Poly(Ethylene Glycol): An Ideal Spacer for Molecular Recognition Force Microscopy/Spectroscopy.

In this review, we report recent molecular recognition studies of our group. The surface chemistry by which ligands are covalently coupled to force microscopy tips is described. Poly(ethylene glycol), which is used as spacer for the ligands, was shown to be a most suitable crosslinker for force spectroscopy and microscopy experiments. Basic principles of force spectroscopy are discussed and the successful application of this technique to several biological systems is demonstrated. Information about kinetic rates, affinities, and the dynamic structure of the binding pocket are obtained. Furthermore, it is shown that combining molecular recognition with dynamic force microscopy leads to recognition imaging and renders localization of binding sites with nm accuracy possible. These techniques show State Physics, University of Linz great potential for investigating the molecular dynamics of ligand-receptor binding and the epitope mapping of recptors during biological processes.