Casciola M, Bonhenry D, Liberti M, Apollonio F, Tarek M
Dipartimento di Ingegneria Informatica, Elettronica e Telecomunicazioni (D.I.E.T), University of Rome "La Sapienza", Roma, Italy; Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, 00161 Roma, Italy; Université de Lorraine, Theory, Modeling and Simulation Group, UMR 7565, F-54506 Vandoeuvre-lès-Nancy, France.
Université de Lorraine, Theory, Modeling and Simulation Group, UMR 7565, F-54506 Vandoeuvre-lès-Nancy, France.
Bioelectrochemistry. 2014 Dec;100:11-7. doi: 10.1016/j.bioelechem.2014.03.009. Epub 2014 Mar 28.
We report on a molecular dynamics (MD) simulation study of the electroporation of lipid bilayers at different cholesterol contents using protocols mimicking "traditional" electroporation, i.e. low intensity millisecond pulses (msEP), and high intensity nanosecond electric pulses (nsEP). The results show that addition of cholesterol in concentrations of lipid:sterol ranging from 20 to 50 mol% enhances substantially the membrane cohesion, which is manifested by an increase of the electroporation threshold (U(thr)). This increase is steady in the case of the nsEP protocol, reaching roughly a factor 2 in the 50 mol% samples. In contrast, for the msEP protocol, U(thr) increases by 50% upon addition of 30 mol% cholesterol then levels off. Furthermore, pores formed under msEP are found to possess morphologies much different from the usually reported hydrophilic "electropores" encountered under the nsEP protocol, which may have profound consequences on the transport properties of "electroporated" membranes. Hence, this study reveals that cell membrane models containing the ubiquitous cholesterol component respond quite differently to the two electroporation techniques, in contrast to what has been found for simple zwitterionic bilayers.
我们报告了一项分子动力学（MD）模拟研究，该研究使用模拟“传统”电穿孔的方案，即低强度毫秒脉冲（msEP）和高强度纳秒电脉冲（nsEP），对不同胆固醇含量的脂质双层进行电穿孔。结果表明，以脂质：甾醇浓度范围为20至50 mol%添加胆固醇，可显著增强膜凝聚力，这表现为电穿孔阈值（U(thr)）增加。在nsEP方案中，这种增加是稳定的，在50 mol%的样品中达到约2倍。相比之下，对于msEP方案，添加30 mol%胆固醇后U(thr)增加50%，然后趋于平稳。此外，发现msEP下形成的孔具有与nsEP方案下通常报道的亲水性“电穿孔”非常不同的形态，这可能对“电穿孔”膜的传输特性产生深远影响。因此，本研究表明，与简单两性离子双层的情况相反，含有普遍存在的胆固醇成分的细胞膜模型对两种电穿孔技术的反应截然不同。
