Fig 1.
Experimental setup for applying an electric field to GUV.
(A) Laboratory setup showing the microchamber positioned on the microscope stage during experiments. (B) Schematic illustration of the microchamber and the arrangement of gold-coated electrodes. The microchamber was constructed by placing a U-shaped silicone rubber spacer on a glass slide to maintain structural integrity. (C) Graph depicting the applied pulsating DC signal with a frequency of 1.1 kHz over time (ON time 200 μs). (D) Diagram representing a single GUV suspended between the gold-coated electrodes, where E denotes the applied electric field. The transmembrane potential (Vm) is dependent on the angle (θ) relative to the electric field direction. (E) Phase-contrast microscope image of an intact GUV before exposure to the electric field. (F) Phase-contrast image showing the same GUV after undergoing rupture due to applied electric field.
Fig 2.
Electric field-induced rupture of DOPG/DOPC/GrA-GUVs at different GrA% under σe = 8 mN/m.
Typical fluorescence microscopic images illustrate the rupture progression of (A) DOPG/DOPC (40/60)-GUVs, (B) DOPG/DOPC/GrA (40/59.9/0.1)-GUVs, and (C) DOPG/DOPC/GrA (40/57/3)-GUVs. The applied electric field (E) is directed as indicated by the arrow on the left. The time in seconds after applying the electric field is noted in each image.
Fig 3.
Analysis of rupture time (trup) of DOPG/DOPC/GrA-GUVs at different GrA% under σe = 8 mN/m.
(A–C) Stochastic rupture behavior of many ‘single GUVs’ in one independent experiment at (A) 0% GrA, (B) 0.1% GrA, and (C) 3% GrA. The x-axis represents the GUV label number (m). (D) Probability of rupture (Prup) as a function of GrA%, showing an initial decrease followed by an increase with higher GrA%.
Fig 4.
Rupture kinetics of DOPG/DOPC/GrA-GUVs at different GrA% under σe = 8 mN/m.
(A) Time-dependent fraction of intact GUVs (Pintact) for 0, 0.01, 0.05, and 5% GrA, showing the exponential decay behavior. The coefficient of determination (R2) was evaluated for the goodness of fit shown in (A). The values of R2 were obtained 0.90, 0.91, 0.91, and 0.79 for 0, 0.01, 0.05, and 5% GrA, respectively. (B) GrA%-dependent variation in kr, highlighting a non-monotonic trend in rupture susceptibility. The error bars in (B) represent the standard error of the mean rate constants derived from 3–4 independent experiments for each GrA%.
Fig 5.
Rate constant of rupture of DOPG/DOPC/GrA-GUVs at different GrA% and electric tensions.
Different symbols indicate distinct GrA% in the membranes. Error bars represent standard deviations.
Fig 6.
The energy landscape of a system undergoing conformational changes in the process of pore formation.
This consists of a prepore region and the rupture region. The curve illustrates the transition from a stable prepore state to an unstable pore state at the energy barrier Ub, followed by progression toward membrane rupture. The critical pore radius rc marks the transition point between reversible pore formation and irreversible rupture.
Fig 7.
Dependence of lnkr on 1/(σe + B) for DOPG/DOPC/GrA-GUVs at various GrA%.
Each symbol represents a different GrA%, as indicated in the legend. The solid lines represent best-fit theoretical curves based on Eq (8), demonstrating the relationship between membrane tension and rupture kinetics across different GrA conditions.
Table 1.
Rate constant, probability of rupture, and pore-edge tension in DOPG/DOPC/GrA-GUVs with varying GrA% under σe = 8 mN/m.
Fig 8.
Schematic representation of GrA incorporation and electromechanical response of the lipid bilayer under an applied electric field.
GrA monomers insert perpendicularly into each lipid leaflet and can dimerize across the bilayer to form ion-conducting channels spanning the membrane. Upon exposure to an external electric field, electric tension (σₑ) acts laterally on the bilayer, promoting local deformation and pore initiation. The balance between the applied σₑ and intrinsic line tension (Γ) governs the stability of the pore edge. Depending on the GrA content and field strength, these perturbations can facilitate membrane thinning and transient pore formation, providing a mechanistic basis for electroporation behavior in peptide-doped membranes.