Electrospun regenerated silk fibroin mats with enhanced mechanical properties

In this paper, a simple and effective method was applied to enhance regenerated silk fibroin (RSF) mats electrospun from aqueous solution. The mats were first mechanically drawn in 90 vol.% ethanol aqueous solution and then immersed in the same solution for 30 min. The morphology, structure, thermal and mechanical properties of the RSF mats with different draw rates and draw ratios were investigated by scanning electron microscope (SEM), Raman spectroscopy, wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and tensile test. Results revealed that the content of β-sheet conformation, the crystallinity and the number of fibers aligned to the drawing direction increased evidently with the draw ratio. The breaking strength and breaking energy of the post-treated mats at 1.4× draw ratio and 0.1 mm/s draw rate were 8.6 MPa and 172.2 J/kg, respectively. However, those of the as-spun mats were only 1.8 MPa and 93.2 J/kg, respectively. The enhanced RSF mats prepared from entirely aqueous solutions may have extensive applications for tissue engineering.