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| 2. |
- Valle-Delgado, J. J., et al.
(författare)
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Interaction forces between BSA layers adsorbed on silica surfaces measured with an atomic force microscope
- 2004
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 108:17, s. 5365-5371
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Tidskriftsartikel (refereegranskat)abstract
- The interaction forces between bovine serum albumin (BSA) layers adsorbed on silica surfaces have been measured using an atomic force microscope (AFM) in Conjunction with the colloid probe technique. Measurements of force-distance curves were made at different pH values and electrolyte concentrations (NaCl and CaCl2). The interaction at long range is dominated by electrical double-layer forces, while at short surface separations an additional repulsion due to the compression of the adsorbed protein layers appears. However, prior to this steric interaction, when the pH is above the isoelectric point of the protein and at high salt concentration, a non-DLVO repulsive interaction is observed. This behavior is explained if the presence of hydration forces in the system is assumed. Theoretical predictions including a hydration term in the DLVO theory fit the experimental results satisfactorily. The results presented in this article provide a direct confirmation that the AFM colloid probe technique can provide a useful way of directly quantifying the interaction of biological macromolecules.
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| 3. |
- Valle-Delgado, J. J., et al.
(författare)
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Interactions between bovine serum albumin layers adsorbed on different substrates measured with an atomic force microscope
- 2004
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 6:7, s. 1482-1486
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Tidskriftsartikel (refereegranskat)abstract
- By the aid of an atomic force microscope (AFM) and the colloid probe technique, the interaction forces between bovine serum albumin (BSA) layers adsorbed on different substrates (silica and polystyrene) have been measured directly as a function of pH and salt concentration. Electrostatic and steric forces dominate the interactions at low salt concentrations. At high salt concentrations, when electrostatic interactions are screened, a very strange behaviour is found as a function of pH. The behaviour around the i.e.p. of the protein is also very striking: the interaction is attractive at low salt concentration, but it is repulsive at high salt concentration. These results could be explained if the presence of hydration forces is assumed. Theoretical predictions including a hydration term in the DLVO theory fit the experimental results satisfactorily.
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| 4. |
- Valle-Delgado, J. J., et al.
(författare)
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Measurement of interactions between protein layers adsorbed on silica by atomic force microscopy
- 2004
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Ingår i: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 16:26, s. 2383-2392
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Tidskriftsartikel (refereegranskat)abstract
- The present work, using an atomic force microscope and the colloid probe technique, investigates the interaction forces between bovine serum albumin (BSA) layers and between apoferritin layers adsorbed on silica surfaces. The measurements have been carried out in an aqueous medium at different pH values and NaCl concentrations. Similar behaviours have been found with both proteins. Electrostatic and steric forces dominate the interactions between the protein layers at low NaCl concentrations. However, a very strange behaviour is found as a function of pH at high NaCl concentrations. The results obtained under these conditions could be explained if the presence of hydration forces in these systems is assumed.
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