An Iodinated DAPI-Based Reagent for Mass Cytometry

Multiparametric single cell analysis has seen dramatic improvements with the introduction of Mass Cytometry (MC) and Imaging Mass Cytometry (IMC™). These technologies expanded the number of biomarkers that can be identified simultaneously by using heavy isotope-tagged antibody reagents. Small molecule probes bearing heavy isotopes are emerging as additional useful functional reporters of cellular features. Realizing this, we explored the iodination of DAPI to produce a heavy atom substituted derivative of the commonly used fluorescent DNA stain. Although exhibiting a drastically reduced fluorescence emission profile, I-DAPI retains strong binding affinity for DNA. I-DAPI was used to detect cellular DNA in MC and IMC™ assays with comparable efficiency to known Ir containing DNA intercalators. This work suggests repurposing of well-known colorimetric stains through simple reactions could be an effective strategy to develop new, functional MC and IMC™ reagents.