Ion-Triggered Hydrogels Self-Assembled from Statistical Copolypeptides

Statistical copolypeptides comprising lysine and tyrosine with unprecedented ion-induced gelation behavior are reported. Copolypeptides are obtained by one-step N-carboxyanhydride (NCA) ring-opening polymerization. The gelation mechanism is studied by in situ SAXS analyses, in addition to optical spectroscopy and transmission electron microscopy (TEM). It is found that the gelation of these statistically polymerized polypeptides is due to the formation of stable intermolecular beta-sheet secondary structures induced by the presence of salt ions as well as the aggregation of an alpha-helix between the copolypeptides. This behavior is unique to the statistical lysine/tyrosine copolypeptides and was not observed in any other amino acid combination or arrangement. Furthermore, the diffusion and mechanical properties of these hydrogels can be tuned through tailoring the polypeptide chain length and ion strength.

Automated summary

The ion-induced gelation behavior of statistical copolypeptides comprising lysine and tyrosine is studied, and it is found that the gelation mechanism is related to the formation of stable intermolecular beta-sheet secondary structures induced by the presence of salt ions as well as the aggregation of an alpha-helix between the copolypeptides. The diffusion and mechanical properties of the hydrogels can be tuned by adjusting the polypeptide chain length and ion strength.