scholarly journals Immobilization of immunoglobulins on silica surfaces. Kinetics of immobilization and influence of ionic strength

1985 ◽  
Vol 227 (2) ◽  
pp. 373-378 ◽  
Author(s):  
U Jönsson ◽  
M Malmqvist ◽  
I Rönnberg
Keyword(s):  
Ionic Strength ◽  
Surface Chemistry ◽  
Solid Surface ◽  
Surface Concentration ◽  
Covalent Attachment ◽  
Exchange Reactions ◽  
Silica Surfaces ◽  
Measuring Devices ◽  
Different Types ◽  
Kinetics Of

The kinetics of, and the influence of ionic strength on, the immobilization of rabbit immunoglobulin G (IgG) on different types of well-characterized silica surfaces were investigated. Adsorptive immobilization was compared with covalent attachment via thiol-disulphide exchange reactions. The amount of immobilized IgG on five different types of silica surfaces as a function of IgG concentration, at two different ionic strengths, was determined. The IgG-solid-surface interaction involved different types of interaction forces, depending on the surface chemistry of the solid surface. The solid-surface chemistry is an important parameter determining the immobilized amount of IgG. When conditions for covalent attachment of IgG to the surfaces were fulfilled, the IgG showed high affinity and the immobilized amount of IgG showed a fast saturation. Changes in ionic strength showed no significant influence on the kinetics of immobilization on these surfaces. The amount of covalently attached IgG was partially ionic-strength-dependent, indicating that adsorptive interactions were involved. The results are of fundamental interest for the development of new immunosensors based on surface-concentration-measuring devices.

scholarly journals Immobilization of immunoglobulins on silica surfaces. Stability

1985 ◽  
Vol 227 (2) ◽  
pp. 363-371 ◽  
Author(s):  
U Jönsson ◽  
M Malmqvist ◽  
I Rönnberg
Keyword(s):  
Covalent Binding ◽  
Chemical Vapour ◽  
Surface Concentration ◽  
Solid Surfaces ◽  
Exchange Reactions ◽  
Covalent Bonds ◽  
Silica Surfaces ◽  
Chemically Modified Silica ◽  
Reactive Groups ◽  
Covalently Bound

The development of new immunosensors based on surface-concentration-measuring devices requires a stable and reproducible immobilization of antibodies on well-characterized solid surfaces. We here report on the immobilization of immunoglobulin G (IgG) on chemically modified silica surfaces. Such surfaces may be used in various surface-oriented analytical methods. Reactive groups were introduced to the silica surfaces by chemical-vapour deposition of silane. The surfaces were characterized by ellipsometry, contact-angle measurements and scanning electron microscopy. IgG covalently bound by the use of thiol-disulphide exchange reactions, thereby controlling the maximum number of covalent bonds to the surface, was compared with IgG adsorbed on various silica surfaces. This comparison showed that the covalently bound IgG has a superior stability when the pH was lowered or incubation with detergents, urea or ethylene glycol was carried out. The result was evaluated by ellipsometry, an optical technique that renders possible the quantification of amounts of immobilized IgG. The results outline the possibilities of obtaining a controlled covalent binding of biomolecules to solid surfaces with an optimal stability and biological activity of the immobilized molecules.

The Properties of Liquid Phase Embryos at the Intersections of Plane Solid Surfaces

1952 ◽  
Vol 5 (4) ◽  
pp. 618
Author(s):  
RG Wylie
Keyword(s):  
Contact Angle ◽  
Solid Surface ◽  
Contact Angles ◽  
Solid Surfaces ◽  
Boundary Line ◽  
Pure Liquid ◽  
Liquid Droplets ◽  
Free Energies ◽  
Different Types ◽  
Kinetics Of

In order to calculate the probabilities of nucleation of liquid droplets at different types of site on a solid surface, the properties of embryonic droplets which may exist in complete thermodynamic equilibrium at those sites must be known. The general properties of liquid embryos formed on a plane solid surface, or at lines or points of intersection of plane solid surfaces, are considered. It is shown that, although an edge free energy associated with the boundary line may substantially affect the properties -of embryos at small contact angles, the effect is probably not large, for embryos of the sizes of interest, when the contact angle is larger than about π/4. The areas, volumes, total surface free energies, and free energies of formation are found for embryos at these sites as functions of the contact angle, any edge free energies being neglected. The extension to the formation of bubbles at plane solid surfaces in a pure liquid is indicated. The results are applied in a following paper to the kinetics of condensation of a vapour at an imperfect crystalline surface.

