Mechanical investigation of bilayer vascular grafts electrospun from aliphatic polyesters

Abstract

Electrospun biodegradable vascular grafts provide a wide range of design components from the selection of materials to the modification of fiber structure. In this study, both single layer and bilayer tubular scaffolds with inner diameter of 6 mm were electrospun from polycaprolactone with different molecular weights and poly(l‐lactide) caprolactone polymers. Bilayer scaffolds were designed by using different combinations of the polymer types in each layer and obtaining fiber orientation in outer layers. Scaffolds were analyzed morphologically and mechanically. Obtained results of mechanical performance were discussed according to the used polymer‐type composition, fiber orientation, and composite effect of both layer in the final graft. Smooth muscle cells were seeded on the scaffolds to test biocompatibility of presented scaffolds. Results indicate that the use of different biodegradable polymers in different combinations in each layer causes notable differences in fiber morphology and mechanical performance of the scaffolds. Moreover, fiber orientation in outer layer improves tensile strength and burst pressures in radial directions while creating a suitable fibrous layer for smooth muscle cells by mimicking the extracellular matrix of tunica media in native vessels. Copyright © 2016 John Wiley & Sons, Ltd.

Development of biodegradable webs of PLA/PCL blends prepared via electrospinning: Morphological, chemical, and thermal characterization

“…When comparing all samples regardless of polymer type, it is possible to notice the effect of fiber diameter on pore size results. Current literature confirms the case that fiber diameter affects the average pore area of the fibrous surface, and the average pore area increases with increasing fiber diameter 4,29 . The pore sizes of the samples follow a trend similar to the fiber diameter distributions (PLA8 < PCL10 < PLA10 < PLA/PCL), but considering the standard deviations, the differences between them are not very large.…”

“…Biocompatibility, biodegradability, and non‐toxic behavior are the crucial limits for the physical and chemical structures of the scaffolds 3 . Besides, a scaffold must have sufficient tensile strength and keep its mechanical integrity under certain loads 4 . Pore characteristic is one of the main structural parameters that come to the forefront in evaluating the performance of any fibrous webs for tissue engineering applications.…”

“…Although chloroform is the most preferred solvent for electrospinning of PCL with relatively less toxicity, unstable Taylor cone formation, resulting in irregular fiber formation limits its usage 29 . For this purpose, researchers tend to use the less toxic solvent systems with solvents such as acetone, acetic acid, formic acid, methanol, and ethanol together with chloroform 4,23,30‐33 . Although many tissue‐engineering surfaces have been studied in the literature on these polymers, most of the studies involve high‐damage solvent systems.…”

A Preliminary Study Examining the Burst Strength of Vascular Tubular Scaffolds

“…Yalcin-Enis et al ( 2017) designed surfaces with randomly oriented fibers and oriented fibers using PCL and poly(L-lactide) caprolactone (PLC) with various molecular weights, and then they examined the mechanical strength of those surfaces. The study's findings showed that the molecular weight and surface orientation both affected the burst strength of the graft formations [12].…”

Effect of different emitter types on the production of nanofibrous tubular structures: Thickness uniformity and productivity

“…Other potential application is their use as scaffolds for vascular tissue regeneration. [7][8][9] Regardless of application, nanofibrous tubes must meet certain requirements concerning their mechanical strength and stability. For example, vascular grafts need to be strong enough to withstand arterial pressure, 10 but they also need to withstand increased longitudinal and transverse strain as they integrate into the surrounding tissues.…”