Methods for reducing nonspecific interaction in antibody-antigen assay via atomic force microscopy

Jun'ichi Wakayama, Hiroshi Sekiguchi, Satoshi Akanuma, Toshio Ohtani, Shigeru Sugiyama

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

We developed a method to measure the rupture forces between antibody and antigen by atomic force microscopy (AFM). Previous studies have reported that in the measurement of antibody-antigen interaction using AFM, the specific intermolecular forces are often obscured by nonspecific adhesive binding forces between antibody immobilized cantilever and substrate surfaces on which antigen or nonantigen are fixed. Here, we examined whether detergent and nonreactive protein, which have been widely used to reduce nonspecific background signals in ordinary immunoassay and immunoblotting, could reduce the nonspecific forces in the AFM measurement. The results showed that, in the presence of both nonreactive protein and detergent, the rupture forces between anti-ferritin antibodies immobilized on a tip of cantilever and ferritin (antigen) on the substrate could be successfully measured, distinguishing from nonspecific adhesive forces. In addition, we found that approach/retraction velocity of the AFM cantilever was also important in the reduction of nonspecific adhesion. These insights will contribute to the detection of specific molecules at nanometer scale region and the investigation of intermolecular interaction by the use of AFM.

Original languageEnglish
Pages (from-to)51-58
Number of pages8
JournalAnalytical Biochemistry
Volume380
Issue number1
DOIs
Publication statusPublished - 2008 Sep 1
Externally publishedYes

Keywords

  • Antibody
  • Antigen
  • Atomic force microscopy
  • Ferritin
  • Immunoassay

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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