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Biophysical Journal, Volume 89, Issue 3, 1 September 2005, Pages L19-L21
Stefanie Breisch, Julian Gonska, Helmut Deissler and Martin Stelzle
AbstractThe disruption force of specific biotin-streptavidin bonds was determined using DNA oligomers as force tags. Forces were generated by an electric field acting on a biotinylated fluorescently labeled DNA oligomer. DNA oligomers were immobilized via biotin-streptavidin bonds on the walls of microfluidic channels. Channel layout and fluid-based deposition process were designed to enable well-defined localized deposition of the oligomers in a narrow gap of the microchannel. Electric fields of up to 400V/cm were applied and electric field induced desorption of DNA oligomers was observed. At ≈ 30°C, field-induced desorption of both a 12 mer as well as a 48 mer yielded a streptavidin-biotin disruption force of 75 fN. Streptavidin-functionalized surfaces remained intact and could be reloaded with biotinylated oligomers. At ≈20°C, however, no field-induced unbinding of the oligomers was observed at electric field strength of up to 400V/cm, indicating a significant temperature dependence of the bond strength.
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Abstract | Full Text | PDF (254 kb) - Dissecting Streptavidin-Biotin Interaction with a Laminar Fl...Dissecting Streptavidin-Biotin Interaction with a Laminar Flow Chamber
Biophysical Journal, Volume 82, Issue 6, 1 June 2002, Pages 3214-3223
Anne Pierres, Dominique Touchard, Anne-Marie Benoliel and Pierre Bongrand
AbstractA laminar flow chamber was used to study single molecule interactions between biotinylated surfaces and streptavidin-coated spheres subjected to a hydrodynamic drag lower than a piconewton. Spheres were tracked with 20ms and 40nm resolution. They displayed multiple arrests lasting between a few tens of milliseconds and several minutes or more. Analysis of about 500,000 positions revealed that streptavidin-biotin interaction was multiphasic: transient bound states displayed a rupture frequency of 5.3s and a rate of transition toward a more stable configuration of 1.3s. These parameters did not display any significant change when the force exerted on bonds varied between 3.5 and 11 pN. However, the apparent rate of streptavidin-biotin association exhibited about 10-fold decrease when the wall shear rate was increased from 7 to 22s, which supports the existence of an energy barrier opposing the formation of the transient binding state. It is concluded that a laminar flow chamber can yield new and useful information on the formation of molecular bonds, and especially on the structure of the external part of the energy landscape of ligand-receptor complexes.
Abstract | Full Text | PDF (138 kb) - …more
Copyright © 1996 The Biophysical Society. All rights reserved.
Biophysical Journal, Volume 70, Issue 5, 2437-2441, 1 May 1996
doi:10.1016/S0006-3495(96)79814-4
Research Article
Specific antigen/antibody interactions measured by force microscopy
U. Dammer, M. Hegner, D. Anselmetti, P. Wagner, M. Dreier, W. Huber and H.J. Güntherodt
Institute of Physics, University of Basel, Basel, Switzerland.
Abstract
Molecular recognition between biotinylated bovine serum albumin and polyclonal, biotin-directed IG antibodies has been measured directly under various buffer conditions using an atomic force microscope (AFM). It was found that even highly structured molecules such as IgG antibodies preserve their specific affinity to their antigens when probed with an AFM in the force mode. We could measure the rupture force between individual antibody-antigen complexes. The potential and limitations of this new approach for the measurement of individual antigen/antibody interactions and some possible applications are discussed.
