Background: The interaction between a biomaterial and the constituents of blood flow are critical to the long-term patency and integrity of vascular grafts. Poly(vinyl alcohol) (PVA) is under investigation as a material for vascular grafts due to its tunable mechanical properties, non-thrombogenic surface, and amenability to luminal surface modifications. However PVA, by virtue of its inherent surface composition, discourages the migration of endothelial cells and ultimately prevents the considerable long-term benefits of endothelialization in vivo. Plasma treatment of the luminal surface of PVA grafts offers the opportunity to promote cell migration while maintaining or enhancing the desirable mechanical properties and non-thrombogenicity of PVA as a vascular graft.

Aims: 

• Systematically evaluate plasma treatments of PVA and characterize elemental changes in surface composition in order to establish critical guidelines toward the creation of a long-term, small diameter, artificial graft.

• Determine the relationship between amide density and cell migration.

Methods: Dry PVA films were placed in a plasma chamber with either 02, N2, or Ar gas to treat the films for 0.5, 1, and 5 min. The composition of the films was interrogated using x-ray photoelectron spectroscopy (XPS). Surface topography was investigated using AFM, SEM, and ESEM. Contact angle measurements were also performed to quantify the change in hydrophobicity of the films.

Results: Figure 1 shows the percent composition of PVA films without plasma treatment and with exposure to 02 and N2 plasma. The results show that with this plasma treatment, nitrogen present on the surface of the film (Figure 1 insert) increases from a negligible percentage to 5.2%.

Conclusions: The increase in nitrogen content of the plasma-treated PVA surface indicates the presence of amine and amide groups critical for integrin binding. An increase in binding sites should increase cell migration and thus native endothelialization of PVA vascular grafts improving their long-term patency.