Dewetting-induced formation and mechanical properties of synthetic bacterial outer membrane models (GUVs) with controlled inner-leaflet lipid composition.
Dewetting-induced formation and mechanical properties of synthetic bacterial outer membrane models (GUVs) with controlled inner-leaflet lipid composition.
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DOI：
10.1039/c9sm00223e
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发表时间：
2019-05
期刊：
影响因子：
3.4
通讯作者：
Sepehr Maktabi;Jeffrey W. Schertzer;P. Chiarot
中科院分区：
文献类型：
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作者：
Sepehr Maktabi;Jeffrey W. Schertzer;P. Chiarot
革兰氏阴性菌的双膜细胞包膜使它们能够忍受恶劣的环境，并代表了许多临床可用抗生素的屏障。外膜（OM）暴露于环境中，是参与细菌过程（如信号传导、发病机制和运动性）的第一个接触点。与细胞质膜一样，革兰氏阴性菌中的OM具有富含磷脂的内小叶和主要由脂多糖（LPS）组成的外小叶。我们报告了一种微流控技术，用于制造具有革兰氏阴性细菌OM脂质组合物的单分散不对称巨单层囊泡（GUV）。我们的连续微流控制造技术可高通量生成直径为50-150 μm的水包油包水双重乳液。水-油和油-水界面促进磷脂和LPS分子的自组装以分别产生脂质双层的内小叶和外小叶。双重乳液具有聚乙烯油壳，其最小化残留有机溶剂的量，所述残留有机溶剂保持截留在GUV膜的小叶之间。通过乙醇和微量吸液管抽吸鱼油壳的提取过程触发在水-油和油-水界面上组装的两个脂质单层之间的粘附相互作用（即，去湿转变），迫使它们接触并形成脂质双层膜。研究了不同内小叶脂质组合物对乳液/囊泡稳定性和去湿转变的影响。我们还报告了合成的不对称模型膜的弯曲模量和面积膨胀模量的值，该膜具有与铜绿假单胞菌中的OM生理相关的脂质组成/结构。
The double-membrane cellular envelope of Gram-negative bacteria enables them to endure harsh environments and represents a barrier to many clinically available antibiotics. The outer membrane (OM) is exposed to the environment and is the first point of contact involved in bacterial processes such as signaling, pathogenesis, and motility. As in the cytoplasmic membrane, the OM in Gram-negative bacteria has a phospholipid-rich inner leaflet and an outer leaflet that is predominantly composed of lipopolysaccharide (LPS). We report on a microfluidic technique for fabricating monodisperse asymmetric giant unilamellar vesicles (GUVs) possessing the Gram-negative bacterial OM lipid composition. Our continuous microfluidic fabrication technique generates 50-150 μm diameter water-in-oil-in-water double emulsions at high-throughput. The water-oil and oil-water interfaces facilitate the self-assembly of phospholipid and LPS molecules to create the inner and outer leaflets of the lipid bilayer, respectively. The double emulsions have ultrathin oil shells, which minimizes the amount of residual organic solvent that remains trapped between the leaflets of the GUV membrane. An extraction process by ethanol and micropipette aspiration of the ultrathin oil shells triggers an adhesive interaction between the two lipid monolayers assembled on the water-oil and oil-water interfaces (i.e., dewetting transition), forcing them to contact and form a lipid bilayer membrane. The effect of different inner-leaflet lipid compositions on the emulsion/vesicle stability and the dewetting transition is investigated. We also report on the values for bending and area expansion moduli of synthetic asymmetric model membranes with lipid composition/architecture that is physiologically relevant to the OM in Pseudomonas aeruginosa bacteria.