Small-angle neutron scattering study of the n-decane effect on the bilayer thickness in extruded unilamellar dioleoylphosphatidylcholine liposomes Original Research Article

Dioleoylphosphatidylcholine (DOPC) and n-decane were mixed and hydrated afterwards in an excess of heavy water at 1 wt.% of DOPC. From this dispersion, unilamellar liposomes were prepared by extrusion through polycarbonate filter with 500-Å pores. Small-angle neutron scattering (SANS) was conducted on these liposomes. From the Kratky–Porod plot ln[I(Q)Q2] vs. Q2 of SANS intensity I(Q) in the range of scattering vectors Q corresponding to the interval 0.001 Å−2≤Q2≤0.006 Å−2, the liposome bilayer radius of gyration Rg and the bilayer thickness parameter dg=120.5Rg were obtained. The values of dg indicated that the bilayer thickness is within the experimental error constant up to n-decane/DOPC∼0.5 molar ratio, and then increases by 2.4±1.3 Å up to n-decane/DOPC=1.2 molar ratio.