Fluidization of a Dipalmitoyl Phosphatidylcholine Monolayer by Fluorocarbon Gases: Potential Use in Lung Surfactant Therapy

Abstract

Fluorocarbon gases (gFCs) were found to inhibit the liquid-expanded (LE)/liquid-condensed (LC) phase transition of dipalmitoyl phosphatidylcholine (DPPC) Langmuir monolayers. The formation of domains of an LC phase, which typically occurs in the LE/LC coexistence region upon compression of DPPC, is prevented when the atmosphere above the DPPC monolayer is saturated with a gFC. When contacted with gFC, the DPPC monolayer remains in the LE phase for surface pressures lower than 38 mN m(-1), as assessed by compression isotherms and fluorescence microscopy (FM). Moreover, gFCs can induce the dissolution of preexisting LC phase domains and facilitate the respreading of the DPPC molecules on the water surface, as shown by FM and grazing incidence x-ray diffraction. gFCs have thus a highly effective fluidizing effect on the DPPC monolayer. This gFC-induced fluidizing effect was compared with the fluidizing effect brought about by a mixture of unsaturated lipids and proteins, namely the two commercially available lung surfactant substitutes, Curosurf and Survanta, which are derived from porcine and bovine lung extracts, respectively. The candidate FCs were chosen among those already investigated for biomedical applications, and in particular for intravascular oxygen transport, i.e., perfluorooctyl bromide, perfluorooctylethane, bis(perfluorobutyl)ethene, perfluorodecalin, and perfluorooctane. The fluidizing effect is most effective with the linear FCs. This study suggests that FCs, whose biocompatibility is well documented, may be useful in lung surfactant substitute compositions.

A Nonpolar, Nonamphiphilic Molecule Can Accelerate Adsorption of Phospholipids and Lower Their Surface Tension at the Air/Water Interface

“…These effects are relevant to the engineering of emulsions and bubbles with FC components and to lung surfactant replacement compositions. [1,2,15,16] …”

“…[14] The notion that FCs might be useful in lung surfactant replacement preparations rests on the observation that FC gases inhibit the formation of the liquid condensed phase in Langmuir monolayers of dipalmitoylphosphatidylcholine, which remains in the liquid expanded phase. [15,16] In all of these situations, the potential influence of the FC on the adsorption of the PLs to the air/water interface, and on their dynamic surface-tension properties, is a key issue.…”

Compression of Self‐Assembled Nano‐Objects: 2D/3D Transitions in Films of (Perfluoroalkyl)Alkanes—Persistence of an Organized Array of Surface Micelles

“…These characteristics endow FnHm diblocks with specific properties in both the solid (liquid-crystal behavior) [14,15] and liquid states (surface freezing), [16] in solutions (micelle formation in both hydrocarbons and fluorocarbons), [17][18][19] and at interfaces (formation of stable Langmuir films). [20] FnHm diblocks were also found to substantially modify, and usually stabilize, the interfacial films of emulsions, [8] vesicles, [12,21] phospholipid films, [22] and other micro-and nanostructures. [23] Due to a reduced set of interactions at interfaces, FnHm diblocks also provide simple models for investigating the self-assembling behavior of amphiphiles.…”

Fluidizing and Solidifying Effects of Perfluorooctylated Fatty Alcohols on Pulmonary Surfactant Monolayers

“…In particular, their thermal stability or resistance is considered a great advantage in terms of long-time storage and high-volume production. Currently, the application of air saturated with fluorocarbon gases for RDS treatments has been used 37,38 because of the properties of fluorocarbon such as low intermolecular cohesiveness, high vapor pressures relative to the molecular weights 2 , and, in particular, high-dissolving oxygen capacity. A predominant symptom of RDS patients is dyspnea caused by the dysfunction and inactivation of PS; thus, partial ventilation with air and fluorocarbon gases is considered useful for treating RDS.…”