Biophysics Research Laboratory, Department of Physics, Bangladesh University of Engineering and Technology (BUET), Dhaka, 1000, Bangladesh.
Department of Biomedical Physics and Technology, University of Dhaka, Dhaka, 1000, Bangladesh.
Eur Biophys J. 2019 Dec;48(8):731-741. doi: 10.1007/s00249-019-01398-9. Epub 2019 Sep 24.
Stretching in membranes of cells and vesicles plays important roles in various physiological and physicochemical phenomena. Irreversible electroporation (IRE) is the irreversible permeabilization of the membrane through the application of a series of electrical field pulses of micro- to millisecond duration. IRE induces lateral tension due to stretching in the membranes of giant unilamellar vesicles (GUVs). However, the effects of electrically induced (i.e., IRE) constant tension in the membranes of GUVs have not been investigated yet in detail. To explore the effects of electrically induced tension on GUVs, firstly a microcontroller-based IRE technique is developed which produces electric field pulses (332 V/cm) with pulse width 200 µs. Then the electrodeformation, electrofusion and membrane rupture of GUVs are investigated at various constant tensions in which the membranes of GUVs are composed of dioleoylphosphatidylglycerol (DOPG) and dioleoylphosphatidylcholine (DOPC). Stochastic electropore formation is observed in the membranes at an electrically induced constant tension in which the probability of pore formation is increased with the increase of tension from 2.5 to 7.0 mN/m. The results of pore formation at different electrically-induced constant tensions are in agreement with those reported for mechanically-induced constant tension. The decrease in the energy barrier of the pre-pore state due to the increase of electrically-induced tension is the main factor increasing the probability of electropore formation. These investigations help to provide an understanding of the complex behavior of cells/vesicles in electric field pulses and can form the basis for practical applications in biomedical technology.
在细胞膜和囊泡中拉伸在各种生理和物理化学现象中起着重要作用。不可逆电穿孔（IRE）是通过施加微秒到毫秒持续时间的一系列电场脉冲来实现细胞膜的不可逆穿孔。IRE 由于大单层囊泡（GUV）的膜拉伸而产生横向张力。然而，尚未详细研究电诱导（即 IRE）GUV 膜中的恒定张力的影响。为了探索电诱导张力对 GUV 的影响，首先开发了一种基于微控制器的 IRE 技术，该技术产生具有 200µs 脉冲宽度的电场脉冲（332V/cm）。然后在各种恒定张力下研究 GUV 的电极变形、电融合和膜破裂，其中 GUV 的膜由二油酰基磷脂酰甘油（DOPG）和二油酰基磷脂酰胆碱（DOPC）组成。在电诱导的恒定张力下观察到膜中的随机电孔形成，随着张力从 2.5 增加到 7.0 mN/m，孔形成的概率增加。在不同电诱导恒定张力下的孔形成结果与机械诱导恒定张力下的结果一致。由于电诱导张力的增加而降低的前孔状态的能垒是增加电孔形成概率的主要因素。这些研究有助于了解细胞/囊泡在电场脉冲中的复杂行为，并为生物医学技术中的实际应用提供基础。
