale manufacture ( 4 , 5 ). A remarkable diversity of structural color-producing three-dimensional (3D) biophotonic nanostructures has been characterized within the chitinaceous exoskeletons of invertebrates ( 1 , 2 , 6 ).…”

Controlling colloidal crystals via morphing energy landscapes and reinforcement learning

“…Controlling assembly of colloidal particles into different microstructures and morphologies could provide a basis to fabricate hierarchically structured materials with nontrivial emergent properties (e.g., optical, mechanical, thermal, and acoustic) important to numerous technologies ( 1 ). Many naturally occurring biological materials provide inspiration for creating periodic microstructures with unique multifunctional properties, where these microstructures often have repeat units that could be realized by assembling colloidal components ( 2 , 3 ). However, despite a common recognition that colloidal assembly could provide a route to synthetic materials that mimic biological material structures and properties, many approaches are limited by defects, as well as scalability and structural diversity.…”

Evolution of Single Gyroid Photonic Crystals in Bird Feathers

“…Structural coloration is an important aspect of their appearance, and often functions in social and sexual signaling (3). Physicists and engineers are increasingly interested in animal structural coloration as a source for inspiration for mesoscale manufacture (4,5). A remarkable diversity of structural-color producing 3D biophotonic nanostructures has been characterized within the chitinaceous exoskeletons of invertebrates (1,2,6).…”