Red blood cell rouleaux formation in dextran solution: Dependence on polymer conformation

Gregory Barshtein, Ilana Tamir, Saul Yedgar*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

51 Scopus citations


The velocity of rouleaux formation (RF), as previously shown, increases with increasing dextran concentration up to a critical concentration (C(a)), beyond which the addition of dextran reduces the RF velocity (RFV). de Gennes' model for polymer solutions suggests that dextrans exist in two conformations: a coil structure at low concentrations, which changes to a network beyond a critical concentration (C*). In the present study we examined the relation between C(a) and C* for dextrans of different molecular weight, and found that they coincide. This suggests that the change in dextran behavior, from increasing to decreasing RFV, occurs when their conformation changes from coil to network. In addition, it has been reported that in dilute dextran solutions the intercellular distance (D) between RBC in rouleaux increases with the molecular weight of the dextran. We found that D correlates with R(f), the end-to-end distance of the polymer molecule, and for all dextrans D ≤ 1.5 R(f). In accord with de Gennes' Model for polymers between surfaces, this corresponds to intercellular interaction with two overlapping surface-associated polymer layers, which may extend 'tails' to interact with the opposing cells.

Original languageAmerican English
Pages (from-to)177-181
Number of pages5
JournalEuropean Biophysics Journal
Issue number2
StatePublished - 1998

Bibliographical note

Funding Information:
Acknowledgements This study was supported by a grant to S. Yedgar from the USA-Israel Binational Science Foundation (No. 91-00164), and from the Israel Ministry of Health (No. 2813).


  • Erythrocyte aggregation
  • Intercellular distance
  • Overlap concentration
  • Polymer conformation
  • Rouleaux


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