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  1. Article ; Online: Continuous Microfluidic Production of Citrem-Phosphatidylcholine Nano-Self-Assemblies for Thymoquinone Delivery

    Esra Ilhan-Ayisigi / Aghiad Ghazal / Barbara Sartori / Maria Dimaki / Winnie Edith Svendsen / Ozlem Yesil-Celiktas / Anan Yaghmur

    Nanomaterials, Vol 11, Iss 1510, p

    2021  Volume 1510

    Abstract: Lamellar and non-lamellar liquid crystalline nanodispersions, including liposomes, cubosomes, and hexosomes are attractive platforms for drug delivery, bio-imaging, and related pharmaceutical applications. As compared to liposomes, there is a modest ... ...

    Abstract Lamellar and non-lamellar liquid crystalline nanodispersions, including liposomes, cubosomes, and hexosomes are attractive platforms for drug delivery, bio-imaging, and related pharmaceutical applications. As compared to liposomes, there is a modest number of reports on the continuous production of cubosomes and hexosomes. Using a binary lipid mixture of citrem and soy phosphatidylcholine (SPC), we describe the continuous production of nanocarriers for delivering thymoquinone (TQ, a substance with various therapeutic potentials) by employing a commercial microfluidic hydrodynamic flow-focusing chip. In this study, nanoparticle tracking analysis (NTA) and synchrotron small-angle X-ray scattering (SAXS) were employed to characterize TQ-free and TQ-loaded citrem/SPC nanodispersions. Microfluidic synthesis led to formation of TQ-free and TQ-loaded nanoparticles with mean sizes around 115 and 124 nm, and NTA findings indicated comparable nanoparticle size distributions in these nanodispersions. Despite the attractiveness of the microfluidic chip for continuous production of citrem/SPC nano-self-assemblies, it was not efficient as comparable mean nanoparticle sizes were obtained on employing a batch (discontinuous) method based on low-energy emulsification method. SAXS results indicated the formation of a biphasic feature of swollen lamellar (L α ) phase in coexistence with an inverse bicontinuous cubic Pn3m phase in all continuously produced TQ-free and TQ-loaded nanodispersions. Further, a set of SAXS experiments were conducted on samples prepared using the batch method for gaining further insight into the effects of ethanol and TQ concentration on the structural features of citrem/SPC nano-self-assemblies. We discuss these effects and comment on the need to introduce efficient microfluidic platforms for producing nanocarriers for delivering TQ and other therapeutic agents.
    Keywords thymoquinone ; inverse bicontinuous cubic Pn3m phase ; microfluidics ; nanoparticle tracking analysis ; synchrotron small-angle scattering ; Chemistry ; QD1-999
    Subject code 500
    Language English
    Publishing date 2021-06-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Carboxymethyl-Dextran-Coated Superparamagnetic Iron Oxide Nanoparticles for Drug Delivery

    Chiara Turrina / Davide Milani / Anna Klassen / Diana M. Rojas-González / Jennifer Cookman / Matthias Opel / Barbara Sartori / Petra Mela / Sonja Berensmeier / Sebastian P. Schwaminger

    International Journal of Molecular Sciences, Vol 23, Iss 14743, p

    Influence of the Coating Thickness on the Particle Properties

    2022  Volume 14743

    Abstract: Carboxymethyl-dextran (CMD)-coated iron oxide nanoparticles (IONs) are of great interest in nanomedicine, especially for applications in drug delivery. To develop a magnetically controlled drug delivery system, many factors must be considered, including ... ...

