Biomembranes and Lipids

Most biochemical reactions take place at membranes composed of phospholipid bilayers surrounding or inside cells. The membrane affects protein folding and creates specific microenvironments where the reactions take place. To understand and mimic real biological systems, it is essential to study these interactions in an environment that closely mimics natural conditions. Langmuir monolayers of membrane phospholipids have been verified as excellent model systems for biological membranes.

A Langmuir monolayer of lipids is analogous to half a biomembrane. Such layers can be used as model membranes, and have been verified to be excellent models for biological systems in the literature. Using a combination of LB and LS dipping, it is also possible to create a supported bilayer with lipid composition that is asymmetric between the sides.

In a freely floating monolayer the molecular diffusion and dynamics are close to what they are in real systems. In nature, most of biochemical reactions take place at biomembrane interfaces, and freely floating model membranes allow natural diffusion and migration of molecules. A Langmuir trough can be integrated with a variety of sensors and instruments in addition to the Langmuir film balance in order to study membranes. Additional techniques include PM-IRRAS, BAM, SPOT, fluorescence microscopy and traditional microscopy, which make it possible to study interactions, molecular orientation, packing, and domain formation in the monolayer.

LB and LS dipping are two methods for preparing supported bilayers of phospholipids with layers of different lipid composition. For example, it is possible to prepare biochemical sensors for use in Surface Plasmon Resonance Spectroscopy, Quartz Crystal Microbalance measurements, and X-Ray Photoelectron Spectroscopy.

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