Comparison at the microscopic scale of mixed fatty acid-protein Langmuir-Blodgett films resulting from horizontal or vertical transfer

Abstract

Résumé. 2014 Microsc. Microanal. Microstruct. 5 (1994)

Mixed Langmuir Films of Glucose Oxidase and Behenic Acid: Structure and Dynamics

“…molecule. Dipole/dipole interactions also cannot be excluded; this assumption would be consistent with the orientaTherefore, we may conclude that the slope change at 28 mN/m observed during the pressure evolution experiments tion of GOx molecules in well-organized 2D crystals observed previously by SFM (15)(16)(17). is due to the adsorption of GOx molecules at the air/water interface and corresponds to the limit pressure of incorporaFor surface pressure values above 30 mN/m, when the pressure was kept constant we observed a relaxation phetion of the GOx molecules in the behenic acid film at the air/water interface.…”

Adsorbed and free lipid bilayers at the solid-liquid interface

“…At surface pressure as low as 30 mN/m, the transfer rate was 0.9 ± 0.1. At higher surface pressures, up to collapse, the transfer rate was the same [4]. At lower surface pressures, down to 15 mN/m, the transfer rate significantly decreased.…”

“…This quick rearrangement is different from the (slower) flip-flop within an already formed bilayer. The substrate surface is covered by zero or two layers, nowhere by one layer [4,19]. Thus, with global transfer rates of 0.97 and 0.9, we can infer that a single bilayer covers 93% of the substrate.…”

“…During the deposition of a single bilayer, the lipids of both monolayers are likely to mix to protect hydrophobic tails from water [4]. This quick rearrangement is different from the (slower) flip-flop within an already formed bilayer.…”

“…A good local probe for in-plane imaging of phospholipid bilayers is atomic force microscopy in non-contact mode [4]. On the other hand, to obtain pertinent information at atomic scales on the structure of the layer normal to its plane, a technique routinely used consists in reflecting a radiation with a wavelength, λ, of a few angstroms.…”