Effect of Shear on Structural Organization of Various Recombinant Spidroins

To follow the structural reorganization of spidroin during its spinning, the rheological behavior of low-concentration solution of recombinant spidroins rS1/9 and rS2/12 is studied on different stages of separation, purification, and lyophilization. It is shown that spidroin solutions with concentration of 1 mg mL(-1) appear to be structured liquids with yield stress around value 0.2 Pa. Distribution of hydrodynamic radii of spidroins reveals two peaks due to presence of single particles and aggregates both. Their ability for spidroin transformation from micellar to fibrillar structure under shear stress is demonstrated. Studying rheological behavior of recombinant spidroin solutions and their supramolecular organization is necessary to select the optimal spinning parameters to produce fibrous materials with required physicochemical properties.