Nonlinear cell response to strong electric fields

Area of Science:

• Biophysics
• Cellular Electrophysiology
• Computational Biology

Background:

• Externally applied electric fields can cause tissue damage through cell membrane rupture, especially in elongated cells like skeletal muscle fibers.
• Previous models assumed linear (Ohmic) membrane conductivity and were limited to sinusoidal fields.
• This damage mechanism is distinct from Joule heating effects.

Purpose of the Study:

• To investigate a theoretical model of a long cylindrical cell (nerve or muscle) subjected to electric fields.
• To incorporate arbitrary time dependence and nonlinear (non-Ohmic) membrane conductivity.
• To compare the predicted membrane electric field intensities between linear and nonlinear models.

Main Methods:

• Developed a model of a long cylindrical cell using the electroquasistatic approximation.
• Derived a system of coupled first-order differential equations for the membrane electric field.
• Analyzed model behavior in both linear and nonlinear regimes for various applied fields.

Main Results:

• The nonlinear model predicts peak membrane electric fields approximately twice as intense as the linear model under low-frequency electrical trauma conditions.
• Demonstrated the impact of nonlinear membrane response on field intensification.
• Showcased the model's ability to handle arbitrary time-dependent external fields.

Conclusions:

• Nonlinear membrane conductivity significantly increases electric field intensification across cell membranes.
• This finding has critical implications for understanding and mitigating electrical trauma, particularly in nerve and muscle tissues.
• The developed model provides a more accurate framework for studying cellular responses to electric fields.