| Popis: |
A variety of natural silk secretions (from spiders, silkworms and aquatic insect larvae), and also reconstituted silk solutions, are able to form a nematic liquid crystalline phase. The anisotropic structures that self-assemble in this phase are formed from the isotropic phase by aggregation of molecules, rather than by individual molecules undergoing a conformational change to a rod-like form. This enables the molecules to retain their solubility in water while, simultaneously, the viscosity of the solution is reduced. The liquid crystalline phase is stable under a wide range of equilibrium conditions, but its ability to form is sensitive to the rate at which the initially isotropic solution is allowed to dry. The kinetics of phase transitions exhibited by solutions of silk proteins must be taken into account if solutions of silk fibroin are to be successfully processed in vitro. |
