Elsevier

Available online 2 November 2020, 107689

Bioelectrochemistry

Highlights

Electroporation synchronized with fluorescence and temperature measurements.

Lipid bilayer packing (as generalized polarization) changes due to electroporation.

ROS production and lipid peroxidation due to electroporation.

Fast lipid unpacking (thermal) after pulses delivery in higher conductivity buffers.

Slow lipid tightening (non-thermal) related to ROS production.

Abstract

Electropermeabilization of the cell membrane is a technique used to facilitate penetration of impermeant molecules into cells. Although there are studies regarding the mechanism of processes occurring after electropermeabilization, the relationship between electropermeabilization and associated phenomena (e.g. generation of reactive oxygen species, endocytosis, lipid peroxidation, etc.) is yet to be elucidated. This work aimed to get information on the changes in the packing of the bilayer lipids and their peroxidation induced by application of electroporation pulses. We used a specially designed system of electrodes which allowed performing electropermeabilization of cells in suspension simultaneously with time-dependent measurements of fluorescence and temperature. The kinetics of membrane packing and production of reactive oxygen species were studied using various conductivity buffers (0.01, 0.04 and 0.14 S/m) and different number of 1 kV/cm bipolar pulses (1 to 50). Two categories of effects were observed: a thermal effect, consisting in an increased bilayer disorder (a deeper penetration of water into the hydrophobic core), and a nonthermal effect, leading to a higher degree of lipids packing, the latter being attributed to a peroxidation process. An analysis of the permeabilization conditions in which one of these two processes predominates was performed.

Keywords

electroporation

real-time measurements

generalized polarization

Laurdan

membrane lipid peroxidation

ROS production

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