Surface Modification by Covalent Attachment of Monomolecular Tetraetherlipid Films

Ulrich Rothe1, H. Bakowsky1, Carsten Kneuer3, and Udo Bakowsky2

1Martin-Luther-University, Institute of Physiological Chemistry, Hollystraße 1, D-06097 Halle, Germany
2Saarland University, Biopharmaceutics and Pharmaceutical Technology, Geb. 8.1, Im Stadtwald, D-66123 Saarbrücken, Germany, and
3SIT Surface and Interface Technologies Rosenhof GmbH, D-37308 Heiligenstadt, Germany




Thermoplasma acidophilum is a thermoacidophilic archaebacterium, which has been isolated by Darland et al. (1970) from a steaming coal refuse pile. Oxidative degradation of pyrrit-containing material generates an environmental milieu of pH 2 and 56°C. The membrane-spanning tetraether of such lipids consist of two repetitively methyl-branched, saturated C40 hydrocarbon chains, linked to two glycerol moities (lipid thickness 5-6 nm). The absence of double bonds in the hydrocarbon chain and the ether bonds to the glycerols guarantee the resistance towards hydrolytic, oxidative and other (bio)chemical attack.

Because of the high chemical and thermal stability, the tetraether lipids might be useful for the sealing of all types of vulnerable surfaces. It could be shown, that stable, biologically inert and compatible surface coatings can be produced on a number of different materials, including glas, glassy carbon or metals such as titanium. The sealant film could be attached covalently to the surface and is constituted of a highly ordered impermeable monolayer. For the preparation of such supported tetraether lipid films, the self assembly technique and the preorganising Langmuir Blodgett technique were applied. Their physicochemical, biological and mechanical properties were examined by scanning force microscopy, ellipsometry, FT-IR, contact angle measurements and cyclic voltammetry. It was found possible to control the surface morphology in the nanometer scale by choice of the process parameters.