Silk Vascular Grafts with Optimized Mechanical Properties for the Repair and Regeneration of Small Caliber Blood Vessels

Abstract

As the incidence of cardiovascular diseases has been growing in recent years, the need for small-diameter vascular grafts is increasing. Considering the limited success of synthetic grafts, vascular tissue engineering/repair/regeneration aim to find novel solutions. Silk fibroin (SF) has been widely investigated for the development of vascular grafts, due to its good biocompatibility, tailorable biodegradability, excellent mechanical properties, and minimal inflammatory reactions. In this study, a new generation of three-layered SF vascular scaffolds has been produced and optimized. Four designs of the SILKGraft vascular prosthesis have been developed with the aim of improving kink resistance and mechanical strength, without compromising the compliance with native vessels and the proven biocompatibility. A more compact arrangement of the textile layer allowed for the increase in the mechanical properties along the longitudinal and circumferential directions and the improvement of the compliance value, which approached that reported for the saphenous and umbilical veins. The higher braid density slightly affected the grafts’ morphology, increasing surface roughness, but the novel design mimicked the corrugation approach used for synthetic grafts, causing significant improvements in kink resistance.

Silk Fibroin Materials: Biomedical Applications and Perspectives

“…In addition, morphological and mechanical properties also play a primary role in the development of innovative devices. Hence, it has been proven that a braid scaffold morphology allows for deformation in the radial direction yielded by blood pressure, thus allowing for higher stretchability and, in turn, a reduced risk of graft occlusions [183].…”

The Influence of Textile Structure Characteristics on the Performance of Artificial Blood Vessels

“…In recent years, SF has also become a commonly used material in artificial blood vessel engineering and can play a role in small-diameter blood vessel grafts [ 140 , 141 ]. Not only does it have good biocompatibility and controllable biodegradability, but it also exhibits excellent mechanical properties and minimal inflammatory responses [ 142 ]. A research team designed a novel SF biomimetic scaffold composed of three different layers, with the tubular braided layer in the middle and the inner and outer layers constructed through freeze-drying.…”

MCP-1-Loaded Poly(l-lactide-co-caprolactone) Fibrous Films Modulate Macrophage Polarization toward an Anti-inflammatory Phenotype and Improve Angiogenesis

“…The fiber samples were incubated in an 80 RPM shaker at 37 °C for 28 days. The supernatants were completely removed and stored at −80 °C, and an equal amount of fresh PBS (pH 7.4) was supplemented each time at 1,2,3,4,5,6,7,8,10,12,14,16,18,20,22,24,26, and 28 days. The accumulated amounts of drug released were quantified using an MCP-1 ELISA kit (Peprotech Nordic, Sweden).…”

“…The commercially available synthetic vascular grafts fabricated from non-biodegradable polymers, such as expanded polytetrafluoroethylene (ePTFE) and polyethylene terephthalate (PET), have been clinically used for large-diameter vessels (>6 mm) . However, they are apt to fail in small-diameter vessels due to intimal hyperplasia, thrombosis formation, chronic foreign body reaction (FBR), mechanical mismatch, and a lack of functional endothelial coverage. ,, Small-diameter blood vessels remain a clinical challenge, and there is an urgent need for alternative solutions. , Recently, tissue engineering of small-diameter blood vessels has emerged as a promising solution with suitable mechanical properties and better biocompatibility. ,, As a promising tissue engineering approach, the electrospinning technique can fabricate nanofibrous scaffolds that have the potential to address these issues. ,− …”