A Crayon Box For The Biotech Set

By replacing the bases in DNA with different fluorophores, chemists at Stanford University have created a palette of 23 dyes that can be excited at one wavelength (J. Am. Chem. Soc., DOI: 10.1021/ja805502k). The new dyes could find broad use as biological labels, according to the researchers, particularly in systems where classical fluorophores fail, such as in moving organisms. Eric T. Kool, Yin Nah Teo, and James N. Wilson create the labels by assembling three to five fluorophores—typically aromatic hydrocarbons or heterocycles—into a DNA-like chain. Dubbed oligodeoxyfluorosides (ODFs), each fluorophore takes the place of the DNA base on the deoxyribose unit, making it possible for a DNA synthesizer to knit together a chain of the oligomers. The DNA backbone brings the aromatic species into close contact so the researchers are able to excite multiple fluorophores with one wavelength of light, thereby generating different colors simultaneously. Classical fluorophores typically require multiple excitation wavelengths, and therefore multiple fluorescence experiments, to observe multiple colors. The Stanford team used the ODFs to image several biological systems, including live zebrafish, in many colors at once.