The performance of endothelium layer under the effect of blood shear force depends fundamentally on the rheological parameters of the blood flow, characteristic structure and physiological response of this lining layer to the shear effect. This includes the nano-scale geometry of blood cells and endothelium surface, shear rate and blood viscosity, in addition to endothelial mechanical properties. Principally, the elucidation of these nanoscale interactions will contribute the explanation and better understanding of cardiovascular diseases that are the main causes of death and health suffering for millions of people all over the world. As an attempt to build up a tangible contribution for this revelation, a simulation analysis has been performed to study the effects of blood shear stress and blood dynamic viscosity on the rate of attachment and detachment of blood over the endothelium layer in the form of adhesion and rolling. In particular, the nature of each effect has been determined and the numerical ranges for each parameter have been estimated for the physiological range of shear rates. The results reveal that shear rate G enhances the blood cell rolling starting from 20 s−1 up to 90 s−1 then it tends to have constant contribution regardless its value ever greater than 90 s−1. Likewise, higher and moderate blood viscosity μ (i.e., 0.5–2.5 cP) supports rolling up to 4 cP, then it starts to keep its influence constant similar to that of shear rate. However, lower μ enhances the enhances the steady rolling at low rolling velocity, which open a room for primary and/or permanent adhesion. The rolling starts at μ = 0.0.5 cP, then jumped to higher values when μ was increased. The effect of μ on rolling is similar to that of shear rate because of their jointed role in the hemodynamic force, such that the increase of both of them drives the cell for faster rolling up to maximum limit, then discontinue affecting. Fundamentally, the most effective biophysiological range of μ on cell rolling is 0.1–3.0 cP, which is suggested by this study and mainly used in the previous investigations. However, the most frequent used rang of μ was 1–2 cP.

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