PLATELET-ADHESION TO POLYURETHANE BLENDED WITH POLYTETRAMETHYLENE OXIDE

The surface and blood compatibility characteristics of Pellethane poly urethane blended with 1% or 5% (w/w) polytetramethylene oxide (PTMO) w ere evaluated. Analysis by X-ray photoelectron spectroscopy indicated that blending of PTMO caused an increased amount of amide wax, a proce ssing agent present in Pellethane, to be expressed on the surface of t he blended films in vacuo. Dynamic contact angle measurements in water , however, showed that PTMO was preferentially expressed on the blend film surfaces in water. The two lower molecular weight species, PTMO a nd amide wax, were thus capable of reorienting, depending on the envir onmental conditions. An in vitro assay of platelet adherence and throm bosis showed that polyurethane blended with 5% PTMO had about two-thir ds fewer adherent platelets compared to unblended polyurethane and tha t a blend containing 1% PTMO was intermediate in platelet adherence. M easurements of albumin adsorption from binary solution with fibrinogen indicated that PTMO blends did not preferentially adsorb albumin comp ared to unblended polyurethane. (C) 1996 John Wiley & Sons, Inc.