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  • 1.
    Bahmanzadeh, Safiyeh
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Analytical Research Laboratory, Department of Chemistry, University of Sistan and Baluchestan, P.O. Box 98135-674, Zahedan, Iran.
    Ruzgas, Tautgirdas
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Sotres, Javier
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Proteolytic degradation of gelatin-tannic acid multilayers2018In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 526, p. 244-252Article in journal (Refereed)
    Abstract [en]

    Hypothesis Gelatin is one of the most popular constituents of biodegradable/edible films. Because of its poor mechanical properties, it typically needs to be cross-linked. In this regard, the use of tannic acid has attracted significant interest. Whereas the biodegradability of gelatin is well established, little is known on how different crosslinking methods affect biodegradability. In most cases, the ionic strength at which protein films are grown has a drastic effect on their structure. Thus, it is expected that by controlling the ionic strength during the growth of cross-linked gelatin films it should be possible to tune the access to relevant cleavage sites by proteases and, therefore, their biodegradability. Experiments Gelatin-tannic acid were grown at different ionic strengths by means of the layer-by-layer self-assembly method. The growth of these multilayers and their response to the presence of different proteases were monitored by means of Electrochemical Impedance Spectroscopy and Quartz Crystal Microbalance with Dissipation. Findings Gelatin-tannic acid multilayers grown at low ionic strength exhibited a swollen structure that allowed easy access to their cleavage sites by proteases. Multilayers formed at physiological ionic strength exhibited a compacter structure, which limited their proteolytic degradation.

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  • 2.
    Barrantes, Alejandro
    et al.
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Santos, Olga
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Sotres, Javier
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Arnebrant, Thomas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Influence of pH on the build-up of poly-L-lysine/heparin multilayers2012In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 388, no 1, p. 191-200Article in journal (Refereed)
    Abstract [en]

    The effect of pH on the build-up-of polyelectrolyte multilayers, PEMs, composed by poly-L-lysine and heparin onto two different substrates, silica and gold, has been studied by means of ellispmetry and quartz crystal microbalance with dissipation, QCM-D. Ellipsometry results indicate that the dry mass grows exponentially with the number of layers, and that this amount is larger as the pH values are raised. From QCM-D data the viscoelastic properties of the multilayered structure have been obtained. These data reflect that PEMs become more viscoelastic as the pH values are increased for silica substrates, while for gold the highest viscoelastic behavior is obtained at neutral pH and the elastic behavior becomes dominant as the pH is further increased or decreased. By combining these two surface techniques it has been also possible to determine the solvent content in the multilayers and reach a deeper understanding of the internal structure.

  • 3.
    Barrantes, Alejandro
    et al.
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Department of Biomaterials, Institute of Clinical Dentistry, University of Oslo, P.O. Box 1109 Blindern, 0317 Oslo, Norway.
    Wengenroth, Jonas
    Department of Biomaterials, Institute of Clinical Dentistry, University of Oslo, P.O. Box 1109 Blindern, 0317 Oslo, Norway.
    Arnebrant, Thomas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Haugen, Håvard J.
    Department of Biomaterials, Institute of Clinical Dentistry, University of Oslo, P.O. Box 1109 Blindern, 0317 Oslo, Norway.
    Poly-L-lysine/heparin multilayer coatings prevent blood protein adsorption2017In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 485, p. 288-295Article in journal (Refereed)
    Abstract [en]

    The adsorption of blood proteins, serum albumin (BSA), immunoglobulin G (IgG) and fibrinogen (FGN), onto model SiO2 planar surfaces coated with poly-L-lysine/heparin multilayers (PLL/HEP) has been investigated by means of ellipsometry and quartz crystal microbalance with dissipation. Aiming at the development of low fouling coatings, this study has been focused on the effects that the number of layers and the type of polyelectrolyte present on the topmost layer have on the adsorption of these proteins. The three proteins interact with PLL-ended coatings whereas HEP-ended coatings prevent the adsorption of both BSA and IgG and induce a decrease in the adsorbed amount of FGN, down to 0.4 mg/m(2) for three bilayers, as the number of PLL/HEP bilayers increases. These results suggest that heparin-ended multilayers prevent protein adsorption, which is an indicative of good blood compatibility. As a consequence we propose that PLL/HEP coatings could be used for the development of vascular medical devices. (C) 2016 Elsevier Inc. All rights reserved.

  • 4.
    Björklund, Sebastian
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Kocherbitov, Vitaly
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Water vapor sorption-desorption hysteresis in glassy surface films of mucins investigated by humidity scanning QCM-D2019In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 545, p. 289-300Article in journal (Refereed)
    Abstract [en]

    Hypothesis: Investigating the origin of water sorption-desorption hysteresis in glassy biopolymers is important for understanding the properties of biological barriers, such as the mucus epithelium. In general, hysteresis is a result of a complex interplay between diffusion of water and relaxation of the polymer matrix. Our hypothesis is that for thin films, typical for quartz crystal microbalance with dissipation monitoring (QCM-D) experiments performed in gas phase with defined relative humidity, the diffusion limitation is eliminated and hysteresis results only from relaxation of the polymer matrix. Experiments: We use a recently developed humidity scanning (HS) QCM-D method to obtain water sorption-desorption isotherms of mucin films under controlled conditions where water diffusion is not the limiting factor, neither in the vapor phase nor in the glassy mucin film. Findings: We present new results on the water sorption-desorption behavior of glassy mucin films with nanoscale thicknesses. Despite the fact that water diffusion is not the limiting factor, the sorption-desorption branches show clear hysteresis effects that are similar to those typically observed in bulk samples. The hydration-induced glass transition, resolved from monitoring the rheological behavior of the films, is shown to be in excellent agreement with the onset of the sorption-desorption hysteresis. We suggest that the hysteresis effect is related to a difference in dynamical and structural properties of the glassy materials depending on the hydration history of the films.

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  • 5.
    Björklund, Sebastian
    et al.
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö högskola, Biofilms Research Center for Biointerfaces.
    Quoc Dat, Pham
    Physical Chemistry, The Center for Chemistry and Chemical Engineering, Lund University, Box 124, SE-221 00 Lund, Sweden.
    Bastholm Jensen, Louise
    LEO Pharma A/S, Industriparken 55, DK-2750 Ballerup, Denmark.
    Østergaard Knudsen, Nina
    LEO Pharma A/S, Industriparken 55, DK-2750 Ballerup, Denmark.
    Dencker Nielsen, Lars
    LEO Pharma A/S, Industriparken 55, DK-2750 Ballerup, Denmark.
    Ekelund, Katarina
    LEO Pharma A/S, Industriparken 55, DK-2750 Ballerup, Denmark.
    Ruzgas, Tautgirdas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö högskola, Biofilms Research Center for Biointerfaces.
    Engblom, Johan
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö högskola, Biofilms Research Center for Biointerfaces.
    Sparr, Emma
    Physical Chemistry, The Center for Chemistry and Chemical Engineering, Lund University, Box 124, SE-221 00 Lund, Sweden.
    The effects of polar excipients transcutol and dexpanthenol on molecular mobility, permeability, and electrical impedance of the skin barrier2016In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 479, p. 207-220Article in journal (Refereed)
    Abstract [en]

    In the development of transdermal and topical products it is important to understand how formulation ingredients interact with the molecular components of the upper layer of the skin, the stratum corneum (SC), and thereby influence its macroscopic barrier properties. The aim here was to investigate the effect of two commonly used excipients, transcutol and dexpanthenol, on the molecular as well as the macroscopic properties of the skin membrane. Polarization transfer solid-state NMR methods were combined with steady-state flux and impedance spectroscopy measurements to investigate how these common excipients influence the molecular components of SC and its barrier function at strictly controlled hydration conditions in vitro with excised porcine skin. The NMR results provide completely new molecular insight into how transcutol and dexpanthenol affect specific molecular segments of both SC lipids and proteins. The presence of transcutol or dexpanthenol in the formulation at fixed water activity results in increased effective skin permeability of the model drug metronidazole. Finally, impedance spectroscopy data show clear changes of the effective skin capacitance after treatment with transcutol or dexpanthenol. Based on the complementary data, we are able to draw direct links between effects on the molecular properties and on the macroscopic barrier function of the skin barrier under treatment with formulations containing transcutol or dexpanthenol.

