Giant unilamellar vesicles (GUVs) are used extensively as models that mimic cell membranes. The cholesterol (Chol) content in the fiber cell plasma membranes of the eye lens is extremely high, exceeding the solubility threshold in the lenses of old humans. Thus, a methodological paper pertaining to preparations of model lipid bilayer membranes with high Chol content would significantly help the study of properties of these membranes. Lipid solutions containing 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine (POPC) and Chol were fluorescently labeled with phospholipid analog 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate (DiIC₁₈(3)) and spin-coated to produce thin lipid films. GUVs were formed from these films using the electroformation method and the results were obtained using fluorescent microscopy. Electroformation outcomes were examined for different electrical parameters and different Chol concentrations. A wide range of field frequency–field strength (ff–fs) combinations was explored: 10–10,000 Hz and 0.625–9.375 V/mm peak-to-peak. Optimal values for GUVs preparation were found to be 10–100 Hz and 1.25–6.25 V/mm, with largest vesicles occurring for 10 Hz and 3.75 V/mm. Chol:POPC mixing ratios (expressed as a molar ratio) ranged from 0 to 3.5. We show that increasing the Chol concentration decreases the GUVs size, but this effect can be reduced by choosing the appropriate ff–fs combination.

中文翻译：

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电参数和胆固醇浓度对巨大单层囊泡电形成的影响。

巨大的单层囊泡 (GUV) 被广泛用作模拟细胞膜的模型。眼睛晶状体的纤维细胞质膜中的胆固醇（Chol）含量极高，超过了老年人晶状体中的溶解度阈值。因此，关于制备具有高 Chol 含量的模型脂质双层膜的方法论论文将大大有助于研究这些膜的特性。含有 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine (POPC) 和 Chol 的脂质溶液用磷脂类似物 1,1'-双十八烷基-3,3,3',3'-四甲基吲哚羰花青高氯酸盐 (DiIC ₁₈(3)) 并旋涂以产生薄的脂质膜。GUVs 是使用电铸法从这些薄膜形成的, 结果是使用荧光显微镜获得的。针对不同的电参数和不同的 Chol 浓度检查了电形成结果。探索了广泛的场频-场强 (ff-fs) 组合：10-10,000 Hz 和 0.625-9.375 V/mm 峰峰值。发现 GUV 制备的最佳值为 10–100 Hz 和 1.25–6.25 V/mm，最大囊泡发生在 10 Hz 和 3.75 V/mm。Chol:POPC 混合比（以摩尔比表示）范围为 0 到 3.5。我们表明，增加 Chol 浓度会降低 GUV 的大小，但可以通过选择适当的 ff-fs 组合来减少这种影响。