Invitrogen™ SYTOX™ Blue Nucleic Acid Stain - 5 mM Solution in DMSO

The binding mode of SYTO nucleic acid stains is unknown. However, the behavior of these and related nucleic acid dyes suggests the following binding properties:

1.They appear to contact the solvent (suggested by sensitivity to salt, divalent cations, and in particular, SDS) and thus are likely to have contacts in the grooves.
2.All SYTO dyes appear to show some base selectivity and are thus likely to have minor groove contacts.
3.They can be removed from nucleic acid via ethanol precipitation; this characteristic is not shared by ethidium bromide and other intercalators. Likewise, the dyes are not removed from nucleic acid via butanol or chloroform extraction. These extraction methods do remove ethidium bromide from nucleic acid. 4. SYTO binding is not affected by nonionic detergents.
5. SYTO dyes are not quenched by BrdU, so they do not bind nucleic acids in precisely the same way as Hoechst 33342 and DAPI ((4′,6-diamidino-2-phenylindole).

SYBR Green I has shown little mutagenicity on frameshift indicator strains, indicating that it isn't likely to strongly intercalate.

SYTOX AAdvanced labels only dead cells because it is a cell impermeant dye. The dye can only enter cells that have a compromised plasma membrane. Trypsinization may cause temporary disruption of the plasma membrane, sufficient to allow staining with a cell impermeant dye. You can reduce the “false-dead” problem by either reducing the amount of trypsin and/or reduce the incubation time for trypsinization or use a gentler dissociation reagent such as TrypLE Express, TrypLESelect reagents, or Versene. After trypsinization, wash well, and if possible, allow a recovery time in normal culture media before staining with any of the SYTOX dyes.

SYTOX dyes are only tested for end-point assays, not for leaving in cell solutions long term. Therefore, we do not recommend using SYTOX Blue Nucleic Acid Stain - 5 mM Solution in DMSO for long-term imaging.