Fabrication and modification of wavy multicomponent vascular grafts with biomimetic mechanical properties, antithrombogenicity, and enhanced endothelial cell affinity

Abstract

A mismatch of mechanical properties and a high rate of thromboses are two critical challenges of creating viable artificial small‐diameter vascular grafts (SDVGs). Herein, we propose a method to fabricate wavy multicomponent vascular grafts (WMVGs) via electrospinning using an assembled rotating collector. The WMVGs consisted of a wavy silk/poly(lactic acid) (PLA) inner layer and a thermoplastic polyurethane (TPU) outer layer, which mimic the structures and properties of collagen and elastin in native blood vessels, respectively. Attributed to the wavy structure and the combination of rigid silk/PLA and elastic TPU biomaterials, WMVGs are capable of mimicking the nonlinear tensile stress–strain relationship and “toe region” of native blood vessels. In addition, they have sufficient mechanical strength to meet implantation requirements in terms of tensile strength, suture retention, and burst pressure. Further modification of silk/PLA fibers with dopamine and heparin gave the grafts antithrombogenic properties and greatly enhanced endothelial cell affinities. Human umbilical vein endothelial cells (HUVECs) cultured on modified silk/PLA showed high viability, high proliferation rate, and favorable cell–substrate interactions. Moreover, HUVECs were able to fully cover and freely migrate upward on the lumen of the modified WMVGs without needing a special circulation bioreactor. Therefore, the modified WMVGs possessed biomimetic properties, antithrombogenicity, and enhanced endothelialization, making them a promising candidate for SDVGs. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2397–2408, 2019.

Rational design of biodegradable thermoplastic polyurethanes for tissue repair

“…However, common PUs easily trigger material-induced thrombosis. To enhance their nonthrombogenicity for blood contact implant use, nonthrombogenic moieties were physically or chemically combined with biodegradable PUs, such as phosphorylcholine (PC) [ [173] , [174] , [175] ], sulfobetaine [ 176 , 177 ], sulfate [ [178] , [179] , [180] ], PEG [ 181 ], and antithrombogenic drugs (e.g., clopidogrel, aspirin, and dipyridamole) [ 182 ]. In addition to physical blending and surface modification by nonthrombogenic moieties [ 175 , 177 ], these nonthrombogenic moieties can be covalently incorporated into the PU backbone or grafted onto the polymer chain as pendants.…”

Evaluation of human umbilical vein endothelial cells growth onto heparin-modified electrospun vascular grafts

“…Similarly, Shi and coworkers reported a significant increase in graft endothelialization in vivo in a rat model for electrospun PCL/gelatin loaded with heparin compared to non-loaded ones [60]. Moreover, the heparin surface modification of silk fibroin / PLLA and PLGA / PLLA / PLCL grafts led to an increase in HUVECs attachment, proliferation and migration [61,62]. Also in good agreement, the addition of heparin to modified PTFE grafts was shown to increase HUVECs proliferation compared to grafts without heparin [63].…”

Updates on polyurethane and its multifunctional applications in biomedical engineering

“…It has been demonstrated that a coating containing antioxidants on the surface can decrease oxidative degradation [181]. Also, designing a vascular graft based on PU/glycosaminoglycans has shown promising results [182][183][184]. Moreover, PU-nanofibres are nontoxic materials that can provide an environment and substrate for the human umbilical cord vein endothelial cells [184].…”