Soft perforation of planar bilayer lipid membranes of dipalmitoylphosphatidylcholine at the temperature of the phase transition from the liquid crystalline to the gel state

Abstract

In contrast to the widely used method of electroporation, the method of soft perforation of lipid bilayers is proposed. It is based on the structural rearrangement of the lipid bilayer formed from disaturated phospholipids at the temperature of the phase transition from the liquid crystalline state to the gel state. This allows us to obtain a lipid pore population without the use of a strong electric field. It is shown that the planar lipid bilayer membrane (pBLM) formed from dipalmitoylphosphatidylcholine in 1 M LiCl aqueous solution exhibits the appearance of up to 50 lipid pores per 1 mm(2) of membrane surface, with an average single pore conductivity of 31 +/- 13 nS. The estimation of a single pore radius carried out with water-soluble poly(ethylene glycol)s (PEGs) showed that the average pore radius ranged between 1.0-1.7 nm. It was found experimentally that PEG-1450, PEG-2000, and PEG-3350 should be in a position to block the single pore conductivity completely, while PEG-6000 fully restored the ionic conductivity. The similarity of these PEG effects to ionic conductivity in protein pores makes it possible to suggest that the partition of the PEG molecules between the pore and the bulk solution does not depend on the nature of the chemical groups located in the pore wall.

Polystyrene nanoparticle exposure induces ion-selective pores in lipid bilayers

“…However, Antonov et al [39] reported the selectivity order of monovalent cations for soft perforation pores generated at the BLM’s phase transition temperature. They suggested that the hydration force is responsible for cation selectivity of planar BLM at soft perforation.…”

“…This variety is to be expected, given the fluidity of BLM and the possibility of multiple modes of interaction between PNP and BLM, including PNP aggregation at, or in, BLM to form an ion-transporting complex [40]. Alternatively, PNP could cause a phase transition in BLM at the point of contact [41], which could trigger pore formation due to structural rearrangement from the liquid crystalline state to the gel state [39]. …”

A lipocentric view of peptide-induced pores

“…They exhibit quantized currents corresponding to large pores with a narrow distribution of sizes (Antonov et al. 1980, 2005; Boheim et al. 1980) and moderate ion selectivity (Antonov et al.…”

“…1980) and moderate ion selectivity (Antonov et al. 2005). The presence of lysolipids at the gel-to-liquid phase transition dramatically enhances membrane leakage, and this is proposed to occur through lysolipid-stabilized pores in the boundary of the partially melted solid phase (Mills and Needham 2005).…”

Voltage-Gated Lipid Ion Channels

“…This finding was first reported by Yafuso and collaborators (2) on oxidized cholesterol membranes. Numerous subsequent reports show that one finds channel-like events in synthetic lipid membranes in the complete absence of proteins (3)(4)(5)(6)(7)(8)(9)(10). The channels reported in those studies are typically of similar conductance (several 10 to 100 pS) and lifetime (a few ms to several 100 ms) than those of protein channels.…”