Enhanced Stability of Peptide Nanofibers Coated with a Conformal Layer of Polydopamine.

The susceptibility of self-assembled materials to changes of environmental conditions and mechanical forces often limits their utility for many applications. In this work, the surface of nanofibers formed by β-sheet peptide self-assemblies were coated by polydopamine (PDA) deposition. This conformal coating process rendered the nanofiber dimensions and internal π-stacking chirality impervious to changes in pH, temperature, and physical processing by spin-coating onto a silicon wafer. Whereas sonication-induced shearing of the dopamine/naphthalenediimide-dilysine (DA/NDI-KK) composite irreversibly shortened the nanofibers into 100-200 nm segments, the uncoated nanofibers unraveled into single strands upon similar treatment. Additionally, the PDA-coated nanofibers could be wrapped by an additional layer comprised of a positively charged polyelectrolyte polymer.