posted on 2019-12-05, 19:11authored byJulia Alvarez-Malmagro, Dorota Matyszewska, Ewa Nazaruk, Piotr Szwedziak, Renata Bilewicz
The effect of phytantriol (PT)-based liquid-crystalline
nanoparticles,
cubosomes, on the lipid bilayer membranes has been investigated using
the combined Langmuir–Blodgett/Langmuir–Schaefer (LB-LS)
technique to form an h-1,2-dimyristoyl-sn-glycero-3-phosphocholine
(DMPC) monolayer at the air–water interface and transfer the
lipid bilayer onto the Au(111) substrate. Changes of the compression
isotherms confirmed incorporation of cubosomes dispersed in the subphase
into the h-DMPC monolayer at the air–water
interface. The photon polarization modulation infrared reflection
absorption spectroscopy (PM-IRRAS) measurements of the gold electrode
covered by the transferred DMPC bilayer showed for the first time
how the incorporation of cubosome material affects the orientation
and conformation of lipid molecules in the membrane. Exposure to cubosomes
affected the packing of d54-DMPC bilayers
and introduced disorder of chains by increasing the contribution of
gauche conformation. The decrease of the tilt angle of the acyl chains
of adsorbed DMPC in the whole range of potentials applied to the gold
electrode confirmed that incorporation of cubosome material results
in a more tightly packed bilayer. The presence of phytantriol molecules
within the d63-DMPC matrix was confirmed
by PM-IRRAS studies of the PT-related bands. The LB and PM-IRRAS studies
demonstrated in a convincing way that PT-based cubosomes change the
organization of model lipid layers leading to structural changes of
the membranes which have to be taken into consideration when PT-cubosomes
are employed as drug carriers.