Tanzende Vesikel: Proteinoszillationen führen zu periodischer Membranverformung

Switching ON of Transcription-Translation System Using GUV Fusion by Co-supplementation of Calcium with Long-Chain Polyethylene Glycol

Giant unilamellar vesicles (GUVs) have been used as a material for bottom-up synthetic biology. However, due to the semi-permeability of the membrane, the need for methods to fuse GUVs has increased. To this aim, methods that are simple and show low leakage during fusion are important. In this study, we report a method of GUV fusion by a divalent cation (Ca²⁺ ) enhanced with a long chain polyethylene glycol (PEG20k). The methods showed significant GUV fusion without leakage of internal components of GUVs and maintained cell-free transcription-translation ability inside the GUVs without external supplementation of macromolecules. We demonstrate that the Ca-PEG method can be applied for switching ON of transcription-translation in GUVs in a fusion-dependent manner. The method developed here can be applied to extend bottom-up synthetic biology and molecular robotics that use GUVs as a chassis.

Division and Regrowth of Phase-Separated Giant Unilamellar Vesicles*

Success in the bottom‐up assembly of synthetic cells will depend on strategies for the division of protocellular compartments. Here, we describe the controlled division of phase‐separated giant unilamellar lipid vesicles (GUVs). We derive an analytical model based on the vesicle geometry, which makes four quantitative predictions that we verify experimentally. We find that the osmolarity ratio required for division is 2 , independent of the GUV size, while asymmetric division happens at lower osmolarity ratios. Remarkably, we show that a suitable osmolarity change can be triggered by water evaporation, enzymatic decomposition of sucrose or light‐triggered uncaging of CMNB‐fluorescein. The latter provides full spatiotemporal control, such that a target GUV undergoes division whereas the surrounding GUVs remain unaffected. Finally, we grow phase‐separated vesicles from single‐phased vesicles by targeted fusion of the opposite lipid type with programmable DNA tags to enable subsequent division cycles.

Non-Equilibrium Large-Scale Membrane Transformations Driven by MinDE Biochemical Reaction Cycles

The MinDE proteins from E. coli have received great attention as a paradigmatic biological pattern-forming system. Recently, it has surfaced that these proteins do not only generate oscillating concentration gradients driven by ATP hydrolysis, but that they can reversibly deform giant vesicles. In order to explore the potential of Min proteins to actually perform mechanical work, we introduce a new model membrane system, flat vesicle stacks on top of a supported lipid bilayer. MinDE oscillations can repeatedly deform these flat vesicles into tubules and promote progressive membrane spreading through membrane adhesion. Dependent on membrane and buffer compositions, Min oscillations further induce robust bud formation. Altogether, we demonstrate that under specific conditions, MinDE self-organization can result in work performed on biomimetic systems and achieve a straightforward mechanochemical coupling between the MinDE biochemical reaction cycle and membrane transformation.

Exosome-Mimetic Supramolecular Vesicles with Reversible and Controllable Fusion and Fission*

The fusion and fission behaviors of exosomes are essential for the cell-to-cell communication. Developing exosome-mimetic vesicles with such behaviors is of vital importance, but still remains a big challenge. Presented herein is an artificial supramolecular vesicle that exhibits redox-modulated reversible fusion-fission functions. These vesicles tend to fuse together and form large-sized vesicles upon oxidation, undergo a fission process and then return to small-sized vesicles through reduction. Noteworthy, the aggregation-induced emission (AIE) characteristics of the supramolecular building blocks enable the molecular configuration during vesicular transformation to be monitored by fluorescence technology. Moreover, the presented vesicles are excellent nanocarrier candidates to transfer siRNA into cancer cells.