TY - JOUR
T1 - The mechanism of the dextran-induced red blood cell aggregation
AU - Pribush, A.
AU - Zilberman-Kravits, D.
AU - Meyerstein, N.
N1 - Funding Information:
Acknowledgments We wish to express our sincere gratitude to Prof. H. J. Meiselman from the University of Southern California (USA) for providing the shear viscosity data. This study was supported by a grant from the Israel Science Foundation, No. 457/02.
PY - 2007/2/1
Y1 - 2007/2/1
N2 - In order to clarify the mechanism of dextran-induced aggregation, the effect of the ionic strength (I) on the minimal shear stress (τ c ) required to rupture RBC doublets was studied for suspensions with the external media containing 76 and 298 kDa dextrans. At low and high ionic strengths, τ c increases with increasing I, whereas at intermediate I values, τ c versus I dependencies reveal a plateau step. The non-monotonous shape of these curves disagrees with the depletion model of RBC aggregation and is consistent with the predictions of the bridging mechanism. Literature reports point out that elastic behavior of dextran molecules in low and high I regions is fairly typical of Hookean springs and hence predict an increase in τ c with increasing I. A plateau step is accounted for by the enthalpic component of the dextran elasticity due to the shear-induced chair-boat transition of the dextran's glucopyranose rings. A longer plateau step for suspensions with a higher molecular weight dextran is explained by a larger contribution of the enthalpic component to the dextran elasticity. Thus, the results reported in this study provide evidence that RBC aggregation is caused by the formation of dextran bridges between the cells.
AB - In order to clarify the mechanism of dextran-induced aggregation, the effect of the ionic strength (I) on the minimal shear stress (τ c ) required to rupture RBC doublets was studied for suspensions with the external media containing 76 and 298 kDa dextrans. At low and high ionic strengths, τ c increases with increasing I, whereas at intermediate I values, τ c versus I dependencies reveal a plateau step. The non-monotonous shape of these curves disagrees with the depletion model of RBC aggregation and is consistent with the predictions of the bridging mechanism. Literature reports point out that elastic behavior of dextran molecules in low and high I regions is fairly typical of Hookean springs and hence predict an increase in τ c with increasing I. A plateau step is accounted for by the enthalpic component of the dextran elasticity due to the shear-induced chair-boat transition of the dextran's glucopyranose rings. A longer plateau step for suspensions with a higher molecular weight dextran is explained by a larger contribution of the enthalpic component to the dextran elasticity. Thus, the results reported in this study provide evidence that RBC aggregation is caused by the formation of dextran bridges between the cells.
KW - Bridging
KW - Depletion layer models
KW - Eythrocyte aggregation
UR - http://www.scopus.com/inward/record.url?scp=33846629853&partnerID=8YFLogxK
U2 - 10.1007/s00249-006-0107-1
DO - 10.1007/s00249-006-0107-1
M3 - Article
AN - SCOPUS:33846629853
SN - 0175-7571
VL - 36
SP - 85
EP - 94
JO - European Biophysics Journal
JF - European Biophysics Journal
IS - 2
ER -