Fibrin has larger pores when formed in the presence of erythrocytes.

Due to difficulties caused by the presence of hemoglobin-containing erythrocytes, the structures of whole blood clots have not been reported. A perfusion technique described herein allowed the study of plasma and blood clots. Gel fiber diameter, fiber mass-to-length ratio, and average pore diameter were calculated from measurements of solvent flow through gels. When perfused with saline, intact erythrocytes washed from clots of whole blood. Subsequent perfusion with water resulted in rapid hemolyzing of remaining erythrocytes and flushing of hemoglobin from the network. The minimal impact of erythrocytes on fibrin fiber structure was indicated by similar fiber mass-to-length ratios, 7.4 vs. 9.3 X 10(13) Da/cm, for plasma and blood clots, respectively. Pore sizes were larger in gels formed in the presence of erythrocytes, increasing from 3.3 X 10(-4) cm for plasma gels to 5.1 X 10(-4) for gels containing 20% erythrocytes. The washing of red cells from clots confirmed calculated clot pore sizes (approximately 5 microns) and was testimony to the size of the spaces within the gel. Egress of cells and macromolecules to the site of injury during wound healing may be a function of the size of these spaces. The demonstrated applicability of this technique should allow study of this question.