Modulating water-responsive actuation energy of regenerated silk fibroin via tyrosine modification

Water-responsive actuation energy density of regenerated silk fibroin is doubled through tyrosine residue modification, increasing from 1.6 MJ m^-3 to 3.5 MJ m^-3. FTIR spectroscopy showed the modification results in a higher proportion of mobile water, suggesting that water-responsive performance of regenerated silk is highly sensitive to the properties of confined water and that tyrosine residue modification could serve as a scalable method for developing silk-based WR actuators.