Kinetics of self-exchange of bis(1,4,7-trithiacyclononane)iron(III)/(II) in acetonitrile and in acidic aqueous solution

1990 ◽  
Vol 68 (12) ◽  
pp. 2228-2233 ◽  
Author(s):  
Hideo Doine ◽  
Thomas W. Swaddle
Keyword(s):  
Aqueous Solution ◽  
Electron Transfer ◽  
Ionic Strength ◽  
Line Broadening ◽  
Acidic Water ◽  
Exchange Reactions ◽  
Acidic Aqueous Solution ◽  
Spontaneous Reduction ◽  
Kinetics Of ◽  
C Nmr

The rate constant kex of the [Formula: see text] self-exchange reaction cannot be measured in most common solvents because of spontaneous reduction of the [Formula: see text] ion, which is also sensitive to photolysis by visible light. However, in CD3CN at −41 to −19 °C, reproducible proton-decoupled 13C NMR line broadening measurements are possible, and give kex = (5.3 ± 0.3) × 104 kg mol−1s−1 at 0 °C, ΔH* = 10.3 ± 1.8 kJ mol−1, and ΔS* = −116 ± 7 J K−1 mol−1, at ionic strength I = 0.1 mol kg−1. Proton NMR line broadening experiments are marginally practicable in very acidic water (2.0 mol kg−1 D2SO4/D2O) near 0 °C, and give kex = 3.2 × 106 kg mol−1 s−1 at 1 °C. The relative kex values of these and other low-spin/low-spin FeIII/II self-exchange reactions follow the predictions of the Marcus–Hush theory at least qualitatively. The effect of ionic strength, however, is less than predicted, probably because of the formation of less reactive anion–cation pairs. Keywords: electron transfer kinetics, crown thioether complexes.

Antibacterial properties and release kinetics of chlorhexidine diacetate from montmorillonite and palygorskite clays

2019 ◽  
Vol 34 (8) ◽  
pp. 1052-1058
Author(s):  
Héctor A Lobato-Aguilar ◽  
Gabriel Lizama-Uc ◽  
Jorge A Uribe-Calderon ◽  
Juan Cauich-Rodriguez ◽  
Nayeli Rodriguez-Fuentes ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Release Kinetics ◽  
Antibacterial Properties ◽  
Luria Broth ◽  
Exchange Reactions ◽  
Order Model ◽  
Modified Montmorillonite ◽  
Different Types ◽  
Bacterial Growth Inhibition ◽  
Kinetics Of

Organoclays were prepared by means of cation-exchange reactions using different concentrations of chlorhexidine diacetate and two different types of clays: montmorillonite and palygorskite. The antibacterial activity against Escherichia coli was evaluated by means of disk diffusion tests as well as through bacterial growth inhibition (monitored by optical density measurements) in Luria broth media. Results indicate that modified palygorskites showed a greater antibacterial activity than those exhibited by modified montmorillonite, as latter only displayed antibacterial properties at the highest chlorhexidine diacetate loading. Modeling of chlorhexidine release was also performed and the models best described the drug release phenomena depended on the type of clay; being the Higuchi model and Korsemeyer–Peppas model for montmorillonite, whereas the zero-order model and Korsemeyer–Peppas model for palygorskite.

Study of the Cu(II) removal from aqueous solutions by adsorption on titania

2013 ◽  
Vol 12 (3) ◽  
pp. 239-247
Keyword(s):  
Heavy Metals ◽  
Ionic Strength ◽  
Toxic Metals ◽  
Low Cost ◽  
Lateral Interaction ◽  
Tio2 Surface ◽  
High Toxicity ◽  
Removal Of Heavy Metals ◽  
Solution Parameters ◽  
Kinetics Of

The removal of heavy metals from wastewaters is a matter of paramount importance due to the fact that their high toxicity causes major environmental pollution problems. One of the most efficient, applicable and low cost methods for the removal of toxic metals from aqueous solutions is that of their adsorption on an inorganic adsorbent. In order to achieve high efficiency, it is important to understand the influence of the solution parameters on the extent of the adsorption, as well as the kinetics of the adsorption. In the present work, the adsorption of Cu(II) species onto TiO2 surface was studied. It was found that the adsorption is a rapid process and it is not affected by the value of ionic strength. In addition, it was found that by increasing the pH, the adsorbed amount of Cu2+ ions and the value of the adsorption constant increase, whereas the value of the lateral interaction energy decreases.

