Manipulation and sorting of membrane proteins using patterned diffusion-aided ratchets with AC fields in supported lipid bilayers

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Matthew R. Cheetham, Jonathan P. Bramble, Duncan G. G. McMillan, Richard J. Bushby, Peter D. Olmsted, Lars J. C. Jeuken and Stephen D. Evans

Soft Matter, 2012,8, 5459-5465

We present ratchets capable of directing the movement of charged components within supported bilayer lipid membranes. These ratchets make use of asymmetrically patterned features and AC electric fields, and have been demonstrated to transport charged species such as lipids and transmembrane proteins between two reservoirs. Proteins were present in both orientations in the membrane, with only those with their extra-membranous domain orientated away from the glass substrate being mobile. Proteins in the mobile orientation were transported using these ratchets, thereby sorting the two orientations from one another, and creating an area of the membrane containing five times more protein in one orientation than the other.