Compact Disc Puts Lab in a Spin
NASA is adapting tiny laboratories embedded in compact discs (CDs) to conduct biological tests aboard the International Space Station and to eventually look for life on other planets.
|The robotic arm of the Mars Viking 2 Lander extends to collect a sample of soil for analysis. In the mid-1970s, the Viking Lander mission’s Gas Exchange Experiment detected strong chemical activity in the martian soil. Credit: NASA.|
The CDs, with embedded biological tests, are under evaluation by NASA scientists, and several academic and industrial partners. The miniature laboratories were adapted to detect life forms and chemicals derived from life. NASA’s partners are Stanford University, Stanford, Calif.; Nanogen, Inc., La Jolla, Calif.; and the University of California, Irvine, Calif.
"This type of technology will enhance the International Space Station capability as a biological laboratory with greatly increased throughput and state-of-the-art techniques," said G. Scott Hubbard, director of the NASA Ames Research Center (ARC), Moffett Field, Calif. "Someday, this technology could allow astronauts or robots to search for life on other planets or moons," Hubbard said.
|The CDs, with embedded biological tests, are under evaluation by NASA scientists, and several academic and industrial partners. The miniature laboratories were adapted to detect life forms and chemicals derived from life. Microscopic views of simple demonstration tests (banner image) done by "Lab-on-a-CD to determine live and dead cells.
To process the CDs, the researchers adapted a suitcase-sized prototype instrument undergoing laboratory trials at ARC. There are two versions of the CDs, which are about the same size as music CDs. One is plastic, similar to a standard CD, and is disposable. The other is made of glass and is reusable.
"These tiny labs on CDs allow you to do thousands of tests of biological samples quickly and in the field," said Michael Flynn, a scientist at ARC. "On the Space Station, the types of tests you would do are DNA analyses," Flynn said.
To begin a test, a scientist places a liquid sample into a small opening near the center of the CD. The researcher puts the disc in the prototype machine that spins the CD. Centrifugal force spreads the sample fluid from the center of the CD through tiny, capillary-like pipes and valves towards the outer edges of the disc and several clear observation areas.
During the journey, special dyes in the CD combine with the sample. The dyes glow when exposed to specific proteins and other chemicals, including particular portions of DNA. The instrument shines a specific color light on the specimen, and if it glows in another specific color, the specimen contains the substance the dye was designed to detect. The CD system can even sample water. In 1998, NASA’s Associate Administrator Wesley Huntress, Jr., stated , "Wherever liquid water and chemical energy are found, there is life. There is no exception." The instrument’s field-test software has image analysis capability that can discriminate between cells and debris. A microscope and digital camera built into the prototype instrument take images of the glowing test sample in the clear observation area after the disc stops spinning.
"There’re already thousands of fluorescent test solutions available for conducting biological tests on bacteria, proteins, viruses and other life-related chemicals," Flynn said. "The lab-on-a-CD system allows us to automate a process that traditionally was very time-consuming and expensive."
The next step in evaluation of the prototype is to develop more tests to determine how well the device works. Eventually, researchers want to add a multi-disk changer to the instrument, so it can test several CDs.
"We have worked with many different commercial vendors and individuals to combine a variety of commercially available technologies into an integrated microgravity-compatible instrument," Flynn said. Potential spin-offs could be clinical uses in hospitals, physicians’ offices and laboratories.