A novel Silk/Polyester woven small diameter arterial prosthesis: Degumming and the influence on cytocompatibility

Abstract

Sericin gum is like a two edged sword! It acts as the natural binder to maintain the structural integrity of silk filaments as well as to make the yarn more abrasion resistant. However, when used as an implantable device, for example, an arterial prosthesis, the presence of sericin increases the toxicity of the material. It is therefore necessary to remove all sericin before implantation. Although there are many methods to remove the sericin in the silk yarns or flat fabrics fabricated from silk yarns, there is little report about the method to degum silk in the tubular fabrics especially about small diameter (d≤6 mm) ones. In this study, small diameter arterial prostheses were woven using silk yarns still coated in sericin until the weaving process was completed. Then the samples were scoured to remove the sericin gum in sodium carbonate (0.05 wt. %) at 87 °C for 90 min with mechanical action. In order to make sure 90 min is enough to remove the sericin, the degumming time was extended to 210 min for some samples. Moreover, the degumming effect was examined on both inner and outer surfaces of the tubular samples to test the efficiency of the degumming method. The samples were first dyed with a picric acid-camine compound dye liquor which produces a red color with sericin and a yellow color with silk fibroin. After 90 min scouring, the samples showed a yellow color which indicates that the sericin had been removed completely by the degumming process. The effect of degumming was confirmed gravimetrically by measuring the weight loss, which was between 13.79 % and 23.99 % and remained steady after 90 min. Above all, the cytotoxicity was applied as one of the method to inspect the efficiency of degumming, which showed the result that, after degumming the samples were cytocompatible which is fit for implantation.