Single-molecule detection on a protein-array assay platform for the exposure of a tuberculosis antigen

Ronny Schmidt, Jaroslaw Jacak, Christopher Schirwitz, Volker Stadler, Gerd Michel, Nicole Marmé, Gerhard J. Schütz, Jörg D. Hoheisel, Jens Peter Knemeyer

Research output: Contribution to journalArticlepeer-review

36 Citations (Scopus)


Based on a single-molecule sensitive fluorescence-linked immunosorbent assay, an analytical platform for the detection of lipoarabinomannan (LAM), a lipopolysaccharide marker of tuberculosis, was established that is about 3 orders of magnitude more sensitive than comparable current ELISA assays. No amplification step was required. Also, no particular sample preparation had to be done. Since individual binding events are detected, true quantification was possible simply by counting individual signals. Utilizing a total internal reflection configuration, unprocessed biological samples (human urine and plasma) to which LAM was added could be analyzed without the requirement of sample purification or washing steps during analysis. Samples containing about 600 antigen molecules per microliter produced a distinct signal. The methodology developed can be employed for any set of target molecules for which appropriate antibodies exist.

Original languageEnglish
Pages (from-to)1316-1322
Number of pages7
JournalJournal of Proteome Research
Issue number3
Publication statusPublished - 4 Mar 2011


  • Antibody detection
  • quantification
  • single-molecule sensitivity
  • tuberculosis
  • Lipopolysaccharides/analysis
  • Antigens/analysis
  • Humans
  • Sensitivity and Specificity
  • Immunosorbent Techniques/instrumentation
  • Tuberculosis/immunology
  • Fluorescent Dyes/chemistry


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