Hoechst dyes are cell membrane-permeant, minor groove-binding blue fluorescent DNA stains. Hoechst dyes are widely used in cell cycle and apoptosis studies and also as nuclear counterstains. Hoechst 33342 is reported to be slightly more membrane-permeable than Hoechst 33258. Either dye can be used to stain live or fixed cells in buffer or medium at 1 ug/mL with no wash step. Biotium also offers Hoechst 33342, 10 mg/mL in H2O.    &lamba;Ex/&lamba;Em (with DNA) = 350/461 nm  Pale yellow solid soluble in water up to 2% (w/v)  Store at 4°C and protect from light  C27H31Cl3N6O.3H2O  MW: 615.98  [23491-52-3]