Biothreat detection takes concentration
BEADS, short for Biodetection Enabling Analyte Delivery System, purifies and concentrates environmental samples containing potential biothreats. BEADS can be used as the front end for sensitive detectors because it captures contaminants of interest from dirty environmental samples. "BEADS isolates what's important in the sample," said Cindy Bruckner-Lea, a scientist involved in the project. "Some compounds like humic acids in soil can interfere with detection, but washing away interfering compounds in the sample makes for better detection."
In addition to purifying and concentrating samples, BEADS has its own detector and can link to other detectors. Currently, BEADS is linked to detectors at other national laboratories as part of a DOE plan to use it on biodetection units for homeland defense applications.
Here's how it works. Liquid samples flow over a packed bed of beads, literally tiny glass, polymer or magnetic spheres. Solid samples, such as soil, are liquefied and then pass over the beads. Bacteria, spores, viruses or their DNA bind onto the beads, while the other material is washed away. When enough contaminants are collected, they are extracted from the beads and analyzed, or analyzed in place.
Because BEADS is automated, it can be used in situations that may be dangerous to people, such as monitoring water sources like rivers or reservoirs during military operations. It also may be installed in ships, spacecraft or submarines to make sure limited water supplies are not contaminated.