Detection of DNA hybridization by use of a lanthanide fluorescent intercalator that specifically binds to double stranded DNA.

Toward development of a DNA microarray system in which neither labeling nor amplification of the nucleic acids from living cell is required, we have developed a new method for the detection and quantification of target DNA hybridized with probe DNA fixed on a solid surface. This method utilizes a fluorescent intercalator: naphthalene diimide derivative carrying two fluorescent tetradentate beta-diketone-Eu3+ chelates. This compound selectively binds to double stranded DNA (dsDNA) fixed on a plastic assay plate. The amount of the compound bound to single stranded DNA (ssDNA) is negligible. The fluorescent intensity of Eu3+ was in proportion to the amount of the fixed DNA, showing that the compound quantitatively binds to dsDNA. Therefore, this method can be used not only to detect dsDNA, but also to measure the amount of DNA on a solid surface.