Application Note: Hoechst & DAPI dyes for nuclear staining
16 April 2024

Hoechst and DAPI are widely used blue fluorescent dyes for nuclear staining of live or fixed cells, with a preference for A/T-rich regions of DNA. They become brightly fluorescent upon binding to DNA and can be used without a wash step. While both dyes are stable and have low toxicity, Hoechst is preferred for live cell staining due to its lower toxicity and better cell permeability, while DAPI is preferred for fixed cell staining. Biotium provides recommendations for staining concentrations, storage, and precautions, along with protocols for staining live cells and fixed cells or tissue sections. Additionally, considerations for staining bacteria or yeast and strategies to avoid photoconversion by UV light are discussed, along with technical information and product catalog numbers for both dyes.

This article includes:

  • A detailed comparison between Hoechst and DAPI for live and fixed cell staining.
  • Advice and tips on avoiding issues with Hoechst and DAPI photoconversion.
  • A convenient Hoechst or DAPI staining protocol you can take to the lab.