Formation of a Gel-Supported Lipid Membrane Array on a Micropatterned Substrate

Abstract

An artificial lipid membrane is a suitable platform for the optical and electrophysiological in vitro analysis of membrane peptides and proteins. Suspended lipid membranes are intrinsically fragile and require a water permeable mechanical and functional supports. Here, we describe the preparation of long-lived lipid membranes gently supported on gels, which provide a water permeable support.The microwell array was fabricated on a Si substrate using a conventional photolithographic and etching technique. The gel was prepared by photo-initiating free radical polymerization from gel-precursor solution. The gels were only formed on the substrate where light was irradiated. The lipid membrane on the gel-confined microwell was prepared by rupturing negatively charged small unilamellar vesicles (SUVs) with a smaller diameter than the microwells. The lipid membrane formation on the gel-confined microwell array was observed by fluorescence microscopy.When positively charged gels were confined in the microwells, gel-supported lipid membranes were formed. Lipid membrane formation was not observed at the microwells either without positive gels or with neutral gels. The gel-supported lipid membrane sealed the microwells with gigaohm resistance and the seal was maintained for at least three weeks. These results indicate that function of gels confined in the microwells mechanically stabilizes lipid membranes as well as facilitates the formation of lipid membrane by an attractive electrostatic interaction between SUVs and gels.We expect these gel supports to allow us to prepare a lipid membrane from a proteoliposome. Since the chemical composition of a gel is easily modified, we can obtain a gel array with desirable properties such as mechanical strength, electric charge, and responsiveness to a stimulus.