Fig. 6

Effects of biochemical treatment and shear flow on clot stiffening. Strong correlation between microclot stiffness and microclot contractile force (a) and between microclot volume and microclot contractile force (b) exists for various coagulation conditions under biochemical treatments. Abciximab (Abci.), Blebbistatin (Bleb.), VWD (VWD patient sample), acetylsalicyclic acid (ASA), anti-GpIbα antibody (HIP1). c, d Comparison of linear regressions between biochemical treatment condition and shear flow condition. Strong correlation between microclot mechanical properties also exists under varied shear flow (solid, black line). No significant difference was found for the regression slopes between biochemical treatment condition and shear flow condition. The significant difference of slopes and intercepts for two linear regressions was measured using a method equivalent to analysis of covariance (ANCOVA). Correlation between groups was analyzed using Pearson correlation coefficients. e Finite element model of the microclot before and under platelet-generated contraction. Simulated effective stress contour is plotted over undeformed and deformed model geometry. Active contraction of platelet population is represented by the contractility of every single element. Due to the geometrical restriction by two micropillars at both ends, microclot contraction causes volume shrinkage and the development of necking in the middle section, mimicking the microclot retraction process observed in the experiment. Color scale indicates normalized effective stress level. f Simulated decrease in microclot volume almost linearly correlates with increased contractile stress, recapitulating the experimental correlation between these two measurements. Data are presented as mean ± standard deviation