The Reduction in Electroporation Voltages by the Addition of a Surfactant to Planar Lipid Bilayers

Abstract

The effects of a nonionic surfactant, octaethyleneglycol mono n-dodecyl ether (C12E8), on the electroporation of planar bilayer lipid membranes made of the synthetic lipid 1-pamitoyl 2-oleoyl phosphatidylcholine (POPC), was studied. High-amplitude ( approximately 100-450 mV) rectangular voltage pulses were used to electroporate the bilayers, followed by a prolonged, low-amplitude ( approximately 65 mV) voltage clamp to monitor the ensuing changes in transmembrane conductance. The electroporation thresholds of the membranes were found for rectangular voltage pulses of given durations. The strength-duration relationship was determined over a range from 10 micros to 10 s. The addition of C12E8 at concentrations of 0.1, 1, and 10 microM to the bath surrounding the membranes decreased the electroporation threshold monotonically with concentration for all durations (p < 0.0001). The decrease from control values ranged from 10% to 40%, depending on surfactant concentration and pulse duration. For a 10-micros pulse, the transmembrane conductance 150 micros after electroporation (G150) increased monotonically with the surfactant concentration (p = 0.007 for 10 microM C12E8). These findings suggest that C12E8 incorporates into POPC bilayers, allowing electroporation at lower intensities and/or shorter durations, and demonstrate that surfactants can be used to manipulate the electroporation threshold of lipid bilayers.

Triton X-100 concentration effects on membrane permeability of a single HeLa cell by scanning electrochemical microscopy (SECM)

“…Although there have been many quantitative studies of the TX100 molecule and its interaction with artificial lipid bilayers (21)(22)(23)(24)(25), there have been none with a living cell membrane and its behavior in terms of its permeability, morphology, and metabolic behavior in real time. We report here how the single live cell permeability and morphology are affected by TX100, the most commonly used surfactant for permeabilization in many fluorescent and toxicological studies.…”

A System for the Determination of Planar Lipid Bilayer Breakdown Voltage and Its Applications

“…Some of them were already proposed by other authors. We have determined the capacitance of lipid bilayers [18] and the breakdown voltage of planar lipid bilayers using rectangular pulses [14], [21], [24] as well as linear rising signals [38].…”

“…The amplitude of the voltage pulse is incremented in small steps until the breakdown of the bilayer is reached [14]. First, the voltage pulse charges up the planar lipid bilayer.…”

“…Two measurement principles of planar lipid bilayer's properties are mainly used: the voltage-clamp method [14]- [25] and the current-clamp method [26]- [37]. In addition, due to the steadily growing use of wireless communication systems, application of electromagnetic waves is their alternative (see Fig.…”

“…The simplest as well as the most often used shape of the voltage signal is a square voltage pulse [14], [18], but other shapes have also been used [15], [21], [38], [39]. Some experiments were done by using two sinus-shaped voltage signals: the first with a low frequency and large amplitude, and the second with a high frequency and low amplitude that was added to the first one.…”