How medium osmolarity influences dielectrophoretically assisted on-chip electrofusion

Area of Science:

• Cell biology
• Biophysics
• Microfluidics

Background:

• Dielectrophoresis (DEP) is a force generated by electric field gradients, crucial for aligning cells before electrofusion.
• Electrofusion involves applying electric pulses to induce membrane fusion in contacting cells.
• The success of DEP pairing and electrofusion is significantly influenced by medium properties like osmolarity and conductivity.

Purpose of the Study:

• To investigate the impact of medium osmolarity on cell volume, viability, and electrical properties.
• To characterize the real-time effects of cell electropermeabilization on dielectrophoretic responses.
• To establish an optimized electrofusion protocol based on identified cellular and medium parameters.

Main Methods:

• Utilized a microfluidic device with specific field topologies for cell manipulation.
• Monitored real-time changes in cell dielectrophoretic responses during electropermeabilization.
• Correlated experimental observations with numerical analysis of the Clausius-Mossotti factor.
• Defined an optimal medium composition (100 mOsm, 0.03 S/m) for cell electrofusion.

Main Results:

• Determined the influence of medium osmolarity on cell volume, viability, and electrical characteristics.
• Characterized the dynamic changes in dielectrophoretic behavior post-electropermeabilization.
• Achieved up to 75% simultaneous binuclear rapid electrofusions.
• Recorded average membrane fusion durations under 12 seconds.

Conclusions:

• Medium osmolarity critically affects cell properties and electrofusion outcomes.
• Real-time monitoring and numerical analysis provide insights into electropermeabilization effects.
• The developed protocol in an optimized medium (100 mOsm, 0.03 S/m) significantly enhances electrofusion efficiency and speed.