Transient features in nanosecond pulsed electric fields differentially modulate mitochondria and viability.

Area of Science:

• Cell Biology
• Biophysics
• Electroporation

Background:

• Nanosecond pulsed electric fields (nsPEFs) are utilized in various biomedical applications.
• The interaction of nsPEFs with cellular structures is crucial for their effects.
• Understanding the role of pulse transient features, like rise and fall times, is key to optimizing nsPEF applications.

Purpose of the Study:

• To investigate the impact of high-frequency components in nsPEFs on cellular membranes.
• To determine how pulse rise and fall times influence mitochondrial and plasma membrane integrity.
• To elucidate the relationship between nsPEF characteristics, membrane potential, calcium influx, and cell death.

Main Methods:

• N1-S1 hepatocellular carcinoma cells were exposed to single 600 ns pulses with varying electric fields and rise/fall times (15 ns vs. 150 ns).
• Plasma membrane integrity was assessed via calcium influx using Fluo-4.
• Mitochondrial membrane potential (ΔΨm) was measured using tetramethylrhodamine ethyl ester (TMRE).

Main Results:

• Short rise/fall times in nsPEFs led to electric field-dependent calcium influx, mitochondrial membrane potential dissipation, and cell death.
• Longer rise/fall times resulted in electric field-dependent calcium influx but with reduced effects on mitochondrial membrane potential and cell viability.
• High-frequency components differentially affected mitochondria membranes compared to plasma membranes.

Conclusions:

• High-frequency components of nsPEFs, determined by pulse transient features, significantly influence cell death pathways.
• Mitochondrial membrane potential dissipation, driven by calcium influx, is critically dependent on nsPEF high-frequency content.
• Optimizing nsPEF pulse characteristics, particularly rise and fall times, is essential for targeted cellular effects and therapeutic outcomes.