A research group headed by Dan Luo, Cornell assistant professor of biological engineering, has created "nanobarcodes" that fluoresce under ultraviolet light in a combination of colors that can be read by a computer scanner or observed with a fluorescent light microscope.
Other methods of identifying biological molecules that are available or being developed mostly involve expensive equipment, Luo said. "We wanted something that could be done with inexpensive, readily available equipment," he said. Several years ago researchers created probes consisting of nanoscale bars of metal actually etched with conventional bar codes. Since then, most molecular tagging devices have been referred to as "barcodes," even though there are no bars involved.
The researchers have tested their system using samples containing various combinations of E. coli, anthrax and tularemia bacteria and ebola and SARS viruses, and have found the color codes could clearly distinguish several different pathogens simultaneously.
The research is described in a paper, "DNA fluorescence nanobarcodes for multiplexed pathogen detections," by Luo, Yougen Li, a former Cornell graduate student now at California Institute of Technology, and Yen Thi Hong Cu, a current graduate student, to be published in the July 2005 issue of the journal Nature Biotechnology and available after June 12 in the online version of the journal.
The idea is one of several applications the researchers have found for what they call "dendimer-like DNA," consisting of many short Y-shaped strands of DNA linked together in a treelike structure. The
Contact: Blaine P. Friedlander Jr.
Cornell University News Service