Electroporation of the photosynthetic membrane

Abstract

The study examines the relationship between electric field-induced conductivity and permeability changes in a biological membrane (electroporation) and the amplitude-duration parameters of the externally applied electric field. These reversible changes were characterized in giant photosynthetic membrane vesicles by means of the calibrated response of an intrinsic voltage-sensitive optical probe (electrophotoluminescence) and by the uptake studies of dextran-FITC fluorescent probes of different molecular weights. We quantitatively monitored electric field-induced conductivity changes by translating the electrophotoluminescence changes into conductivity changes. This was carried out by measuring the attenuation of the electrophotoluminescent signal after the addition of known amounts of gramicidin. The results demonstrate that electroporation involves the reversible formation of discrete holes in the membrane having radii <5.8 nm. The total area of the electric field-induced holes was 0.075% of the total surface of the vesicle. The formation of the electropores was affected differently by the electric field strength than by its duration. Increase in electric field strength caused increase in the total area of the vesicle that undergoes electroporation. Increase in the duration of the electric field increases the area of single electropores. Each of the two electric parameters can be rate limiting for the dynamics of electropore formation. These results are in accordance with the model of electroporation based on electric field-induced expansion of transient aqueous holes.

Size‐Dependent Electroporation of Dye‐Loaded Polymer Nanoparticles for Efficient and Safe Intracellular Delivery

“…Together these results indicate that the largest pores formed during electroporation, which have a sufficient lifetime for NPs to pass, are of the order of 30 nm. This is in line with early estimations of pore sizes using large macromolecules (dextrans), for which pore sizes of close to 10 nm were obtained, [ 59–61 ] and more recent studies suggesting that transiently larger pores can be formed. [ 62 ]…”

Electropermeabilization of Mammalian Cells to Macromolecules: Control by Pulse Duration

“…It was suggested that excessive field strength could lead to permeation of a wider area, or forming larger pores that may exceed the resealing limit (Hui, 1996). The same conclusion was also reported by Rosemberg and Korenstein (1990); E controlling the total area of membrane that undergoes permeabilization, and T the diameter of "electropores." Longer pulses corresponding to low field strength were reported to be more advantageous than the short ones in terms of transfection success (Kubiniec et al, 1988).…”

“…Several models assumed that transfer across the membrane occurred across pores, which has never been observed. Different calculations of the "electropores" diameter have been proposed, from 0.39 to 5.8 nm, that correspond to 0.01-0.1% of the membrane area (Sowers and Lieber, 1986;Kinosita et al, 1988;Rosemberg and Korenstein, 1990;Hibino et al, 1993;Neumann et al, 1996). If these values are compatible with the size of small molecules (M w Ͻ 10), they cannot support the penetration of macromolecules such as plasmid DNA and enzymes.…”

Loss of intracellular glycerol from Dunaliella by electroporation at constant osmotic pressure: subsequent restoration of glycerol content and associated volume changes

“…Electroporation is generally considered to enhance the transient formation of aqueous pores in the plasmalemma, as a result of the abnormally high electrical potential difference imposed on those parts of the membrane perpendicular to the externally applied field (Rosemberg & Korenstein 1990). More than one type of process is involved depending on the field strength, the membrane conductivity, and the pulse number, duration and polarity (Rosemberg & Korenstein 1990;Toner & Cravalho 1990). The permeation of solutes through these enlarged pores is driven by a transmembrane concentration gradient in the case of uncharged molecules such as glycerol, or by a combination of concentration and electrical gradients in the case of ions.…”