Studies on the Behavior Some Paints in Electro-insulating Fluid Based on Vegetable Esters

2018 ◽  
Vol 69 (5) ◽  
pp. 1139-1144
Author(s):  
Iosif Lingvay ◽  
Adriana Mariana Bors ◽  
Livia Carmen Ungureanu ◽  
Valerica Stanoi ◽  
Traian Rus
Keyword(s):  
Structural Changes ◽  
Oxidation Processes ◽  
High Oleic ◽  
Painting Materials ◽  
Insulating Paper ◽  
Different Types ◽  
Mechanism And Kinetics ◽  
Kinetics Of ◽  
Natural Ester

For the purpose of using three different types of painting materials for the inner protection of the transformer vats, their behavior was studied under actual conditions of operation in the transformer (thermal stress in electro-insulating fluid based on the natural ester in contact with copper for electro-technical use and electro-insulating paper). By comparing determination of the content in furans products (HPLC technique) and gases formed (by gas-chromatography) in the electro-insulating fluid (natural ester with high oleic content) thermally aged at 130 �C to 1000 hours in closed glass vessels, it have been found that the presence the investigated painting materials lead to a change in the mechanism and kinetics of the thermo-oxidation processes. These changes are supported by oxygen dissolved in oil, what leads to decrease both to gases formation CO2, CO, H2, CH4, C2H4 and C2H6) and furans products (5-HMF, 2-FOL, 2 -FAL and 2-ACF). The painting materials investigated during the heat treatment applied did not suffer any remarkable structural changes affecting their functionality in the electro-insulating fluid based on vegetable esters.

Kinetics of hydrolysis of peroxodisulphate ions in acidic medium to peroxomonosulphuric acid

1981 ◽  
Vol 46 (5) ◽  
pp. 1229-1236 ◽  
Author(s):  
Jan Balej ◽  
Milada Thumová
Keyword(s):  
Ionic Strength ◽  
Rate Constants ◽  
Acidic Medium ◽  
Measured Data ◽  
Molar Ratios ◽  
Starting Solution ◽  
Kinetics Of Hydrolysis ◽  
Rate Of Hydrolysis ◽  
Kinetics Of ◽  
Hydrolysis Of

The rate of hydrolysis of S2O82- ions in acidic medium to peroxomonosulphuric acid was measured at 20 and 30 °C. The composition of the starting solution corresponded to the anolyte flowing out from an electrolyser for production of this acid or its ammonium salt at various degrees of conversion and starting molar ratios of sulphuric acid to ammonium sulphate. The measured data served to calculate the rate constants at both temperatures on the basis of the earlier proposed mechanism of the hydrolysis, and their dependence on the ionic strength was studied.

Kinetics and Mechanism of Hexachloroiridate(IV) Oxidation of Arsenic(III) in Acidic Perchlorate Solutions

1992 ◽  
Vol 57 (7) ◽  
pp. 1451-1458 ◽  
Author(s):  
Refat M. Hassan
Keyword(s):  
Ionic Strength ◽  
Fractional Order ◽  
Activation Parameters ◽  
Order Reaction ◽  
First Order Reaction ◽  
Intermediate Complex ◽  
Constant Ionic Strength ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Kinetics Of

The kinetics of oxidation of arsenic(III) by hexachloroiridate(IV) at lower acid concentrations and at constant ionic strength of 1.0 mol dm-3 have been investigated spectrophotometrically. A first-order reaction in [IrCl62-] and fractional order with respect to arsenic(III) have been observed. A kinetic evidence for the formation of an intermediate complex between the hydrolyzed arsenic(III) species and the oxidant was presented. The results showed that decreasing the [H+] is accompanied by an appreciable acceleration of the rate of oxidation. The activation parameters have been evaluated and a mechanism consistent with the kinetic results was suggested.

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