Electric Field-Mediated DNA Encapsulation into Large Liposomes

Insights into the mechanisms of electromediated gene delivery and application to the loading of giant vesicles with negatively charged macromolecules

“…However, they could not directly observe the liposomes because of their small size. The conclusions of 18 were subsequently questionned by Lurquin and Athanasiou 19 , who observed that giant (≈ 10 µm) EB-loaded DPPC liposomes pulsed with DNA did actually show the bright fluorescence of DNA/EB complexes before (or even without) sonication. These results support a mechanism involving electropores and a direct entrance of DNA into the liposomes.…”

The rate of electrical energy dissipation (power) and the RC constant unify all electroporation parameters

“…Molecules present in the surrounding medium are then able to diffuse through the temporary pores thus formed. Experiments with artificial liposomes support this model (Lurquin and Athanasiou 2000). …”

“…In practice, bacterial cells are porated around 12–16 kV/cm, microeukaryotes at about 1 kV/cm, and eukaryotic cells at about 0.3–0.7 kV/cm (Lurquin 1997). Large liposomes (2.5–20 μ in diameter) made of di-palmitoyl-phosphatidyl-choline or l -α-phosphatidyl-choline are efficiently electroporated at 1.5 kV/cm (Lurquin and Athanasiou 2000). Thus, the first rule of electroporation is to achieve membrane breakdown, which is dependent on cell size, not cell type (Lurquin 1997).…”

“…For large liposomes, efficient poration is seen at P  = 1,700 J/s (at RC = 12 ms) (Lurquin and Athanasiou 2000). Since energy factors are the same for capacitor discharges and square pulses (albeit calculated differently) (Lurquin 1997; Lurquin 2002), it is likely that power correlation with pulse length leads to similar electroporation efficiency with both techniques.…”

DNA translocation to giant unilamellar vesicles during electroporation is independent of DNA size

“…8 On the other hand, Lurquin et al observed no endocytosis of DNA molecules (B7600 bp) into giant unilamellar vesicles (GUVs, mean size B 2.5-20 mm) during electroporation, suggesting a mechanism of direct entry (or transport) through the electro-pores formed during electroporation. 9 To resolve this discrepancy, recently Portet et al (2011) conducted experiments using GUVs (mean diameter B 20 mm) and pDNA (B4700 bp). 10 Combining experiments with a proposed theoretical framework, they concluded direct entry of DNA molecules through electro-pores via electrophoresis as the mode of transport instead of electroinduced endocytosis.…”