Study of Adhesion Interaction Using Atomic Force Microscopy
J. Gryboś, G. Pyka-Fościak, K. Lebed, M. Lekka, Z. Stachura and J. Styczeń
The Henryk Niewodniczański Institute of Nuclear Physics Polish Academy of Sciences, Radzikowskiego 152, 32-341 Cracow, Poland
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Received: April 26, 2004
An atomic force microscope is a useful tool to study the interaction forces at molecular level. In particular the atomic force microscope can measure an unbinding force needed to separate the two single molecule complexes. Recent studies have shown that such unbinding force depends linearly on the logarithm of the applied loading rate, defined as a product of scanning velocity and the spring constant characterizing the investigated system (cantilever vs. surface). This dependence can be used to study the energy landscape shape of a molecular complex by the estimation of energy barrier locations and the related dissociation rates. In the present work the complex consisting of ethylene(di)aminetetraacetic acid and the bovine serum albumin was measured. The dependence between the unbinding force and the logarithm of the loading rate was linear. Using the Bell model describing the dissociation of the above molecules caused by the action of the external bond breaking force, two parameters were estimated: the dissociation rate and the position of the energy barrier needed to overcome during a transition from a bound to unbound state. The obtained results are similar to those obtained for a typical ligand--receptor interaction.
DOI: 10.12693/APhysPolA.105.501
PACS numbers: 87.64.Dz, 68.35.Gy