POLYMERIZATION OF FIBRIN IN SHEAR-FLOW FIELDS

The reaction of fibrinogen with thrombin to produce fibrin goes through a multistep sequence in which up to four peptides are cleaved off. When this reaction takes place at pH 6.3 in a shear flow field, the formation of fibrous product is retarded as compared with stagnant conditions. The retardation is greater at 50 s−1 than at 135 s−1. The morphology of the coagulated product appears to be different when produced at 50 s−1 than at either stagnant or 135 s−1, with the material at 50 s−1 having a sheetlike appearance in contrast to a fibrous appearance for the material at 135 s−1 and stagnant conditions: The explanation of the retardation may lie in the separation of thrombin from fibrinogen during the sheared reactions. Shear rate varies more in the vascular bed than does pH or ionic strength and probably is a more important factor in controlling physiological coagulation than these more frequently studied variables. Copyright © 1979 Society of Plastics Engineers, Inc.