Atomic force microscopy allows
students to “touch” adenoviruses
Virtual
Viruses
T
HROUGHOUT HISTORY, THE DEVELOPMENT
of each new type of microscope has propelled
science into new microworlds. Today, students
can experience the range of microscopy—from
looking at cork cells like those used in Robert
Hooke’s 1655 experiments to “feeling” the shape and
texture of viruses with an atomic force microscope and
a nanoManipulator. Most schools have access to standard
optical microscopes, but because of the cost, electron
microscopy is usually beyond the reach of students.
Recent developments in Internet capabilities along with
advances in microscopy enable students in rural and
remote areas to experience cutting-edge science.
Today there is a new form of microscopy, the
atomic force microscope, which allows scientists to
explore the physical and tactile properties of tiny objects. Unlike optical microscopes, atomic force microscopes do not use a lens to form a light image of the
object. Instead, there is a tiny, pointed probe that
moves across the object. As the tip of the probe rides
gently on the sample, its up-and-down motion is recorded and displayed as an image on a computer screen.
The probe can be used in air or liquid and can be used
to create an image or to push or press on a sample.
The resolution of the atomic force microscope is
incredible—it can detect individual atoms and molecules
M. GAIL JONES, RICHARD SUPERFINE,
AND RUSSELL M. TAYLOR II
48
T H E
S C I E N C E
that are measured in nanometers. (A nanometer is one
billionth of a meter and is 100 000 times smaller than the
width of a human hair.) As a point of comparison, cells
are typically about 10 000 nanometers across, and the
viruses we discuss here are about 80 nanometers in
diameter. Nanoscience has opened a variety of new
fields of study from imaging the individual molecular
gateways to isolating cells to pulling on single chemical
bonds of DNA.
Scientists at the University of North Carolina at
Chapel Hill (UNC) have taken the technology a step
further and developed the nanoManipulator, a tool that
allows scientists to feel and manipulate nano-sized materials. This tool looks like an ink pen or slim joystick and
is attached to a computer that allows scientists to remotely control the movement and pressure of the atomic
force microscope tip. As the microscope tip moves
across the surface of a sample such as a virus, the tip
sends signals back through the computer to the pen that
allow the investigator to feel pressure, size, stickiness,
and shape. With the push of a button, the user can
control the microscope tip to manipulate objects on the
surface.
At the UNC Gene Therapy Center, scientists
have taken full advantage of the nanoManipulator technology and used it to examine adenoviruses; because
these viruses are used as vectors in gene therapy, scientists are interested in understanding how they stick to
and move around on cell surfaces.
T E A C H E R
PHOTO BY TODD GAUL
TOUCHING VIRUSES
A team of university physicists, computer scientists,
science educators, and high school teachers worked
together to bring atomic force microscopy and the
nanoManipulator to high school students via the Internet.
The microscope and virus samples were housed at the
university, and the nanoManipulator, computer, and
students were located at a rural high school about 30
kilometers away. Students were able to manipulate
adenoviruses by sending the control pen signals through
the Internet to the microscope in the lab at UNC. Students were able to work in real time as if they were in the
laboratory with the microscope.
The experience was wonderful and surreal. Students could see the virus on the computer screen—it
looked like a large lump of angular clay. By moving the
pen in their hands, students could feel the platform that
held the virus. When they pushed the pen and bumped
into the virus they found it resistant and yet strangely soft.
If they watched the screen while pushing the virus,
students could see the virus roll and move across the
platform. As students held the pen, the thought struck
them that they were actually touching a virus no one had
ever seen. The experience made students wonder what
else they could touch. What would DNA feel like? Could
the strands be teased apart? What would bacteria phages
feel like? This experience gave students the opportunity to
ask the same questions that scientists were just beginning
to explore. The atomic force microscope and nano- MaO C T O B E R
nipulator allowed students to experience science as a way
of knowing and not just as a body of knowledge.
D I M E N S I O N A L U N D E R S TA N D I N G
The scientists and educators involved in this project
were highly motivated to share the atomic force microscope and nanoManipulator with students. However, we
wanted to know what students would get out of the
experience beyond an appreciation of the technology. A
team of researchers followed 19 of these high school
students through three days of computer exploration
and created a before-and-after profile of student knowledge. Each student was required to make a clay model of
an adenovirus, take a written test, and participate in an
interview before and after using the atomic force microscope and nanoManipulator. The interviews were used
to measure how students’ knowledge of viruses and
microscopy changed as a result of the experience.
