(541b) Investigation of Shear and Extensional Rheology of Silk Fibroin in Applications of Tissue Engineering

Many tissues of the body rely on innate elastic properties to convey the proper function of the tissue. Loss of elasticity, especially in blood vessels, often leads to the onset of pathology. The tissue composition of blood vessels contain a high percentage of a protein that is called elastin. Elastin is largely responsible for the expansion and recoil of the vessel wall throughout the cardiac cycle. Elastin is notoriously challenging to process ex vivo while still retaining the same level of mechanical properties. Silk fibroin (SF) is an elastic protein, similar to elastin, that has impressive mechanical properties and biocompatibility, making it an attractive material in the development of tissue engineered blood vessels. Silk fibroin can be easily isolated from Bombyx mori silkworm cocoons however, the regenerated SF in water is an unstable solution delivering inhomogeneous results. The goal of this research is to control and characterize the SF at each step of the extraction-solubilization process to produce regenerated SF (rSF) in water. The resulting rSF solution is characterized via small amplitude oscillatory shear measurements and extensional rheology. The rSF is then processed using electrospinning or dip-coating to form a tube that is mechanically characterized via burst pressure and compliance measurements. Relationships can be formed between the rheological measurements and resulting mechanics of the tube. Furthermore, based on the rheological characterization of the solution, we can predict the successful application of a processing method and mechanical output of the final product.