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Dependence of Impedance of Embedded Single Cells on Cellular Behaviour

View Article: PubMed Central - PubMed

ABSTRACT

Non-invasive single cell analyses are increasingly required for the medical diagnostics of test substances or the development of drugs and therapies on the single cell level. For the non-invasive characterisation of cells, impedance spectroscopy which provides the frequency dependent electrical properties has been used. Recently, microfludic systems have been investigated to manipulate the single cells and to characterise the electrical properties of embedded cells. In this article, the impedance of partially embedded single cells dependent on the cellular behaviour was investigated by using the microcapillary. An analytical equation was derived to relate the impedance of embedded cells with respect to the morphological and physiological change of extracellular interface. The capillary system with impedance measurement showed a feasibility to monitor the impedance change of embedded single cells caused by morphological and physiological change of cell during the addition of DMSO. By fitting the derived equation to the measured impedance of cell embedded at different negative pressure levels, it was able to extrapolate the equivalent gap and gap conductivity between the cell and capillary wall representing the cellular behaviour.

No MeSH data available.


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A: Measured impedance spectra for a L929 cell captured at the tip of capillary and for a capillary without cell, B and C: Change of impedance magnitude (/Z/capture − /Z/non-capture) at 100 Hz in response on the following events: (a) capture, (b) application of DMSO (100 μl of culture medium with 5% DMSO into 1 ml medium in the dish, (c) cell membrane breakdown, and (d) release, In panel B, the impedance for a latex bead captured at the capillary is shown additionally.
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f4-sensors-08-01198: A: Measured impedance spectra for a L929 cell captured at the tip of capillary and for a capillary without cell, B and C: Change of impedance magnitude (/Z/capture − /Z/non-capture) at 100 Hz in response on the following events: (a) capture, (b) application of DMSO (100 μl of culture medium with 5% DMSO into 1 ml medium in the dish, (c) cell membrane breakdown, and (d) release, In panel B, the impedance for a latex bead captured at the capillary is shown additionally.

Mentions: During the aspiration with negative pressure, a L929 cell was moved to the capillary entrance along the fluid and captured at the tip of capillary. Then, a part of elastic cell was expanded in the capillary in dependency on the pressure level. When a single L929 cell was captured at the capillary tip at a negative pressure of 9 mbar, the measured impedance magnitude in the frequency range of 100 Hz to 100 kHz was shown in Figure 4A. In the low frequency range of 100 Hz to 1 kHz, the impedance magnitude and phase were 7.12 ± 0.02 MΩ and − 2.41 ± 0.92° for no capture (No Cell), but 8.95 ± 0.14 MΩ and − 2.58 ± 1.15° for the captured cell (L929), respectively. The phase almost zero at the frequencies below 1 kHz indicates that the low frequency current flows mostly through the extracellular space between the low conductive cell membrane and capillary wall. With increase of frequency, the current is able to penetrate the cell membrane and insulated capillary wall, and therefore the decreases of phase and impedance magnitude are observed. The measured impedance was not distinguished between when the cell is captured and not at the frequencies higher than 20 kHz. Therefore, the capillary with impedance measurement system is proper to measure the impedance of embedded cell in the low frequency range related with extracellular behaviour (e.g. membrane morphology and integrity). It was able to monitor the effect of DMSO causing the membrane alteration on the impedance of embedded cell by using the capillary with impedance measurement system. The following events were reflected in the change of impedance at 100 Hz (Figure 4B and 4C):a)


Dependence of Impedance of Embedded Single Cells on Cellular Behaviour
A: Measured impedance spectra for a L929 cell captured at the tip of capillary and for a capillary without cell, B and C: Change of impedance magnitude (/Z/capture − /Z/non-capture) at 100 Hz in response on the following events: (a) capture, (b) application of DMSO (100 μl of culture medium with 5% DMSO into 1 ml medium in the dish, (c) cell membrane breakdown, and (d) release, In panel B, the impedance for a latex bead captured at the capillary is shown additionally.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3927517&req=5

f4-sensors-08-01198: A: Measured impedance spectra for a L929 cell captured at the tip of capillary and for a capillary without cell, B and C: Change of impedance magnitude (/Z/capture − /Z/non-capture) at 100 Hz in response on the following events: (a) capture, (b) application of DMSO (100 μl of culture medium with 5% DMSO into 1 ml medium in the dish, (c) cell membrane breakdown, and (d) release, In panel B, the impedance for a latex bead captured at the capillary is shown additionally.
Mentions: During the aspiration with negative pressure, a L929 cell was moved to the capillary entrance along the fluid and captured at the tip of capillary. Then, a part of elastic cell was expanded in the capillary in dependency on the pressure level. When a single L929 cell was captured at the capillary tip at a negative pressure of 9 mbar, the measured impedance magnitude in the frequency range of 100 Hz to 100 kHz was shown in Figure 4A. In the low frequency range of 100 Hz to 1 kHz, the impedance magnitude and phase were 7.12 ± 0.02 MΩ and − 2.41 ± 0.92° for no capture (No Cell), but 8.95 ± 0.14 MΩ and − 2.58 ± 1.15° for the captured cell (L929), respectively. The phase almost zero at the frequencies below 1 kHz indicates that the low frequency current flows mostly through the extracellular space between the low conductive cell membrane and capillary wall. With increase of frequency, the current is able to penetrate the cell membrane and insulated capillary wall, and therefore the decreases of phase and impedance magnitude are observed. The measured impedance was not distinguished between when the cell is captured and not at the frequencies higher than 20 kHz. Therefore, the capillary with impedance measurement system is proper to measure the impedance of embedded cell in the low frequency range related with extracellular behaviour (e.g. membrane morphology and integrity). It was able to monitor the effect of DMSO causing the membrane alteration on the impedance of embedded cell by using the capillary with impedance measurement system. The following events were reflected in the change of impedance at 100 Hz (Figure 4B and 4C):a)

View Article: PubMed Central - PubMed

ABSTRACT

Non-invasive single cell analyses are increasingly required for the medical diagnostics of test substances or the development of drugs and therapies on the single cell level. For the non-invasive characterisation of cells, impedance spectroscopy which provides the frequency dependent electrical properties has been used. Recently, microfludic systems have been investigated to manipulate the single cells and to characterise the electrical properties of embedded cells. In this article, the impedance of partially embedded single cells dependent on the cellular behaviour was investigated by using the microcapillary. An analytical equation was derived to relate the impedance of embedded cells with respect to the morphological and physiological change of extracellular interface. The capillary system with impedance measurement showed a feasibility to monitor the impedance change of embedded single cells caused by morphological and physiological change of cell during the addition of DMSO. By fitting the derived equation to the measured impedance of cell embedded at different negative pressure levels, it was able to extrapolate the equivalent gap and gap conductivity between the cell and capillary wall representing the cellular behaviour.

No MeSH data available.


Related in: MedlinePlus