High-resolution topographic imaging of environmentally responsive, elastin-mimetic hydrogels

The morphological changes in the microstructure of an environmentally responsive protein polymer and hydrogel are investigated upon phase transition using high resolution topographic images. These images are obtained under native, hydrated conditions using a combination of extremely rapid cryo-immobilization and in-lens field emission SEM at low temperature. Results show that the local conformation of the polypeptide chain undergoes reversible conversion from a random coil to a type II beta-turn as the temperature approaches the coacervation point. These results suggest that the polymer behaved as a coil of effective polymer segment and that the conformational change in elastin-mimetic polypeptides is equal with the microstructural reorganization.