Simultaneous topography and recognition imaging: Physical aspects and optimal imaging conditions

Johannes Preiner, Andreas Ebner, Lilia Chtcheglova, Rong Zhu, Peter Hinterdorfer

Research output: Contribution to journalArticlepeer-review

49 Citations (Scopus)

Abstract

Simultaneous topography and recognition imaging (TREC) allows for the investigation of receptor distributions on natural biological surfaces under physiological conditions. Based on atomic force microscopy (AFM) in combination with a cantilever tip carrying a ligand molecule, it enables us to sense topography and recognition of receptor molecules simultaneously with nanometre accuracy. In this study we introduce optimized handling conditions and investigate the physical properties of the cantilever-tip-sample ensemble, which is essential for the interpretation of the experimental data gained from this technique. In contrast to conventional AFM methods, TREC is based on a more sophisticated feedback loop, which enables us to discriminate topographical contributions from recognition events in the AFM cantilever motion. The features of this feedback loop were investigated through a detailed analysis of the topography and recognition data obtained on a model protein system. Single avidin molecules immobilized on a mica substrate were imaged with an AFM tip functionalized with a biotinylated IgG. A simple procedure for adjusting the optimal amplitude for TREC imaging is described by exploiting the sharp localization of the TREC signal within a small range of oscillation amplitudes. This procedure can also be used for proving the specificity of the detected receptor-ligand interactions. For understanding and eliminating topographical crosstalk in the recognition images we developed a simple theoretical model, which nicely explains its origin and its dependence on the excitation frequency.

Original languageEnglish
Article number215103
Pages (from-to)215103
JournalNanotechnology
Volume20
Issue number21
DOIs
Publication statusPublished - 27 May 2009

Keywords

  • Avidin/chemistry
  • Computer Simulation
  • Image Enhancement/methods
  • Immunoglobulin G/chemistry
  • Micromanipulation/methods
  • Microscopy, Atomic Force/methods
  • Models, Chemical
  • Molecular Probe Techniques
  • Nanotechnology/methods
  • Protein Interaction Mapping/methods

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