Himedia Bisbenzimide (Hoechst 33342)

Bisbenzimide dyes(Hoechst 33342 and Hoechst 33258) are specific fluorescent DNA stains that specifically bind to ssDNA and dsDNA in AT rich regions of the minor groove. They do not bind RNA. Hence, presence of RNA does not affect DNA staining in cell preparation, eliminating the need of pre-treatment with RNase. H33342 is more cell permeant than H33258. Hoechst dyes are less toxic than DAPI, which ensures a higher viability of stained cells. Unlike other fluorescent stains such as DAPI and propidium iodide, Hoechst stains can permeate live cells and are, therefore, known as vital stains. Hoechst 33342 can also be used to stain fixed cells.