Carnegie Mellon University scientists have married bright fluorescent dye molecules with DNA nanostructure templates to make nanosized fluorescent labels that hold considerable promise for studying fundamental chemical and biochemical reactions in single molecules or cells. According to Armitage- The high brightness of the nanotags should be of very helpful in detecting rare cancer cells within tissue biopsies, for example, which is important in determining whether treatments have been successful or if recurrence is likely. In addition, DNA nanotags offer the opportunity to perform multicolor experiments which is useful for imaging applications, as the multiple colors can be seen simultaneously, requiring only one experiment using one laser and one fluorescence-imaging machine. The scientist modeled their DNA nanotags on the structure of phycobiliproteins. Found in certain types of algae, these proteins contain multiple, fluorescent pigments that work together to absorb light energy that is then transferred to chlorophyll, where it is used for photosynthesis. The Carnegie Mellon team assembled well-defined nanostructured DNA templates that bind multiple fluorescent dye molecules between base pairs in the DNA helix to achieve greater brightness. DNA nanotags contain "light-harvesting" dyes within the DNA helix that are excited by one wavelength of light and then transfer that excitation energy to "light-emitting" dyes on the nanotag’s surface which made multicolor experiments possible.

"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.
Source