title: Nanopore-spanning lipid bilayers on silicon nitride membranes that seal and selectively transport ions.
abstract: We report the formation of POPC lipid bilayers that span 130 nm pores in a freestanding silicon nitride film supported on a silicon substrate. These solvent-free lipid membranes self-assemble on organosilane-treated Si3N4 via the fusion of 200 nm unilamellar vesicles. Membrane fluidity is verified by fluorescence recovery after photobleaching (FRAP), and membrane resistance in excess of 1 GΩ is demonstrated using electrical impedance spectroscopy (EIS). An array of 40,000 membranes maintained high impedance over 72 h, followed by rupture of most of the membranes by 82 h. Membrane incorporation of gramicidin, a model ion channel, resulted in increased membrane conductance. This membrane conductance was diminished when the gramicidin channels were blocked with CaCl2, indicating that the change in membrane conductance results from gramicidin-mediated ion transport. These very stable, biologically functional pore-spanning membranes open many possibilities for silicon-based ion-channel devices for applications such as biosensors and high-throughput drug screening.
authors.affiliation: Department of Mechanical and Aerospace Engineering, University of California, Davis, California 95616, USA.
authors.forename: Christopher E
authors.initials: CE
authors.lastname: Korman
authors.forename: Mischa
authors.initials: M
authors.lastname: Megens
authors.forename: Caroline M
authors.initials: CM
authors.lastname: Ajo-Franklin
authors.forename: David A
authors.initials: DA
authors.lastname: Horsley
mesh_terms: D001692:Biological Transport; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism*; D006096:Gramicidin / Q000378:metabolism; D007477:Ions / Q000378:metabolism; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism*; D058608:Nanopores; D012825:Silicon / Q000737:chemistry; D017655:Silicon Compounds / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D007477:Ions; D008051:Lipid Bilayers; D017655:Silicon Compounds; D006096:Gramicidin; C032734:silicon nitride; D012825:Silicon