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Dielectric breakdown of cell membranes
Biophysical Journal
|November 1, 1974
Summary
Dielectric breakdown of cell membranes in red blood cells and E. coli B was demonstrated using electric fields. This breakdown, occurring at a specific membrane potential, causes hemoglobin loss in red blood cells and is influenced by cell volume and growth phase.
Area of Science:
- Biophysics
- Cell Biology
- Electrochemistry
Background:
- Dielectric breakdown of cell membranes is a critical phenomenon in cell biology and biophysics.
- Understanding the electric field thresholds for membrane breakdown is essential for various applications, including electroporation and cell sorting.
- Previous studies have explored membrane electrical properties, but precise breakdown potentials and influencing factors require further investigation.
Purpose of the Study:
- To demonstrate and quantify dielectric breakdown of cell membranes in human and bovine red blood cells and Escherichia coli B.
- To determine the membrane potential at which dielectric breakdown occurs and investigate its dependence on cell volume.
- To explore the influence of cell growth phase on membrane dielectric breakdown characteristics.
Main Methods:
- Utilized a Coulter Counter with hydrodynamic focusing to measure cell size distributions and pulse heights against increasing electric field strength.
- Applied Laplace's equation to calculate the electric field generated at dielectric breakdown.
- Investigated dielectric breakdown in a homogeneous electric field using a high-voltage capacitor discharge system.
Main Results:
- Observed a sharp deviation from linear pulse height versus electric field strength curves, indicating dielectric breakdown.
- Calculated a membrane potential of approximately 1.6 V at breakdown for red blood cells and bacteria, consistent with theoretical models.
- Demonstrated that dielectric breakdown leads to complete hemoglobin loss in red blood cells and is volume-dependent, aligning with theoretical predictions.
Conclusions:
- Dielectric breakdown of cell membranes occurs at a critical membrane potential, independent of cell volume.
- The electric field strength at breakdown is comparable to that of oil bilayers, suggesting a universal breakdown mechanism.
- Cellular growth phase significantly influences membrane dielectric breakdown properties, as evidenced by changes in critical voltage in E. coli B.