Detection of the Malaria causing Plasmodium Parasite in Saliva from Infected Patients using Topoisomerase I Activity as a Biomarker

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal article

    Marianne Smedegaard Hede, Zymonostics ApS, Aarhus, Denmark.,
  • Søren Fjelstrup
  • Felix Lötsch, Department of Medicine, I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, Vienna, Austria., Rella Manego Zoleko, Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon., Anna Klicpera, Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon., Mirjam Groger, Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon., Johannes Mischlinger, Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany., Lilian Endame, Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon., Luzia Veletzky, Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon., Ronja Neher, Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany., Anne Katrine Wrist Simonsen,
  • Eskild Petersen
  • Ghyslain Mombo-Ngoma, Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany.,
  • Magnus Stougaard
  • Yi-Ping Ho, Division of Biomedical Engineering, Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China.,
  • Rodrigo Labouriau
  • Michael Ramharter, Institut für Tropenmedizin, Universität Tübingen, Tübingen, Germany.,
  • Birgitta Ruth Knudsen

Malaria is among the major threats to global health with the main burden of disease being in rural areas of developing countries where accurate diagnosis based on non-invasive samples is in high demand. We here present a novel molecular assay for detection of malaria parasites based on technology that may be adapted for low-resource settings. Moreover, we demonstrate the exploitation of this assay for detection of malaria in saliva. The setup relies on pump-free microfluidics enabled extraction combined with a DNA sensor substrate that is converted to a single-stranded DNA circle specifically by topoisomerase I expressed by the malaria causing Plasmodium parasite. Subsequent rolling circle amplification of the generated DNA circle in the presence of biotin conjugated deoxynucleotides resulted in long tandem repeat products that was visualized colorimetrically upon binding of horse radish peroxidase (HRP) and addition of 3,3',5,5'-Tetramethylbenzidine that was converted to a blue colored product by HRP. The assay was directly quantitative, specific for Plasmodium parasites, and allowed detection of Plasmodium infection in a single drop of saliva from 35 out of 35 infected individuals tested. The results could be determined directly by the naked eye and documented by quantifying the color intensity using a standard paper scanner.

Original languageEnglish
JournalScientific Reports
Volume8
Issue number1
Pages (from-to)4122
Number of pages12
ISSN2045-2322
DOIs
StatePublished - 7 Mar 2018

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