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Erythrocyte Sedimentation Rate: A Physics-Driven Characterization in a Medical Context
Published on: March 24, 2023
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Imaging Erythrocyte Sedimentation in Whole Blood
Alexis Darras1, Hans Georg Breunig2, Thomas John1
1Experimental Physics, Saarland University, Saarbrücken, Germany.
Frontiers in Physiology
|February 14, 2022
Summary
Erythrocytes form a continuous colloidal gel network, not separate aggregates, during sedimentation. This finding, visualized using advanced microscopy, clarifies the structure of red blood cells in blood at rest.
Area of Science:
- Biophysics
- Colloid Science
- Hematology
Background:
- The erythrocyte sedimentation rate (ESR) is a long-standing diagnostic tool.
- Current debate exists regarding the structure formed by erythrocytes during sedimentation.
- Previous visualization methods were limited by 2D or low hematocrit conditions.
Purpose of the Study:
- To directly probe the in-situ structure of erythrocytes in blood at stasis.
- To resolve the debate between separate aggregates versus a percolating gel structure.
- To characterize the erythrocyte network at physiological hematocrit.
Main Methods:
- Direct optical imaging of blood samples at rest.
- Utilized three techniques: light transmission, two-photon microscopy, and light-sheet microscopy.
- Examined samples with controlled hematocrit (45%) and varying thicknesses (150 μm to 3 mm).
Main Results:
- Erythrocytes form a continuous network with characteristic cracks, indicative of a colloidal gel.
- The observed structure requires a field of view of approximately 1 mm for statistical relevance.
- Characteristic crack distances were measured to be around 100 μm.
Conclusions:
- Erythrocytes in blood at stasis form a colloidal gel network.
- This direct visualization challenges the conventional view of separate erythrocyte aggregates.
- Further experimental refinement is needed for quantitative analysis of erythrocyte interactions.
