Biomimetic Colorants and Coatings Designed with Cephalopod-Inspired Nanocomposites

Abstract

Brilliant\nand dynamic colors in nature have stimulated the design\nof dyes and pigments with broad applications ranging from electronic\ndisplays to apparel. Inspired by the nanostructured pigment granules\npresent in cephalopod chromatophore organs, we describe the design\nand fabrication of biohybrid colorants containing the cephalopod-specific\npigment, xanthommatin (Xa), encased within silica-based nanostructures.\nWe employed a biomimetic approach to encapsulate Xa with amine-terminated\npolyamidoamine (PAMAM) dendrimer templates, which helped stabilize\nthe pigment during encapsulation. Depending on the concentration of\nXa used in the reaction, the resultant biohybrid nanomaterials generated\na range of neutral colors of differing hues. When applied as coatings,\nthese colorants can be triggered to change color from yellow/gold\nto red in the presence of a chemical reducing agent, as we leverage\nthe natural redox-dependent color change of Xa. Altogether, these\ncapabilities demonstrated the ability to process biochromes like Xa\nas nanomaterials that can be applied as coatings with a tunable and\ndynamic range.