Direct calibration of colloidal probe cantilevers via Derjaguin, Landau, Verwey, and Overbeek surface forces in electrolyte solution

2008 ◽  
Vol 79 (12) ◽  
pp. 123709 ◽  
Author(s):  
Xiaoting Hong ◽  
Gerold A. Willing
Keyword(s):  
Electrolyte Solution ◽  
Surface Forces ◽  
Colloidal Probe

Electrohydrodynamics and Surface Force Analysis in AFM Imaging of a Charged, Deformable Biological Membrane in a Dilute Electrolyte Solution

2003 ◽  
Author(s):  
Tai-Hsi Fan ◽  
Andrei G. Fedorov
Keyword(s):  
Cell Membrane ◽  
Double Layer ◽  
Electrolyte Solution ◽  
Electrostatic Field ◽  
Biological Membrane ◽  
Equilibrium Shape ◽  
Surface Force ◽  
Surface Forces ◽  
Contact Mode ◽  
Afm Imaging

Surface forces arising in AFM imaging of a deformable, negatively charged biological membrane in an electrolyte solution are investigated in the limit of continuous electrohydrodynamics. Specifically, we extend our previous analysis [1] of purely hydrodynamic interactions between an AFM tip and the elastic cell membrane by accounting for electric double-layer forces under the assumption of a dilute electrolyte solution and local electrochemical equilibrium. The solution of the problem is obtained by integrating the quasisteady, electrically-forced Stokes equation for the electrohydrodynamic field, the linearized Poisson-Boltzmann equation for the electrostatic field in the electrolyte inside and outside of the cell, and the Laplace equation for the electrostatic field within a dielectric AFM tip. The Helfrich and Zhongcan’s equation for an equilibrium shape of the cell membrane is employed as a quasi-steady, nonlinear boundary condition linking the stress fields on both sides of the cell membrane augmented by the local membrane incompressibility condition in order to find the local tension/compression force acting on the membrane. For the first time, an integrated framework for the dynamic coupling of the membrane double-layer effects and the AFM tip-electrolyte-membrane motion is established that allows for characterizing of the local electrolyte flow field, the electrostatic field, the elastic deformation of the membrane, and the electrohydrodynamic surface force acting on the AFM tip in great detail. The results of the analysis provide information on the motion of the membrane and the surface forces induced by both an electrolyte motion and the Maxwell stresses resulting from the charge double-layer screening effect for a full cycle motion of the AFM tip in a non-contact mode imaging of the cell membrane.

scholarly journals Surface Forces between Nanomagnetite and Silica in Aqueous Ca2+ Solutions Studied with AFM Colloidal Probe Method

2020 ◽  
Vol 4 (3) ◽  
pp. 41
Author(s):  
Illia Dobryden ◽  
Elizaveta Mensi ◽  
Allan Holmgren ◽  
Nils Almqvist
Keyword(s):  
Iron Ore ◽  
Adhesion Force ◽  
Surface Forces ◽  
Adhesion Forces ◽  
Interaction Forces ◽  
Colloidal Probe ◽  
Force Microscopy ◽  
Atomic Force ◽  
Repulsive Forces ◽  
Qualitative Changes

Dispersion and aggregation of nanomagnetite (Fe3O4) and silica (SiO2) particles are of high importance in various applications, such as biomedicine, nanoelectronics, drug delivery, flotation, and pelletization of iron ore. In directly probing nanomagnetite–silica interaction, atomic force microscopy (AFM) using the colloidal probe technique has proven to be a suitable tool. In this work, the interaction between nanomagnetite and silica particles was measured with AFM in aqueous Ca2+ solution at different pH levels. This study showed that the qualitative changes of the interaction forces with pH and Ca2+ concentrations were consistent with the results from zeta-potential measurements. The repulsion between nanomagnetite and silica was observed at alkaline pH and 1 mM Ca2+ concentration, but no repulsive forces were observed at 3 mM Ca2+ concentration. The interaction forces on approach were due to van der Waals and electrical double-layer forces. The good fitting of experimental data to the DLVO model and simulations supported this conclusion. However, contributions from non-DLVO forces should also be considered. It was shown that an increase of Ca2+ concentration from 1 to 3.3 mM led to a less pronounced decrease of adhesion force with increasing pH. A comparison of measured and calculated adhesion forces with a few contact mechanics models demonstrated an important impact of nanomagnetite layer nanoroughness.

