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The newspaper of The Johns Hopkins University February 19, 2007 | Vol. 36 No. 22
SoM's Mass Spectrometry Experts Will Aid Search for Life on Mars

A Rover-riding mass spectrometer will have to be the size of a shoebox.
Photo by Neil A. Grauer

By Audrey Huang
Johns Hopkins Medicine

Biomedical scientists at the Johns Hopkins School of Medicine have won a $750,000 NASA grant to design the prototype for a mini mass spectrometer that fits on a Mars Rover and can analyze the chemicals of life as it crawls over the Red Planet's dust.

Pharmacologist and molecular scientist Robert J. Cotter said that a team including specialists from JHU's Applied Physics Laboratory and the University of California, Santa Barbara are designing the tailored mass spec to probe Mars core samples for evidence of proteins or genetic information-carrying nucleic acids in a mission scheduled to launch in 2013.

"What a mass spectrometer can identify are chemical signatures of life or the building blocks of life that may have at some point existed on the Red Planet," said Cotter, a professor in the School of Medicine, who developed the design concept for the specific type of mass spectrometer — a low-voltage ion trap mass spectrometer — that will be used in this mission.

Mars is one of four so-called terrestrial planets with a metal core and rocky surface in Earth's solar system. Researchers hope that by studying Mars' past and present biological potential they can better understand how life started on Earth as well as Mars' habitability.

The assignment is a natural for Cotter, who for almost 30 years at Johns Hopkins has been designing and improving mass spec's ability to measure a chemical's mass (size and weight). Every protein is composed of chemicals with a distinct "mass" profile, which can be used to deduce the contents of an unknown sample.

"Where once we had to use pure samples to get a reading, we are now beginning to look at whole cells, which contain thousands of different proteins, and get a catalog of what's in the mix," said Cotter of how mass specs have improved.

While getting better, the tool has gotten smaller as well, he said. "Original versions were just so big and took up so much space that it was impossible to do much else in the lab," said Cotter, adding that the components now can fit into a machine the size of a mini-fridge. For a mass spec to be able to sit on a Rover for travel via rocket all the way to Mars, however, Cotter and his team will have to design a small one, the size of a shoebox.

"It's going to be tough, not only to miniaturize all the intricate functions but to build the instrument to survive the harsh travel conditions en route and the environmental conditions once it lands," Cotter said. In addition, he said, Mars is dusty, a condition that could interfere with fine machinery and circuitry.

True to his medical school base, Cotter's interest in mini mass spectrometers is not limited to the search for Martian life. The devices hold promise as powerful diagnostic tools, he said, and may someday be used in the clinic.


Related Web site

MAMS Laboratory


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