Endothelialization of lumen of tubular scaffolds fabricated by electrospinning

Keywords:
tubular scaffold, electrospinning, nanofiber, endothelial cells, vascular graft

Abstract:
Quick establishment of a confluent and stable endothelial cell (EC) layer in lumen of vascular graft is critical for long-term patency of small-diameter vascular grafts (< 6mm) [1]. The objective of the study is to fabricate porous tubular scaffolds composed of electrospun polymer nanofibers which can ensure quick, stable endothelialization and phenotype maintenance of ECs. The poly(L-lactic acid)-co-poly(ε-caprolactone) P(LLA-CL 70:30) tubular scaffolds with inner diameter of 3 mm, fiber diameter distribution in range of 400-800 nm and wall thickness of around 150 µm were fabricated by electrospinning collected on a rotating metallic mandrel (Figure 1). Structure of the scaffolds were observed by scanning electron microscopy (SEM) and compared with the GORE-TEX® 3 mm vascular grafts which are commonly used in current small-diameter vascular surgeries (Figure 2). Before cell culture, the tubular scaffolds were treated by air plasma followed by collagen coating, method of which was reported before [2]. Human coronary artery endothelial cells (HCAECs) were seeded onto the lumen of the tubular scaffold connected in a customized bioreactor rotating at speed of 6 rpm for 4 hours, and then cultured in a static environment. Evenly distributed and well spread EC layer was found throughout the tube from one day onwards to 10 days (Figure 3). On day 10, subconfluent HCAECs existed as a monolayer on the lumen of the tubular scaffold and no cell filtration was found (Figure 4c). Also HCAECs maintained the original phenotypic expression PECAM-1(Platelet Endothelial Cell Adhesion Molecule-1) (Figure 4d). However, on the lumen of the GORE-TEX® vascular grafts, few ECs were found (data now shown). The electrospun porous and biodegradable tubular scaffolds are potential materials for tissue engineered vascular grafts which may enable effective endothelialization. Further studies will focus on the mechanical properties of the tubular scaffolds such as the burst pressure, Suturability, and compliance.

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Nanotech 2006 Conference Program Abstract