Investigation and modification of molecular structures with the nanoManipulator

The nanoManipulator system adds a virtual reality interface to an atomic force microscope (AFM), thus providing a tool that enables the user not only to image brit also to manipulate nanometer-sized molecular structures. As the AFM rip scans the surface of these structures, the tip-sample interaction forces are monitored, which in turn provide information about the frictional, mechanical, and topological properties of the sample. Computer graphics are used to reconstruct the surface for the user, with color or contours overlaid to indicate additional data sets. Moreover by means of a force-feedback pen, which is connected to the scanning tip via software, the riser can touch the surface under investigation to feel it and to manipulate objects on ii. This system has been used to investigate carbon nanotubes, fibrin, DNA, adenovirus, and tobacco mosaic virus Nanotubes have been bent, translated and rotated to understand their mechanical properties and to investigate friction on the molecular level. AFM lithography is being combined,vith the nanoManipulator to investigate the electromechanical properties of carbon nanotubes. The rupture forces of fibrin and DNA have been measured. This article discusses how some of the graphics and interface features of the nanoManipulator made these novel investigations possible. Visitors have used the system to examine chromosomes, bacterial pili fibers, and nnrlochrrin aggregates (NCAs). Investigators are invited to apply to rise the system as described on the web at http://www.cs.unc.edu/Research/nano/doc/biovisit.html. (C) 2000 by Elsevier Science Inc.