Montal-Mueller method

BLMs can also be formed by the Montal-Mueller method [391,392], In this procedure, the surfactant (or liquid), dissolved in an apolar solvent, is spread on the water surface on both sides of the pinhole so as to form monolayers below the level of the pinhole. Careful injection of an electrolyte solution below the surface raises the water level above the pinhole and brings the monolayers into apposition to form the BLM. An advantage of the Montal-Mueller method is that it permits the formation of solventless (in reality, containing only a few solvent molecules) [387] and dissymmetrical BLMs (i.e. those containing different surfactants in the apposed monolayers). However, the necessity of a rather small pinhole ( > 0.5mm) is a disadvantage of the Montal-Mueller method. BLMs have also been prepared from surfactant vesicles (SUVs) via the Montal-Mueller method [391-399]. SUVs injected into an aqueous solution formed monolayers which, in turn, could be converted into BLMs (Fig. 60). 

First of all, the capacitance of lecithin-hexadecane membrane is about 0.62 yF/cm. This value is smaller than the capacitance of biological membranes, i.e., 1 yF/cm2. The difference is perhaps partially due to the absence of proteins in artificial membranes. In addition, it is known that the presence of solvents decreases the values of membrane capacitance. For example, membranes formed by the Montal-Mueller Method (21), which are believed to be free of solvents, have a capacitance of 0.7 yF/cm2 (22). Thus, the capacitance of bilayer membranes shown in this figure may be in error by about 0.1 yF/cm2 because of the presence of solvent molecules. However, it is more important to note that membrane capacitance is independent of frequency, which provides unequivocal evidence that there is no relaxation process in lipid membranes in this frequency range. Coster and Smith (23) reported that they observed a frequency dispersion of membrane capacitance of artificial layers at very... 

Fig. 6.10 Methods of preparation of bilayer lipid membranes. (A) A Teflon septum with a window of approximately 1mm2 area divides the solution into two compartments (a). A drop of a lipid-hexane solution is placed on the window (b). By capillary forces the lipid layer is thinned and a bilayer (black in appearance) is formed (c) (P. Mueller, D. O. Rudin, H. Ti Tien and W. D. Wescot). (B) The septum with a window is being immersed into the solution with a lipid monolayer on its surface (a). After immersion of the whole window a bilayer lipid membrane is formed (b) (M. Montal and P. Mueller). (C) A drop of lipid-hexane solution is placed at the orifice of a glass capillary (a). By slight sucking a bubble-formed BLM is shaped (b) (U. Wilmsen, C. Methfessel, W. Hanke and G. Boheim)...

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