The Experts below are selected from a list of 33 Experts worldwide ranked by ideXlab platform

P. Dokić - One of the best experts on this subject based on the ideXlab platform.

  • Influence of Surfactant-Protein Interaction on the Wall Structure of Microcapsules
    Journal of Colloid and Interface Science, 1993
    Co-Authors: Verica J. Sovilj, Ljubomir Djaković, P. Dokić
    Abstract:

    Abstract Adsorption from solutions of sodium dodecylbenzene sulfonate (SDBS) and gelatin mixtures, on the dispersed paraffin oil droplets surface has been investigated. The adsorbed amount of SDBS and gelatin was estimated by the concentration determinations in the continuous phase, after the oil droplets were removed by centrifugation. From adsorption data, total adsorbed mass of SDBS and gelatin per unit surface area, adsorbed mass of each component, and moles of adsorbed SDBS per gram of gelatin have been calculated. From the prepared emulsions, containing SDBS, gelatin, and formaldehyde (as a crosslinking agent), microcapsules have been produced by the spray drying method, and stability of microcapsules was observed during six months of storage at room temperature. It was possible to obtain stable microcapsules only when emulsions were prepared with preadsorbed SDBS. It was found that stability of microcapsules depended not only on the amount of SDBS and gelatin adsorbed, but also on the type of molecular Interaction. The stable microcapsules were formed when the adsorbed mass of gelatin was greater than that of SDBS i.e., when an ionic mechanism of Interaction in the adsorption layer was present. With increasing adsorption of the SDBS molecule, a hydrophobic mechanism of Interaction appears, which changes the conformational properties of gelatin molecules and reduces the stability of microcapsules.

Verica J. Sovilj - One of the best experts on this subject based on the ideXlab platform.

  • Influence of Surfactant-Protein Interaction on the Wall Structure of Microcapsules
    Journal of Colloid and Interface Science, 1993
    Co-Authors: Verica J. Sovilj, Ljubomir Djaković, P. Dokić
    Abstract:

    Abstract Adsorption from solutions of sodium dodecylbenzene sulfonate (SDBS) and gelatin mixtures, on the dispersed paraffin oil droplets surface has been investigated. The adsorbed amount of SDBS and gelatin was estimated by the concentration determinations in the continuous phase, after the oil droplets were removed by centrifugation. From adsorption data, total adsorbed mass of SDBS and gelatin per unit surface area, adsorbed mass of each component, and moles of adsorbed SDBS per gram of gelatin have been calculated. From the prepared emulsions, containing SDBS, gelatin, and formaldehyde (as a crosslinking agent), microcapsules have been produced by the spray drying method, and stability of microcapsules was observed during six months of storage at room temperature. It was possible to obtain stable microcapsules only when emulsions were prepared with preadsorbed SDBS. It was found that stability of microcapsules depended not only on the amount of SDBS and gelatin adsorbed, but also on the type of molecular Interaction. The stable microcapsules were formed when the adsorbed mass of gelatin was greater than that of SDBS i.e., when an ionic mechanism of Interaction in the adsorption layer was present. With increasing adsorption of the SDBS molecule, a hydrophobic mechanism of Interaction appears, which changes the conformational properties of gelatin molecules and reduces the stability of microcapsules.

Ljubomir Djaković - One of the best experts on this subject based on the ideXlab platform.

  • Influence of Surfactant-Protein Interaction on the Wall Structure of Microcapsules
    Journal of Colloid and Interface Science, 1993
    Co-Authors: Verica J. Sovilj, Ljubomir Djaković, P. Dokić
    Abstract:

    Abstract Adsorption from solutions of sodium dodecylbenzene sulfonate (SDBS) and gelatin mixtures, on the dispersed paraffin oil droplets surface has been investigated. The adsorbed amount of SDBS and gelatin was estimated by the concentration determinations in the continuous phase, after the oil droplets were removed by centrifugation. From adsorption data, total adsorbed mass of SDBS and gelatin per unit surface area, adsorbed mass of each component, and moles of adsorbed SDBS per gram of gelatin have been calculated. From the prepared emulsions, containing SDBS, gelatin, and formaldehyde (as a crosslinking agent), microcapsules have been produced by the spray drying method, and stability of microcapsules was observed during six months of storage at room temperature. It was possible to obtain stable microcapsules only when emulsions were prepared with preadsorbed SDBS. It was found that stability of microcapsules depended not only on the amount of SDBS and gelatin adsorbed, but also on the type of molecular Interaction. The stable microcapsules were formed when the adsorbed mass of gelatin was greater than that of SDBS i.e., when an ionic mechanism of Interaction in the adsorption layer was present. With increasing adsorption of the SDBS molecule, a hydrophobic mechanism of Interaction appears, which changes the conformational properties of gelatin molecules and reduces the stability of microcapsules.

F. Pitré - One of the best experts on this subject based on the ideXlab platform.

  • Structural study of AOT reverse micelles containing native or modified proteins: influence of surfactant-enzyme Interaction☆
    Colloids and Surfaces B: Biointerfaces, 1995
    Co-Authors: M. P. Pileni, G. Cassin, F. Michel, F. Pitré
    Abstract:

    Abstract In this paper, the solubilization effect of different proteins in sodium di(2-ethylhexyl)sulfosuccinate (AOT) reverse micelles is studied. From results obtained with chemically modified proteins, it is shown that the nature of the Surfactant-Protein Interaction controls the intermicellar potential, not the location of the proteins within the droplets. By binding hydrophobic molecules onto the surface of α-chymotrypsin and ribonuclease, we force these hydrophobic enzymes to interact, via hydrophobic forces, with the droplet's interface. Small-angle X-ray scattering (SAXS) and conductivity measurements suggest that modification of the intermicellar potential is not required when the enzymes are modified. Conversely, electrostatic forces play an important role, as is observed using cytochrome c and its derivatives differing in their superficial charge.

José A. Teruel - One of the best experts on this subject based on the ideXlab platform.

  • Interaction of a dirhamnolipid biosurfactant with sarcoplasmic reticulum calcium ATPase (SERCA1a).
    Archives of biochemistry and biophysics, 2021
    Co-Authors: Alfonso Oliva, Scheherezade García-carrillo, Antonio Ortiz, Francisco J. Aranda, José A. Teruel
    Abstract:

    Abstract The Interaction of a dirhamnolipid biosurfactant secreted by Pseudomonas aeruginosa with calcium ATPase from sarcoplasmic reticulum (SR) was studied by means of different approaches, such as enzyme activity, fluorescence spectroscopy, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and molecular docking simulations. The ATP hydrolysis activity was fully inhibited by incubation with dirhamnolipid (diRL) up to 0.1 mM concentration, corresponding to a surfactant concentration below membrane solubilization threshold. Surfactant-Protein Interaction induced conformational changes in the protein observed by an increase in the accessibility of tryptophan residues to the aqueous phase and by changes in the secondary structure of the protein as seen by fluorescence and FTIR spectroscopy. As a consequence, the protein become more unstable and denatured at lower temperatures, as seen by enzyme activity and DSC studies. Finally, these results were explained at molecular level throughout molecular docking simulations. It is concluded that there is a specific dirhamnolipid-protein Interaction not related to the surface activity of the surfactant but to the particular physicochemical properties of the biosurfactant molecule.