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  • 6.
    Boyd, Hannah
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Gonzalez-Martinez, Juan F
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Welbourn, Rebecca J L
    ISIS Facility, STFC, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, UK.
    Gutfreund, Philipp
    Institut Laue Langevin, 71 avenue des Martyrs, Grenoble 38000, France.
    Klechikov, Alexey
    Institut Laue Langevin, 71 avenue des Martyrs, Grenoble 38000, France; Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden.
    Robertsson, Carolina
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces.
    Wickström, Claes
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces.
    Arnebrant, Thomas
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Barker, Robert
    School of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NH, UK.
    Sotres, Javier
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    A comparison between the structures of reconstituted salivary pellicles and oral mucin (MUC5B) films.2021In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 584, p. 660-668, article id S0021-9797(20)31464-8Article in journal (Refereed)
    Abstract [en]

    HYPOTHESIS: Salivary pellicles i.e., thin films formed upon selective adsorption of saliva, protect oral surfaces against chemical and mechanical insults. Pellicles are also excellent aqueous lubricants. It is generally accepted that reconstituted pellicles have a two-layer structure, where the outer layer is mainly composed of MUC5B mucins. We hypothesized that by comparing the effect of ionic strength on reconstituted pellicles and MUC5B films we could gain further insight into the pellicle structure.

    EXPERIMENTS: Salivary pellicles and MUC5B films reconstituted on solid surfaces were investigated at different ionic strengths by Force Spectroscopy, Quartz Crystal Microbalance with Dissipation, Null Ellipsometry and Neutron Reflectometry.

    FINDINGS: Our results support the two-layer structure for reconstituted salivary pellicles. The outer layer swelled when ionic strength decreased, indicating a weak polyelectrolyte behavior. While initially the MUC5B films exhibited a similar tendency, this was followed by a drastic collapse indicating an interaction between exposed hydrophobic domains. This suggests that mucins in the pellicle outer layer form complexes with other salivary components that prevent this interaction. Lowering ionic strength below physiological values also led to a partial removal of the pellicle inner layer. Overall, our results highlight the importance that the interactions of mucins with other pellicle components play on their structure.

  • 7.
    Correa, Yubexi
    et al.
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Del Giudice, Rita
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Waldie, Sarah
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Life Sciences Group, Institut Laue Langevin, Grenoble F-38042, France; Partnership for Structural Biology, Grenoble F-38042, France.
    Thépaut, Michel
    Univ. Grenoble Alpes, CNRS, CEA, IBS, 71 avenue des Martyrs, F-38000 Grenoble, France.
    Micciula, Samantha
    Life Sciences Group, Institut Laue Langevin, Grenoble F-38042, France; Large Scale Structures, Institut Laue Langevin (ILL), Grenoble F-38042, France.
    Gerelli, Yuri
    Marche Polytechnic University, Department of Life and Environmental Sciences, Via Brecce Bianche 12, 60131 Ancona, Italy; CNR-ISC and Department of Physics, Sapienza University of Rome, Piazzale A. Moro 2, Rome, Italy.
    Moulin, Martine
    Life Sciences Group, Institut Laue Langevin, Grenoble F-38042, France; Partnership for Structural Biology, Grenoble F-38042, France.
    Delaunay, Clara
    Univ. Grenoble Alpes, CNRS, CEA, IBS, 71 avenue des Martyrs, F-38000 Grenoble, France.
    Fieschi, Franck
    Partnership for Structural Biology, Grenoble F-38042, France; Univ. Grenoble Alpes, CNRS, CEA, IBS, 71 avenue des Martyrs, F-38000 Grenoble, France; Institut universitaire de France (IUF), Paris, France.
    Pichler, Harald
    Austrian Centre of Industrial Biotechnology, Petersgasse 14, 8010 Graz, Austria; Graz University of Technology, Institute of Molecular Biotechnology, NAWI Graz, BioTechMed Graz, Petersgasse 14, 8010 Graz, Austria.
    Haertlein, Michael
    Life Sciences Group, Institut Laue Langevin, Grenoble F-38042, France; Partnership for Structural Biology, Grenoble F-38042, France.
    Forsyth, V Trevor
    Life Sciences Group, Institut Laue Langevin, Grenoble F-38042, France; Partnership for Structural Biology, Grenoble F-38042, France; Faculty of Medicine, Lund University, 22184 Lund, Sweden; LINXS Institute for Advanced Neutron and X-ray Science, Scheelevagen 19, 22370 Lund, Sweden.
    Le Brun, Anton
    National Deuteration Facility, Australian Nuclear Science and Technology Organization (ANSTO), New Illawarra Road, Lucas Heights, NSW 2234, Australia.
    Moir, Michael
    National Deuteration Facility, Australian Nuclear Science and Technology Organization (ANSTO), New Illawarra Road, Lucas Heights, NSW 2234, Australia.
    Russell, Robert A
    National Deuteration Facility, Australian Nuclear Science and Technology Organization (ANSTO), New Illawarra Road, Lucas Heights, NSW 2234, Australia.
    Darwish, Tamim
    National Deuteration Facility, Australian Nuclear Science and Technology Organization (ANSTO), New Illawarra Road, Lucas Heights, NSW 2234, Australia.
    Brinck, Jonas
    Karolinska Institute, Stockholm, Sweden.
    Wodaje, Tigist
    Karolinska Institute, Stockholm, Sweden.
    Jansen, Martin
    Institute of Clinical Chemistry and Laboratory Medicine, Medical Centre, University of Freiburg, Freiburg Im Breisgau, Germany.
    Martín, César
    Department of Molecular Biophysics, Biofisika Institute (University of Basque Country and Consejo Superior de Investigaciones Científicas (UPV/EHU, CSIC)), 48940 Leioa, Spain.
    Roosen-Runge, Felix
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Cárdenas, Marité
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Department of Molecular Biophysics, Biofisika Institute (University of Basque Country and Consejo Superior de Investigaciones Científicas (UPV/EHU, CSIC)), 48940 Leioa, Spain; School of Biological Sciences, Nanyang Technological University, Singapore; IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
    High-Density Lipoprotein function is modulated by the SARS-CoV-2 spike protein in a lipid-type dependent manner.2023In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 645, p. 627-638, article id S0021-9797(23)00736-1Article in journal (Refereed)
    Abstract [en]

    There is a close relationship between the SARS-CoV-2 virus and lipoproteins, in particular high-density lipoprotein (HDL). The severity of the coronavirus disease 2019 (COVID-19) is inversely correlated with HDL plasma levels. It is known that the SARS-CoV-2 spike (S) protein binds the HDL particle, probably depleting it of lipids and altering HDL function. Based on neutron reflectometry (NR) and the ability of HDL to efflux cholesterol from macrophages, we confirm these observations and further identify the preference of the S protein for specific lipids and the consequent effects on HDL function on lipid exchange ability. Moreover, the effect of the S protein on HDL function differs depending on the individuals lipid serum profile. Contrasting trends were observed for individuals presenting low triglycerides/high cholesterol serum levels (LTHC) compared to high triglycerides/high cholesterol (HTHC) or low triglycerides/low cholesterol serum levels (LTLC). Collectively, these results suggest that the S protein interacts with the HDL particle and, depending on the lipid profile of the infected individual, it impairs its function during COVID-19 infection, causing an imbalance in lipid metabolism.

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  • 8.
    Correa, Yubexi
    et al.
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Waldie, Sarah
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Life Sciences Group, Institut Laue Langevin, Grenoble F-38042, France; Partnership for Structural Biology, Grenoble F-38042, France.
    Thépaut, Michel
    Univ. Grenoble Alpes, CNRS, CEA, IBS, 71 avenue des Martyrs, F-38000 Grenoble, France.
    Micciula, Samantha
    Large Scale Structures, Institut Laue Langevin (ILL), Grenoble F-38042, France.
    Moulin, Martine
    Life Sciences Group, Institut Laue Langevin, Grenoble F-38042, France; Partnership for Structural Biology, Grenoble F-38042, France.
    Fieschi, Franck
    Partnership for Structural Biology, Grenoble F-38042, France; Univ. Grenoble Alpes, CNRS, CEA, IBS, 71 avenue des Martyrs, F-38000 Grenoble, France.
    Pichler, Harald
    Austrian Centre of Industrial Biotechnology, Petersgasse 14, 8010 Graz, Austria; Graz University of Technology, Institute of Molecular Biotechnology, NAWI Graz, BioTechMed Graz, Petersgasse 14, 8010 Graz, Austria.
    Trevor Forsyth, V
    Life Sciences Group, Institut Laue Langevin, Grenoble F-38042, France; Partnership for Structural Biology, Grenoble F-38042, France; Faculty of Natural Sciences, Keele University, Staffordshire ST5 5BG, UK.
    Haertlein, Michael
    Life Sciences Group, Institut Laue Langevin, Grenoble F-38042, France; Partnership for Structural Biology, Grenoble F-38042, France.
    Cárdenas, Marité
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    SARS-CoV-2 spike protein removes lipids from model membranes and interferes with the capacity of high density lipoprotein to exchange lipids2021In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 602, p. 732-739, article id S0021-9797(21)00930-9Article in journal (Refereed)
    Abstract [en]

    Cholesterol has been shown to affect the extent of coronavirus binding and fusion to cellular membranes. The severity of Covid-19 infection is also known to be correlated with lipid disorders. Furthermore, the levels of both serum cholesterol and high-density lipoprotein (HDL) decrease with Covid-19 severity, with normal levels resuming once the infection has passed. Here we demonstrate that the SARS-CoV-2 spike (S) protein interferes with the function of lipoproteins, and that this is dependent on cholesterol. In particular, the ability of HDL to exchange lipids from model cellular membranes is altered when co-incubated with the spike protein. Additionally, the S protein removes lipids and cholesterol from model membranes. We propose that the S protein affects HDL function by removing lipids from it and remodelling its composition/structure.

