Study type: Medical/biological study (experimental study)

Nanoelectropulse-Induced Phosphatidylserine Translocation. med./bio.

Published in: Biophys J 2004; 86 (6): 4040-4048

Aim of study (acc. to author)

To study the membrane phospholipid rearrangement that appears after ultrashort pulse exposure and to evaluate the electrophysical boundaries of the pulsed field exposures that produce membrane phospholipid translocation.

Background/further details

Phosphatidylserine (PS) is a key phospholipid component of eucaryotic cell membrane and found almost exclusively on inner leaflet of the plasma membrane lipid bilayer in normal healthy cells. PS externalization is an important physiological signal.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 20 Hz
Modulation type: pulsed
Exposure duration: 50 pulses
Exposure 2: 2 Hz–2 kHz
Modulation type: pulsed
Exposure duration: 50 pulses
Exposure 3:
  • unspecified
Modulation type: pulsed
Exposure duration: not given in the article
Exposure 4:
  • unspecified
Modulation type: pulsed
Exposure duration: not given in the article

Exposure 1

Main characteristics
Frequency 20 Hz
Type
Exposure duration 50 pulses
Modulation
Modulation type pulsed
Pulse width 7 ns
Rise time 2 ns
Exposure setup
Exposure source
Setup Cells were placed in a rectangular channel (100 µm wide, 30 µm deep, 12 mm long) with gold plated electrode walls microfabricated on a glass microscope slide
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 4,000 kV/m maximum - - 0, 1, 1.5, 2.5, 3.5, 4 MV/m

Exposure 2

Main characteristics
Frequency 2 Hz–2 kHz
Type
Exposure duration 50 pulses
Additional info The following pulse repetition rate were used: 0 Hz, 2 Hz, 20 Hz, 200 Hz and 2000 Hz
Modulation
Modulation type pulsed
Pulse width 7 ns
Rise time 2 ns
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 2,500 kV/m - - - -

Exposure 3

Main characteristics
Frequency
  • unspecified
Type
Exposure duration not given in the article
Modulation
Modulation type pulsed
Pulse width 1 µs
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 1,000 kV/m - - - with 30 µJ/pulse

Exposure 4

Main characteristics
Frequency
  • unspecified
Type
Exposure duration not given in the article
Modulation
Modulation type pulsed
Pulse width 30 ns
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 2,500 kV/m - - - with 5µJ/pulse

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • during exposure

Main outcome of study (acc. to author)

1.5 MV/m pulses produce an intermediate level of PS translocation, above background but less than maximum response observed with higher amplitudes, indicating that the field threshold for PS externalization with 7 ns pulses lies between 1.0 and 1.5 MV/m. At higher field strengths a plateau in the response is revealed. Pulses of 2.5, 3.5, and 4.0 MV/m induce PS translocation in approximately the same fraction of the population (30-40% of the cells). Varying the pulse repetition rate over three orders of magnitude for 50 pulses, 7 ns, 2.5 MV/m exposures reveals a decline in PS externalization at 2000 Hz and an enhancement at 2 Hz.
It is also shown that nanoelectropulse-induced phosphatidylserine translocation does not require calcium in the external medium, and that the pulse regimens used in these experiments do not cause significant intra- or extracellular Joule heating.

Study character:

Study funded by

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