Effects of changes in some electrospinning parameters on fibroin nanofibers morphology

Silk fibroin (SF) is a natural fibrous protein that has been widely studied for application in the biomedical field as a matrix for tissue engineering. Pure fibroin was extracted from silk cocoon by degumming method using aqueous Na۲CO۳ solution followed by solubilizing in CaCl۲-C۲H۵OH-H۲O aqueous solution and frozen in liquid nitrogen, then lyophilized in freeze-dryer. SF fibers with diameters down to the nanometer range are formed by subjecting a fluid jet to a high electric field. The electrospinning of the SF sponge was performed with formic acid, as a spinning solvent, at ۷% (w/w) fibroin concentration. In this regard, electrospinning parameters including voltage, flow rate, and distance were used as variable parameters, and the effect of changes in these parameters was investigated. The morphology of SF nanofibers was characterized by SEM. As the flow-rate increased, the available polymer volume was high, increasing the nanofiber diameter. Also, the lower the solution flow rate, the smaller the diameter of the resultant electrospun nanofibers and bead defects. With an increase in the distance between the capillary and the collector the nanofiber diameter initially decreased to a minimum and then increased.