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  • 9.
    Fagerström, Anton
    et al.
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Kocherbitov, Vitaly
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Westbye, Peter
    Bergström, Karin
    Arnebrant, Thomas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Engblom, Johan
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Surfactant softening of plant leaf cuticle model wax: a Differential Scanning Calorimetry (DSC) and Quartz Crystal Microbalance with Dissipation (QCM-D) study2014In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 426, p. 22-30Article in journal (Refereed)
    Abstract [en]

    The aim was to quantify the softening effect that two surfactants (C10EO7 and C8G1.6) have on a plant leaf cuticle model wax. Effects on the thermotropic phase behavior and fluidity of the wax (C22H45OH/C32H66/H2O) were determined. The model wax is crystalline at ambient conditions, yet it is clearly softened by the surfactants. Both surfactants decreased the transition temperatures in the wax and the G″/G' ratio of the wax film increased in irreversible steps following surfactant exposure. C10EO7 has a stronger fluidizing effect than C8G1.6 due to stronger interaction with the hydrophobic waxes. Intracuticular waxes (IW) comprise both crystalline and amorphous domains and it has previously been proposed that the fluidizing effects of surfactants are due to interactions with the amorphous parts. New data suggests that this may be a simplification. Surfactants may also absorb in crevices between crystalline domains. This causes an irreversible effect and a softer cuticle wax.

  • 10.
    Falco, Cigdem Yucel
    et al.
    University of Copenhagen, Department of Food Science, Rolighedsvej 30, DK-1958 Frederiksberg, Copenhagen, Denmark.
    Sotres, Javier
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö högskola, Biofilms Research Center for Biointerfaces.
    Rascon, Ana
    Lund University, Food for Health Science Centre, 22100 Lund, Sweden.
    Risbo, Jens
    University of Copenhagen, Department of Food Science, Rolighedsvej 30, DK-1958 Frederiksberg, Copenhagen, Denmark.
    Cárdenas, Marité
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö högskola, Biofilms Research Center for Biointerfaces. University of Copenhagen, Department of Chemistry, Universitetsparken 5, DK-2100 Copenhagen, Denmark.
    Design of a potentially prebiotic and responsive encapsulation material for probiotic bacteria based on chitosan and sulfated beta-glucan2017In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 487, p. 97-106Article in journal (Refereed)
    Abstract [en]

    Hypothesis: Chitosan and sulfated oat beta-glucan are materials suitable to create a prebiotic coating for targeted delivery to gastrointestinal system, using the layer by layer technology. Experiment: Quartz crystal microbalance with dissipation (QCM-D), spectroscopic ellipsometry (SE) and atomic force microscopy (AFM) were used to assess the multilayer formation capacity and characterize the resulting coatings in terms of morphology and material properties such as structure and rigidity. The coating of colloidal materials was proven, specifically on L acidophilus bacteria as measured by changes in the bacterial suspension zeta potential. Viability of coated cells was shown using plate counting method. The coatings on solid surfaces were examined after exposure to mimics of gastrointestinal fluids and a commercially available beta-glucanase. Findings: Successful build-up of multilayers was confirmed with QCM-D and SE. Zeta potential values proved the coating of cells. There was 2 log CFU/mL decrease after coating cells with four alternating layers of chitosan and sulfated p-glucan when compared to viability of uncoated cells. The coatings were partially degraded after exposure to simulated intestinal fluid and restructured as a result of beta-glucanase treatment, mimicking enzymes present in the microflora of the human gut, but seemed to resist acidic gastric conditions. Therefore, coatings of chitosan and sulfated beta-glucan can potentially be exploited as carriers for probiotics and delicate nutraceuticals. (C) 2016 Elsevier Inc. All rights reserved.

  • 11.
    Gonzalez-Martinez, Juan F
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Boyd, Hannah
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Gutfreund, Philipp
    Institut Laue Langevin, 71 avenue des Martyrs, Grenoble 38000, France.
    Welbourn, Rebecca J L
    ISIS Facility, STFC, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, United Kingdom.
    Robertsson, Carolina
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces.
    Wickström, Claes
    Malmö University, Faculty of Odontology (OD). Malmö University, Biofilms Research Center for Biointerfaces.
    Arnebrant, Thomas
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Richardson, Robert M
    School of Physics, University of Bristol, Tyndall Avenue, BS8 1TL Bristol, United Kingdom.
    Prescott, Stuart W
    School of Chemical Engineering, University of New South Wales, Sydney, NSW 2052, Australi.
    Barker, Robert
    School of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NH, United Kingdom.
    Sotres, Javier
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    MUC5B mucin films under mechanical confinement: A combined neutron reflectometry and atomic force microscopy study.2022In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 614, p. 120-129, article id S0021-9797(22)00109-6Article in journal (Refereed)
    Abstract [en]

    HYPOTHESIS: Among other functions, mucins hydrate and protect biological interfaces from mechanical challenges. Mucins also attract interest as biocompatible coatings with excellent lubrication performance. Therefore, it is of high interest to understand the structural response of mucin films to mechanical challenges. We hypothesized that this could be done with Neutron Reflectometry using a novel sample environment where mechanical confinement is achieved by inflating a membrane against the films.

    EXPERIMENTS: Oral MUC5B mucin films were investigated by Force Microscopy/Spectroscopy and Neutron Reflectometry both at solid-liquid interfaces and under mechanical confinement.

    FINDINGS: NR indicated that MUC5B films were almost completely compressed and dehydrated when confined at 1 bar. This was supported by Force Microscopy/Spectroscopy investigations. Force Spectroscopy also indicated that MUC5B films could withstand mechanical confinement by means of steric interactions for pressures lower than ∼ 0.5 bar i.e., mucins could protect interfaces from mechanical challenges of this magnitude while keeping them hydrated. To investigate mucin films under these pressures by means of the employed sample environment for NR, further technological developments are needed. The most critical would be identifying or developing more flexible membranes that would still meet certain requirements like chemical homogeneity and very low roughness.

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  • 12.
    Gunnarsson, Maria
    et al.
    Division of Physical Chemistry, Department of Chemistry, Lund University, Box 124, SE-221 00 Lund, Sweden.
    Mojumdar, Enamul Haque
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Division of Physical Chemistry, Department of Chemistry, Lund University, Box 124, SE-221 00 Lund, Sweden.
    Topgaard, Daniel
    Division of Physical Chemistry, Department of Chemistry, Lund University, Box 124, SE-221 00 Lund, Sweden.
    Sparr, Emma
    Division of Physical Chemistry, Department of Chemistry, Lund University, Box 124, SE-221 00 Lund, Sweden.
    Extraction of natural moisturizing factor from the stratum corneum and its implication on skin molecular mobility2021In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 604, p. 480-491, article id S0021-9797(21)01070-5Article in journal (Refereed)
    Abstract [en]

    The natural moisturizing factor (NMF) is a mixture of small water-soluble compounds present in the upper layer of the skin, stratum corneum (SC). Soaking of SC in water leads to extraction of the NMF molecules, which may influence the SC molecular properties and lead to brittle and dry skin. In this study, we investigate how the molecular dynamics in SC lipid and protein components are affected by the removal of the NMF compounds. We then explore whether the changes in SC components caused by NMF removal can be reversed by a subsequent addition of one single NMF component: urea, pyrrolidone carboxylic acid (PCA) or potassium lactate. Samples of intact SC were investigated using NMR, X-ray diffraction, infrared spectroscopy and sorption microbalance. It is shown that the removal of NMF leads to reduced molecular mobility in keratin filaments and SC lipids compared to untreated SC. When the complex NMF mixture is replaced by one single NMF component, the molecular mobility in both keratin filaments and lipids is regained. From this we propose a general relation between the molecular mobility in SC and the amount of polar solutes which does not appear specific to the precise chemical identify of the NMF compounds.

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  • 13.
    Hedegaard, Sofie Fogh
    et al.
    Centerfor Biopharmaceuticals and Biobarriers in Drug Delivery, Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark.
    Bruhn, Dennis Skjøth
    PHYLIFE, Physical Life Science, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense SØ, Denmark.
    Khandelia, Himanshu
    PHYLIFE, Physical Life Science, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense SØ, Denmark.
    Cárdenas, Marité
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Nielsen, Hanne Mørck
    Centerfor Biopharmaceuticals and Biobarriers in Drug Delivery, Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark.
    Shuffled lipidation pattern and degree of lipidation determines the membrane interaction behavior of a linear cationic membrane-active peptide.2020In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 578, p. 584-597, article id S0021-9797(20)30740-2Article in journal (Refereed)
    Abstract [en]

    HYPOTHESIS: Permeation of macromolecular drugs across biological plasma membranes is a major challenge in drug delivery. Cationic cell-penetrating peptides (CPPs) are attractive functional excipient candidates for the delivery of macromolecules across membrane barriers, due to their membrane translocating ability. The properties of CPPs can be tailored by lipidation, a promising approach to facilitate enhanced membrane insertion, potentially promoting increased translocation of the CPP and cargo.

