Counting cells in the waters under Antarctica

Before astrobiologists can figure out whether the icy oceans on other worlds, such as Jupiter’s moon Europa, harbor life, they need to better understand life under the ice of our own oceans and thus need instruments that can detect signs of life while operating in extremely cold, watery conditions. The ocean under the Antarctic ice shelf is the most analogous environment to Europa here on Earth. At the ACS national meeting, Nicholas Speller of the Georgia Institute of Technology reported on the portable microfluidic cell counter he and his colleague Michael Cato built for deployment on Icefin, a vehicle designed for exploration underneath the Antarctic ice. Because Icefin is designed to fit through narrow boreholes in the ice, it doesn’t have room for a conventional flow cytometer. Instead, the researchers built a miniature version that can withstand high pressures and low temperatures. To detect cells in the 0.2–10 μm range, the researchers use DNA-binding fluorescent probes and laser-induced fluorescence detection. They have successfully demonstrated the instrument in the lab but had a disappointing first deployment when a wiring harness was damaged during transport and couldn’t be repaired in the field. For future prototypes, the researchers are looking to drastically reduce the system’s footprint while further improving its robustness.