CHARACTERIZATION OF THE ADHESION FORCE BETWEEN AVIDIN-FUNCTIONALIZED AFM TIPS AND BIOTINYLATED AGAROSE BEADS

With AFM related techniques we investigated the specific interaction b etween 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 mea surements. The strength of the interaction between the tip and the bea d was found to depend on the force applied by the AFM tip on the polym er beads. By regulating the contact via indentation, the interaction c an vary from one to as much as 100 biotin-avidin pairs. When surface i nteraction is minimized, quantized interaction between avidin and biot in was observed. This approach induces minimal stress on the interacti ng molecules.