    EXPERIMENTS: To explore the impact that site and degree of lipidation have on the membrane interaction of a cationic CPP, we designed and investigated CPP conjugates with one or two fatty acid chains.

    FINDINGS: Compared to the parent CPP and the single-lipidated conjugates, the double-lipidated conjugate exhibited the most pronounced membrane perturbation effects, as measured by several biophysical techniques. The experimental findings were supported by molecular dynamics (MD) simulations, demonstrating that all CPP conjugates interacted with the membrane by insertion of the lipid chain(s) into the core of the bilayer. Moreover, membrane-thinning effects and induced membrane curvature were displayed upon CPP interaction. Our results demonstrate that the impact exerted by the CPP on the membrane is notably affected by positioning and especially the degree of lipidation, which might influence the properties of CPPs as functional excipients.

  • 14.
    Kamal, Mohammad Arif
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Lund Univ, Dept Chem, Div Phys Chem, Lund, Sweden..
    Brizioli, Matteo
    Univ Milan, Dept Med Biotechnol & Translat Med, Milan, Italy..
    Zinn, Thomas
    ESRF European Synchrotron, Grenoble, France.;Diamond Light Source Ltd, Didcot, England..
    Narayanan, Theyencheri
    ESRF European Synchrotron, Grenoble, France..
    Cerbino, Roberto
    Univ Vienna, Fac Phys, Vienna, Austria..
    Giavazzi, Fabio
    Univ Milan, Dept Med Biotechnol & Translat Med, Milan, Italy..
    Pal, Antara
    Stockholm Univ, Dept Phys, Stockholm, Sweden.;MAX IV Lab, Lund, Sweden..
    Dynamics of anisotropic colloidal systems: What to choose, DLS, DDM or XPCS?2024In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 660, p. 314-320Article in journal (Refereed)
    Abstract [en]

    Investigation of the dynamics of colloids in bulk can be hindered by issues such as multiple scattering and sample opacity. These challenges are exacerbated when dealing with inorganic materials. In this study, we employed a model system of Akaganeite colloidal rods to assess three leading dynamics measurement techniques: 3D -(depolarized) dynamic light scattering (3D-(D)DLS), polarized -differential dynamic microscopy (P-DDM), and x-ray photon correlation spectroscopy (XPCS). Our analysis revealed that the translational and rotational diffusion coefficients captured by these methods show a remarkable alignment. Additionally, by examining the q -ranges and maximum volume fractions for each approach, we offer insights into the best technique for investigating the dynamics of anisotropic systems at the colloidal scale.

  • 15.
    Kocherbitov, Vitaly
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    A model for water sorption isotherms and hydration forces in sugar surfactants2023In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 633, p. 343-351Article in journal (Refereed)
    Abstract [en]

    HYPOTHESIS: Hydration forces between surfactant bilayers can be assessed using water sorption isotherms of surfactants. For a quantitative description, a water sorption model that relates water activity to water content in surfactant-based systems should be proposed.

    THEORY AND SIMULATIONS: A water sorption model for nonionic surfactant systems based on the idea on partial solvent accessibility is proposed. The model contains only two parameters: one describes the strength of interactions, the other describes the fraction of surfactant available for water. For comparison, molecular dynamics simulations of bilayers of n-octyl β-d-glucoside with different water contents are presented.

    FINDINGS: The model provides an excellent fit of experimental data on water sorption isotherms of two sugar surfactants. The results of the fitting are compared with molecular dynamics simulations and show a good correlation between simulations and the theory proposed. Analysis of interaction energies shows weakly endothermic hydration both in the simulations and in the sorption model, which agrees with calorimetric data on hydration. The model also shows a non-exponential decay of hydration forces with respect to the distance between bilayers; an expression for the decay length is derived.

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  • 16.
    Krikstolaityte, Vida
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Ave, 639798 Singapore, Singapore; Residues and Resource Reclamation Centre (R3C), Nanyang Environment and Water Research Institute (NEWRI), Nanyang Technological University, CleanTech One, 637141Singapore, Singapore.
    Hamit-Eminovski, Jildiz
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Abariute, Laura
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Division of Solid State Physics, NanoLund, Lund University, 221 00 Lund, Sweden.
    Niaura, Gediminas
    Department of Organic Chemistry, Center for Physical Sciences and Technology, Sauletekio 3, LT-10257 Vilnius, Lithuania.
    Meskys, Rolandas
    Department of Molecular Microbiology and Biotechnology, Institute of Biochemistry, Life Sciences Center, Vilnius University, Sauletekio 7, LT-10257 Vilnius, Lithuania.
    Arnebrant, Thomas
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Lisak, Grzegorz
    School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Ave, 639798 Singapore, Singapore; Residues and Resource Reclamation Centre (R3C), Nanyang Environment and Water Research Institute (NEWRI), Nanyang Technological University, CleanTech One, 637141Singapore, Singapore.
    Ruzgas, Tautgirdas
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Impact of molecular linker size on physicochemical properties of assembled gold nanoparticle mono-/multi-layers and their applicability for functional binding of biomolecules2019In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 543, p. 307-316Article in journal (Refereed)
    Abstract [en]

    In this work the impact of molecular inter-linker size on gold nanoparticle (AuNP) mono-/multilayer structural properties, density and homogeneity has been investigated. These characteristics are of great importance for functional binding of biomolecules. Positively charged high or low molecular weight inter-linkers, poly-L-lysine (PLL) or N-(6-mercapto)hexylpyridinium (MHP), were used to attach negatively charged AuNPs on a planar gold surface as well as to further interlink into a multilayer structure via layer-by-layer deposition. The inter-particle interaction within the assembled AuNP films was adjusted by the ionic strength in the AuNPs dispersions The AuNP layer density and structural/viscoelastic properties were evaluated by the quartz crystal microbalance with dissipation (QCM-D) technique. The validity of the commercial Voigt model, specifically developed for quantitative QCM-D data analysis of homogeneous viscoelastic films, was evaluated by a model independent analysis when comparing the assembled AuNP films with a homogeneous layer of a mucin from bovine submaxillary glands. Both AuNP mono- and multilayers, attached/interlinked via long flexible PLL molecules assembled to denser and more soft/viscous structures compared to those interlinked by short MHP compounds. Thus, PLL-interlinked AuNP mono-/multilayer structures were further investigated as a platform for laccase enzyme functional adsorption via qualitative assessment of bioelectrochemical characteristics of the enzyme. (C) 2019 Elsevier Inc. All rights reserved.

  • 17.
    Labecka, Nikol
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Division of Physical Chemistry, Chemistry Department, Lund University, SE-221 00 Lund, Sweden.
    Szczepanczyk, Michal
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Mojumdar, Enamul Haque
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Division of Physical Chemistry, Chemistry Department, Lund University, SE-221 00 Lund, Sweden; CR Competence AB, Box 124, 22100 Lund, Sweden.
    Sparr, Emma
    Division of Physical Chemistry, Chemistry Department, Lund University, SE-221 00 Lund, Sweden.
    Björklund, Sebastian
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Unraveling UVB effects: Catalase activity and molecular alterations in the stratum corneum.2024In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 666, p. 176-188, article id S0021-9797(24)00709-4Article in journal (Refereed)
    Abstract [en]

    AIM: Ultraviolet B (UVB) radiation can compromise the functionality of the skin barrier through various mechanisms. We hypothesize that UVB induce photochemical alterations in the components of the outermost layer of the skin, known as the stratum corneum (SC), and modulate its antioxidative defense mechanisms. Catalase is a well-known antioxidative enzyme found in the SC where it acts to scavenge reactive oxygen species. However, a detailed characterization of acute UVB exposure on the activity of native catalase in the SC is lacking. Moreover, the effects of UVB irradiation on the molecular dynamics and organization of the SC keratin and lipid components remain unclear. Thus, the aim of this work is to characterize consequences of UVB exposure on the structural and antioxidative properties of catalase, as well as on the molecular and global properties of the SC matrix surrounding the enzyme.

    EXPERIMENTS: The effect of UVB irradiation on the catalase function is investigated by chronoamperometry with a skin covered oxygen electrode, which probes the activity of native catalase in the SC matrix. Circular dichroism is used to explore changes of the catalase secondary structure, and gel electrophoresis is used to detect fragmentation of the enzyme following the UVB exposure. UVB induced alterations of the SC molecular dynamics and structural features of the SC barrier, as well as its water sorption behavior, are investigated by a complementary set of techniques, including natural abundance 13C polarization transfer solid-state NMR, wide-angle X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, and dynamic vapor sorption microbalance.

