Blends of stearyl poly(ethylene oxide) coupling-polymer in chitosan as coating materials for polyurethane intravascular catheters

To optimize the surface biocompatibility of the intravascular catheter, an amphiphilic coupling-polymer of stearyl poly (ethylene oxide) -co- 4,4 ' -m ethylene diphenyl diisocyanate-co- stearyl poly (ethylene oxide), for short MSPEO, was specially designed as the surface modifying additive (SMA), The blend of MSPEO in chitosan was coated on the outer wall of the catheters b y the dip-coating method. The surface analysis was carried out by ATR-FTIR and contact angle measurements. The surface enrichment of MSPEO was confirm ed. On the water interface, the larger the molecular weight of PEO was, the higher the surface enrichment, While on air interface, the case was the co ntrary, Three kinds of static test of clotting time, plasma recalcification time (PRT), prothrombin time (PT), and thrombin time (TT), as well as the static platelet adhesion experiment were carried out. The results indicated that the coated surface could resist the clotting effectively. In order to test the blood-compatibility of the coated catheters under a shear of bloo d flow, the dynamic experiment was performed through a closed-loop tubular system with the shear rate of 1500 s(-1). The results of blood regular test ing at six different times (0, 5,10, 20, 30, and 60 min) indicated that the biocompatibility of the coating was nearly ideal. Finally, the SMA-MSPEO w as proved to be non-chronic-toxic by animal experiments with rats and suita ble as a coating material for clinical use. (C) 2001 John Wiley & Sons. Inc .