Suture retention strength of bilayer vascular grafts made of PCL, PLA and their copolymer

Abstract

The mechanical characteristics of small-diameter vascular grafts, including factors like modulus, elasticity, compliance, burst strength, and suture retention strength, need to be in line with those of native blood vessels. Even a slight mismatch in mechanical properties between the graft and the native vessel can lead to graft failure. Suture retention strength, a critical mechanical aspect, represents the force needed to remove a stitch from the graft or cause the graft wall to rupture. This property is vital for preventing leaks, maintaining proper blood flow, aiding tissue healing, ensuring long-term durability, and reducing complications in vascular grafts. In this study, bilayered vascular grafts are fabricated by electrospinning using polycaprolactone (PCL), poly (lactic acid) (PLA), and poly(l-lactide-co-caprolactone) (PLCL) polymers. The actual suturing conditions of vascular scaffolds are simulated and how the choice of polymer for the inner layer affects suture retention strength is assessed. At the post-mechanical stage, the morphologies of the scaffolds are investigated to gain a clearer understanding of how the material reacts to applied forces. The findings reveal that all the fabricated bilayer vascular scaffolds exhibit excellent suture performance, with strength values exceeding 10 N, and that polymer selection for the inner layer for the grafts significantly influences the results. Blending PCL and PLA in the inner layer is found to reduce suture retention strength, while using neat polymers results in better retention strength. This experiment offers a more precise assessment of suture retention strength for bilayer vascular grafts, facilitating further optimization of tissue-engineered grafts to meet specific mechanical requirements.