Prior to the experience, none of the students could
describe the metric size of viruses; after instruction,
about two-thirds of the students were able to accurately
describe viruses as nanometer-sized. One of the most
interesting outcomes was students’ development of a
concept of the dimensionality of viruses. After the activity, 42 percent of students described viruses as having
three dimensions (none of them described viruses as
three-dimensional in the pre-assessments). In addition,
after the activity students noted the spherical shape (53
percent), the texture (11 percent), and the flexibility (5.2
1 9 9 9
49
percent) of viruses. The development of students’ understandings of dimensionality was particularly noticeable
in the clay viruses they made. Before instruction, students typically designed flat models of the “lunar-landing” phages they frequently saw in textbooks. After using
the atomic force microscope and nanoManipulator, students tended to create clay models that were threedimensional (88 percent), had facets (82 percent), and
were spherical (88 percent).
PHOTO COURTESY OF THE AUTHORS
CLASSROOM COMMUNITY
THROUGH THE EYES OF SCIENTISTS
We expected that students would learn more about
microscopy and relative sizes of objects, but we were
surprised by their enthusiasm and new knowledge of the
nature of science. When students were asked how enjoyable the experience was on a scale of 1 to 10, the mean
response was nearly 9. (This experience took place two
weeks before the end of the school year—a time when it
is hard to motivate any student!) Students’ comments on
the activity included: “really neat,” “exhilarating,” “cool
to touch a virus,” and “awesome.” When asked what else
they would like to do with the atomic force microscope
and nanoManipulator, students said they were interested
in “touching DNA,” “seeing AIDS and Ebola viruses,” and
seeing if they could “push viruses together to see if they
would separate, explode, or pop like a water balloon.” Not
a single student left without ideas for future exploration.
Students were also interested in knowing more about
the technology and history of the development of the
nanoManipulator and microscope. Students wanted to know
how nanotechnology could be used in medicine. Other
students asked about the professors’ careers, working environments, and processes of scientific development and
research.
When students were asked if the experience had
changed the way that they felt about doing science, more
than 84 percent of the students said yes. Their reasons
included: “This showed new worlds within worlds,” and
“I didn’t know you could do this. It makes me think that
there is more to science than what is learned in school.”
We asked students if the experience had given
them new perspectives or impressions of physicists,
computer scientists, and biologists. A large majority of
students said yes (84 percent). Students were impressed
50
that scientists “can’t do it by themselves. They have to
rely on others to provide part of the experiment.” Students developed an appreciation of the interdisciplinary
nature of the project, “I didn’t know microscopy had
anything to do with physics, computers, and biology”
and “I didn’t know what a computer scientist was and
now I know more.” Another student reported that her
beliefs about scientists had changed. She said, “I never
realized how interesting their jobs are, how elevated
technology is, and how fast it is changing. The scientists
go against the stereotype.”
T H E
S C I E N C E
There were numerous benefits for our team including a
greater appreciation of students’ interests and knowledge, closer ties with the school community, increased
public relations for the university, and the joy of sharing
our life’s work. The students left the experience not only
with increased knowledge of microscale and microscopy
but also a new appreciation of science research. If
teachers invited more scientists into the classroom to
share the excitement of their work, we could help more
students move science from the pages of textbooks into
the real world of human exploration. This pilot test to see
how the technology would operate from a remote location was a huge success and left us imagining a future
when students around the world can have access to
cutting-edge technology regardless of their school’s location or proximity to a university. ✧
M. Gail Jones is an associate professor in the School
of Education (e-mail: [email protected]); Richard
Superfine is an associate professor in the Department
of Physics and Astronomy (e-mail:rsuper@physics.
unc.edu); and Russell M. Taylor II is a research assistant professor in the Department of Computer Science
(e-mail:[email protected]); all at the University of
North Carolina at Chapel Hill, Chapel Hill, NC 27599.
FOR FURTHER READING
Carey, J. 1996. UNC: Tools to manipulate virtual worlds. Business Week 3532:102.
Illman, D. 1994. Researchers Make Progress in Applying Virtual Reality to Chemistry. Chemical and Engineering News
72(12):22–25.
Schmidt, K. 1996. Bend it, shake it. New Scientist
151(2045):22–23.
Taubes, G. August 12, 1994. Taking the data in hand—literally—with virtual reality. Science (265):884–886.
University of North Carolina at Chapel Hill nanoManipulator
project: www.cs.unc.edu/Research/nano.
Wilson, J. 1997. Shrinking micromachines: A new generation
of tools will make molecule-sized machines a reality. Popular
Mechanics 174(11):55.
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