IUPAC Recognizes NRL Researchers for Optical Chromatography Technique

2/9/2009 - 1-09r
Contact: Donna McKinney, (202) 767-2541

Researchers in the Naval Research Laboratory's Chemistry Division have received an award for their research on laser separation of biological species. The award, which is sponsored by the International Union of Pure and Applied Chemistry (IUPAC), was presented to the group that submitted the best manuscript and presented the best oral presentation at the recent Chemical and Biological Defense Program (CBDP) conference.

The NRL group was recognized for their research and paper entitled "Laser Separation for Pathogen Bioenrichment, Purification, and Detection" under the category of detection capability area; it was selected from a total of approximately 200 papers, in each of five research categories. Dr. John W. Jost, the executive director of IUPAC, presented the award. The NRL researchers, led by Dr. Sean Hart, are Mr. Alex Terray, Dr. Doug Ladouceur, Dr. Steven Sundbeck, Mr. Jonathan Arnold, and Dr. Tomasz Leski (who now works in NRL's Center for Biomolecular Science and Engineering).

The NRL research team has developed a technique called optical chromatography, where a lightly focused laser beam is introduced into a counter-propagating fluid containing the particles to be trapped. The particle trapping and separation occur through a balance of the fluidic drag force and the optical force. The optical force that the laser exerts on a particle depends in part on its size, shape, and refractive index or chemical composition. So particles with a larger size or refractive index experience greater optical pressure and hence move farther upstream. The particles move against the fluid flow until reaching an equilibrium position where the fluid and optical forces are balanced.

The research team has separated and studied several important samples of biological origin, including bacterial cells, spores, and pollens. The work for which they have received the CBDP award is aimed at separation of biological agents from each other or from contaminants that would inhibit identification techniques such as DNA detection using polymerase chain reaction (PCR). This involves separating relatively large quantities (thousands) of spores and cells - enough to couple with existing technologies for the purpose of sample purification and concentration. The system is capable of purifying a large number of spores in a chemically contaminated sample, containing environmental inhibitors such as humic acid, for PCR detection. Without the use of the optical chromatographic separation device, the sample yields a false negative (non-detect) using PCR. With the use of the laser in the NRL system, a positive detect occurs because the spores have been separated from the inhibitors. This approach should work effectively for chemical and particulate contaminants, given the ability to fractionate samples based upon microorganism properties.

This research is funded by the Defense Threat Reduction Agency (DTRA) in the 6.2 point detection program managed by Dr. Bryan Horner and Dr. Ngai Wong, the capability area program officer. The Joint Science and Technology Office (JSTO) and DTRA within the Chemical and Biological Defense Program hosted the inaugural Chemical and Biological Defense Physical Science and Technology Conference, in New Orleans, LA, in November 2008. The conference discussed current and future CB defense challenges for both military and first responders. Oral and poster presentations addressed all areas of physical science and technology relevant to future chemical and biological defense requirements.

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