Rheometrical and molecular dynamics simulation studies of incipient clot formation in fibrin-thrombin gels: An activation limited aggregation approach

D. J. Curtis, M. R. Brown, K. Hawkins, P. A. Evans, M. J. Lawrence, P. Rees, P. R. Williams

Research output: Contribution to journalArticle

22 Scopus citations

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 languageEnglish (US)
Pages (from-to)932-938
Number of pages7
JournalJournal of Non-Newtonian Fluid Mechanics
Volume166
Issue number16
DOIs
StatePublished - 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

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