In vitro studies on blood protein adsorption to gold and pyrolytic carbon at pre-set electrical potentials

Ellipsometric in situ studies were made on the deposition of human serum and plasma proteins to gold (Au) and St. Jude Medical pyrolytic carbon (PC) without and with applied electrical potentials between 0 and - 1 V versus Ag/AgCl. The results show that Au adsorbs less blood proteins than PC, and more proteins were adsorbed from serum to both materials when a cathodic pulsed potential was applied for 20 min. After 1 min of plasma incubation, polyclonal anti-fibrinogen deposited at equal amounts to both materials independent of applied potential. No anticomplement factor 3c deposited to the materials after 1 min of serum incubation but did so after 20 min of incubation, and significantly more to PC. No anti-properdin bound to serum-coated surfaces after either incubation time, and only low depositions of high molecular weight kininogen were found. This study indicates that neither material activates the intrinsic pathway of coagulation and that both are pro-inflammatory owing to their high deposition of anti-fibrinogen and anti-complement factor 3 with time. (C) 1998 Elsevier Science B.V. All rights reserved.