Mass In Situ Hybridization Enables Mass Cytometry to Detect Telomere Length

Single-cell resolution detection of DNA sequences is crucial for advancing our understanding of cellular differentiation and disease mechanisms. Mass cytometry has had a transformative impact on single-cell protein analysis; however, the potential of mass cytometry in genomics remains limited due to the inability to integrate DNA sequence detection. Bridging this gap is essential to expanding the capabilities of mass cytometry for comprehensive genomic and proteomic studies. In this work, we presented a novel mass in situ hybridization (MISH) strategy that enables the detection of specific DNA sequences─telomeres at single-cell resolution. At first, we synthesized a dendritic oligomer chelated with holmium (Ho), which had enough sensitivity and proper molecular size, and then conjugated it with a high-specificity telomere oligo-DNA probe containing the (AATCCC)₃ sequence, a short complementary nucleic acid sequence of telomere. Finally, we successfully applied MISH to detect the telomere length via mass cytometry and imaging mass cytometry (IMC). Our method establishes the first successful strategy for telomere length detection via mass cytometry, marking a significant technological breakthrough. This innovation offers considerable potential for expanding the application of mass cytometry for the detection of specific DNA sequences.