Cell membrane voltage during electrical cell fusion calculated by re-expansion method
Cell membrane voltage during electrical cell fusion calculated by re-expansion method
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DOI：
10.1016/j.elstat.2006.12.001
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发表时间：
2007-08-01
影响因子：
1.8
通讯作者：
Techaumnat, Boonchai
中科院分区：
文献类型：
--
作者：
Washizu, Masao;Techaumnat, Boonchai
在电细胞融合中，首先通过介电电泳使两个细胞接触，然后施加脉冲电压以在接触点处诱导可逆的膜击穿，由此两个细胞的膜重新连接以形成融合细胞。膜电压的预测是高融合产率的关键问题，然而，它的数学表达式是已知的，只有一个孤立的细胞在一个均匀的外场的情况下。在本文中，我们采用重展开法的瞬态场分析这样的多细胞系统。每个细胞是由一个无限薄的球形绝缘膜在导电介质中，当施加一个外部电场时，发生自由电荷的积累。结果表明，该系统具有两个时间常数：（a）由介质的电导率和介电常数决定的时间常数和（B）通过导电介质对膜电容充电的时间常数，前者远短于后者。因此，由于前者的时间变化被忽略，以获得膜电压的简化表达式。通过将电势展开为勒让德谐波分量，并基于再展开法将每个单元的系数关联起来，得到了控制膜电压建立的微分方程。数值计算进行了轴对称的情况下，两个电池接触，其中一个步进电压施加。结果表明，最大膜电压最初出现在接触点，但当达到稳态时，它向细胞对的两端移动，并可能导致不成功的融合。分析表明，高产量的融合可以通过应用较短的脉冲，或一个不均匀的字段集中在接触点的电压降来实现。(C)2007 Elsevier B.V.保留所有权利。
In electrical cell fusion, two cells are first brought into contact by dielectrophoresis, and then a pulsed voltage is applied to induce reversible membrane breakdown at the contact point, by which the membranes of the two cells are reconnected to form a fusant cell. The prediction of the membrane voltage is a crucial issue for high fusion yield, however, its mathematical expression is known only for the case of an isolated cell in a uniform external field. In this paper, we employ the re-expansion method for the transient field analysis of such a multiple cell system. Each cell is modeled by an infinitesimally thin spherical insulating membrane in conducting media, on which accumulation of free charge occurs when an external field is applied. It is shown that the system has two time constants: (a) that governed by the conductivity and the permittivity of the media and (b) that of charging the membrane capacitance through the conducting media, and that the former is far shorter than the latter. Hence, the time variation due to the former is neglected to obtain a simplified expression for the membrane voltage. By expanding the potential into Legendre harmonic components and relating the coefficients for each cell based on the re-expansion method, a differential equation governing the membrane voltage buildup is obtained. The numerical calculation is performed for the axisymmetric case of two cells in contact, to which a step-wise voltage is applied. It is found that the maximum membrane voltage occurs initially at the contact point, but when the steady state is reached, it moves to the ends of the cell pair, and might lead to unsuccessful fusion. The analysis suggests that high-yield fusion may be achieved by an application of shorter pulse, or of a non-uniform field to concentrate the voltage drop at the contact point. (C) 2007 Elsevier B.V. All rights reserved.