By installing a biomimetic dityrosine bond in a covalent self-assembly of short peptides, D.-P. Kim et. al., as reported in their Communication on
page 6925 ff., achieved the direct synthesis of fluorescent peptide hollow nanocages and free-standing thin films without the aid of a template. The crosslinked peptide thin films exhibited superior mechanical and conformational durability compared to the noncovalent peptides.