Atomic Force Microscopy Observation of Membrane Proteins Suspended over Carbon Nanotube Network

Atomic force microscopy (AFM) imaging of membrane proteins suspended over a nanostructure in liquid is a promising way to understand the structure and function of working proteins, although the membrane deformation that occurs during scanning makes it difficult to obtain a high resolution image. This study proposes an artificial cell system for the AFM observation of functional membrane proteins that consists of a sub-micron well on Si, a biological membrane, and a carbon nanotube (CNT) network. We successfully observed molecular-scale images of a purple membrane suspended over sub-micron well patterns. By using a CNT network to hold the suspended membrane, we suppressed the membrane deformation caused by the "imaging force". The CNT network takes the place of a cytoskeleton in supporting the cell membrane suspended over the well thus improving the spatial resolution of AFM measurement. (C) 2009 The Japan Society of Applied Physics