Surface Properties and Miscibility of Monolayers of Dimyristoylphosphatidylcholine and Poly(Ethylene oxide) Lipids at the Water/Air Interface

Abstract

The miscibility of dimyristoylphosphatidylcholine (DMPC) and poly(ethylene oxide) lipids (PEO lipids) in monolayers has been assessed through surface pressure and surface potential measurements. These experiments performed under equilibrium conditions at constant area revealed a strong dependence of the interfacial behavior of these mixtures on the polymer chain length. While for the lipid with the short PEO chain composed of 5 monomer units the mixtures with DMPC displayed almost an ideal behavior, for longer PEO chains (13 and 31 monomer units) π−δ isotherms considerably deviated from ideality. The effect of hydrocarbon and polymer chain orientation and of the structuring of interfacial water induced by PEO lipids on their mixing behavior with DMPC and on calculated effective dipole moments is discussed and analyzed.

Mixed monolayers of Bauhinia monandra and Concanavalin A lectins with phospholipids, part II

“…The surface potential of the DPPE-BmoLL mixed film would thus benefit from the significant restructuring of the water molecules in the vicinity of the lipid head group. Similar effects of disorganization of lipid head group structure on its interaction with protein, cyclodextrins and amphiphilic polymers have been previously reported by one of us [16,19,20].…”

Temperature dependence of the organization and molecular interactions within phospholipid/diacetylene Langmuir films

“…The high value of limiting molecular area and the relatively high stability of the expanded phase at this temperature is characteristic of the two alkyl-chain structure of phospholipids [25][26][27]. However, the expanded phase appeared less stable at 18 and 5 • C which featured phase transitions at around 40 and 15 mN m −1 , respectively [28][29][30]. This transition corresponds to the formation of a more organized condensed monolayer phase stabilized by the lower thermal motion of the phospholipid alkyl chains.…”

Spontaneous association of hydrophobized dextran and poly-β-cyclodextrin into nanoassemblies.

“…In pure water, the flexible linear MD polymer adsorbs with its dodecyl moieties exposed towards the air phase, whereas its hydrophilic polysaccharide chains remain immersed into the solution. The conformation of the sugar skeleton in the subphase dictates the orientation of the alkyl chains more or less tilted toward the plane of the interface [12,39].…”

“…The present study aimed at gaining information on the mechanism of formation of the MDpβCD nanoassemblies, which has not yet been fully elucidated, and to determine whether a hydrophobic guest drug might be solubilized into these nanoassemblies without interfering with their formation and stability. The interaction of the host and guest polymers leading to the formation of the nanoassemblies was analysed by surface tension measurements [38][39][40][41][42][43][44] in the absence and in the presence of a model guest hydrophobic molecule (benzophenone). 1 H NMR spectroscopy was used to determine the inner structure of the nanoassemblies and locate the guest molecules in the CDs inclusion complexes [45][46][47].…”