Abstract

The antimicrobial peptide (AMP) magainin 2 induces nanopores in the lipid membranes of giant unilamellar vesicles (GUVs), as observed by the leakage of water-soluble fluorescent probes from the inside to the outside of GUVs through the pores. However, molecular transport through a single nanopore has not been investigated in detail yet and is studied in the present work by simulation. A single pore was designed in the membrane of a GUV using computer-aided design software. Molecular transport, from the outside to the inside of GUV through the nanopore, of various fluorescent probes such as calcein, Texas-Red Dextran 3000 (TRD-3k), TRD-10k and TRD-40k was then simulated. The effect of variation in GUV size (diameter) was also investigated. A single exponential growth function was fitted to the time course of the fluorescence intensity inside the GUV and the corresponding rate constant of molecular transport was calculated, which decreases with an increase in the size of fluorescent probe and also with an increase in the size of GUV. The rate constant found by simulation agrees reasonably well with reported experimental results for inside-to-outside probe leakage. Based on Fick’s law of diffusion an analytical treatment is developed for the rate constant of molecular transport that supports the simulation results. These investigations contribute to a better understanding of the mechanism of pore formation using various membrane-active agents in the lipid membranes of vesicles and the biomembranes of cells.

中文翻译：

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使用 COMSOL 模拟研究通过单个纳米孔的巨大单层囊泡膜中的分子传输

摘要

抗菌肽 (AMP) magainin 2 在巨大的单层囊泡 (GUV) 的脂质膜中诱导纳米孔，如水溶性荧光探针通过孔从 GUV 的内部泄漏到外部所观察到的。然而，尚未详细研究通过单个纳米孔的分子传输，并且在目前的工作中通过模拟进行研究。使用计算机辅助设计软件在 GUV 的膜中设计了一个孔。然后模拟了各种荧光探针（如钙黄绿素、德克萨斯红葡聚糖 3000 (TRD-3k)、TRD-10k 和 TRD-40k）从 GUV 外部到内部通过纳米孔的分子传输。还研究了 GUV 尺寸（直径）变化的影响。将单个指数增长函数拟合到 GUV 内荧光强度的时间过程，并计算相应的分子传输速率常数，该速率常数随着荧光探针尺寸的增加和 GUV 尺寸的增加而减小. 通过模拟发现的速率常数与报告的内部到外部探头泄漏的实验结果相当吻合。基于 Fick 扩散定律，开发了支持模拟结果的分子传输速率常数的分析处理。这些研究有助于更好地理解在囊泡的脂质膜和细胞的生物膜中使用各种膜活性剂的孔形成机制。它随着荧光探针尺寸的增加和 GUV 尺寸的增加而减小。通过模拟发现的速率常数与报告的内部到外部探头泄漏的实验结果相当吻合。基于 Fick 扩散定律，开发了支持模拟结果的分子传输速率常数的分析处理。这些研究有助于更好地理解在囊泡的脂质膜和细胞的生物膜中使用各种膜活性剂的孔形成机制。它随着荧光探针尺寸的增加和 GUV 尺寸的增加而减小。通过模拟发现的速率常数与报告的内部到外部探头泄漏的实验结果相当吻合。基于 Fick 扩散定律，开发了支持模拟结果的分子传输速率常数的分析处理。这些研究有助于更好地理解在囊泡的脂质膜和细胞的生物膜中使用各种膜活性剂的孔形成机制。基于 Fick 扩散定律，开发了支持模拟结果的分子传输速率常数的分析处理。这些研究有助于更好地理解在囊泡的脂质膜和细胞的生物膜中使用各种膜活性剂的孔形成机制。基于 Fick 扩散定律，开发了支持模拟结果的分子传输速率常数的分析处理。这些研究有助于更好地理解在囊泡的脂质膜和细胞的生物膜中使用各种膜活性剂的孔形成机制。