Cross-Linked, Self-Fluorescent Gold Nanoparticle/Polypeptide Nanocapsules Comprising Dityrosine for Protein Encapsulation and Label-Free Imaging

Cross‐linked, self‐fluorescent Au nanoparticle/polypeptide nanocapsules comprising dityrosine are prepared by the self‐assembly of the random copolypeptides comprising L‐lysine and L‐tyrosine upon subsequent cross‐linking of tyrosine residues by chloroaurate reduction. These nanocapsules are demonstrated be useful as encapsulants for protein encapsulation and as optical probes for label‐free cell imaging. The reduction process is so mild that the protein can still retain its function.