Thrombosis and
infection are two common problems associated with blood-contacting medical devices such as
catheters.
Nitric oxide (NO) is known to be a potent
antimicrobial agent as well as an inhibitor of platelet activation and adhesion. Healthy endothelial cells that line the inner walls of all blood vessels exhibit a NO flux of 0.5~4×10-10 mol cm-2 min-1 that helps prevent
thrombosis. Materials with a NO flux that is equivalent to this level are expected to exhibit similar anti-thrombotic properties. In this study, NO-releasing
catheters were fabricated by incorporating
S-nitroso-N-acetylpenicillamine (SNAP) in the Elast-eon E2As
polymer. The SNAP/E2As
catheters release physiological levels of NO for up to 20 d, as measured by chemiluminescence. Furthermore, SNAP is stable in the E2As
polymer, retaining 89% of the initial SNAP after
ethylene oxide (EO) sterilization. The SNAP/E2As and E2As control
catheters were implanted in sheep veins for 7 d to examine the effect on
thrombosis and bacterial adhesion. The SNAP/E2As
catheters reduced the
thrombus area when compared to the control (1.56 ± 0.76 and 5.06 ± 1.44 cm2, respectively). A 90% reduction in bacterial adhesion was also observed for the SNAP/E2As
catheters as compared to the controls. The results suggest that the SNAP/E2As
polymer has the potential to improve the hemocompatibility and bactericidal activity of intravascular
catheters, as well as other blood-contacting medical devices (e.g., vascular grafts, extracorporeal circuits).