Filtyp
The captive bubble method was used to describe the wetting characteristics of a number of commercial ultrafiltration (UF) membranes. The membranes belonged to one of two homologous (same material, different cut-off) series made by the same manufacturer. One series was made of polysulphone and the other one of cellulose triacetate. The porosimetric characteristics of the membranes have also been me
The adsorption from a mixture of SDS and β-Lactoglobulin, 1:5 (), onto a methylated silica surface was studied in situ by ellipsometry. The amounts adsorbed from different concentrations of the mixture, at pH 7, were compared with those adsorbed from the corresponding pure SDS and β-lactoglobulin solutions. At high concentrations of the mixture, where the CMC of SDS is approached or exceeded, the The adsorption from a mixture of SDS and β-Lactoglobulin, 1:5 (), onto a methylated silica surface was studied in situ by ellipsometry. The amounts adsorbed from different concentrations of the mixture, at pH 7, were compared with those adsorbed from the corresponding pure SDS and β-lactoglobulin solutions. At high concentrations of the mixture, where the CMC of SDS is approached or exceeded, the
The elutability of adsorbed fibrinogen by cationic surfactants of different chain lengths (dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, cetyltrimethylammonium bromide), and an anionic surfactant (sodium dodecyl sulphate (SDS)) was studied using in situ ellipsometry. The concentrations of the surfactants were twice the CMC in water and for fibrinogen, 0.4 mg ml−1. The inve
The interaction between a cationic surfactant (dodecyltrimethylammonium bromide) and six model proteins adsorbed on to methylated silica and silica surfaces was investigated. The proteins were bovine serum albumin, cytochrome c, β-lactoglobulin, α-lactalbumin, lysozyme and ovalbumin. The adsorption of the proteins at pH 7 and their subsequent removal by surfactant were studied by in situ ellipsome
The change in the secondary structure of T4 lysozyme upon adsorption to silica particles was studied with circular dichroism. Two different mutants of the protein along with the wild type were investigated. The mutants differ from wild type by substitution of isoleucine for cysteine or tryptophan at position 3 and were chosen to represent a range of stability as quantified by their energies of the
Adsorption onto hydrophobic surfaces of α-, β-, γ-, and ω-gliadins from the wheat variety Chinese Spring was studied by means of in situ ellipsometry. Most measurements were conducted in 0·01m phosphate buffer, pH 6·0, with the protein concentrations 1, 5 and 25 μg/mL. The adsorbed amount varied between 1·3 and 11·4 mg/m2, which is high considering the low protein concentrations. The concentration
The adsorption of β-lactoglobulin to stainless steel and its subsequent removal were followed using in situ null ellipsometry. The influence of the surface pretreatment on the protein removal by the surfactant SDS and by sodium hydroxide was studied. All surfaces were precleaned in strongly alkaline solution. Some surfaces received no further pretreatment, while others were either passivated in ni
The adsorption of β-lactoglobulin to stainless steel and its subsequent alkali-induced removal were followed using ellipsometry. New steel samples differing in bulk composition, surface finish or chemical pretreatment were used. All surfaces were precleaned in strongly alkaline solution, and some were subsequently passivated in nitric acid. Furthermore, on surfaces differing in pretreatment measur
The adsorption of human carbonic anhydrase II pseudo-wild type (HCAIIpwt) and an N-terminally truncated version thereof onto silica surfaces were studied. The amount adsorbed and the adsorption kinetics were measured using in situ ellipsometry. A substantial difference was seen between the two proteins. The adsorbed amount of the truncated version (2.53 mg/m2) indicates an end-on orientation, whil
The effects of protein addition (lysozyme and bovine serum albumin) on surface tension reduction and cloud point of a surfactant (Pentaethyleneglycol Mono n-Dodecyl Ether (C12E5)) were studied. The minimum surface tension was in all cases 27 mN/m but was reached at a higher surfactant concentration for the BSA/ C12E5 solution than for the pure surfactant or the lysozyme/surfactant mixture, indicat
