BIOCOMPATIBILITY OF SULFONATED POLYURETHANE SURFACES

Surfaces of medical devices made of polymeric materials may promote th rombosis and inflammation. Therefore, in an attempt to produce surface s which might diminish biomaterial-mediated thrombosis and inflammatio n, surface derivatization with 2-acrylamido-2-methylpropanesulphonic a cid (AMPS(R)) was carried out. The derivatization procedure generates free radicals which initiate the copolymerization of AMPS monomers dir ectly to a polyurethane surface. In an in vitro blood loop study using non-anticoagulated human blood, the resulting AMPS-derivatized materi al completely abrogates the generation of fibrinopeptide A, decreases the production of beta-thromboglobulin and C3a, and decreases the adhe rence of platelets. The derivatized material also attracts fewer adher ent neutrophils when implanted in mice. However, AMPS derivatization u nexpectedly increases the recruitment of macrophages to implanted mate rial and promotes the formation of adherent sleeve thrombi on central venous catheters indwelling in non-anticoagulated canine femoral veins . Thus, AMPS derivatization has highly variable effects on inflammator y and thrombotic systems. Further investigation is clearly required to determine the mechanisms underlying both desired and adverse effects. (C) 1996 Elsevier Science Limited.