Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, United States.
Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, United States.
Acta Biomater. 2018 Mar 15;69:313-322. doi: 10.1016/j.actbio.2018.01.033. Epub 2018 Feb 2.
Small-caliber vascular grafts used in coronary artery bypass procedures typically fail due to the development of intimal hyperplasia or thrombosis. Our laboratory has developed a multilayered vascular graft with an electrospun polyurethane outer layer with improved compliance matching and a hydrogel inner layer that is both thromboresistant and promotes endothelialization. Initial in vivo studies showed that hydrogel particulates were dislodged from the hydrogel layer of the grafts during suturing. To address this problem, we developed and characterized a new hydrogel formulation that resists damage during suturing. Introduction of sacrificial, hydrogen bonds to poly(ethylene glycol)-based hydrogels via co-polymerization with n-vinyl pyrrolidone (NVP) increased the fracture energy as determined by single edge notch testing. This enhanced defect tolerance resulted in a hydrogel layer that was resistant to suture-induced damage with no dislodged particles observed. Importantly, the incorporation of NVP did not affect the thromboresistance, bioactivity, or biostability of the hydrogel layer. In addition to eliminating complications due to hydrogel particle generation in our multilayer graft design, this defect tolerant hydrogel formulation has broad potential use in many cardiovascular and soft tissue applications.
Small-caliber vascular grafts used in coronary artery bypass procedures typically fail due to development of intimal hyperplasia or thrombosis. Our laboratory has developed a multilayered vascular graft with an electrospun polyurethane outer layer with improved compliance matching and a hydrogel inner layer that is both thromboresistant and promotes endothelialization. However, hydrogel particulates were dislodged from the hydrogel layer during suturing in vivo. This work describes a hydrogel formulation based on poly(ethylene glycol) that is resistant to suture-induced damage. The introduction of sacrificial, hydrogen bonds by co-polymerization with n-vinyl pyrrolidone (NVP) resulted in an increase fracture energy without affecting the thromboresistance, bioactivity, or biostability. This defect-tolerant hydrogel formulation and the methodology to assess hydrogel defect tolerance has broad potential use in cardiovascular and soft tissue applications.
用于冠状动脉旁路手术的小口径血管移植物通常会因内膜增生或血栓形成而失效。我们的实验室开发了一种具有多层结构的血管移植物，其外层是电纺的聚氨酯，具有改善的顺应性匹配，内层是水凝胶，既具有抗血栓性又能促进内皮化。初步的体内研究表明，水凝胶颗粒在缝合过程中从移植物的水凝胶层中脱落。为了解决这个问题，我们开发并表征了一种新的水凝胶配方，该配方在缝合过程中能抵抗损伤。通过与 N-乙烯基吡咯烷酮（NVP）共聚，在基于聚乙二醇的水凝胶中引入牺牲氢键，通过单边缺口试验确定了断裂能的增加。这种增强的缺陷容忍度导致水凝胶层具有抵抗缝合引起的损伤的能力，没有观察到脱落的颗粒。重要的是，NVP 的掺入并不影响水凝胶层的抗血栓性、生物活性或生物稳定性。除了消除我们的多层移植物设计中由于水凝胶颗粒产生而导致的并发症外，这种具有缺陷容忍度的水凝胶配方在许多心血管和软组织应用中有广泛的潜在用途。
