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On-slide detection of enzymatic activities in selected single cells

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  • Josephine Geertsen Keller
  • Cinzia Tesauro
  • Andrea Coletta, Aarhus University
  • ,
  • Astrid Damgaard Graversen, Aarhus University
  • ,
  • Yi-Ping Ho, Department of Biomedical Engineering, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China.
  • ,
  • Peter Kristensen, Department of Engineering, Gustav Wieds Vej 10, Bldg 3142, Aarhus University, 8000 Aarhus C, Denmark.
  • ,
  • Magnus Stougaard
  • Birgitta Ruth Knudsen

With increasing recognition of the importance in addressing cell-to-cell heterogeneity for the understanding of complex biological systems, there is a growing need for assays capable of single cell analyses. In the current study, we describe the measurement of human topoisomerase I activity in single CD44 positive Caco2 cells specifically captured from a mixed population on glass slides, which were dual functionalized with anti-CD44-antibodies and specific DNA primers. On-slide lysis of captured CD44 positive cells, resulted in the release of human topoisomerase I, allowing the enzyme to circularize a specific linear DNA substrate added to the slides. The generated circles hybridized to the anchored DNA primers and acted as templates for a solid support rolling circle amplification reaction leading to the generation of long tandem repeat products that were detected at the single molecule level in a fluorescent microscope upon hybridization of fluorescent labelled probes. The on-slide detection system was demonstrated to be directly quantitative and specific towards CD44 positive cells. Moreover, it allowed reproducible detection of human topoisomerase I activity in single cells.

Original languageEnglish
Pages (from-to)13546-13553
Number of pages8
Publication statusPublished - 2017

    Research areas

  • Journal Article

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