脉宽为ns级、场强≥10kV/cm的脉冲电场能够对细胞内部结构产生影响而不会导致细胞外膜穿孔,即细胞内电处理效应。尽管细胞内电处理效应的机理目前还不是很清楚,但国内外学者一致认为细胞内电处理的根本原因是ns脉冲电场在细胞内膜上诱导出的跨膜电位超过了穿孔临界值,从而导致内膜穿孔。基于以上研究详细介绍了目前关于细胞内外膜跨膜电位的计算模型、方法及仿真计算结果,探讨了细胞内电处理的机理。宽脉冲电场难以透过外膜进入细胞内部,主要作用在外膜上,导致外膜发生电穿孔。随着脉冲宽度变小,电场对内膜作用增强。当脉宽减小到ns级时,脉冲电场感应出的内膜跨膜电位比外膜大,电场主要作用于膜内细胞器,诱导内膜穿孔,细胞结构和功能改变,即进行细胞内电处理。
The recent experimental studies have shown that pulsed electric fields of nanosecond duration and above 10 kV/cm amplitude can affect the subcellular structures but do not lead to formation of pores in the outer membrane. This phenomenon is called intracellular electromanipulation effect. Although the mechanism of intracellular electromanipulation has not yet been completely understood at present, all the researchers in the world believe that the intracellular electromanipulation effect is due to that the voltage across inner membrane induced by nanosecond pulsed electric field is larger than a critical value so that inner membrane is perforated. In the studies, the available models, methods and results of calculating voltages across inner and outer membrane are described in details, and the mechanism of intracellular electromanipulation is also discussed. The results show that long pulsed electric field is difficult to penetrate the outer membrane and mainly targets on the outer membrane because of its low equivalent frequency. As a result, the outer membrane is perforated. As the pulse duration decreases, the transmembrane voltage of inner membrane increases and electroporation effect changes from outer membrane to intracellular organdie membranes gradually. When the duration decreases to tens of nanosecond, the transmembrane voltage of inner membrane will exceed that of outer membrane, therefore, the external field will mainly target on inner membrane. When the field is enough high, pores will be formed in the inner membrane and many conformational and functional changes will occur, in other words, intracellular electromanipulation effect is induced.