    FINDINGS: The findings show that UVB exposure impairs the antioxidative function of catalase by deactivating both native catalase in the SC matrix and lyophilized catalase. However, UVB radiation does not alter the secondary structure of the catalase nor induce any observable enzyme fragmentation, which otherwise could explain deactivation of its function. NMR measurements on SC samples show a subtle increase in the molecular mobility of the terminal segments of the SC lipids, accompanied by a decrease in the mobility of lipid chain trans-gauche conformers after high doses of UVB exposure. At the same time, the NMR data suggest increased rigidity of the polypeptide backbone of the keratin filaments, while the molecular mobility of amino acid residues in random coil domains of keratin remain unaffected by UVB irradiation. The FTIR data show a consistent decrease in absorbance associated with lipid bond vibrations, relative to the main protein bands. Collectively, the NMR and FTIR data suggest a small modification in the composition of fluid and solid phases of the SC lipid and protein components after UVB exposure, unrelated to the hydration capacity of the SC tissue. To conclude, UVB deactivation of catalase is anticipated to elevate oxidative stress of the SC, which, when coupled with subtle changes in the molecular characteristics of the SC, may compromise the overall skin health and elevate the likelihood of developing skin disorders.

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  • 18.
    Larsson, Johan
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Lund Univ, Dept Chem, Phys Chem, Box 124, S-22100 Lund, Sweden.
    Williams, Ashley P.
    Monash Univ, Sch Chem, Clayton, Vic 3800, Australia..
    Wahlgren, Marie
    Lund Univ, Food Technol Nutr & Engn, Box 124, S-22100 Lund, Sweden.;Enza Biotech AB, Scheelevagen 22, S-22363 Lund, Sweden..
    Porcar, Lionel
    Inst Laue Langevin, DS LSS, 71 Ave Martyrs, F-38000 Grenoble, France..
    Ulvenlund, Stefan
    Lund Univ, Food Technol Nutr & Engn, Box 124, S-22100 Lund, Sweden.;Enza Biotech AB, Scheelevagen 22, S-22363 Lund, Sweden..
    Nylander, Tommy
    Lund Univ, Dept Chem, Phys Chem, Box 124, S-22100 Lund, Sweden.;Lund Univ, NanoLund, Lund, Sweden..
    Tabor, Rico F.
    Monash Univ, Sch Chem, Clayton, Vic 3800, Australia..
    Sanchez-Fernandez, Adrian
    Lund Univ, Food Technol Nutr & Engn, Box 124, S-22100 Lund, Sweden..
    Shear-induced nanostructural changes in micelles formed by sugar-based surfactants with varied anomeric configuration2022In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 606, p. 328-336Article in journal (Refereed)
    Abstract [en]

    Hypothesis: The self-assembly of long tail sugar-based surfactants into worm-like micelles has recently been demonstrated, and the rheological properties of such systems have been shown to be tuneable through subtle modifications of the molecular characteristics of the surfactant monomer. In particular, the anomeric configuration of the hexadecylmaltoside headgroup was shown to induce profound changes in the nanostructure and rheology of the system. The origin of such changes is hypothesised to arise from differences in the structure and relaxation of the micellar networks in the semi-dilute regime. Experiments: Here we explore the molecular background to the flow properties of the two anomers of hexadecylmaltoside (alpha- and beta-C(16)G(2)) by directly connecting their rheological behaviour to the micelle morphology. For this purpose, 1-3 plane rheo-small-angle neutron scattering measurements, using a Couette cell geometry, probed the structural changes in the micellar phase under shear. The effect of surfactant anomeric configuration, surfactant concentration, temperature and mixing ratio of the two anomers were investigated. The static micelle structure in the semi-dilute regime was determined using the polymer reference interaction site model. Findings: The segmental alignment of the micellar phase was studied under several flow conditions, showing that the shear-thinning behaviour relates to the re-arrangement of beta-C(16)G(2) worm-like micelles, whilst shorter alpha-C(16)G(2) micelles are considerably less affected by the flow. The results are rationalised in terms of micelle alignment and disruption of the entangled network, providing a detailed mechanism by which sugar-based surfactants control the rheology of the fluid. To further enable future studies, we provide the complete code for modelling micelle structure in the semi-dilute regime using the polymer reference interaction site model. (C) 2021 The Authors. Published by Elsevier Inc.

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  • 19.
    Lind, Tania K.
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Nilsson, Emelie J.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Wyler, Benjamin
    LONZA AG, Switzerland.
    Scherer, Dieter
    LONZA AG, Switzerland.
    Skansberger, Tatyana
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Morin, Maxim
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Kocherbitov, Vitaly
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Engblom, Johan
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Effects of ethylene oxide chain length on crystallization of polysorbate 80 and its related compounds2021In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 592, p. 468-484, article id S0021-9797(21)00078-3Article in journal (Refereed)
    Abstract [en]

    As a result of the synthesis protocol polyoxyethylene sorbitan monooleate (polysorbate 80, PS80) is a highly complex mixture of compounds. PS80 was therefore separated into its main constituents, e.g. polyoxyethylene isosorbide esters and polyoxyethylene esters, as well as mono- di- and polyesters using preparative high-performance liquid chromatography. In this comprehensive study the individual components and their ethoxylation level were verified by matrix assisted laser desorption/ionization time-of-flight and their thermotropic behavior was analyzed using differential scanning calorimetry and X-ray diffraction. A distinct correlation was found between the average length of the ethylene oxide (EO) chains in the headgroup and the individual compounds' ability to crystallize. Importantly, a critical number of EO units required for crystallization of the headgroup was determined (6 EO units per chain or 24 per molecule). The investigation also revealed that the hydrocarbon tails only crystallize for polyoxyethylene sorbitan esters if saturated. PS80 is synthesized by reacting with approximately 20 mol of EO per mole of sorbitol, however, the number of EO units in the sorbitan ester in commercial PS80 products is higher than the expected 20 (5 EO units per chain). The complex behavior of all tested compounds revealed that if the amount of several of the linear by-products is reduced, the number of EO units in the chains will stay below the critical number and the product will not be able to crystallize by the EO chains.

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  • 20.
    Luchini, Alessandra
    et al.
    Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark.
    Sebastiani, Federica
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Tidemand, Frederik Grønbæk
    Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark.
    Batchu, Krishna Chaithanya
    Institut Laue Langevin, 71 avenue des Martyrs, 38000 Grenoble, France.
    Campana, Mario
    ISIS-STFC, Rutherford Appleton Laboratory, Chilton, Oxon OX11 0QX, United Kingdom.
    Fragneto, Giovanna
    Institut Laue Langevin, 71 avenue des Martyrs, 38000 Grenoble, France.
    Cárdenas, Marité
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Arleth, Lise
    Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark.
    Peptide discs as precursors of biologically relevant supported lipid bilayers2021In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 585, p. 376-385, article id S0021-9797(20)31605-2Article in journal (Refereed)
    Abstract [en]

    Supported lipid bilayers (SLBs) are commonly used to investigate the structure and dynamics of biological membranes. Vesicle fusion is a widely exploited method to produce SLBs. However, this process becomes less favoured when the vesicles contain complex lipid mixtures, e.g. natural lipid extracts. In these cases, it is often necessary to change experimental parameters, such as temperature, to unphysiological values to trigger the SLB formation. This may induce lipid degradation and is also not compatible with including membrane proteins or other biomolecules into the bilayers. Here, we show that the peptide discs, ~10 nm discoidal lipid bilayers stabilized in solution by a self-assembled 18A peptide belt, can be used as precursors for SLBs. The characterizations by means of neutron reflectometry and attenuated total reflectance-FTIR spectroscopy show that SLBs were successfully formed both from synthetic lipid mixtures (surface coverage 90-95%) and from natural lipid mixtures (surface coverage ~85%). Traces of 18A peptide (below 0.02 M ratio) left at the support surface after the bilayer formation do not affect the SLB structure. Altogether, we demonstrate that peptide disc formation of SLBs is much faster than the SLB formation by vesicle fusion and without the need of altering any experimental variable from physiologically relevant values.

