Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, The Netherlands.
Small. 2019 Sep;15(38):e1902898. doi: 10.1002/smll.201902898. Epub 2019 Jul 31.
Recent years have seen a tremendous interest in the bottom-up reconstitution of minimal biomolecular systems, with the ultimate aim of creating an autonomous synthetic cell. One of the universal features of living systems is cell growth, where the cell membrane expands through the incorporation of newly synthesized lipid molecules. Here, the gradual tension-mediated growth of cell-sized (≈10 µm) giant unilamellar vesicles (GUVs) is demonstrated, to which nanometer-sized (≈30 nm) small unilamellar vesicles (SUVs) are provided, that act as a lipid source. By putting tension on the GUV membranes through a transmembrane osmotic pressure, SUV-GUV fusion events are promoted and substantial growth of the GUV is caused, even up to doubling its volume. Thus, experimental evidence is provided that membrane tension alone is sufficient to bring about membrane fusion and growth is demonstrated for both pure phospholipid liposomes and for hybrid vesicles with a mixture of phospholipids and fatty acids. The results show that growth of liposomes can be realized in a protein-free minimal system, which may find useful applications in achieving autonomous synthetic cells that are capable of undergoing a continuous growth-division cycle.
近年来，人们对自下而上重建最小生物分子系统产生了浓厚的兴趣，其最终目标是创建一个自主的合成细胞。生命系统的一个普遍特征是细胞生长，其中细胞膜通过新合成的脂质分子的掺入而扩展。在这里，展示了逐渐的张力介导的细胞大小（≈10 µm）的巨大单层囊泡（GUV）的生长，向其提供纳米大小（≈30 nm）的小单层囊泡（SUV），它们作为脂质源。通过跨膜渗透压对 GUV 膜施加张力，促进 SUV-GUV 融合事件，并导致 GUV 大量生长，甚至达到其体积的两倍。因此，提供了实验证据表明，仅膜张力就足以引起膜融合，并且对于纯磷脂脂质体和具有磷脂和脂肪酸混合物的混合囊泡都证明了生长。结果表明，在无蛋白质的最小系统中可以实现脂质体的生长，这可能在实现能够经历连续生长-分裂周期的自主合成细胞方面找到有用的应用。
