Do you have any dyes that can stain the nuclei in live cells? Are they also fixable and can I use them to stain fixed cells?

DAPI and Hoechst 33258, 33342 and 34580 can be used to stain nuclei in either live or fixed cells. Unfortunately, when exposed to UV light during imaging, the blue dyes can photoconvert into green and red-emitting forms, potentially confusing the interpretation of multicolor experiments. DAPI is toxic to cells unless extremely diluted, and so is typically used for fixed-cell staining. 

Nuclear LCS1/LCS2 is a novel series of cell-permeable, DNA-selective dyes for staining DNA content in living cells that covers most of the visual spectrum, avoiding photoconversion issues:

• Nuclear Violet™ LCS1 can stain live and fixed cells. Nuclear Violet™ LCS1 is fixable.
• Nuclear Green™ LCS1 can stain live and fixed cells. Nuclear Green™ LCS1 is fixable.
• Nuclear Orange™ LCS1 can stain live and fixed cells. Nuclear Orange™ LCS1 is fixable.
• Nuclear Red™ LCS1 can stain live cells and fixed cells. Nuclear Red™ LCS1 is fixable.
• Nuclear Red™ LCS2 can stain live and fixed cells. Nuclear Red™ LCS2 is fixable.

*Note: for fixable nuclei stains, stain cells first and then fix in 4% formaldehyde.