Biobased Chemistry and Technology, Wageningen University and Research, Bornse Weilanden 9, PO Box 17, 6708 WG, Wageningen, The Netherlands.
TiFN, P.O. Box 557, 6700 AN, Wageningen, The Netherlands.
Soft Matter. 2023 Aug 23;19(33):6355-6367. doi: 10.1039/d3sm00449j.
It has been reported that lipid droplets (LDs), called oleosomes, have an inherent ability to inflate or shrink when absorbing or fueling lipids in the cells, showing that their phospholipid/protein membrane is dilatable. This property is not that common for membranes stabilizing oil droplets and when well understood, it could be exploited for the design of responsive and metastable droplets. To investigate the nature of the dilatable properties of the oleosomes, we extracted them from rapeseeds to obtain an oil-in-water emulsion. Initially, we added an excess of rapeseed oil in the dispersion and applied high-pressure homogenization, resulting in a stable oil-in-water emulsion, showing the ability of the molecules on the oleosome membrane to rearrange and reach a new equilibrium when more surface was available. To confirm the rearrangement of the phospholipids on the droplet surface, we used molecular dynamics simulations and showed that the fatty acids of the phospholipids are solubilized in the oil core and are homogeneously spread on the liquid-like membrane, avoiding clustering with neighbouring phospholipids. The weak lateral interactions on the oleosome membrane were also confirmed experimentally, using interfacial rheology. Finally, to investigate whether the weak lateral interactions on the oleosome membrane can be used to have a triggered change of conformation by an external force, we placed the oleosomes on a solid hydrophobic surface and found that they destabilise, allowing the oil to leak out, probably due to a reorganisation of the membrane phospholipids after their interaction with the hydrophobic surface. The weak lateral interactions on the LD membrane and their triggered destabilisation present a unique property that can be used for a targeted release in foods, pharmaceuticals and cosmetics.
据报道，脂滴（LDs），也称为油体，在细胞内吸收或供应脂质时具有膨胀或收缩的固有能力，表明其磷脂/蛋白质膜具有可扩张性。这种特性对于稳定油滴的膜来说并不常见，而当我们充分理解它时，就可以利用它来设计响应性和亚稳性的液滴。为了研究油体可扩张特性的本质，我们从油菜籽中提取它们以获得水包油乳液。最初，我们在分散体中加入过量的菜籽油，并进行高压匀质处理，得到稳定的水包油乳液，这表明油体膜上的分子在有更多表面积时能够重新排列并达到新的平衡。为了证实滴表面磷脂的重排，我们使用分子动力学模拟表明，磷脂的脂肪酸溶解在油核中，并均匀地分布在类液相膜上，避免与相邻的磷脂聚集。油体膜上较弱的侧向相互作用也通过界面流变学实验得到了证实。最后，为了研究油体膜上较弱的侧向相互作用是否可以用于通过外部力触发构象变化，我们将油体置于疏水固体表面上，发现它们变得不稳定，允许油漏出，这可能是由于膜磷脂在与疏水表面相互作用后重新排列。LD 膜上较弱的侧向相互作用及其触发的不稳定性提供了一种独特的性质，可以用于食品、制药和化妆品中的靶向释放。
