Cell biology 

Ethidium Homodimer, first developed by Dr. Le Pecq and his colleagues, is a high affinity fluorescent nucleic acid stain. It binds to both DNA and RNA in a sequence-independent manner and with a >30-fold fluorescence enhancement. The DNA binding of each Ethidium Homodimer covers four base pairs and is believed to occur by intercalation. Because the dye is highly positively charged, it can not cross cell membranes to stain living cells. However, it is very useful to detect nucleic acids in solution, or cells with disintegrated cell membranes. Biotium offers a high purity grade Ethidium Homodimer that is not available from anywhere else. Ethidium Homodimer from other suppliers often contains a high amount (as much as 20%) of inorganic salt that lowers the weight percent purity.

• λ_Ex/λ_Em (with DNA) = 528/617 nm
• λ_Ex/λ_Em (in H₂O, no DNA) = 493 nm
• Red solid soluble in DMSO or MeOH
• Store at 4°C and protect from light
• C₄₆H₅₀Cl₄N₈
• Mwt: 857