Mixed Monolayers of Lipids

The spread mixed lipid monolayer studies provide information about the packing and orientation of such molecules at the water interface. These interfacial characteristics affect many other systems. For instance, mixed surfactants are used in froth flotation. The monolayer surface pressure of a pure surfactant is measured after the injection of the second surfactant. From the change in n, the interaction mechanism can be measured. The monolayer method has also been used as a model biological membrane system. In the latter BLM, lipids are found to be mixed with other lipidlike molecules (such as cholesterol). Hence, mixed monolayers of lipids + cholesterol have been found to provide much useful information on BLM. The most important BLM and temperature melting phenomena is the human body temperature regulation. Normal body temperature is 37°C (98°F), at which all BLM function efficiently. 

In biological systems, the lung fluid exhibits surface pressure characteristics that are related to its lipid composition. The ratio between two different lipids has been shown to be critical for lung function in newborn babies. Recent studies of mixed monolayers have been made using AFM (Birdi, 2002a). 

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While the approach curves for monolayers of pure C-16 and DPHC lipids were reproducible, the kf obtained at mixed monolayers of lipids showed larger variations. Some values of kf obtained from different approach curves were very close to those for pure C-16 and DPHC monolayers. This was explained by segregation of lipids in the monolayer into separate do-... 

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