ExoMars Sweet Spot

Artist’s conception of the European Space Agency’s ExoMars rover, which will search for signs of life on Mars.
Credit: ESA

Scientists looking for evidence of life on Mars have turned to technology invented by University of North Carolina at Chapel Hill researchers to help with their mission.

A team from NASA’s Jet Propulsion Laboratory in Pasadena, Calif., has created a device for use on the European ExoMars rover mission scheduled for launch in 2013. That space voyage is one of several planned expeditions to the red planet that will follow in the footsteps of NASA’s Phoenix mission, which landed on Mars late last month and this week began preparing to test soil samples.

The microfluidic or “lab-on-a-chip” device – which takes its name from the fact that the credit-card sized invention can perform multiple detailed laboratory tests – could be used to analyze martian soil and rock for traces of biological compounds such as amino acids, the building blocks of proteins.

But until they turned to materials called perfluoropolyethers (PFPEs), which were first pioneered for use in the field of microfluidics by Joseph DeSimone, Ph.D., Chancellor’s Eminent Professor of Chemistry and Chemical Engineering and his colleagues in UNC’s College of Arts and Sciences, the NASA team was having trouble making a chip that could withstand the rigors of the proposed mission.

Jason Rolland, Ph.D., who helped invent PFPE materials for microfluidic devices when he was a graduate student in DeSimone’s lab, said the tiny apparatus handle very small volumes of liquids through tiny channels, and are similar to microelectronic chips, but for fluids. The elastic nature of PFPEs makes it possible to incorporate moving parts such as tiny valves into the devices.

This image shows a photograph of a portion of the integrated, four-layer lab-on-a-chip. Although small in size, the credit-card sized device can perform multiple laboratory tests.
Credit: Willis et al., 2008; Peter A. Willis, Lab Chip, 2008, DOI: 10.1039/b804265a


This image is a close-up of the martian ground obtained by NASA’s Phoenix lander. ExoMars will use the lab-on-a-chip to analyze the martian soil for biological signatures.
Credit: NASA/JPL-Caltech/University of Arizona

In a paper co-written by Rolland and published recently in the Royal Society of Chemistry journal Lab on a Chip, the NASA team, led by Peter Willis, Ph.D., said devices made using PFPE membranes sandwiched between layers of glass were easier to make and greatly outperformed other materials such as PDMS and PTFE, commercially known as Teflon®.

The chips also held up to severe stress testing, surviving the equivalent of 1 million operations at temperatures ranging from 50 degrees Celsius to minus 50 degrees Celsius virtually unscathed.

“It turned out that the material fit right into the sweet spot of what NASA’s Jet Propulsion Laboratory needed to enable this device to work,” said Rolland, co-founder and director of research and development at Liquidia Technologies, a company which licensed the PFPE technology from UNC.

“There are several reasons to suspect that amino acids and other biological molecules could be found on the surface of Mars,” Rolland said. “If this device is able to confirm this, it would obviously be one of the most important discoveries of all time. It’s exciting to think that UNC and Liquidia Technologies could be a part of that.”

To see the study, go to: http://www.rsc.org/Publishing/Journals/LC/article.asp?doi=b804265a. For more information about Liquidia, go to http://www.liquidia.com.

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