Layer-by-Layer Assembly of Supported Lipid Bilayer Poly-L-Lysine Multilayers

Area of Science:

• Biomaterials Science
• Membrane Biophysics
• Nanotechnology

Background:

• Multilayer lipid membranes are crucial for biological functions like electrical insulation and increased surface area.
• Existing methods for creating artificial multilayer membranes are often complex or limited in scope.

Purpose of the Study:

• To develop a simple layer-by-layer methodology for constructing artificial multilayer lipid membranes.
• To investigate the influence of polymer linker properties (pH, chain length) on multilayer structure.
• To assess the functional properties, specifically lipid and protein diffusion, within the fabricated multilayers.

Main Methods:

• Layer-by-layer assembly of lipid vesicles onto supported lipid bilayers (SLBs) using poly L-lysine (PLL).
• Monitoring assembly using quartz crystal microbalance with dissipation (QCM-D) and atomic force microscopy (AFM).
• Assessing diffusion using fluorescence recovery after photobleaching (FRAP) and AFM.

Main Results:

• Successful formation of up to six lipid bilayers using the vesicle rupture method.
• Demonstrated control over multilayer thickness and lipid bilayer separation by varying buffer pH and PLL chain length.
• Observed minimal dependence of lipid and membrane protein diffusion on the number of lipid bilayers or their separation.

Conclusions:

• The developed method offers a straightforward route to creating complex membrane structures.
• The fabricated multilayer lipid membranes exhibit functional properties relevant to biological systems.
• Potential applications include energy production, biosensing, and fundamental studies of membrane biophysics.