Abstract
A rheometrical investigation of incipient clots formed in fibrin-thrombin gels is reported in which the Gel Point (GP) is characterised by frequency independence of the loss tangent in small amplitude oscillatory shear measurements over a wide range of thrombin concentration. Values of the fractal dimension (Df) of the GP network calculated from measurements are consistent with those reported in simulations of diffusion limited cluster-cluster aggregation (DLCCA) and reaction limited cluster-cluster aggregation (RLCCA), but differ insofar as the values of Df calculated from the present experiments increase progressively with a reduction in gel formation time. A molecular dynamics simulation (MDS) of systems of rod-like particles was designed to (i) test the hypothesis that the presence of an activation profile in a cluster aggregation model could account for the trend of Df as a function of gel formation time observed experimentally in fibrin-thrombin gels and whole heparinised blood without recourse to the inclusion of fibrinogen-specific interactions; and (ii) to explore the effect of monomer activation kinetics on the microstructure of fractal clusters formed in systems of rigid rod-like particles. The results identify two possible mechanisms for the increase in Df as the gel formation time decreases, both being a consequence of altering the evolution of the clustering dynamics by a process referred to herein as activation limited aggregation (ALA). This ALA-based MDS substantiates the experimental findings by confirming the trend evident in the formation of incipient clots in fibrin-thrombin gels and in whole heparinised blood. A mechanism for ALA involving the aggregation of pre-GP sub-clusters is proposed.
Original language | English (US) |
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Pages (from-to) | 932-938 |
Number of pages | 7 |
Journal | Journal of Non-Newtonian Fluid Mechanics |
Volume | 166 |
Issue number | 16 |
DOIs | |
State | Published - Sep 1 2011 |
Keywords
- Fibrin gels
- Fractal clusters
- Molecular dynamics
- Rheometry
ASJC Scopus subject areas
- Condensed Matter Physics
- Mechanical Engineering
- Chemical Engineering(all)
- Materials Science(all)
- Applied Mathematics