Negative visualization of DNA in agarose gel by eosin Y and its related mechanism.

We report here a sensitive and environmentally benign technique for the visualization of DNA by using eosin Y, which appeared as a transparent and colorless band under the opaque gel matrix background. As low as 0.2-0.6 ng of DNA can be visualized within 1 h, similar to that of the most commonly used ethidium bromide stain. Furthermore, the mechanism of the newly developed method was also described. According to the results, it can be concluded that the complex between DNA and eosin Y is mainly formed by the function of groove binding, but not intercalate itself into the double helix structure of DNA.