DAPI is a popular blue DNA dye that is used as a nuclear counterstain in fluorescence microscopy, chromosome staining and flow cytometry. The dye binds to the minor groove of dsDNA with approximately 20-fold fluorescence enhancement, with higher affinity for A-T rich regions. DAPI dilactate is essentially the same as DAPI dihydrochloride, but with a different counterion. The dilactate salt form of the dye is more water soluble than the dihydrochloride salt, and therefore DAPI dilactate is a better choice for preparing stock solutions in water.

<ul>
<li>Classic blue nuclear counterstain for fixed cells</li>
<li>Can be used at higher concentrations to stain live cells</li>
<li>&lamba;_Ex/&lamba;_Em(DNA) = 358/461 nm</li>
<li>Yellow solid soluble in water</li>
<li>Store at 4°C and protect from light, especially in solution</li>
<li>C₂₂H₂₇N₅O₆</li>
<li>MW: 457.49</li>
</ul>