Polyelectrolyte multilayers under compression: concurrent osmotic stress and colloidal probe atomic force microscopy

Soft Matter ◽  
2018 ◽  
Vol 14 (6) ◽  
pp. 961-968 ◽  
Author(s):  
Bo Wu ◽  
Guangming Liu ◽  
Guangzhao Zhang ◽  
Vincent S. J. Craig
Keyword(s):  
Atomic Force Microscopy ◽  
Osmotic Stress ◽  
Surface Forces ◽  
Polyelectrolyte Multilayers ◽  
Colloidal Probe ◽  
Force Microscopy ◽  
Colloidal Interactions ◽  
Atomic Force

Colloidal interactions have been characterised using both osmotic stress and surface forces.

Probing the effect of superplasticizer adsorption on the surface forces using the colloidal probe AFM technique

2005 ◽  
Vol 35 (1) ◽  
pp. 133-140 ◽  
Author(s):  
Annika Kauppi ◽  
Karin M. Andersson ◽  
Lennart Bergström
Keyword(s):  
Surface Forces ◽  
Colloidal Probe

scholarly journals Investigation of Surface Forces in Highly Viscous Polymer Solutions by Colloidal Probe AFM Method

2015 ◽  
Vol 52 (4) ◽  
pp. 188-195
Author(s):  
Takeshi Mori ◽  
Yuichi Iwakata ◽  
Tomohiro Matsuda ◽  
Hidehiro Kamiya
Keyword(s):  
Polymer Solutions ◽  
Surface Forces ◽  
Colloidal Probe ◽  
Viscous Polymer

Decoration of specific sites on freeze-fractured membranes

1978 ◽  
Vol 36 (2) ◽  
pp. 140-141
Author(s):  
H. Gross ◽  
H. Moor
Keyword(s):  
Pure Water ◽  
Freeze Fracture ◽  
Chemical Properties ◽  
Surface Forces ◽  
Sulfate Pentahydrate ◽  
Copper Sulfate Pentahydrate ◽  
Physico Chemical ◽  
Water Of Hydration ◽  
Small Container ◽  
Binding Forces

Fracturing under ultrahigh vacuum (UHV, p ≤ 10-9 Torr) produces membrane fracture faces devoid of contamination. Such clean surfaces are a prerequisite foe studies of interactions between condensing molecules is possible and surface forces are unequally distributed, the condensate will accumulate at places with high binding forces; crystallites will arise which may be useful a probes for surface sites with specific physico-chemical properties. Specific “decoration” with crystallites can be achieved nby exposing membrane fracture faces to water vopour. A device was developed which enables the production of pure water vapour and the controlled variation of its partial pressure in an UHV freeze-fracture apparatus (Fig.1a). Under vaccum (≤ 10-3 Torr), small container filled with copper-sulfate-pentahydrate is heated with a heating coil, with the temperature controlled by means of a thermocouple. The water of hydration thereby released enters a storage vessel.

Ultrastructural Changes of Canine Kidneys During 24-Hour Perfusion on a LI-400 Preservation System

1971 ◽  
Vol 29 ◽  
pp. 316-317
Author(s):  
M. O. Magnusson ◽  
D. G. Osborne ◽  
T. Shimoji ◽  
W. S. Kiser ◽  
W. A. Hawk
Keyword(s):  
Electron Microscopy ◽  
Electrolyte Solution ◽  
Ultrastructural Changes ◽  
Midline Incision ◽  
Short Term ◽  
Pentobarbital Anesthesia ◽  
Pulsatile Perfusion

Short term experimental and clinical preservation of kidneys is presently best accomplished by hypothermic continuous pulsatile perfusion with cryoprecipitated and millipore filtered plasma. This study was undertaken to observe ultrastructural changes occurring during 24-hour preservation using the above mentioned method.A kidney was removed through a midline incision from healthy mongrel dogs under pentobarbital anesthesia. The kidneys were flushed immediately after removal with chilled electrolyte solution and placed on a LI-400 preservation system and perfused at 8-10°C. Serial kidney biopsies were obtained at 0-½-1-2-4-8-16 and 24 hours of preservation. All biopsies were prepared for electron microscopy. At the end of the preservation period the kidneys were autografted.

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