Scientists Develop DNA "Nanotags"

By adhering fluorescent dye molecules to DNA, scientists at Carnegie Mellon have created nano-sized labels that could one day detect rare cancer cells in tissue biopsies. The "nanotags" hold considerable promise for the future of medical diagnostics.

"Our DNA nanotags offer unprecedented densities of fluorescent dyes and, thus, the potential for extremely bright fluorescent labels," said graduate student Andrea Benvin. "We've put it all into a very small package, which will allow us to detect molecules with great sensitivity without interfering with the biological processes we are trying to understand."

DNA nanotags also offer the opportunity to perform multicolor experiments. According to Professor Bruce Armitage, who oversees the laboratory in which these nanotags were created, this feature is extremely useful for imaging applications because the multiple colors can be seen simultaneously. Therefore, only one experiment is required using one laser and one fluorescence-imaging machine.

"For example, two different populations of cells — one healthy and the other cancerous — could be distinguished based on labeling them with different color nanotags," Armitage explained.

The incredibly bright, fluorescent labels were created by mimicking a light-harvesting process that occurs in red and blue algae found in fresh and marine waters. Armitage believes this work is just the tip of the iceberg.

"The primary advantages of our system are the simplicity of its design combined with the ease with which the fluorescence brightness and color can be tuned," Armitage said. "We really feel that nanotags 100 times brighter than existing labels can be developed in any color," he said.

Related Links: Molecular Biosensor and Imaging Center  Chemistry Department  Mellon College of Science