Coaxial electrospinning of P(LLA-CL)/heparin biodegradable polymer nanofibers: potential vascular graft for substitution of femoral artery.

Electrospinning is one of the most simple and effective methods to prepare polymer fibers with the diameters ranging from nanometer to several micrometers. Poly(L-lactide)-co-poly (ɛ-caprolactone) (P(LLA-CL)) fibers and P(LLA-CL)/heparin coaxial composite fibers herein were successfully prepared by single electrospinning and coaxial electrospinning, respectively. The prepared endothelialized P(LLA-CL) and P(LLA-CL)/heparin vascular grafts were used in the Beagle dogs experiment to evaluate the feasibility of thus made different scaffolds for substitution of dog femoral artery in early period, medium term, and long term, meanwhile the pure P(LLA-CL) vascular graft was used as the control group during all the experiments. The animal model was established by using the graft materials to anastomose both femoral arteries of dogs. The vascular grafts patency rates (i.e., the unobstructed capacity of blood vessel) were detected by color Doppler flow imaging technology and digital subtraction angiography. To observe the histological morphology at different periods, the vascular grafts were removed after 7, 14, and 30 days, and the corresponding histological changes were evaluated by hematoxylin and eosin staining. The experimental results show that in the early period, the patency rates of pure P(LLA-CL) graft, endothelial P(LLA-CL) graft, and P(LLA-CL)/heparin graft were 75%, 75%, and 100%, respectively; in the medium term, the patency rates of pure P(LLA-CL) graft and endothelial P(LLA-CL) graft were 25%, whereas that of P(LLA-CL)/heparin graft was 50%; the patency rates of pure P(LLA-CL) graft and endothelial P(LLA-CL) graft were down to 0%, whereas the patency rate of P(LLA-CL)/heparin graft was 25% in the long term. This preliminary study has demonstrated that P(LLA-CL)/heparin coaxial composite fiber maybe a reliable artificial graft for the replacement of femoral artery. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.