(754g) Fabrication of Tubular Scaffolds from Silk Fibroin Using Biologically Inspired Gel Spinning Technique

The applications for tubular scaffolds within the field of tissue engineering are numerous, provided they could be engineered with the proper mechanical, biological, and degradation properties. Previously, we demonstrated the utility of tubes fabricated from silk fibroin to fulfill this need (Lovett et al., 2007). Tubes covering a wide range of diameters (0.2 to 6.0 mm) were produced quickly and simply using a dipping method, whereby a rod was successively dipped in a silk fibroin solution and a methanol solution to induce beta-sheet formation. We have since developed a gel spinning technique to fabricate tubes with improved biological and mechanical properties. In this process, the silk is driven through a small gauge needle, which induces a shear stress upon the amorphous concentrated fibroin (silk I) helping to exclude water from the protein solution, align the silk fibrils, and induce silk II (antiparallel β-sheet, aqueous insoluble) structure. This process mimics the process of protein spinning in the native silkworm, where fibroin concentration and physical shear play critical roles in the spinneret. The gel spinning process allows properties such as winding pattern, tube porosity, and tube composition to be controlled in the new process described here, with further options during post-winding processing via treatment with methanol, air-drying, and/or lyophilization. Silk fibroin tubes generated using this new process have applications within tissue engineering, from blood vessel grafts and nerve guidance channels to in vitro migration assays, permeability studies, and novel composite scaffolds in general.

Lovett, M., Cannizzaro, C., Daheron, L., Messmer, B., Vunjak-Novakovic, G., and Kaplan, D. L. (2007): Silk fibroin microtubes for blood vessel engineering. Biomaterials 28, 5271-5279.