Abstract
Transient physical disruption of cell membranes by electric pulses (or electroporation) has significance in biomedical and biological applications requiring the delivery of exogenous (bio)molecules to living cells. We demonstrate that actin networks regulate the cell membrane permeability during electroporation. Disruption of actin networks increases the uptake of membrane-impermeable molecules such as propidium iodide during electroporation. Our experiments at different temperatures ranging from 11 °C to 37 °C show that molecular uptake during electroporation increases with temperature. Furthermore, by examining the temperature-dependent kinetics of propidium iodide uptake, we infer that the activation energy barrier of electroporation is lowered when the actin networks are disrupted. Our numerical calculations of transmembrane voltage show that the reduced activation energy barrier for the cells with disrupted actin is not a consequence of the changes in transmembrane voltage associated with changes in the cell shape due to the disruption of actin, indicating that this could be due to changes in membrane mechanical properties. Our results suggest that the current theoretical models of electroporation should be advanced further by including the contributions of the cytoskeletal networks on the cell membrane permeability during the delivery of exogenous materials.
Highlights
Cell membranes, which are composed of a lipid bilayer with embedded proteins, act as a protective barrier that separates the intracellular components from the extracellular environment
Our results suggest that the current theoretical models of electroporation should be advanced further by including the contributions of the cytoskeletal networks on the cell membrane permeability during the delivery of exogenous materials
Previous experiments have shown that the incorporation of actin network into giant unilamellar vesicles (GUVs) resulted in a higher molecular uptake through the lipid membrane due to the resulting longer resealing time compared to the empty GUVs [36]
Summary
Cell membranes, which are composed of a lipid bilayer with embedded proteins, act as a protective barrier that separates the intracellular components from the extracellular environment. One of the most common and safest non-viral methods used to transiently increase the cell membrane permeability is the introduction of transient transmembrane pores by subjecting the cell to a pulsed electric field [4,5]. This process is called electroporation or electropermeabilization, with applications including DNA vaccination, electrochemotherapy, and irreversible electroporation for nonthermal ablation of solid tumors and cardiac muscle ablation [6,7,8,9,10,11,12]. The electroporation of giant unilamellar vesicles or GUVs leads to the formation of pores in the size range of micrometers in the membrane ( called macropores) whereas pores of such dimensions are not observed in living cells [22,23,32]
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