The new rapid method represents a field-portable alternative to more expensive procedures, particularly where larger-scale, expensive equipment is not readily accessible. To decrease the time to determine results, the researchers have outfitted a portable kit to test samples for bacterial concentrations.
"We envision a tool that can be used by lifeguards to collect and analyze water samples throughout the day, providing beachgoers with up-to-date, near-real-time data on water conditions," Lee said. "This could also be useful in determining persistence of a bacterial contaminant after a pollution event, such as a sewage spill or a septic tank leaking."
"We are currently applying this method, in a new approach, to identifying contamination sources in which we can adaptively sample the environment in order to hone in on hotspots," Jay said.
The process uses magnetic beads conjugated to specific antibodies that identify and bind fecal bacteria that are used as standards for determining the safety of recreational waters, such as E. coli and Enterococcus.
After a few filtration and isolation steps, the sample organisms are lysed and treated with an enzyme that catalyzes a light-emitting reaction with target ATP, the energy currency of a cell. Cells break down ATP to obtain energy important for cellular processes.
Scientists can then determine bacterial concentrations based on how much light is released by using a luminometer, a device that detects light emissions.
The process is called covalently linked immunomagnetic separation/adenosine triphosphate quantification technique (Cov-IMS/ATP).
The paper's other co-authors are UCLA electrical engineering professor William Kaiser and John Griffith,
|Contact: Matthew Chin|
University of California - Los Angeles