Evaluation of a filter aspiration technique to determine membrane deformability

Area of Science:

• Biophysics
• Hematology
• Cell Biology

Background:

• Red blood cell (RBC) membrane deformability is crucial for microcirculation.
• Accurate measurement of RBC membrane elasticity is essential for understanding various hematological conditions.
• The filter aspiration technique offers a potential method for assessing RBC membrane properties.

Purpose of the Study:

• To evaluate the validity of the filter aspiration technique for measuring red blood cell membrane deformability.
• To compare the results obtained by filter aspiration with the established micropipette technique.
• To assess the technique's performance with normal and altered red blood cell morphologies.

Main Methods:

• Red blood cells were aspirated through micropore filters (0.6 and 1.0 micron) using varying hydrostatic pressures (1-9 mm H2O).
• Aspirated cell portions (tongues) were measured using scanning electron microscopy after fixation.
• The elastic modulus of the RBC membrane was calculated and compared with concurrent micropipette measurements.

Main Results:

• The filter aspiration technique yielded an elastic modulus of 2.9 (+/- 0.4) X 10(-3) dynes/cm for normal RBCs.
• A good correlation (r = 0.74, P < 0.001) was observed between filter aspiration and micropipette methods for normal cells.
• Both methods showed increased elastic modulus for stomatocytes, but filter aspiration yielded normal results for echinocytes, unlike the micropipette method.

Conclusions:

• The filter aspiration technique is a valid method for measuring red blood cell membrane elastic properties.
• The technique shows good agreement with the micropipette method for normal and stomatocyte-like cells.
• Filter aspiration may be unreliable for cells with surface irregularities, such as echinocytes, due to potential measurement interference.