Bioinspired Polypeptide Photonic Films with Tunable Structural Color

We report a new synthetic strategy of combining N-carboxyanhydride (NCA) chemistry and photonic crystals for the fabrication of polypeptide structural color films. Driven by surface-initiated ring-opening polymerization, the di-NCA derivative of L-cystine (Cys) is introduced to replicate the functionalized colloidal crystal templates and construct freestanding P(Cys)films with tunable structural color. Furthermore, the feasibility of preparing patterned polypeptide photonicfilms is demonstrated via templatemicrofabrication. Because of the incorporation ofL-glutamate (Glu) components, the P(Cys-co-Glu) co-polypeptidefilms areendowed with a visual color responsiveness toward pH changes. Additionally, the polypeptide photonic films show on-demanddegradability. Given the large family of amino acid building blocks, this powerful and versatile approach paves the way for chemical derivatization of multifunctional peptide-based optical platforms