Controlling supported membranes in space and time

Hybrid systems consisting of biomolecules coupled to inorganic scaffolds show potential for the design of novel biosensors and research tools. As a two dimensional fluid, supported lipid bilayers add capabilities for dynamic rearrangement not present at other surfaces, but they also provide additional challenges for spatial and temporal manipulation. Recently, several soft lithography techniques for concurrently patterning proteins and lipids have emerged. However, these techniques suffer from limited resolution and efficiency. Traditional lithographic techniques readily scale to sub-cellular resolution; however several practical issues have limited the use of these techniques from patterning lipid membranes. This manuscript provides descriptions of three new tools that overcome these complex challenges to control spatial distributions of supported membranes in space and time at length and time scales relevant to cellular processes. Aluminum films are employed as sacrificial layers that prevent surface fouling during lithography. This technique has proven useful for producing sharp patterns of supported lipid bilayers, biomolecules (such as fibronectin), and provide a mechanism for pattern alignment with inorganic electrodes. Additionally, scanning probe lithography is applied to pattern fluid lipid membranes on glass substrates. Grids of metal lines, pre-patterned onto the silica substrate by electron beam lithography at 100 mn line width, serve to partition the supported membrane into an array of 1microm isolated fluid pixels. Finally, patterned electrodes embedded within the membrane provide a dynamic scaffold for irreversible lipid gating and two-dimensional electrophoretic concentration gradient formation.