PITTSBURGH-Carnegie Mellon University scientist Professor Alan Waggoner
has received a three-year $900,000 award from NASA to develop
fluorescent-dye-based systems to be used in remote operations to detect
life on Mars and in other hostile or distant environments. As part of the
grant, Waggoner’s team will develop new fluorescent dyes that bind to the
common building blocks of life – DNA, lipids, carbohydrates and proteins.
The grant also provides funds to develop an optical system that can spray
these fluorescent dyes on a region of soil to detect life forms in the
environment. This system is expected to be completed within several years.
The Waggoner team is collaborating with researchers at Carnegie Mellon’s
Robotics Institute; the final life detection system should be versatile
enough to couple with different types of rovers used in planetary
expeditions.
The scope of the grant includes developing dyes and testing
their feasibility in local environments, as well as areas hostile to life,
such as the Atacama Desert in northern Chile, where relatively few pockets
of life persist. Given its Mars-like terrain, the Atacama is a favorite
laboratory testing ground for astrobiologists. “It’s tremendously exciting
to extend the work of our team and contribute to interplanetary searches
for life,” says Waggoner, who directs the Molecular Biosensor and Imaging
Center (MBIC) at the Mellon College of Science. “We believe that these
methods will provide the most sensitive means of detecting life with a
remote device.”
The technology has potential beyond Mars, according to
Shmuel Weinstein, project manager. “The scientific impact of our work
begins on earth, with the ability to detect very low concentrations of
living and dead organisms.” Once developed, this system could work in
circumstances such as biohazardous settings or extreme environments, where
an automated, unmanned device would be ideal.
Developing fluorescent
markers to detect life in space for this project presents many technical
challenges, according to Gregory Fisher, project imaging scientist.
Fluorescent markers that bind to their targets must stand out against what
could be a blinding background of natural mineral luminescence.
Additionally, detecting low levels of light emitted from relatively few
organisms could be difficult against reflected light that is originally
emitted from the optical instrument. Just as big a challenge is creating a
detection system that resembles a good epi-fluorescence microscope used on
earth, but one with few, if any, moveable parts. The completed system will
need to focus using a camera range finder (like those found in hand-held
cameras), in addition to providing some additional processing of its own
camera images. “Other testing methods require considerably more sampling
or are less sensitive than what we propose. We don’t know of other remote
methods capable both of detecting low levels of micro-organisms and
visualizing high levels incorporated as biofilms or colonies,” adds Fisher.
Additionally, notes Lauren Ernst, project chemist, Martian life forms may
contain different structural components than those found on earth. “We want
our reagents to visualize any form of life that might be present. We will
define fluorescent probes to detect the smallest amounts of DNA, lipids,
carbohydrates and proteins.”
For example, Ernst will design fluorescent
tags to the materials containing peptide bonds, a signature feature of
proteins. Other tags will target a variety of sugars that comprise
carbohydrates. Moreover, these tags will not be specific for left- or
right-handed structures. Such “handedness,” or chirality, characterizes
proteins and other compounds on earth, but Martian life could exhibit
opposite chirality from our own. Other members of Waggoner’s team who will
be performing critical research as part of this grant include Christoffer
Lagerholm and Byron Ballou.
The fluorescent marker technology proposed is
based on the extensive expertise of the MBIC at Carnegie Mellon.
Established 17 years ago with a multimillion dollar grant from the National
Science Foundation, MBIC combines research on molecular and cellular
sensors along with research in imaging and computation to understand
biological function. The Waggoner team is world renowned for developing
widely commercialized cyanine dye fluorescent labeling reagents that have
played a significant role in the human genome project and are the main dyes
used to analyze gene activity in the regulation of cells and tissues. For
more information about the grant or MBIC, please contact Lauren Ward at
412-268-7761 or wardle@andrew.cmu.edu. For information about interplanetary
research under way at the Robotics Institute, please contact Anne Watzman
at 412-268-3830 or aw16@andrew.cmu.edu.
NOTE TO EDITORS: Dr. Lauren Ernst will be attending the NASA Astrobiology
Institute Meeting, held Feb. 10-12, at Arizona State University, in Tempe,
Ariz. He can be reached directly at the meeting by calling Sheraton Phoenix
Airport Hotel (480-967-6600) or his cell phone (412-389-3083).
