Related Experiment Videos
Dielectric measurements on electro-manipulation media
W M Arnold1, A G Gessner, U Zimmermann
1Lehrstuhl für Biotechnologie, Universität Würzburg, Germany.
Biochimica Et Biophysica Acta
|May 7, 1993
Summary
Dielectric properties of sugar solutions were measured for electric-field applications. High-density media, while useful for cell manipulation, exhibit frequency dispersion, potentially limiting their use in radio-frequency fields.
Area of Science:
- Biophysics
- Materials Science
- Electrochemistry
Background:
- Dielectric properties of solutions are crucial for cell manipulation techniques like dielectrophoresis and electrofusion.
- Understanding the behavior of sugars and sugar alcohols in electric fields is essential for optimizing these processes.
- High-density media are employed to prevent cell sedimentation during electro-manipulation.
Purpose of the Study:
- To measure the permittivity and conductivity of sugar and sugar alcohol solutions across a broad frequency range (30 kHz-12 MHz).
- To investigate the dielectric behavior of various high-density media used in cell electro-manipulation.
- To determine the suitability of these solutions for electric-field applications, particularly concerning frequency dispersion.
Main Methods:
- Measurements were conducted using a parallel-plate impedance chamber with variable electrode spacing.
- Electrode polarization errors were mitigated through linear regression and subtraction of KCl data.
- Permittivity and conductivity were analyzed as functions of concentration and frequency, with molar dielectric increments (delta 1 and delta 2) used for description.
Main Results:
- Sugar solutions up to 1.2 M showed no frequency dispersion in permittivity or conductivity.
- Higher concentrations of sucrose, Metrizamide, and Nycodenz, as well as Percoll, exhibited frequency dispersion.
- Dispersion in high-density media was observed above 0.6 MHz for sucrose, Metrizamide, and Nycodenz, and across the entire range for Percoll.
Conclusions:
- Sugar solutions below 1.2 M are suitable for dielectrophoresis and electrofusion applications due to their lack of dispersion.
- The dispersive properties of high-density media like Percoll, Metrizamide, and Nycodenz may limit their use with radio-frequency fields.
- Careful consideration of dielectric dispersion is necessary when selecting media for electro-manipulation, especially at higher frequencies.