Interactions of poly(ethylene glycol)-grafted cellulose membranes with proteins and platelets

The interactions of proteins and platelets with cellulose membranes grafted with poly(ethylene glycol) were studied. The poly(ethylene glycol) grafting was carried out using poly(ethylene glycol)-monoacid and poly(ethylene glycol)-diacid, which have one and two terminal carboxyl groups, respectively. The grafting operates through esterification between the carboxyl groups of poly(ethylene glycol) and the hydroxyl groups on the membrane surface. Both of the poly(ethylene glycol) grafted membranes reduced the complement activation. Adsorption of bovine serum albumin and gamma-globulin increased when the membrane was grafted with poly(ethylene glycol)-diacid, but did not change when it was grafted with poly(ethylene glycol)-monoacid. When platelets were incubated with serum proteins, the platelet adhesion to the membranes slightly decreased by grafting both the poly(ethylene glycol)-diacid and poly(ethylene glycol)-monoacid. The poly(ethylene glycol)-diacid grafted surface showed more clotting than the poly(ethylene glycol)-monoacid grafted and original surfaces.