DNA Gets New Twist: Scientists Develop Ultra-bright Fluorescent 'DNA Nanotags'

A group of students and researchers associated with Carnegie Mellon University’s Molecular Biosensor and Imaging Center discovered a way to tag different types of cells using multi-color fluorescent nanotags. Basing their research on the structure of phycobiliproteins that are commonly found in algae and absorb light energy that is transferred to chlorophyll, Andrea Benvin was able to not only create a multiple colored image, but these tagged proteins can be simultaneously viewed using one experiment, one later, and one fluorescence-imaging machine. The Carnegie Mellon team was even able to create nanostructured DNA templates that bind multiple fluorescent dye molecules between base pairs in the DNA helix. This allows for a clear and more precise image with a separation of the dye colors that keep the dyes from canceling each other out. The brightness of the nanotags is said to be limitless because the 30 base pairs the team can tab 15 dyes but can simply add more nanotags by increasing the number of DNA pairs in the strand. The multicolor is produced by the dyes ability to harvest light but the dyes are only excited by one wavelength of light and emit the light to its surface creating different colors.

http://www.sciencedaily.com/release/2007/01/070126142051.html