  • 21.
    Luchini, Alessandra
    et al.
    Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark.
    Tidemand, Frederik Grønbæk
    Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark.
    Araya-Secchi, Raul
    Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark.
    Campana, Mario
    ISIS-STFC, Rutherford Appleton Laboratory, Chilton, Oxon OX11 0QX, United Kingdom.
    Cárdenas, Marité
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Arleth, Lise
    Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark.
    Structural model of tissue factor (TF) and TF-factor VIIa complex in a lipid membrane: A combined experimental and computational study2022In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 623, p. 294-305, article id S0021-9797(22)00724-XArticle in journal (Refereed)
    Abstract [en]

    Tissue factor (TF) is a membrane protein involved in blood coagulation. TF initiates a cascade of proteolytic reactions, ultimately leading to the formation of a blood clot. The first reaction consists of the binding of the coagulation factor VII and its conversion to the activated form, FVIIa. Here, we combined experimental, i.e. quartz crystal microbalance with dissipation monitoring and neutron reflectometry, and computational, i.e. molecular dynamics (MD) simulation, methods to derive a complete structural model of TF and TF/FVIIa complex in a lipid bilayer. This model shows that the TF transmembrane domain (TMD), and the flexible linker connecting the TMD to the extracellular domain (ECD), define the location of the ECD on the membrane surface. The average orientation of the ECD relative to the bilayer surface is slightly tilted towards the lipid headgroups, a conformation that we suggest is promoted by phosphatidylserine lipids, and favours the binding of FVIIa. On the other hand, the formation of the TF/FVIIa complex induces minor changes in the TF structure, and reduces the conformational freedom of both TF and FVIIA. Altogether we describe the protein-protein and protein-lipid interactions favouring blood coagulation, but also instrumental to the development of new drugs.

  • 22.
    Santos, Olga
    et al.
    Malmö högskola, Faculty of Health and Society (HS).
    Arnebrant, Thomas
    Malmö högskola, Faculty of Health and Society (HS).
    Silica supported phospholipid layers doped with GM1: A comparison between different methods2009In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 329, no 2, p. 213-221Article in journal (Refereed)
    Abstract [en]

    A method to coat hydrophobic surfaces with lipid molecules in a reproducible manner and in which the lipid molecules are resistant to detergent washings, would benefit the development of new ELISA assays. This work presents different approaches to build 1,2-dioleolyl-sn-glycero-3-phosphocholine (DOPC) layers doped with a monosialoganglioside (GM1) supported on silica surfaces, which are stable toward buffer rinsing and washing with surfactant (Tween 20). The three methods employed were: method 1, coadsorption of DOPC:GM1 (0–10 mol%) with the surfactant n-dodecyl-β-D-maltoside (DDM) from micellar solutions, with successive adsorption and rinsing steps; method 2, vesicle fusion from DOPC: GM1 (0–10 mol%) liposomes; and method 3, deposition of GM1 from organic solvent (chloroform) and exposure to an aqueous environment (hydration method). The vesicle fusion method was also tested in polystyrene surfaces. Cholera toxin subunit B (CTB) was used to detect the presence of GM1 on the formed layers. The results indicated that the vesicle fusion was the only method that was successful in creating stable mono- and bilayers onto hydrophobized and hydrophilic silica, respectively. The mixed micellar solution method was suitable for creating pure lipid (DOPC) monolayers but the incorporation of GM1 in the micelles led to monolayers which were very unstable with respect to buffer rinsing. The hydration method led to monolayers of GM1 that were partly rinsed off by a continuous buffer flow. Adsorption of CTB was found to be proportional to the amount of GM1 present in the liposomes. The amount of CTB adsorbed onto the lipid bilayers was roughly the double as the one determined on the monolayers with the same liposome compositions. The vesicle fusion method was also able to create monolayers of pure DOPC and DOPC:10 mol% GM1 on the polystyrene surfaces.

  • 23.
    Santos, Olga
    et al.
    Malmö högskola, Faculty of Health and Society (HS).
    Kosoric, Jelena
    Hector, Mark P
    Anderson, Paul
    Lindh, Liselott
    Malmö högskola, Faculty of Odontology (OD).
    Adsorption behaviour of statherin and a statherin peptide onto hydroxyapatite and silica surfaces studied by in situ ellipsometry2008In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 318, no 2, p. 175-182Article in journal (Refereed)
    Abstract [en]

    The salivary protein statherin is known to adsorb selectively onto hydroxyapatite (HA), which constitutes the main mineral of the tooth enamel. This adsorption is believed to be crucial for its function as an inhibitor of primary (spontaneous) and secondary (crystal growth) precipitation of calcium phosphate salts present in saliva. A fragment corresponding to the first 21 N-terminus amino acids of statherin (StN21) was previously found to reduce the rate of demineralization of HA. Therefore, the interfacial properties of this peptide and statherin onto silica, hydrophobized silica and HA discs was studied by in situ ellipsometry. Their reversibility induced by dilution and elutability induced by buffer and sodium dodecyl sulfate (SDS) was also determined. The results revealed that statherin adsorbed at a greater extent onto the HA as compared to StN21, suggesting that the hydrogen bonding between the uncharged polar residues at the C-terminal region of statherin and HA contributes to its adsorption. However, on both silica surfaces the peptide adsorption appeared to proceed in a similar way. Onto the hydrophobized silica the adsorption of both peptides was suggested to occur either via multilayer formation or adsorption of aggregates from solution, while onto the hydrophilic silica adsorption of peptide aggregates from solution was the suggested mechanism. Further, both peptides were observed to be strongly adsorbed onto HA, even after SDS treatment, in comparison to the layers adsorbed onto hydrophobized silica. Both peptide layers were found to be weakly adsorbed onto the hydrophilic silica surface as they were totally removed by buffer dilution.

  • 24.
    Sebastiani, Federica
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Yanez Arteta, Marianna
    Advanced Drug Delivery, Pharmaceutical Sciences, R&D, AstraZeneca, Gothenburg, Sweden.
    Lindfors, Lennart
    Advanced Drug Delivery, Pharmaceutical Sciences, R&D, AstraZeneca, Gothenburg, Sweden.
    Cárdenas, Marité
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Screening of the binding affinity of serum proteins to lipid nanoparticles in a cell free environment2021In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 610, p. 766-774, article id S0021-9797(21)02028-2Article in journal (Refereed)
    Abstract [en]

    Lipid nanoparticles (LNPs) are promising drug and gene carriers. Upon intravenous administration, LNPs' experience different degree of cellular uptake depending on their formulation. Currently, in vitro and in vivo studies are the gold standard for assessing the fate of nano carriers once administered, but they are time consuming and expensive. In this work, we propose a time and cost-effective method to screen a wide range of LNP formulations and select the most promising candidates for in vitro and in vivo studies. Two different approaches were explored to investigate the binding affinity between LNPs and serum proteins using sensor functionalisation with either protein specific antibody or PEG specific antibody. The first approach allowed to identify the presence of a specific protein in the protein corona of lipid particles (reconstituted and native high-density lipoproteins (rHDL and HDL), and low-density lipoproteins LDL); while the second one provided a versatile platform for the immobilisation of pegylated-particles in order to follow the interaction with serum proteins and hence predict the composition of LNP protein corona. Sensing was done using Quartz Crystal Microbalance with Dissipation (QCM-D) but the approach is extendable to other surface sensing techniques such as Surface Plasmon Resonance (SPR) or ellipsometry.

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  • 25.
    Sotres, Javier
    et al.
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Madsen, Jan Busk
    Arnebrant, Thomas
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Lee, Seunghwan
    Adsorption and nanowear properties of bovine submaxillary mucin films on solid surfaces: influence of solution pH and substrate hydrophobicity2014In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 428, p. 242-250Article in journal (Refereed)
    Abstract [en]

    The adsorption and mechanical stability of bovine submaxillary mucins (BSM) films at solid–liquid interfaces were studied with respect to both substrate hydrophobicity and solution pH. Dynamic light scattering revealed a single peak distribution in neutral aqueous solution (pH 7.4) and a small fraction with enhanced aggregation was observed in acidic solution (pH 3.8). Both substrate hydrophobicity and solution pH were found to affect the spontaneous adsorption of BSM onto solid surfaces; BSM adsorbed more onto hydrophobic surfaces than hydrophilic ones, and adsorbed more at pH 3.8 than at pH 7.4. Thus, the highest “dry” adsorbed mass was observed for hydrophobic surfaces in pH 3.8 solution. However, a highest “wet” adsorbed mass, i.e. which includes the solvent coupled to the film, was observed for hydrophobic surfaces at pH 7.4. The mechanical stability of the films was studied at the nanoscale with an atomic force microscope operated in the friction force spectroscopy mode. Results revealed that BSM films formed on hydrophobic substrates were stronger than those formed on hydrophilic ones. Moreover, the film stability also depended on the ambient pH and stronger films were formed at acidic conditions, i.e. close to the BSM isoelectric point.

