Deposition of Langmuir-Blodgett alternating bilayers of valinomycin and chemically modified bipolar lipid from archaea

Langmuir-Blodgett films of valinomycin appear to be unstable when kept in normal conditions. To prevent recrystallization of the valinomycin, alternating bilayers of this compound and barium salt of disuccinilated glycerol-dialkyl-glycerol tetraether (DS-GDGT) produced from lipid extract of thermophilic archaeon Sulfolobus solfataricus have been deposited. Optical and electron microscopy observations show that the film morphology does not deteriorate for at least three months after deposition. Study of the structure by the X-ray small-angle diffraction technique proves the suggested alternation of valinomycin and lipid bilayers. The period in the direction normal to the substrate plane equals 5.34 nm while the period of the DS-GDGT barium salt multilayer is equal to 3.97 nm. The thickness of the valinomycin monolayer of 0.68 nm is determined from these data. To clarify some structural peculiarities of the prepared films, alternating bilayers of valinomycin and barium behenate have been deposited and studied as well.