A new approach for small-diameter vascular grafts using combined dip-coating of silk fibroin and elastin-like recombinamers

Abstract

Compliance mismatch and suboptimal hemocompatibility prevent the use of the traditional materials used for vascular prostheses or degradable synthetic polymers as small-diameter vessel bypass grafts. Here, we show the combination of silk fibroin and elastin-like recombinamers in a dip-coating multilayer setup to achieve smooth small-diameter vascular grafts with ultrathin wall thickness. We found in both FTIR and mechanical characterization that the novel material combination was successful through the double crosslinked interpenetrated network formed by elastin-like recombinamers and silk fibroin. This enabled the graft to have mechanical compliance that followed physiological behaviour, differently from the synthetic materials traditionally used in clinics. The mechanical behaviour of these grafts also achieved burst pressure (745.44 ± 102.92 mmHg) and suture retention strength (0.86 ± 0.13 N) required for clinical application. The structure proved to have low platelet adhesion in the thrombogenicity assessment (3.79 ± 3.26 % of platelet area coverage), which is essential for successful outcomes in physiological conditions. Our results demonstrate the successful combination of the two materials in a technology platform that can be adjusted in both diameter and wall thickness and possesses suitable properties as a small-diameter vascular graft. We anticipate these results to be the starting point for more in vitro and in vivo tests possibly transitioning into clinical application.