Influence of electrospinning parameters on morphology and size of silk fibroin fibers

Abstract

The processing of silk fibroin (SF) by means of the electrospinning technique has opened a wide field of pos-sibilities to generate fibrillar membranes at micro and nanometric scale, which together with the biocompati-bility properties and outstanding mechanical properties of this protein, enhance its use in various engineering and biomedical applications. The electrospinning processes are subject to a large number of variables and the interactions between them, which in turn affects the morphological properties of the material obtained. In the present work we used SF from Colombian sericulture residues, dissolved in formic acid at 10% w/w, two electric field conditions were studied (R=1 and 2 kV/cm) at three distances (8, 10 and 12 cm) and under two flow conditions (0.05 and 0.1 mL/h). The fibrous membranes obtained were characterized by scanning elec-tron microscopy (SEM); the images were analyzed with the ImajeJ software to establish the presence of beads defects, their diameters, and distributions. We found that the minor electric field R=1 decreased the appearance of defects. An analysis of variance (ANOVA) was performed under this condition and the comparison of means was made using the Tukey test (P <0.05) for the variables that showed significant differ-ences, using the statistical software R. The results indicate that the parameters with significant effect were the flow and the distance. Therefore, it was established that, among the variables studied, the results obtained with R=1 kV/cm, distance of 12 cm and flow of 0.1 mL/h, promoted the obtaining of fibrillar membranes with uniform nanometric diameters and without beads defects.