Observations of Membrane Domain Reorganization in Mechanically Compressed Artificial Cells

Abstract

Giant unilamellar vesicles (GUVs) are considered to be the gold standard for assembling artificial cells from the bottom up. In this study, we investigated the behavior of such biomimetic vesicles as they were subjected to mechanical compression. A microfluidic device is presented that comprises a trap to capture GUVs and a microstamp that is deflected downwards to mechanically compress the trapped vesicle. After characterization of the device, we show that single‐phase GUVs can be controllably compressed to a high degree of deformation (D=0.40) depending on the pressure applied to the microstamp. A permeation assay was implemented to show that vesicle bursting is prevented by water efflux. Next, we mechanically compressed GUVs with co‐existing liquid‐ordered and liquid‐disordered membrane phases. Upon compression, we observed that the normally stable lipid domains reorganized themselves across the surface and fused into larger domains. This phenomenon, observed here in a model membrane system, not only gives us insights into how the multicomponent membranes of artificial cells behave, but might also have interesting consequences for the role of lipid rafts in biological cells that are subjected to compressive forces in a natural environment.

Membrane permeability to water measured by microfluidic trapping of giant vesicles

“…8,9 The intrinsic permeability of a membrane to a solute is defined by the ratio of the volume flux per unit area per unit time over the concentration gradient. Experiments on GUVs to assess the permeability to water and other molecules include video recording of vesicles undergoing osmotic shrinkage or inflation, 8,[10][11][12][13] confocal microscopy in microfluidic channels, [14][15][16] fluorescence correlation spectroscopy 17 and micropipette aspiration, 8,18,19 but the majority of these approaches suffer from certain disadvantages.…”

Study of the Interaction of a Novel Semi-Synthetic Peptide with Model Lipid Membranes

“…The fluorescence intensity of the calcein within three separate vesicles was monitored while using a confocal laser-scanning microscope (Axiovert 200 M, Zeiss, Oberkochen, Germany), and an appropriate optical filter sets for DiI and calcein. The GUVs were prepared by electroformation following the procedure that was originally described by Angelova et al [ 37 ], but conducted in a modified chamber [ 38 ]. Briefly, the setup used for the preparation of the vesicles consisted of two conductive indium tin oxide (ITO) coated glasses separated by a 1.5 mm thick silicone rubber spacer to maximize the yield of vesicles.…”

Interface Engineering in Multiphase Systems toward Synthetic Cells and Organelles: From Soft Matter Fundamentals to Biomedical Applications

“…[374][375][376][377][378][379] Under applied stress, the membrane of synthetic cells polarizes and protrudes, owing to the arrangement of these cytoskeleton protein fibrils, and their interactions with the membrane component. [374][375][376][377][378][379] Alternatively, the morphology motility of synthetic cells can be induced by external triggers, mostly for synthetic cells constituted by stimuli-responsive materials. For instance, responsive polymersomes and colloidosomes exhibit oscillatory shape changes from buckling to restoring in response to temperature fluctuations and an internal periodic redox reaction (Figure 21c).…”

“…To understand the detailed mechanism, synthetic cells hosting polymerization of actin, tubulin are constructed ( Figure a,b). [ 374–379 ] Under applied stress, the membrane of synthetic cells polarizes and protrudes, owing to the arrangement of these cytoskeleton protein fibrils, and their interactions with the membrane component. [ 374–379 ]…”