Composition of the protein layers adsorbed from blood or plasma to solid surfaces: A perspective

The protein layers deposited from blood onto contacting surfaces are believed to be a strong determinant of ultimate thrombogenesis. Recent research on the composition of these layers is reviewed. The layers are complex and contain a multiplicity of components, most of which are not yet identified. The abundant plasma proteins albumin, IgG and fibrinogen are found on most surfaces but in relatively small amounts. Other proteins found are hemoglobin, IgA, IgD, plasminogen, fibronectin, α‐ and β‐ lipoproteins, and von Willebrand factor. Considerable differences in composition have been found from surface to surface. The composition has also been found to vary with time. For example initially adsorbed fibrinogen is largely replaced by high molecular weight kininogen (HMWK). There is strong involvement of proteins of the contact phase of blood coagulation in the layer, and factor XII, factor XI and HMWK have been shown to be present on various surfaces. Protein alterations such as activation of factor XII and reactions such as degradation of fibrinogen by plasmin have also been shown to occur in the adsorbed layer.