The Formation Mechanism of Guanine Crystals in Snake Iridophores

Coloration in vertebrates is a complex phenomenon and plays an essential role in survival and communication. Snakes exhibit a range of vibrant colors and patterns through the interaction of light with pigments or reflective guanine crystals found within specialized color-producing cells (chromatophores) in the dermis. The formation and development of these chromatophores and their underlying optical materials remain unexplored. Our research shows striking similarities in guanine crystal formation mechanisms across phylogenetically<br/>distant species [1,2], supporting the existing hypothesis that macromolecular sheets within the crystal-containing vesicles universally act as templates for crystal growth [2]. We have conducted in vitro studies examining several factors that affect the biomineralization process. Our research adopts a bottom-up approach to gain insights into the composition and the mechanisms by which macromolecular templates guide the crystallization of guanine. The findings enhance our knowledge of the intricate mechanisms behind color-producing systems in animals, opening possibilities for developing biomimetic materials with tailored optical properties.<br/><br/>1. A. Wagner et al., The nonclassical crystallization mechanism of a composite biogenic<br/>guanine crystal. Advanced Materials. 34 (2022)<br/>2. A. Wagner et al., Macromolecular Sheets direct the morphology and orientation of plate-like<br/>biogenic guanine crystals. Nature Communications. 14 (2023)