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Some surface-related aspects of the cleaning of new and reused stainless-steel surfaces fouled by protein
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
Adsorption of human carbonic anhydrase II onto silicon oxides surfaces : The effects of truncation in the N-terminal region
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 interactions in solution between nonionic surfactants and globular proteins: Effects on cloud point
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
Simple Models for Adsorption Kinetics and Their Correlation to the Adsorption of b-Lactoglobulin A and B
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
Removal of T4 Lysozyme from Silicon Oxide Surfaces by Sodium Dodecyl Sulphate (SDS) : A Comparison between Wild Type Protein and a Mutant with Lower Thermal Stability.
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 Two proteins were investigated, wild type T4 lysozyme and a mutant protein where isoleucine 3 had been replaced by tryptophan (tryptophan mutant).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 studies on the adsorption of human serum albumin (HSA) and anti-HSA to hydrophobic silicon
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
Adsorption of protein fractions from wheat onto methylated silica surfaces
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
Adsorption from lipase-surfactant solutions onto methylated silica surfaces
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
Removal of Lysozyme from Methylated Silica Surfaces by a Nonionic Surfactant Pentaethyleneglycol Mono n-Dodecyl Ether (C12E5)
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
β-Lactoglobulin fouling and its removal upon rinsing and by SDS as influenced by surface characteristics, temperature and adsorption time
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
Time and temperature aspects of β-lactoglobulin removal from methylated silica surfaces by sodium dodecyl sulphate
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
Competition Between Fibrinogen and a Nonionic Surfactant at Adsorption to a Wettability Gradient Surface
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
The adsorption of lysozyme to hydrophilic silicon oxide surfaces: comparison between experimental data and models for adsorption kinetics
The adsorption of lysozyme onto silicon oxide surfaces was investigated using in situ ellipsometry. Both the adsorption kinetics and the desorption upon rinsing with buffer were followed and the experimental data obtained were compared to models for adsorption kinetics. The effects of concentration, time of adsorption, and ionic strength were studied. The adsorbed amount reached a semiplateau with
The Influence of Net Charge and Charge Location on Adsorption and Dodecyltrimethylammonium Bromide-Mediated Elutability of Bacteriophage T4 Lysozyme at Silica Surfaces
The effect of net charge and charge location on the adsorption and dodecyltrimethylammonium bromide (DTAB)-mediated elutability of bacteriophage T4 lysozyme was monitored at hydrophilic and hydrophobic silica surfaces with in situ ellipsometry. Mutant lysozymes were produced by substitution of selected lysine residues with glutamic acid, each substitution thus decreasing the net charge of the prot
Structural Stability Effects on Adsorption and Dodecyltrimethylammonium Bromide-Mediated Elutability of Bacteriophage T4 Lysozyme at Silica Surfaces
The effect of structural stability on the adsorption and dodecyltrimethylammonium bromide (DTAB)-mediated elutability of bacteriophage T4 lysozyme was monitored at hydrophilic and hydrophobic silica surfaces with in situ ellipsometry. Mutant lysozymes were produced by substitution of the isoleucine at amino acid position three, yielding a set of proteins with values of ΔGunfolding ranging from 1.2
Preparation and Characterization of Starch Particles for Use in Pickering Emulsions
Particle-stabilized emulsions, called Pickering emulsions, can be produced by using starch particles. In this work we studied how the properties of the starch particles affect the droplet size and creaming of such emulsions. In the study, various sizes of starch particles were generated by two different methods and used to stabilize Pickering emulsions. Sedimentation according to Stokes’ law was u
Changera in starch structure during manufacturing of starch microspheres for use in parenteral drug formulations: Effects of temperature treatment
Starch microspheres were produced by emulsification of a starch dispersion in an aqueous polyethylene glycol (PEG) solution. Crystalline/ordered structure was formed within these starch droplets during incubation at 6 °C for 25 h followed by incubation at 37 °C for 28 h. After incubation at 37 °C the crystalline structure in the samples was of type B. The crystallization process of microspheres wa