Physical theory of some interface phenomena in hemorheology

The following four subjects are discussed theoretically from a physical standpoint: (1) the effect of the wall of a capillary viscometer on the apparent viscosity of blood; (2) the effect of electric charge on capillary flow; (3) the electric aspect of platelet adhesion and aggregation; and (4) multiphase polymeric materials as antithrombogenic materials. Copley and Scott Blair found a remarkable decrease in the apparent viscosities of blood, plasma, and serum in a fibrin-coated glass tube as compared with those in a glass tube without fibrin-coating. It is shown that the phenomenon cannot be explained by the existence of an electric double layer unless the zeta potential is positive. It is suggested that a reduction of the apparent viscosity of blood may be explained by a slight increase in the thickness of a plasma layer. It is shown that the existence of a slight gap between red cells and the capillary wall due to an electrostatic repulsion will remarkably lower the capillary flow resistance. An electric aspect of endothelial injury is discussed in relation to the adhesion of platelets to the injured endothelium. Platelet aggregation is discussed in accordance with the theory of Verwey and Overbeek , and a possible mechanism of thrombus formation due to a turbulent motion of blood is suggested. The significance of a multiphase polymeric material for an antithrombogenic surface is emphasized. It is suggested that sufficiently large conformational change of macromolecules will be favorable to antithrombogenicity of a polymeric material.