Atomic Force Microscopy Imaging and Electrical Recording of Lipid Bilayers Supported over Microfabricated Silicon Chip Nanopores: Lab-on-a-Chip System for Lipid Membranes and Ion Channels

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• 作者：Arjan P. Quist ; Ami Chand ; Srinivasan Ramachandran ; Chiara Daraio ; Sungho Jin ; and ; Ratnesh Lal
• 刊名：Langmuir
• 出版年：2007
• 出版时间：January 30, 2007
• 年：2007
• 卷：23
• 期：3
• 页码：1375 - 1380
• 全文大小：554K
• 年卷期：v.23,no.3(January 30, 2007)
• ISSN：1520-5827

文摘

We describe a silicon chip-based supported bilayer system to detect the presence of ion channels and their electricalconductance in lipid bilayers. Nanopores were produced in microfabricated silicon membranes by electron beamlithography as well as by using a finely focused ion beam. Thermal oxide was used to shrink pore sizes, if necessary,and to create an insulating surface. The chips with well-defined pores were easily mounted on a double-chamber plasticcell recording system, allowing for controlling the buffer conditions both above and below the window. The double-chamber system allowed using an atomic force microscopy (AFM) tip as one electrode and inserting a platinum wireas the second electrode under the membrane window, to measure electrical current across lipid bilayers that aresuspended over the pores. Atomic force imaging, stiffness measurement, and electrical capacitance measurement showthe feasibility of supporting lipid bilayers over defined nanopores: a key requirement to use any such technique forstructure-function study of ion channels. Online addition of gramicidin, an ion-channel-forming peptide, resulted inelectrical current flow across the bilayer, and the I-V curve that was measured using the conducting AFM tip indicatesthe presence of many conducting gramicidin ion channels.