Fujiwara Shougo, Shoji Kan, Watanabe Chiho, Kawano Ryuji, Yanagisawa Miho
Komaba Institute for Science, The University of Tokyo, Komaba 3-8-1, Meguro, Tokyo 153-8902, Japan.
Department of Applied Physics, Tokyo University of Agriculture and Technology, Naka-cho 2-24-16, Koganei, Tokyo 184-8588, Japan.
Micromachines (Basel). 2020 Jul 20;11(7):701. doi: 10.3390/mi11070701.
Assembled water-in-oil droplets bounded by lipid bilayers are used in synthetic biology as minimal models of cell tissue. Microfluidic devices successfully generate monodispersed droplets and assemble them via droplet interface bilayesr (DIB) formation. However, a honeycomb pattern of DIB-bounded droplets, similar to epithelial tissues, remains unrealized because the rapid DIB formation between the droplets hinders their ability to form the honeycomb pattern. In this paper, we demonstrate the microfluidic formation of a honeycomb pattern of DIB-bounded droplets using two surfactants with different adsorption rates on the droplet surface. A non-DIB forming surfactant (sorbitan monooleate, Span 80) was mixed with a lipid (1,2-dioleoyl-sn-glycero-3-phosphocholine, PC), whose adsorption rate on the droplet surface and saturated interfacial tension were lower than those of Span 80. By changing the surfactant composition, we established the conditions under which the droplets initially form a honeycomb pattern and subsequently adhere to each other via DIB formation to minimize the interfacial energy. In addition, the reconstituted membrane protein nanopores at the DIBs were able to transport molecules. This new method, using the difference in the adsorption rates of two surfactants, allows the formation of a honeycomb pattern of DIB-bounded droplets in a single step, and thus facilitates research using DIB-bounded droplet assemblies.
由脂质双层界定的油包水组装液滴在合成生物学中用作细胞组织的最小模型。微流控装置成功地生成了单分散液滴，并通过液滴界面双层（DIB）的形成将它们组装起来。然而，类似于上皮组织的由DIB界定的液滴的蜂窝状图案尚未实现，因为液滴之间快速的DIB形成阻碍了它们形成蜂窝状图案的能力。在本文中，我们展示了使用两种在液滴表面具有不同吸附速率的表面活性剂，通过微流控形成由DIB界定的液滴的蜂窝状图案。一种不形成DIB的表面活性剂（脱水山梨醇单油酸酯，Span 80）与一种脂质（1,2-二油酰基-sn-甘油-3-磷酸胆碱，PC）混合，该脂质在液滴表面的吸附速率和饱和界面张力低于Span 80。通过改变表面活性剂的组成，我们确定了液滴最初形成蜂窝状图案，随后通过DIB形成相互粘附以最小化界面能的条件。此外，在DIB处重构的膜蛋白纳米孔能够运输分子。这种利用两种表面活性剂吸附速率差异的新方法允许在一步中形成由DIB界定的液滴的蜂窝状图案，从而促进了使用由DIB界定的液滴组件的研究。
