Effect of molecular weight and storage time on the wet- and electro-spinning of regenerated silk fibroin

This study examined the effects of the molecular weight (MW) of silk fibroin (SF) and the storage time of dope on the wet- and electro-spinning of regenerated SF. The viscosity of the SF formic acid solution was reduced slightly but constantly just after the dissolution of SF in formic acid. Nevertheless, the wet- and electro-spinnability of SFL and SFC3 did not deteriorate until 3 days storage time of dope. In addition, the mechanical properties of the SFL and SFC3 wet spun filaments did not decrease until 2 days storage time. This suggests that there was no problem with the wet spinning and electro-spinning of SFL and SFC3 until 2 and 3 days storage of dope, respectively. More rapid biodegradation of the wet spun SF filament could be achieved by decreasing the MW. The mean diameter of the electrospun SF fibre could be controlled from 100 to 800 nm by the change in MW of SF and storage time of dope.