Related Experiment Video
Updated: Dec 11, 2025
10:38
Label-free Isolation and Enrichment of Cells Through Contactless Dielectrophoresis
Published on: September 3, 2013
16.5K
Variable Membrane Dielectric Polarization Characteristic in Individual Live Cells.
Insu Park1, Jong Won Lim2, Sung Hoon Kim3,4
1Holonyak Micro and Nanotechnology Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.
The Journal of Physical Chemistry Letters
|August 20, 2020
Summary
Researchers explored cell membrane dielectric polarization using dielectrophoresis force spectroscopy. They found that external stimuli can alter membrane capacitance, offering new insights into cellular functions and membrane composition.
Area of Science:
- Cellular Biophysics
- Membrane Electrophysiology
Background:
- Dielectric properties of cell membranes are crucial for understanding cellular life and functions.
- Dielectrophoresis force spectroscopy is a key technique for probing these properties.
Purpose of the Study:
- To investigate the variable dielectric polarization characteristics of live cell membranes.
- To explore how external stimuli and membrane composition affect dielectric properties.
Main Methods:
- Utilized dielectrophoresis force spectroscopy to control cell dielectric polarization.
- Modulated frequency direction and sweep rate to observe cellular crossover frequencies.
- Extracted variable capacitance from crossover frequencies.
- Investigated cholesterol-depleted cell membranes to correlate changes with dielectric properties.
Main Results:
- Observed variable dielectric polarization characteristics in cell membranes.
- Identified different cellular crossover frequencies based on frequency modulation.
- Demonstrated a strong correlation between variable dielectric polarization and changes in membrane composition (e.g., cholesterol depletion).
Conclusions:
- Live cell membrane dielectric polarization can be modified by external stimuli.
- Dielectrophoresis force spectroscopy provides a powerful platform for studying dynamic membrane dielectric properties.
- Findings contribute to a deeper understanding of cellular functions and membrane biophysics.
Related Concept Videos
01:31Dielectric Polarization in a Capacitor
5.7K
The presence of a dielectric medium in a capacitor not only changes the voltage and capacitance but also affects the electric field. In general, dielectrics can be of two types: polar and nonpolar. In a polar dielectric, the positive and negative charges in the molecules are separated by a distance and hence have a permanent dipole moment. In contrast, no such charge separation exists in a nonpolar dielectric, however the nonpolar molecules get polarized in the presence of an external electric...
5.7K
01:21The Resting Membrane Potential
140.8K
Overview
140.8K
01:15Potentiometry: Membrane Electrodes
1.4K
Membrane electrodes, also known as p-ion electrodes, use membranes that selectively interact with free analyte ions, generating a potential difference across the membrane. The resulting membrane potential, known as the asymmetry potential, is not zero even when analyte concentrations on both sides of the membrane are equal. The membrane's response is typically not selective to a single analyte but proportional to the concentration of all ions in the sample solution capable of interacting at...
1.4K
01:29Potential Due to a Polarized Object
645
A neutral atom consists of a positively charged nucleus surrounded by a negatively charged electron cloud. When placed in an external electric field, the external electric force pulls the electrons and nucleus apart, opposite to the intrinsic attraction between the nucleus and the electrons. The opposing forces balance each other with a slight shift between the center of masses of the nucleus and the electron cloud, resulting in a polarized atom. On the other hand, a few molecules, like water,...
645
01:24Resting Membrane Potential
20.9K
The relative difference in electrical charge, or voltage, between the inside and the outside of a cell membrane, is called the membrane potential. It is generated by differences in permeability of the membrane to various ions and the concentrations of these ions across the membrane.
The Inside of a Neuron is More Negative
The membrane potential of a cell can be measured by inserting a microelectrode into a cell and comparing the charge to a reference electrode in the extracellular fluid. The...
The Inside of a Neuron is More Negative
The membrane potential of a cell can be measured by inserting a microelectrode into a cell and comparing the charge to a reference electrode in the extracellular fluid. The...
20.9K