Apoptosis progression studied using parallel dielectrophoresis electrophysiological analysis and flow cytometry

Area of Science:

• Cell Biology
• Biophysics

Background:

• Apoptosis involves cellular events like phosphatidylserine (PS) externalization and plasma membrane permeabilization.
• The standard Annexin-V assay detects these two key events.
• Electrophysiology offers complementary insights into cellular changes during apoptosis.

Purpose of the Study:

• To compare the Annexin-V assay with electrophysiology data obtained via dielectrophoresis.
• To investigate the correlation between cytoplasmic conductivity and PS externalization during apoptosis.
• To explore potential mechanisms linking intracellular calcium (Ca2+) to observed cellular changes.

Main Methods:

• Utilized the standard Annexin-V assay to detect PS externalization and membrane permeabilization.
• Employed dielectrophoresis to measure changes in cytoplasmic conductivity and membrane conductance.
• Performed parallel measurements using both methods to compare results.

Main Results:

• Dielectrophoresis identified changes in cytoplasmic conductivity correlating with PS expression and membrane conductance spikes correlating with permeabilization.
• A strong inverse relationship was observed between cytoplasmic conductivity and PS externalization.
• Intracellular Ca2+ increase is proposed as a unifying mechanism for both PS externalization and conductivity changes.

Conclusions:

• Combining Annexin-V assay and dielectrophoresis provides a comprehensive view of apoptosis.
• Cytoplasmic conductivity serves as a reliable indicator of PS externalization.
• Intracellular Ca2+ plays a crucial role in regulating key apoptotic events, including PS externalization and ion channel activity.