Neutrophil chemotaxis on silicone and polyurethane surfaces

Silicone vascular catheters have a greater risk of infection and produce gr eater inflammation in vivo and greater complement activation in vitro than other vascular catheter polymer materials. This study investigated whether polymorphonuclear leukocyte (PMNL) chemotaxis under agarose on silicone sur faces is different than on polyurethane (PU). Glass slides were coated with silicone and PU by use of a constant-speed dipping apparatus. Chemotaxis ( 3 h) in response to (10(-7) mt) FMLP, zymosan-activated serum, and fresh se rum (100%) was greater on silicone than on PU (P <.05), Polyclonal antibody to C5a blocked >50% of the movement toward serum (P <.05), Serum in the PM NL well significantly decreased chemotaxis toward FMLP on silicone (P <.05) but not on PU, These findings suggest that excessive complement activation by silicone may interfere with chemotaxis, but further work is necessary t o determine whether this is relevant to an increased risk of catheter-relat ed infection.