Self-Assembly of Elastin-Mimetic Double Hydrophobic Polypeptides

We have constructed a novel class of double-hydrophobic block polypeptides based on the hydrophobic domains found in native elastin, an extracellular matrix protein responsible for the elasticity and resilience of tissues. The block polypeptides comprise proline-rich poly(VPGXG) and glycinerich poly(VGGVG), both of which dehydrate at higher temperature but form distinct secondary structures, beta-turn and beta-sheet respectively. In water at 45 degrees C, the block polypeptides initially assemble into nanoparticles rich in beta-turn structures, which further connect into long (>10 mu m), beaded nanofibers along with the increase in the beta-sheet content The nanofibers obtained are well dispersed in water, and show thermoresponsive properties. Polypeptides comprising each block component assemble into different morphologies, showing that the conjugation of poly(VPGXG) and poly(VGGVG) plays a role for beaded fiber formation. These results may provide innovative ideas for designing peptide based materials but also opportunities for developing novel materials useful for tissue engineering and drug delivery systems.