NanoManipulator

[Eugene Leitl <eugene.leitl@xxx.xxxxxxxxxxxx.xxx]

http://www.cs.unc.edu/Research/nano/

The nanoManipulator 

Hope you caught the system running over the Internet2 at the Internet2
Spring '99 meeting in D.C. If not, you can catch an interview at the
VideoSpace page. You need to download VideoCharger from that page,
then point at the "April 99" link, then pull down the menu and select
"nanoManipulator " choice, then click "Show Video".

Students in AP Biology at Orange County High School used the
nanoManipulator across the Internet to see, feel and modify Adeno
virus particles. This collaborative work between the departments of
Computer Science, Physics & Astronomy and Education was enabled by an
Information Technology grant from the office of the Chancellor of the
University of North Carolina at Chapel Hill. To see the slides from a
presentation of this work by Richard Superfine, click on the one you
want: Slide 1, Slide 2, Slide 3, Slide 4, Slide 5, Slide 6, Slide 7.

Scanned-probe microscopes (SPMs) allow the investigation and
manipulation of surfaces down to the atomic scale. The nanoManipulator
(nM) system provides a virtual-environment interface to SPMs, which
gives the scientist virtual telepresence on the surface, scaled by a
factor of about a million to one. The nM system is a continually
evolving tool, developed in close collaboration with real users, that
provides new ways of interacting with materials and objects at the
nanometer scale. This has led to new results in the study of biology,
materials science, carbon nanotubes, and electrical engineering.

The nanoManipulator (nM) project is a collaboration between the
departments of Computer Science, Physics & Astronomy, Chemistry, the
school of Library Science and the school of Education at the
University of North Carolina at Chapel Hill. The project is developing
an improved, natural interface to scanning probe microscopes,
including Scanning Tunneling Microscopes (STM) and Atomic Force
Microscopes (AFM).  The nanoManipulator (nM) couples the microscope to
a virtual-reality interface to provide a telepresence system that
operates over a scale difference of about a million to one.

In the image to the right, UNC Physics graduate student Scott Paulson
uses the nanoWorkbench (the newest display in the nanoManipulator
system) to examine a cleaved and bent particle of tobacco mosaic
virus. This image is part of an experiment where we manipulated a
particle of tobacco mosaic virus in order to measure its rigidity
relative to its adhesion to the surface. The nanoManipulator is also
being used by Garrett Matthews to examine and manipulate Adeno virus
particles.  Adeno virus particles are used as vectors in gene therapy,
traveling into cells and then releasing the genetic material contained
in their hollow core.

The image to the left shows how UNC Physics postdoctoral fellow Mike
Falvo used the nanoManipulator to maneuver a colloidal particle into a
gap that had been etched in a thin gold wire. In both images, a
graphics supercomputer computes the shaded images in real time. Mike
directly controls the lateral position of the AFM tip; real-time force
feedback indicating surface height allows him to guide the motion of
the particle during manipulation, when the tip cannot scan the
surface. The area under study is about 1 micron on a side. The
colloidal gold particle is about 15 nm across. The vertical scale has
been exaggerated by a factor of five over the horizontal to bring out
surface features. Yellow lines mark the progress of the tip during
modification.

The nanoManipulator interface was conceived by Warren Robinett at the
UNC-CH Department of Computer Science and Stan Williams, then at the
UCLA Department of Chemistry, now at HP Basic Science labs.
Collaboration between the departments began in 1991 with the
development of a system to control an STM. In 1993, Sean Washburn of
the UNC Physics Department joined the project, leading experiments
that led to our discovery of nanoWelding. He leads our investigation
into the design and fabrication of quantum devices. Richard Superfine
of the UNC Physics Department joined our team in the Spring of 1994,
bringing expertise in AFM and leading our work on biological samples.

Since that time, the project has expanded rapidly, now including 10
graduate students in the Computer Science department and at least 6
Physics graduate students. We are together working with Dorothy Erie's
group at the UNC department of Chemistry and with the Jude Samulski's
group in Gene Therapy, as well as working on carbon nano-tubes and
polymers. The team includes a full-time biology postdoctoral student
(Martin Guthold) who provides outreach to biologists wanting to use
the resource and to study DNA/protein interactions.

The nM also provides access to the CORES image-processing software
developed by the MIDAG medical image group. This software provided the
center tracing for the data analysis done on carbon nanotubes
described in our Nature article and the Tobacco-Mosaic Virus work
described in our Biophysical Journal article.

The team works closely with users in biology, solid-state physics and
gene therapy to develop techniques and displays most useful to solving
problems in their fields.

Biologists interested in coming to use our facility in its capacity as
an NIH National Research Resource should check out our visitor web
page.

               Experiments done using the nanoManipulator. 
                  Quicktime video of the system in use (10MB
     FILE!!!!). 
          A list of publications. 
     Where have I heard of this?"... A list of appearances in the popular
     press. 
          A list of agencies supporting our work 
                              A list of the nanoManipulator Team. 
        Related work, projects at other locations. 
        A description of the source files and other detailed information
     (useful for graduate students on the project). 
        Schedule of meetings and other events of interest to
     nanoMembers. Also, a list of mail aliases to subgroups. 


Scanning Probe Microscopes work by rastering a tip across a surface,
sampling its height at locations on a regular grid. The data is
typically viewed in real time as a grayscale map viewed from above,
(left image). The nM interface tiles the surface with triangles and
uses a highly-parallel graphics supercomputer to render the image as a
shaded surface (right image). Specular highlights bring out features
in the data that are missed in the grayscale image.

SPMs can modify the surface using either voltage pulses or by
physically pressing the tip into the surface. This modification is
normally done under program control, with experiments consisting of
scanning the surface before and after a change. Normally, there is no
feedback during the modification event. The nM uses a force-feedback
probe to allow the user to directly control tip motion during
modification and feel the changes as they are occuring. This provides
much finer control over modification and enables new and fruitful
types of experiments.

Modern SPMs can acquire multiple data sets (conductance, lateral
force, temperature) at the same time they sample the height of the
surface. These are normally displayed as several side-by-side
grayscale images, one per data set. The nM is investigating the use of
color and programmable shading to display these data sets overlaid on
the topography, allowing the scientist to naturally view correlations
between topography and other data. We are also exploring richer force-
feedback models (including adhesion and friction) and the use of
auditory feedback to convey information.

Click here for a 2-page summary of the distributed nanoManipulator
that was handed out at the Internet 2 conference in April '99.

Click here for a summary of our work going forward in this area with
the support of the NSF in High-Performance Computing and
Communications.

Click here for a summary of our work going forward in the area of
force feedback.

Questions and comments should be sent via email to taylorr@sCX3fBfBsMZHRJgIqu-gS6DiOOljn3lTPW8QEYJvgTeArM6KZxa_WcK1Z5Te07vpDRTDFBvAbYHVXgcS.yahoo.invalid