Biologically Functionalized Expanded Polytetrafluoroethylene Blood Vessel Grafts.

Cardiovascular diseases plague human health because of the lack of transplantable small-diameter blood vessel (SDBV) grafts. Although expanded polytetrafluoroethylene (ePTFE) has the potential to be used as a biocompatible material for SDBV grafts, long-term patency is still the biggest challenge. As discussed in this paper, by virtue of a novel material formulation and a new and benign alcohol/water lubricating agent, biofunctionalized ePTFE blood vessel grafts aimed at providing long-term patency were fabricated. Compared to the most prevalent modification of PTFE, namely surface treatment, this method realized bulk treatment, which could guarantee homogeneous and long-lasting performance throughout PTFE products. These blood vessel grafts included embedded functional biomolecules, such as arginylglycylaspartic acid, heparin, and selenocystamine, using water as a solvent in paste extrusion and in the expansion of ePTFE. Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscope results confirmed the existence of these targeting biomolecules in the as-fabricated ePTFE blood vessel grafts. Meanwhile, the greatly improved biological functions of the grafts were demonstrated via live and dead assays, cell morphology, CD31 staining, nitric oxide (NO) release, and anticoagulation tests. This novel and benign material formulation and fabrication method provides an opportunity to produce multibiofunctional ePTFE blood vessel grafts in a single step, thus yielding a potent product with significant commercial and clinical potential.

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

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.