Fabrication of multilayer tubular scaffolds with aligned nanofibers to guide the growth of endothelial cells

Abstract

<jats:p> Aligned electrospun fibers used for the fabrication of tubular scaffolds possess the ability to regulate cellular alignment and relevant functional expression, with applications in tissue engineering. Despite significant progress in the fabrication of small-diameter vascular grafts (SDVGs) over the past decade, several challenges remain; one of the most problematic of these is the fabrication of aligned nanofibers for multilayer SDVGs. Furthermore, delamination between each layer is difficult to avoid during the fabrication of multilayer structures. This study introduces a new fabrication method for minute delamination four-layer tubular scaffolds (FLTSs) that consist of an interior layer with highly longitudinal aligned nanofibers, two middle layers composed of electrospun sloped and circumferentially aligned fibers, and an exterior layer comprising random fibers. These FLTSs are used to simulate the structures and functions of native blood vessels. Here, thermoplastic polyurethane (TPU)/polycaprolactone (PCL)/polyethylene glycol (PEG) were electrospun to fabricate FLTSs or tubular scaffolds with completely random fibers layer (RLTSs). The surface wettability of the TPU/PCL/PEG tubular scaffold was tested by water contact angle analysis. In particular, compared with RLTSs, FLTSs showed excellent mechanical properties, with higher circumferential and longitudinal tensile properties. Furthermore, the high viability of the human umbilical vein endothelial cells (HUVECs) on the FLTSs indicated the biocompatibility of the tubular scaffolds comparing to RLTSs. The aligned and random composite structure of the FLTSs are conducive to promoting the growth of HUVECs, and the cell adhesion and proliferation on these scaffolds was found to be superior to that on RLTSs. These results demonstrate that the fabricated FLTSs have the potential for application in vascular tissue regeneration and clinical arterial replacements. </jats:p>

An integrated strategy for designing and fabricating triple-layer vascular graft with oriented microgrooves to promote endothelialization

“…9 Inspired by the triple-layer structure of natural blood vessels, as well as the mechanical properties and structures of collagen and elastin in blood vessels, we have developed a triple-layer vascular graft with a oriented microgrooves constructed by different materials and technologies. We have prepared multilayer vascular grafts with different materials and structures by electrospinning in previous studies, 10 but the porous nanofiber vascular grafts prepared by electrospinning are prone to liquid leakage under pressure. Fluid leakage under pressure is a potentially fatal risk in the clinical application of nanofiber vascular transplantation.…”

“…9 The outer membrane is formed by the loose fibrous network of fibroblasts. To date, many studies on vascular grafts have focused on simulating the multilayer structure of blood vessels, 7,[10][11][12] and electrospun nanofibers have also been used in the manufacture of vascular grafts due to their ability to mimic the structure of extracellular matrix (ECM). 7,13 Although some of them have shown excellent mechanical properties, they fail to ideal in the endothelialization of blood vessels, and the traditional porous vascular grafts may leak under pressure.…”

“…10 In order to be effective at problem-solving, we are likely to need to select elastic materials with the same compliance approximately as the human arteries, such as TPU. 29 In previous studies, we found that the electrospinning scaffolds after blend rigid PCL and flexible TPU, could simulate the mechanical properties of natural vessels, 10 and albumen/SA hydrogel also has some elasticity and biocompatibility, especially in inducing vascularization within engineered tissues. 30 Therefore, In the present study, we demonstrate a novel approach combining FDM, dip-coating, and electrospinning techniques that overcomes these limitations, enabling the fabrication of biocompatible scaffolds with the three-layer structure of natural blood vessels and the tissue arrangement of HUVECs.…”

Current Strategies for the Regeneration of Skeletal Muscle Tissue

“…The middle inner and outer layers were created by sloped and circumferentially aligned fibers and the exterior layer consisted of random fibers. [ 205 ]. In addition, tubular scaffolds with completely random fiber layers were produced.…”

Tubular Electrospun Vancomycin-Loaded Vascular Grafts: Formulation Study and Physicochemical Characterization

“…The technique is particularly attractive for the production of much smaller diameter fibers; small-diameter tubular grafts result in a prototype with a high surface area, porosity, and an interconnected and even oriented three-dimensional network structure. Moreover, they more closely mimic natural blood vessels’ skeleton structure compared with the tubular scaffold prepared by conventional methods [ 17 , 18 , 19 , 20 , 21 ]. There are some fundamental parameters that have to be taken in consideration to set up a correct electrospinning procedure, i.e., the polymer solution properties and the instrument settings as flow rate, applied electrical potential, working distance, mandrel’s rotation speed, spinneret’s width and speed, humidity, and temperature.…”