Langmuir-Blodgett multilayers of native and synthetic glycerol-dialkylglycerol tetraether derivatives from archaea

Abstract

Langmuir-Blodgett films of monosubstituted glycerol-dialkyl-glycerol tetraether with phosphomyoinositol group extracted from thermophilic archaebacterium Sulfolobus solfataricus are successfully deposited. However, the procedure of film deposition is rather complicated. Reproducibility of the results is not satisfactory. Non-uniform areas are often observed in the films despite the fact that the same optimum conditions of deposition are used. The films do not possess stability in water. To overcome these problems a series of semisynthetic archaeol lipids have been synthesized. The monosuccinilated and disuccinilated glycerol-dialkyl-glycerol tetraethers appeared to be the most promising compounds. Highly uniform films of barium salt of these lipids can be deposited by the Langmuir-Blodgett technique. The multilayers are stable in aqueous solutions. The quality of deposition of disuccinilated tetraether is similar to that of the usual fatty acid salts. The films are studied by optical microscopy, transmission electron microscopy, X-ray small-angle diffraction, and electron diffraction techniques. Contact angles for the deposited films are measured as well. Data obtained from the surface pressure-area isotherms, X-ray diffraction, and contact angle measurements show that the U-shape of molecules is preferred rather than the extended form.