Fibrinogen and albumin adsorption from human blood plasma and from buffer onto chemically functionalized silica substrates

Monolayers of silanes having a variety of chemical functionality were attached to pure silica tubes or plates. These model surfaces were characterized by X-ray photoelectron spectroscopy and advancing water contact angles. The adsorption of albumin and fibrinogen to these surfaces was studied using the radioiodinated proteins. In single protein systems neither albumin nor fibrinogen adsorption was found to be strongly correlated with wettability, although a slight increase in initial rate of adsorption with increasing wettability was noted. Fibrinogen adsorption was most strongly correlated with surface chemistry such that the presence of sulfur coincided with increased adsorption and nitrogen with decreased adsorption. Fibrinogen adsorption from blood plasma exhibited the Vroman effect to varying extents, and was found to be directly correlated with adsorption from buffer on most surfaces. On those surfaces which suppressed the Vroman effect, both sulfonate and amine groups were present.