Hemocompatible polyurethane/gelatin-heparin nanofibrous scaffolds formed by a bi-layer electrospinning technique as potential artificial blood vessels

Abstract

In this paper, a scaffold, which mimics the morphology and mechanical properties of a native blood vessel is reported. The scaffold was prepared by sequential bi-layer electrospinning on a rotating mandrel-type collector. The tubular scaffolds (inner diameter 4 mm, length 3 cm) are composed of a polyurethane (PU) fibrous outer-layer and a gelatin-heparin fibrous inner-layer. They were fabricated by electrospinning technology, which enables control of the composition, structure, and mechanical properties of the scaffolds. The microstructure, fiber morphology and mechanical properties of the scaffolds were examined by means of scanning electron microscopy (SEM) and tensile tests. The PU/gelatin-heparin tubular scaffolds have a porous structure. The scaffolds achieved a breaking strength (3.7±0.13 MPa) and an elongation at break (110±8%) that are appropriate for artificial blood vessels. When the scaffolds were immersed in water for 1 h, the breaking strength decreased slightly to 2.2±0.3 MPa, but the elongation at break increased to 145±21%. In platelet adhesion tests the gelatin-heparin fibrous scaffolds showed a significant suppression of platelet adhesion. Heparin was released from the scaffolds at a fairly uniform rate during the period of 2^nd day to 9^th day. The scaffolds are expected to mimic the complex matrix structure of native arteries, and to have good biocompatibility as an artificial blood vessel owing to the heparin release.

Keywords

electrospinning / artificial blood vessels / scaffold / polyurethane / gelatin / nanofiber / hemocompatibility

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Acknowledgments

This work has been financially supported by the Program for New Century of Excellent Talents in University (NCET-07-0596), Ministry of Education of China, by the International Cooperation from the Ministry of Science and Technology of China (MOST No. 2008DFA51170), and by the Science and Technology Project of Tianjin Municipal Science and Technology Commission (No. 08ZCKFSF03300). The project is funded by the Tianjin University-Helmholtz-Zentrum Geesthacht Joint Laboratory for Biomaterials and Regenerative Medicine, which is financed by MOST and the German Federal Ministry of Education and Research (BMBF).

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