The dilatable membrane of oleosomes (lipid droplets) allows their in vitro resizing and triggered release of lipids.

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.

COvalent monolayer patterns in Microfluidics by PLasma etching Open Technology - COMPLOT.

Plasma microcontact patterning (PµCP) and replica molding were combined to make PDMS/glass microfluidic devices with ß-cyclodextrin (ß-CD) patterns attached covalently on the glass surface inside microchannels. The supramolecular reactivity, reusability and association constant of ß-CD with Cy5-Ad2 was tested by analyzing signal-to-noise ratios of patterns vs. spacing with fluorescence microscopy.

Covalently bound monolayer patterns obtained by plasma etching on glass surfaces.

Micropatterns of ß-cyclodextrin (ß-CD) monolayers on glass are obtained by using a plasma etching approach with polydimethylsiloxane (PDMS) stamps. This simple and versatile approach provides a promising alternative to current techniques for creating patterns of covalently bound molecules. It is also possible to fabricate sub-10 µm sized features.

On-Flow Immobilization of Polystyrene Microspheres on ß-Cyclodextrin-Patterned Silica Surfaces through Supramolecular Host-Guest Interactions.

Species-specific isolation of microsized entities such as microplastics and resistant bacteria from waste streams is becoming a growing environmental challenge. By studying the on-flow immobilization of micron-sized polystyrene particles onto functionalized silica surfaces, we ascertain if supramolecular host-guest chemistry in aqueous solutions can provide an alternative technology for water purification. Polystyrene particles were modified with different degrees of adamantane (guest) molecules, and silica surfaces were patterned with ß-cyclodextrin (ß-CD, host) through microcontact printing (µCP). The latter was exposed to solutions of these particles flowing at different speeds, allowing us to study the effect of flow rate and multivalency on particle binding to the surface. The obtained binding profile was correlated with Comsol simulations. We also observed that particle binding is directly aligned with particle's ability to form host-guest interactions with the ß-CD-patterned surface, as particle binding to the functionalized glass surface increased with higher adamantane load on the polystyrene particle surface. Because of the noncovalent character of these interactions, immobilization is reversible and modified ß-CD surfaces can be recycled, which provides a positive outlook for their incorporation in water purification systems.