July 9, 2013
DNA On Mars? – Researchers Test Sequencing Microchip For A Trip To The Red Planet
Brett Smith for redOrbit.com - Your Universe Online
As space agencies make plans to send scientific equipment to Mars, they must take into consideration the demands of a grueling trek across the solar system. The journey exposes spacecraft and their precious cargo to frigid temperatures and harsh solar radiation, meaning the often sensitive equipment onboard must be designed to handle these physical challenges.
Aiming to build a system that excavates the Red Planet's surface for genetic material, a team of MIT engineers has just successfully put a key component of the equipment through rigorous radiation trials. The component, a DNA-sequencing microchip, was exposed to Mars-mission radiation levels and then passed both an electrical test and a performance test.
"Over time on Mars, a chip's performance could degrade, reducing our ability to get sequence data. The chip might have a higher error rate, or could fail to function at all," said Christopher Carr, a research scientist in MIT's Department of Earth, Atmospheric and Planetary Sciences. "We did not see any of these issues [in our tests]. â€¦ Once this chip has been through two years of a Mars mission, it still will be able to sequence."
According to their report in the journal Astrobiology, the team began working with 40 microchips, first performing electrical testing on 20 chips at NASA's Space Radiation Laboratory at Brookhaven National Laboratory. During the electrical tests, the chip's gain, voltage and micro-wells were calibrated to confirm they were in proper working order.
After the initial test, the team used a linear accelerator and an electron-beam ion source to expose the chips to different levels of radiation. The chips were exposed to even higher levels of radiation than they would receive during a theoretical two-year mission to Mars.
The irradiated chips were then given an electrical performance test that revealed very little disruption in their capabilities.
The team also exposed the other 20 microchips to comparable radiation levels as the first batch. These chips were then used to analyze DNA fragments from E. coli. Once again, the radiation exposure failed to affect the chips' abilities; in this case the ability to correctly identify the bacterial sequences.
"These chips are great candidates to do sequencing on Mars without any modifications that we know of right now," Carr said. "We essentially see no impact from radiation. That was a critical thing for us to show."
Previous work from Carr and his colleagues showed the reagents necessary for DNA sequencing can also endure comparable radiation levels, suggesting genetic sequencing may be possible on other planets or in space.
In addition to Mars, Carr said DNA sequencing technology might also be valuable in places such as Jupiter's moon Europa, where liquid oceans may potentially host some form of life. He also noted Enceladus, one of Saturn's moons that could have a habitable zone, is an even better candidate because it would involve exposure to less intense radiation.
"I do think we'll see DNA sequencing in space at some point," Carr said. "Hopefully we'll get a chance to be a part of that."