Formation of hybrid bilayers on silanized thin-film Ti electrode.

Phospholipid bilayer membranes are essential elements of living organisms as they form boundaries between the intracellular cytoplasm and the extracellular environment, as well as organelles. In this work we report on our attempts to assemble artificial phospholipid bilayer model membranes on Ti surface. To provide hydrophobic cushion for phospholipids, the surface of a thin-film Ti electrode was initially functionalized with trichloro(octadecyl)silane (OTS). Increased hydrophobicity of the solid support allowed vesicle fusion and the formation of a hybrid 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) bilayer, as probed by the electrochemical impedance spectroscopy (EIS), contact angle measurements (CA) also by the Fourier transform-infrared (FT-IR) spectroscopy, spectroscopic ellipsometry (SE) and atomic force microscopy (AFM). Our study demonstrates the applicability of thin-film Ti electrodes for the formation of hybrid bilayer membranes. These membranes allow functional reconstitution of the pore-forming toxins and provide a bioanalytical platform for the detection of the activity of the cholesterol-dependent cytolysins.