A description of general models for adsorption kinetics is given. Combinations of the models are compared with adsorption data for the self-associating proteins β-lactoglobulin A and B, from Elofssonet al.(U. M. Elofsson, M. A. Paulsson, and T. Arnebrant,Langmuir,submitted). The adsorption onto methylated silica surfaces was measured by these authors by ellipsometry in phosphate buffer (0.01M,pH 7
The adsorption and surfactant induced removal of T4 lysozyme was studied by in situ ellipsometry. Two proteins were investigated, wild type T4 lysozyme and a mutant protein where isoleucine 3 had been replaced by tryptophan (tryptophan mutant). The amount adsorbed is higher for the wild type protein than for the tryptophan mutant at the protein concentration employed (0.2 mg/mL). Furthermore, the
Ellipsometry and radio-labelling techniques were employed to study the deposition of human serum albumin (HSA) followed by excess of mono- or polyclonal anti-HSA to methylated silicon. Adsorbed HSA, and [HSA-monoclonal anti-HSA] layers were rapidly removed by 0.1-0.5% SDS, but [HSA-polyclonal anti-HSA] layers were not. The results suggest that antigens and polyclonal antibodies crosslink on surfac
The kinetics of the sequential adsorption of gliadins and water-soluble fraction (WSF) from the wheat variety Kosack onto hydrophobic silica (methylated silica) surfaces were studied by in situ ellipsometry. The measurements were made in water and in 0.01M acetate buffer, pH 4.0 and 5.0, with and without 0.1M NaCl. The concentration of gliadins and WSF was 1.7 µg/ml. The adsorption of gliadins in
In situ ellipsometry was used to study the adsorption/desorption of highly purified lipase from Humicola lanuginosa in mixtures with surfactants, at the solid/liquid interface. The effect of the surfactant was studied both when it was allowed to adsorb in mixture with lipase and when added after lipase adsorption. Silica surfaces, totally or partially methylated, were used and the surfactants wereIn situ ellipsometry was used to study the adsorption/desorption of highly purified lipase from Humicola lanuginosa in mixtures with surfactants, at the solid/liquid interface. The effect of the surfactant was studied both when it was allowed to adsorb in mixture with lipase and when added after lipase adsorption. Silica surfaces, totally or partially methylated, were used and the surfactants were
The removal of lysozyme adsorbed to a hydrophobic surface by a non-ionic surfactant, C12E5, was investigated using in situ ellipsometry. Both the adsorption and removal of protein were studied at different protein and surfactant concentrations. The surfaces used were methylated silica surfaces and the experiments were carried out at pH 5.6 in 0.01 M NaCl solution. The adsorption isotherm of lysozyThe removal of lysozyme adsorbed to a hydrophobic surface by a non-ionic surfactant, C12E5, was investigated using in situ ellipsometry. Both the adsorption and removal of protein were studied at different protein and surfactant concentrations. The surfaces used were methylated silica surfaces and the experiments were carried out at pH 5.6 in 0.01 M NaCl solution. The adsorption isotherm of lysozy
The extensive fouling common in the food industry puts high demands on equipment cleaning. The adsorption of β-lactoglobulin and its removal by the anionic surfactant sodium dodecyl sulphate (SDS) were followed at pH 6.0 using in situ ellipsometry. Hydrophilic chromium oxide and stainless steel together with hydrophobic methylated silica were studied at different temperatures. Differences between
The adsorption of β-lactoglobulin onto methylated silica surfaces and the subsequent protein removal by the anionic surfactant sodium dodecyl sulphate (SDS) were followed using in-situ ellipsometry. Experiments were performed at pH 6.0 in phosphate-buffered saline solution. Parameters varied include temperature, length of time for protein adsorption from solution and surface residence time of β-la
The competition between mixtures of fibrinogen and a non-ionic surfactant (C12E5) with respect to adsorption onto a wettability gradient solid surface was studied by the use of ellipsometry. The effects of surface hydrophobicity and surfactant association were investigated. Furthermore the effect of clouding of the surfactant was studied by performing measurements at temperatures above and below t
