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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.


Related in: MedlinePlus

Micrographs of an embedded cell when the level of negative pressure is 8.3 mbar at 300 s, 11 mbar at 500 s, 15.5 mbar at 700 s, and 21.1 mbar at 900 s (A), the difference of impedance magnitude at 100 Hz during the aspiration (B), arrow: the time of capture.
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f5-sensors-08-01198: Micrographs of an embedded cell when the level of negative pressure is 8.3 mbar at 300 s, 11 mbar at 500 s, 15.5 mbar at 700 s, and 21.1 mbar at 900 s (A), the difference of impedance magnitude at 100 Hz during the aspiration (B), arrow: the time of capture.

Mentions: Figure 5 shows the dependence of the measured impedance of embedded cell on the morphological change of cell resulted from the aspiration with different negative pressures. Figure 5A is the difference of impedance magnitude recorded at 100 Hz during the artificial aspiration. The arrow in the figure indicates the time of capture. Figure 5B shows the micrographs of an embedded cell. The time in the micrographs of Figure 5B is correspondent to the measurement time. The applied negative pressure was 8.3 mbar at around 300 s, 11 mbar at 500 s, 15.5 mbar at 700 s, and 21.1 mbar at 900 s. From 300 s to 900 s of aspiration, the cell external to the capillary entrance kept the surface tension of membrane. During the period, ro and ri were 11.73 ± 0.17 μm and 1.60 ± 0.22 μm, respectively.However, both li and the difference of impedance magnitude were increased with increase of negative pressure level (li, /Z/capture − /Z/non-capture: 4.3 μm, 2.82 MΩ at 300 s, 7.5 μm, 4.26 MΩ at 500 s, 9.9 μm, 5.83 MΩ at 700 s, 13.0 μm, 8.05 MΩ at 900 s). By fitting the derived equation Rdiff to the difference of impedance magnitude in Figure 5, the adjustable parameters g and σg/σm are extrapolated and shown in Figure 6. For an example, if the gap conductivity is same as one of medium (σg/σm= 1), the gap is 41.5 nm at 300 s, 46.0 nm at 500 s, 44.0 nm at 700 s, and 41.1 nm at 900 s. Thus, the relationship between the interfacial parameters g and σg can be used to explain the behaviour of embedded single cells. If σg is determined by means of using the ion channel blockers, the value of g can be achieved. Based on the investigation, it is expected to monitor the interfacial parameters as the response of embedded single cells under various environments. Further, the derived equation can be adapted to various micro fluidic systems for single cell analyses by impedance spectroscopy.


Dependence of Impedance of Embedded Single Cells on Cellular Behaviour
Micrographs of an embedded cell when the level of negative pressure is 8.3 mbar at 300 s, 11 mbar at 500 s, 15.5 mbar at 700 s, and 21.1 mbar at 900 s (A), the difference of impedance magnitude at 100 Hz during the aspiration (B), arrow: the time of capture.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3927517&req=5

f5-sensors-08-01198: Micrographs of an embedded cell when the level of negative pressure is 8.3 mbar at 300 s, 11 mbar at 500 s, 15.5 mbar at 700 s, and 21.1 mbar at 900 s (A), the difference of impedance magnitude at 100 Hz during the aspiration (B), arrow: the time of capture.
Mentions: Figure 5 shows the dependence of the measured impedance of embedded cell on the morphological change of cell resulted from the aspiration with different negative pressures. Figure 5A is the difference of impedance magnitude recorded at 100 Hz during the artificial aspiration. The arrow in the figure indicates the time of capture. Figure 5B shows the micrographs of an embedded cell. The time in the micrographs of Figure 5B is correspondent to the measurement time. The applied negative pressure was 8.3 mbar at around 300 s, 11 mbar at 500 s, 15.5 mbar at 700 s, and 21.1 mbar at 900 s. From 300 s to 900 s of aspiration, the cell external to the capillary entrance kept the surface tension of membrane. During the period, ro and ri were 11.73 ± 0.17 μm and 1.60 ± 0.22 μm, respectively.However, both li and the difference of impedance magnitude were increased with increase of negative pressure level (li, /Z/capture − /Z/non-capture: 4.3 μm, 2.82 MΩ at 300 s, 7.5 μm, 4.26 MΩ at 500 s, 9.9 μm, 5.83 MΩ at 700 s, 13.0 μm, 8.05 MΩ at 900 s). By fitting the derived equation Rdiff to the difference of impedance magnitude in Figure 5, the adjustable parameters g and σg/σm are extrapolated and shown in Figure 6. For an example, if the gap conductivity is same as one of medium (σg/σm= 1), the gap is 41.5 nm at 300 s, 46.0 nm at 500 s, 44.0 nm at 700 s, and 41.1 nm at 900 s. Thus, the relationship between the interfacial parameters g and σg can be used to explain the behaviour of embedded single cells. If σg is determined by means of using the ion channel blockers, the value of g can be achieved. Based on the investigation, it is expected to monitor the interfacial parameters as the response of embedded single cells under various environments. Further, the derived equation can be adapted to various micro fluidic systems for single cell analyses by impedance spectroscopy.

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