Heparin-Modified Small-Diameter Nanofibrous Vascular Grafts

Department of Bioengineering, University of California, Berkeley, CA 94720USA.
IEEE transactions on nanobioscience (Impact Factor: 2.31). 03/2012; 11(1):22-7. DOI: 10.1109/TNB.2012.2188926
Source: PubMed


Due to high incidence of vascular bypass procedures, an unmet need for suitable vessel replacements exists, especially for small-diameter vascular grafts. Here we produced 1-mm diameter vascular grafts with nanofibrous structure via electrospinning, and successfully modified the nanofibers by the conjugation of heparin using di-amino-poly(ethylene glycol) (PEG) as a linker. Antithrombogenic activity of these heparin-modified scaffolds was confirmed in vitro. After 1 month implantation using a rat common carotid artery bypass model, heparin-modified grafts exhibited 85.7% patency, versus 57.1% patency of PEGylated grafts and 42.9% patency of untreated grafts. Post-explant analysis of patent grafts showed complete endothelialization of the lumen and neovascularization around the graft. Smooth muscle cells were found in the surrounding neo-tissue. In addition, greater cell infiltration was observed in heparin-modified grafts. These findings suggest heparin modification may play multiple roles in the function and remodeling of nanofibrous vascular grafts, by preventing thrombosis and maintaining patency, and by promoting cell infiltration into the three-dimensional nanofibrous structure for remodeling.

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    • "Electrospun nanofibers with tunable nanometer size, surface functionality, mechanical properties (Su and Mo, 2011a) find extensive applications in drug delivery, health supplement delivery (Azarbayjani et al., 2010; Ngawhirunpat et al., 2011) and cosmetics applications (Fathi-Azarbayjani et al., 2010; Opanasopit et al., 2008). As wound dressing materials (Chen et al., 2012; Grewal et al., 2012; Jannesari et al., 2011), drug eluting stents (Yoo et al., 2012), transdermal drug delivery patches (Taepaiboon et al., 2007; Ngawhirunpat et al., 2009; Wu et al., 2010) and as blood vessels (Janairo et al., 2012) nanofibers have shown their marked uniqueness. The co-axial electrospinning methodology rendered a sustained mode of delivery of encapsulated drugs through slow degradation of shell polymer (Zhang et al., 2006; Su and Mo, 2011b). "
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