Membrane composition of jetted lipid vesicles: a Raman spectroscopy study

Abstract

Microfluidic jetting is a promising method to produce giant unilamellar phospholipid vesicles for mimicking living cells in biomedical studies. We have investigated the chemical composition of membranes of vesicles prepared using this approach by means of Raman scattering spectroscopy. The membranes of all jetted vesicles are found to contain residuals of the organic solvent decane used in the preparation of the initial planar membrane. The decane inclusions are randomly distributed over the vesicle surface area and vary in thickness from a few to several tens of nanometers. Our findings point out that the membrane properties of jetted vesicles may differ considerably from those of vesicles prepared by other methods and from those of living cells.

Unexpected Membrane Dynamics Unveiled by Membrane Nanotube Extrusion

“…This oil fraction is low enough, however, not to affect the membrane thickness. In comparison, other studies on IE-prepared liposomes reported the presence of <5% of oil in the bilayer (30) or of hydrophobic residues when decane is used instead of oil (46). Considering our results on IE liposomes, PMS from cells, or EF liposomes with added oil, the central point of our study is that it demonstrates that a low fraction of hydrophobic compounds in the lipid bilayer dramatically alters membrane dynamics.…”

Demonstration of the Protein Involvement in Cell Electropermeabilization using Confocal Raman Microspectroscopy

“…Performing the same experiments with a membrane model, Giant Unilamellar Vesicles (GUV), which is a lipid bilayer with a size similar to that of cells44, would allow to focus only on the interaction between pulsed electric fields and a lipid bilayer. Acquiring the Raman signatures of GUVs has already been done with a similar confocal Raman microspectroscope45. The acquisition of the Raman spectra in the HWN region was also used to monitor the transmembrane potential of cells4647.…”

cDICE method produces giant lipid vesicles under physiological conditions of charged lipids and ionic solutions

“…62 Nevertheless, complementary techniques like jetting produce vesicles that appear oil-free by optical microscopy, but can contain decane layers or lenses ~10 nm thick. 63 Thin layers or lenses of oil may be inconsequential in some applications and detrimental in others. For example, Campillo et al pulled nanotubes both from vesicles made by a reverse emulsion technique and from vesicles made by electroformation.…”