We have been informed by the manufacturer of Cy2 that certain aromatic amines such as phenylenediamine can react with Cy2 and cleave away half of the cyanine molecule. Use of phenylenediamine as an anti-fading reagent in mounting media may result in weak and diffused fluorescence after storage of the stained slides. As an alternative, glycerol-based mounting media containing anti-fading agents such as DABCO or n-propyl gallate may be used.
Organic-based mounting media, such as DPX, Permount, or methyl salicylate, also may be used for cyanine dyes. Methyl salicylate remains liquid so the cover slip needs to be sealed with something like nail polish. DPX will harden into a plastic-like permanent mount. DPX is manufactured by BDH in England and distributed in the U.S. by Gallard-Schlesinger Ind. (800-645-3044).