  • 26.
    Stenbæk, Jonas
    et al.
    Section of Microbiology, University of Copenhagen, Copenhagen, Denmark; Danish Technological Institute, Wood and Biomaterials, Gregersensvej 3, 2630 Taastrup, Denmark.
    Löf, David
    Perstorp AB, Industriparken, 284 91 Perstorp, Sweden.
    Falkman, Peter
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Jensen, Bo
    Section of Microbiology, University of Copenhagen, Copenhagen, Denmark.
    Cárdenas, Marité
    Malmö högskola, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    An alternative anionic bio-sustainable anti-fungal agent: Investigation of its mode of action on the fungal cell membrane2017In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 497, p. 242-248Article in journal (Refereed)
    Abstract [en]

    The potential of a lactylate (the sodium caproyl lactylate or C10 lactylate), a typical food grade emulsifier, as an anionic environmental friendly anti-fungal additive was tested in growth medium and formulated in a protective coating for exterior wood. Different laboratory growth tests on the blue stain fungus Aureobasidium pullulans were performed and its interactions on a model fungal cell membrane were studied. Promising short term anti-fungal effects in growth tests were observed, although significant but less dramatic effects took place in coating test on wood panels. Scanning electron microscope analysis shows clear differences in the amount of fungal slime on the mycelium of Aureobasidium pullulans when the fungus was exposed of C10 lactylate. This could indicate an effect on the pullulan and melanin production by the fungus. Moreover, the interaction studies on model fungal cell membranes show that C10 lactylate affects the phospholipid bilayer in a similar manner to other negative charged detergents. (C) 2017 Elsevier Inc. All rights reserved.

  • 27.
    Stenqvist, Björn
    et al.
    Division of Physical Chemistry, Department of Chemistry, Lund University, POB 124, SE-221 00 Lund, Sweden.
    Ericson, Marica B.
    Biomedical Photonics Group, Department of Chemistry and Molecular Biology, University of Gothenburg, SE-412 96 Gothenburg, Sweden.
    Gregoire, Sebastien
    L’Oreal Research & Innovation, 1, avenue Eugène Schueller, 93601 Aulnay-sous-Bois, France.
    Biatry, Bruno
    L’Oreal Research & Innovation, 1, avenue Eugène Schueller, 93601 Aulnay-sous-Bois, France.
    Cassin, Guillaume
    L’Oreal Research & Innovation, 1, avenue Eugène Schueller, 93601 Aulnay-sous-Bois, France.
    Jankunec, Marija
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Institute of Biochemistry Life Sciences Center, Vilnius University, LT-10257 Vilnius, Lithuania.
    Engblom, Johan
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Sparr, Emma
    Division of Physical Chemistry, Department of Chemistry, Lund University, POB 124, SE-221 00 Lund, Sweden.
    Membrane permeability based on mesh analysis2023In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 633, p. 526-535Article in journal (Refereed)
    Abstract [en]

    The main function of a membrane is to control the exchange of matter between the surrounding regions. As such, accurate modeling of membranes is important to properly describe their properties. In many cases in both biological systems and technical applications, the membranes are composite structures where transport properties may vary between the different sub-regions of the membrane. In this work we develop a method based on Mesh analysis that is asymptotically exact and can describe diffusion in composite membrane structures. We do this by first reformulating a generalized Fick’s law to include the effects from activity coefficient, diffusion coefficient, and solubility using a single condensed parameter. We then use the derived theory and Mesh analysis to, in essence, retrieve a finite element method approach. The calculated examples are based on a membrane structure that reassembles that of the brick and mortar structure of stratum corneum, the upper layer of our skin. Resulting concentration profiles from this procedure are then compared to experimental results for the distribution of different probes within intact stratum corneum, showing good agreement. Based on the derived approach we further investigate the impact from a gradient in the fluidity of the stratum corneum mortar lipids across the membrane, and find that it is substantial. We also show that anisotropic organisation of the lipid mortar can have large impact on the effective permeability compared to isotropic mortar lipids. Finally, we examine the effects of corneocyte swelling, and their lateral arrangement in the membrane on the overall membrane permeability.

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  • 28.
    Svendsen, Ida
    et al.
    Malmö högskola, Faculty of Health and Society (HS). Malmö högskola, Faculty of Odontology (OD).
    Lindh, Liselott
    Malmö högskola, Faculty of Health and Society (HS). Malmö högskola, Faculty of Odontology (OD).
    Elofsson, Ulla
    Arnebrant, Thomas
    Malmö högskola, Faculty of Health and Society (HS). Malmö högskola, Faculty of Odontology (OD).
    Studies on the exchange of early pellicle proteins by mucin and whole2008In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 321, no 1, p. 52-59Article in journal (Refereed)
    Abstract [en]

    Adsorption of small pellicle proteins statherin or proline-rich protein 1 (PRP1) respectively, and subsequent adsorption of human whole saliva (HWS) or salivary mucin MUC5B respectively, was studied using ellipsometry and total internal reflectance fluorescence. Differences in elution (using sodium dodecyl sulphate (SDS) solutions) between mixed and single protein films were also investigated. On both hydrophilic and hydrophobized surfaces HWS and MUC5B were found to adsorb to pre-adsorbed layers of statherin and PRP1 respectively. Statherin adsorption on both substrate types showed no or minor exchange by HWS or MUC5B and no change in SDS elution between mixed and single protein films. Small amounts of PRP1 were exchanged by HWS on both surface types and the SDS elutable fractions were similar or larger for mixed films compared to single protein films. PRP1 and MUC5B in sequence showed minor exchange of PRP1 on hydrophilic surfaces, while no exchange could be established on hydrophobized substrates. SDS elutable fractions decreased for PRP1 and MUC5B mixed films compared to single protein films. In conclusion, minor amounts of statherin and PRP1 are exchanged during the time course of the experiments, which indicates that these proteins may to a large extent remain incorporated in the pellicle.

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  • 29.
    Svensson, Olof
    et al.
    Malmö högskola, Faculty of Health and Society (HS).
    Arnebrant, Thomas
    Malmö högskola, Faculty of Health and Society (HS).
    Adsorption of serum albumin on silica: The influence of surface cleaning procedures2010In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 344, no 1, p. 44-47Article in journal (Refereed)
    Abstract [en]

    The objective of the investigation was to study how different surface cleaning procedures affect the subsequent adsorption of bovine serum albumin (BSA) on silica. Ellipsometry was used to monitor the adsorbed amount and thickness of the protein films in situ at physiological buffer conditions. Plasma treatment was found to effectively reduce the amount of BSA on silica and on surfaces cleaned with hydrogen peroxide solutions (RCA method) adsorption was essentially absent. On clean silica surfaces the ellipsometric data furthermore suggest that a depletion zone is present at the surface where the BSA concentration is lower than in the bulk solution. Additional experiments showed that calcium did not promote the adsorption of BSA and that the adsorption of human serum albumin (HSA) is essentially absent on clean silica surfaces in agreement with the results obtained for BSA. The presented work contributes to the general understanding of protein adsorption as well as provides information on how to control serum albumin adsorption on silica based biomedical devices.

  • 30.
    Svensson, Olof
    et al.
    Malmö högskola, Faculty of Health and Society (HS).
    Arnebrant, Thomas
    Malmö högskola, Faculty of Health and Society (HS).
    Antibody–antigen interaction on polystyrene: An in situ ellipsometric study2012In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 368, no 1, p. 533-539Article in journal (Refereed)
    Abstract [en]

    The objective of this investigation was to monitor the adsorption of antibodies to polystyrene surfaces using ellipsometry. Commercial polystyrene slides used for solid state diagnostics were selected as substrates and the adsorption of three different antibodies (human IgG, bovine IgG and goat anti-human IgG) were evaluated. Based on theoretical models describing the ellipsometric data, it was concluded that the adsorption of antibodies should result in layers that are sufficiently thick to be able to monitor the adsorption in terms of adsorbed amount and thickness of the layer with a reasonable precision. The experimental results confirmed this assumption and values of 2.0–2.3 mg/m2 were detected for the adsorbed amount with a corresponding thickness of 10–16 nm. It was furthermore found that the antibodies bound irreversibly with respect to rinsing with protein-free solutions. In additional experiments, the consecutive incubation of human IgG and anti-human IgG was investigated. These results showed that, on average, approximately half of the surface immobilized anti-human IgG molecules are capable of binding to human IgG during its incubation. From the consecutive binding experiments it could also be concluded that antibodies present in the polyclonal anti-human IgG preparation were capable of binding to around four different epitopes on the human IgG. A final set of experiments addressed the stability of adsorbed human IgG layers with respect to drying and incubation with surfactant. The results revealed that the adsorbed antibody layer is relatively resistant to these treatments.

  • 31.
    Svensson, Olof
    et al.
    Malmö högskola, Faculty of Health and Society (HS).
    Halthur, Tobias
    Malmö högskola, Faculty of Health and Society (HS).
    Sjödin, Torgny
    Arnebrant, Thomas
    Malmö högskola, Faculty of Health and Society (HS).
    Adsorption of delmopinol at the solid/liquid interface - the role of the acid-base equilibrium2010In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 350, no 1, p. 275-281Article in journal (Refereed)
    Abstract [en]

    Delmopinol is a tertiary amine surfactant that is used to counteract dental plaque formation. As it is of interest to understand the interfacial behavior from both fundamental and applied perspectives the adsorption of delmopinol to model surfaces was investigated. Adsorption on Teflon, titanium and stainless steel was studied by radioactive labeling and adsorption on silica was studied by quartz crystal microbalance (QCM), ellipsometry and particle electrophoresis. It was shown that the adsorption of delmopinol was complex and strongly influenced by pH and concentration. Pronounced peak values were detected in the adsorption curves (adsorbed amount versus concentration) exceeding the expected value for a bilayer type of structure. To account for this behavior two surface active component were assumed to be present. Accordingly, the high amounts result from the deposition of the component with lower solubility and the decrease at the critical micelle concentration can be explained by solubilization of this component. Based on data from several experimental methods and the pH dependence of the effect we propose an explanation in which the protonated and non-protonated forms of delmopinol represent the two components. However, it cannot be excluded that the component with the lower solubility could be a compound chemically different from delmopinol in the sample.

