Characterization of a PEG-DE cross-linked tubular silk scaffold

Abstract

The secondary structure and compliance of a novel small caliber (≤6 mm) silk fibroin (SF) tubular scaffold (SFTS) were investigated. Imitating the structure of natural vascular tissue, the SFTS consisted of a silk knit as the medium and a poly(ethylene glycol) diglycidyl ether (PEG-DE) cross-linked silk fibroin (SF) membrane as the intimal and adventitial layers, integrated to form a porous tissue. FTIR and XRD results showed that PEG-DE could induce SF molecules to form β-sheets during the cross-linking reaction process, resulting in improved crystallinity. As a result of the silk knit medium the SFTS had excellent mechanical properties. The intimal layer, which is in contact with a continuous flow of blood, must have adequate compliance. The results showed that the intimal layer of the SFTS had good stress-strain resistance when combined with the silk knit medium. When the SFTS was prepared with 6% SF, its axial breaking strength was >62 kPa and breaking elongation could reach about 33%; the circumferential breaking strength was >10 MPa and breaking elongation was >18%. The results of compression testing showed that the radial compression resilience of SFTS reached 94%, which was a significant improvement on commercial artificial blood vessels prepared from Dacron.