Microsc. Microanal. Microstruct. 5, 321-328 (1994)
DOI: 10.1051/mmm:0199400504-6032100

Characterization of the adhesion force between avidin-functionalized AFM tips and biotinylated agarose beads

Markus Ludwig, Vincent T. Moy, Matthias Rief, Ernst-Ludwig Florin et Hermann E. Gaub

Physikdepartment, Technische Universität Müchen, 85748 Garching, Germany

Abstract
With AFM related techniques we investigated the specific interaction between avidin and biotin. The contact rupture force (adhesion) between avidin functionalized tips and biotin, which was covalently linked to agarose beads, was measured and characterized. A comprehensive study of the physical properties of the receptor-functionalized tips and the biotin-labeled agarose bead was carried out. The functional stability of the avidin coated tip persisted for several hundred force scan measurements. The strength of the interaction between the tip and the bead was found to depend on the force applied by the AFM tip on the polymer beads. By regulating the contact via indentation, the interaction can vary from one to as much as 100 biotin-avidin pairs. When surface interaction is minimized, quantized interaction between avidin and biotin was observed. This approach induces minimal stress on the interacting molecules.

PACS
8715K - Molecular interactions; membrane-protein interactions.

Key words
Avidin -- Biotin -- Molecular interaction -- Physical properties -- Agarose -- Proteins -- Biochemistry -- Biological sciences -- Life sciences -- Glycoproteins -- Vitamin


© EDP Sciences 1994