Nanoscale properties of poly(ethylene terephthalate) vascular grafts

Abstract

Vascular grafts are prosthetic tubes that serve as artificial replacements for damaged blood vessels. Poly(ethylene-terephthalate), PET, has been successfully used in large diameter grafts; however, small caliber grafts are still a major challenge in biomaterials. Due to surface forces, blood plasma proteins adsorb to the graft, resulting in inflammation, infection, thrombus formation, and ultimately, vessel reclosure. The object of this project was to characterize and analyze the nanoscale surface properties of three different commercial vascular grafts, woven collagen-coated, knitted collagen- coated, and knitted heparin-bonded, all PET-based. The study was performed in order to ascertain differences in biocompatibility due to surface coating and morphology. Scanning Electron Microscopy, Atomic Force Microscopy and High Resolution Force Spectroscopy techniques were used to characterize the surface of the samples as well as to measure the forces between these surfaces and blood plasma proteins. The results will serve as a basis for the understanding of the nanoscale interactions between the biomaterial and blood plasma proteins. Such interactions are brought about by the different surface topologies and components, therefore a thorough understanding of surface properties will act as a building block for further changes in small caliber vascular grafts in order to enhance their biocompatibility.