Influence of the ionic composition of fluid medium on red cell aggregation

Area of Science:

• Biophysics
• Hematology
• Physical Chemistry

Background:

• Red blood cell (RBC) aggregation is crucial for blood flow dynamics.
• Understanding factors affecting RBC aggregation is vital for diagnosing and treating blood disorders.
• The surface charge of RBCs plays a key role in their interactions.

Purpose of the Study:

• To investigate the impact of ionic strength and cation valency on RBC surface potential and aggregation.
• To elucidate the mechanisms behind dextran-induced RBC aggregation.
• To determine the role of RBC surface charge in cell-to-cell interactions.

Main Methods:

• Microelectrophoresis to measure zeta potential (surface potential).
• Microscopic observation, erythrocyte sedimentation rate, and low-shear viscosity to quantify RBC aggregation.
• Use of normal and neuraminidase-treated RBCs with dextrans (Dx 40, Dx 80) in varying ionic strengths and cation concentrations (Ca++, Mg++, Ba++).

Main Results:

• Decreased ionic strength reduced aggregation in normal RBCs but not in neuraminidase-treated RBCs, indicating increased electrostatic repulsion.
• Divalent cations increased aggregation in normal RBCs but not in treated RBCs, attributed to decreased surface potential and electric double layer shrinkage.
• Findings suggest that the electrostatic repulsive forces, influenced by ionic strength and cation valency, are critical for controlling RBC aggregation.

Conclusions:

• RBC surface charge significantly influences cell-to-cell interactions and aggregation.
• Ionic strength and cation valency are key modulators of RBC aggregation.
• The study provides insights into the biophysical mechanisms governing RBC interactions.