The complexity of blood at simple interfaces

Abstract

In the study of blood at interfaces, a combination of simple questions, techniques, and data is yielding increasingly intricate answers. We had shown earlier that the behavior of the plasma protein, fibrinogen, in blood at interfaces depends on the adsorbing substrate and determines subsequent platelet adhesion. In the present report we show that another plasma protein component, γ-globulin, when adsorbed out of pure solutions onto a hydrophobic rather than a hydrophilic substrate, causes certain white blood cells to adhere. On a wettable surface such as glass, adsorbed γ-globulins cause adhesion of such white cells only if the film had once been dried. Though whole plasma also deposits γ-globulins on these various surfaces, this film—in contrast to one produced by the purified protein solutions—does not markedly enhance white cell deposition. Recording ellipsometry and simpler techniques thus far failed to show differences in orientation of the adsorbed globulin that would account for the described white cell behavior. Our findings suggest that multiple interactions among plasma proteins at interfaces are responsible for the visible results of contact between blood and surfaces. In addition, findings by others indicate that the first phase of blood clotting is interwoven with these interactions, creating both positive and negative feedback systems within these events.