  • 32.
    Svensson, Olof
    et al.
    Malmö högskola, Faculty of Health and Society (HS).
    Lindh, Liselott
    Malmö högskola, Faculty of Odontology (OD).
    Cárdenas, Marité
    Malmö högskola, Faculty of Health and Society (HS).
    Arnebrant, Thomas
    Malmö högskola, Faculty of Health and Society (HS).
    Layer-by-layer assembly of mucin and chitosan - Influence of surface properties, concentration and type of mucin2006In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 299, no 2, p. 608-616Article in journal (Refereed)
    Abstract [en]

    Bovine submaxillary mucin (BSM) and chitosan were used to build layer-by-layer structures on solid substrates. The build-up was monitored using in situ ellipsometry to obtain time resolved values of the thickness and adsorbed amount. Additionally surface morphology during build-up was studied by atomic force microscopy (AFM). It was found that the adsorbed amount of the film increases approximately linearly with each deposition cycle on hydrophobized silica whereas construction on silica was found not to be possible at the experimental conditions used. We conclude that sufficient amount of the first mucin layer is crucial for the subsequent multilayer formation. The complex build-up kinetics on hydrophobized silica is characterized by adsorption and redissolution processes and the overall growth is the sum of both processes. AFM imaging on hydrophobized silica also confirmed the presence of redissolution processes and chitosan addition led to a reduction both in the number of surface aggregates and in the roughness of the surface. The present work also shows that by adjusting the relative concentrations of the polyelectrolytes it is possible to change the growth rate considerably. The final structures after deposition of 8 bilayers were found to have a high content of water and film stability test revealed that a substantial amount dissolves when increasing electrolyte concentration or pH of the ambient solution. Human mucin from saliva (MUC5B) was also used to create multilayers with chitosan on hydrophobized silica and it was revealed that no redissolution appears to be present in this system.

  • 33.
    Svensson, Olof
    et al.
    Malmö högskola, Faculty of Health and Society (HS).
    Thuresson, Krister
    Arnebrant, Thomas
    Malmö högskola, Faculty of Health and Society (HS).
    Interactions between chitosan-modified particles and mucin-coated surfaces2008In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 2, no 325, p. 346-350Article in journal (Refereed)
    Abstract [en]

    Lipid-based particles (Cubosome® particles) were surface-modified by chitosan and the ratio between particles and chitosan was optimized to minimize the free chitosan concentration in the dispersion. The modified particles were characterized by electrophoretic measurements and the pH dependence of the zeta potential could be directly related to the protonation of chitosan. Interaction between the modified particles and mucin-coated silica surfaces were subsequently investigated in situ by ellipsometry to assess the mucoadhesive properties at physiologically relevant conditions. The result showed that a substantial amount of modified particles was adsorbed to mucin-coated silica surfaces at both pH 4 and pH 6, probably due to electrostatic interactions between amino groups in chitosan and negatively charged groups in mucin. Furthermore, the amount of bound particles decreased by less than 15% upon rinsing indicating relatively strong interactions. This investigation demonstrates that ellipsometry is a useful tool to study mucoadhesive properties of particles in the submicrometer range. Moreover, the novel chitosan-modified particles may be of interest for mucosal drug delivery applications.

  • 34.
    Tsompou, Andriani
    et al.
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Kocherbitov, Vitaly
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    The effects of water purity on removal of hydrophobic substances from solid surfaces without surfactants2022In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 608, p. 1929-1941Article in journal (Refereed)
    Abstract [en]

    Hypothesis: Detergents used in everyday life for cleaning and washing are a source of water pollution and can have a negative effect on human health and the environment. To reduce their negative impact, a new trend of using only purified water for washing and cleaning applications is emerging. A scientific basis of this method needs to be established, as its mechanisms and the efficiency should be better understood. Experiments: In this work, we investigate the effect of water purity on the removal of hydrophobic films from solid surfaces using quartz crystal microbalance with dissipation monitoring (QCM-D) and gravimetric experiments. We compared the cleaning efficiency of TAP water, two grades of purified water, NaCl solution and SDS solution. Findings: The QCM-D results show that both grades of purified water remove more than 90% of Vaseline deposited of the surface while tap water only 75%. SDS solution fully removes the deposited layer. Gravimetric experiments with removal of olive oil from hydrophilic and hydrophobic surfaces also indicate higher efficiency of purified water grades. Contact angle experiments show that pure water facilitates roll-up mechanism of cleaning. We suggest that due to lower ionic strength, purified water increases electrostatic repulsion and promotes the cleaning process.

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  • 35.
    Wang, Guang
    et al.
    Chinese Acad Sci, Inst High Energy Phys, Beijing 100049, Peoples R China.;Spallat Neutron Source Sci Ctr, Dongguan 523803, Peoples R China.;Deakin Univ, Inst Frontier Mat, Locked Bag 20000, Geelong, Vic 3220, Australia.;Czech Acad Sci, Inst Macromol Chem, Heyrovskeho Nam 2, Prague 162062 6, Czech Republic..
    Garvey, Christopher J.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Lund Inst Adv Neutron & Xray Sci, S-22370 Lund, Sweden.;Malmo Univ, Fac Hlth & Soc, Biofilm Res Ctr Biointerfaces, S-21119 Malmo, Sweden. ;Tech Univ Munich, Heinz Maier Leibnitz Zentrum MLZ, Lichtenbergstr 1, D-85748 Garching, Germany..
    Gu, Senlin
    Deakin Univ, Inst Frontier Mat, Locked Bag 20000, Geelong, Vic 3220, Australia..
    Gao, Weimin
    Deakin Univ, Inst Frontier Mat, Locked Bag 20000, Geelong, Vic 3220, Australia.;North China Univ Sci & Technol, Sch Met & Energy, Tangshan 063600, Peoples R China..
    O'Dell, Luke A.
    Deakin Univ, Inst Frontier Mat, Locked Bag 20000, Geelong, Vic 3220, Australia..
    Krause-Heuer, Anwen M.
    Australian Nucl Sci & Technol Org, Natl Deuterat Facil, Locked Bag 2001, Kirrawee Dc, NSW 2232, Australia..
    Darwish, Tamim A.
    Australian Nucl Sci & Technol Org, Natl Deuterat Facil, Locked Bag 2001, Kirrawee Dc, NSW 2232, Australia..
    Zhigunov, Alexander
    Czech Acad Sci, Inst Macromol Chem, Heyrovskeho Nam 2, Prague 162062 6, Czech Republic..
    Tong, Xin
    Chinese Acad Sci, Inst High Energy Phys, Beijing 100049, Peoples R China.;Spallat Neutron Source Sci Ctr, Dongguan 523803, Peoples R China..
    Kong, Lingxue
    Deakin Univ, Inst Frontier Mat, Locked Bag 20000, Geelong, Vic 3220, Australia..
    Controlling phase and rheological behaviours of hexagonal lyotropic liquid crystalline templates for nanostructural administration and retention2022In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 607, p. 816-825Article in journal (Refereed)
    Abstract [en]

    Introducing polymerizable monomers into a binary hexagonal lyotropic liquid crystalline (LLC) template is a straightforward way for retaining the nanostructure but will decrease attractive intra-and inter aggregate interactions. It is therefore crucial to understand the interfacial interactions at nanoscale after introducing the monomers but prior to polymerization. Herein, active species, poly (ethylene glycol) diacrylate (PEGDA) and 2-hydroxyethyl methacrylate (HEMA), were introduced into hexagonal LLC of dodecyl trimethylammonium bromide and water to explore the structural variables, dimensional stabil-ity, and dynamic property. At a proper volume ratio of PEGDA/HEMA (1/4), the system presents excellent homogeneity with a higher dimensional stability and lower dynamic property from rheological assess-ments, thereby achieving robust, free-standing, and transparent membranes after photo -polymerization. The unique property of the system also lies in the much lower order-disorder transition temperature (45 degrees C) that facilitates the reorientation of mesochannels. They are in contrast inaccessible for the ternary system only with PEGDA, though the nanostructure for both systems could be retained. An insight into subtle variations in these parameters allows us to prepare a polymerizable template possess-ing higher dimensional stability and suitable flexibility via molecular design, thereby enabling simulta-neous structural alignment and retention for the development of functional nanomaterials. (c) 2021 Elsevier Inc. All rights reserved.

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