    Abstract Carboxymethyl-dextran (CMD)-coated iron oxide nanoparticles (IONs) are of great interest in nanomedicine, especially for applications in drug delivery. To develop a magnetically controlled drug delivery system, many factors must be considered, including the composition, surface properties, size and agglomeration, magnetization, cytocompatibility, and drug activity. This study reveals how the CMD coating thickness can influence these particle properties. ION@CMD are synthesized by co-precipitation. A higher quantity of CMD leads to a thicker coating and a reduced superparamagnetic core size with decreasing magnetization. Above 12.5–25.0 g L −1 of CMD, the particles are colloidally stable. All the particles show hydrodynamic diameters < 100 nm and a good cell viability in contact with smooth muscle cells, fulfilling two of the most critical characteristics of drug delivery systems. New insights into the significant impact of agglomeration on the magnetophoretic behavior are shown. Remarkable drug loadings (62%) with the antimicrobial peptide lasioglossin and an excellent efficiency (82.3%) were obtained by covalent coupling with the EDC/NHS (N-ethyl-N′-(3-(dimethylamino)propyl)carbodiimide/N-hydroxysuccinimide) method in comparison with the adsorption method (24% drug loading, 28% efficiency). The systems showed high antimicrobial activity with a minimal inhibitory concentration of 1.13 µM (adsorption) and 1.70 µM (covalent). This system successfully combines an antimicrobial peptide with a magnetically controllable drug carrier.
    Keywords carboxymethyl dextran ; iron oxide nanoparticles ; antimicrobial peptide ; magnetically controlled drug delivery ; agglomeration behavior ; Biology (General) ; QH301-705.5 ; Chemistry ; QD1-999
    Subject code 620
    Language English
    Publishing date 2022-11-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article: Comparative Perturbation Effects Exerted by the Influenza A M2 WT Protein Inhibitors Amantadine and the Spiro[pyrrolidine-2,2′-adamantane] Variant AK13 to Membrane Bilayers Studied Using Biophysical Experiments and Molecular Dynamics Simulations

    Konstantinidi, Athina / Antonios Kolocouris / Barbara Sartori / Costas Demetzos / Dimitrios Ntountaniotis / Dimitris Kolokouris / Gregor Mali / Heinz Amentisch / Maria Chountoulesi / Nikolaos Naziris / Sophia Kiriakidi / Thomas Mavromoustakos

    Journal of physical chemistry. 2018 Oct. 04, v. 122, no. 43

    2018  

    Abstract: Aminoadamantane drugs are lipophilic amines that block the membrane-embedded influenza A M2 WT (wild type) ion channel protein. The comparative effects of amantadine (Amt) and its synthetic spiro[pyrrolidine-2,2′-adamantane] (AK13) analogue in ... ...

    Abstract Aminoadamantane drugs are lipophilic amines that block the membrane-embedded influenza A M2 WT (wild type) ion channel protein. The comparative effects of amantadine (Amt) and its synthetic spiro[pyrrolidine-2,2′-adamantane] (AK13) analogue in dimyristoylphosphatidylcholine (DMPC) bilayers were studied using a combination of experimental biophysical methods, differential scanning calorimetry (DSC), X-ray diffraction, solid-state NMR (ssNMR) spectroscopy, and molecular dynamics (MD) simulations. All three experimental methods pointed out that the two analogues perturbed drastically the DMPC bilayers with AK13 to be more effective at high concentrations. AK13 was tolerated in lipid bilayers at very high concentrations, while Amt was crystallized. This is an important consideration in the formulations of drugs as it designates a limitation of Amt incorporation. MD simulations verify provided details about the strong interactions of the drugs in the interface region between phosphoglycerol backbone and lipophilic segments. The two drugs form hydrogen bonding with both water and sn-2 carbonyls in their amine form or water and phosphate oxygens in their ammonium form. Such localization of the drugs explains the DMPC bilayers reorientation and their strong perturbing effect evidenced by all biophysical methodologies applied.
    Keywords amines ; ammonium ; differential scanning calorimetry ; drugs ; hydrogen bonding ; influenza ; ion channels ; lipid bilayers ; lipophilicity ; molecular dynamics ; nuclear magnetic resonance spectroscopy ; phosphates ; simulation models ; X-ray diffraction
    Language English
    Dates of publication 2018-1004
    Size p. 9877-9895.
    Publishing place American Chemical Society
    Document type Article
    ISSN 1520-5207
    DOI 10.1021/acs.jpcb.8b07071
    Database NAL-Catalogue (AGRICOLA)

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  4. Article ; Online: Calcium triggered L alpha-H2 phase transition monitored by combined rapid mixing and time-resolved synchrotron SAXS.

    Anan Yaghmur / Peter Laggner / Barbara Sartori / Michael Rappolt

    PLoS ONE, Vol 3, Iss 4, p e

    2008  Volume 2072

    Abstract: Awad et al. reported on the Ca(2+)-induced transitions of dioleoyl-phosphatidylglycerol (DOPG)/monoolein (MO) vesicles to bicontinuous cubic phases at equilibrium conditions. In the present study, the combination of rapid mixing and time-resolved ... ...

    Abstract Awad et al. reported on the Ca(2+)-induced transitions of dioleoyl-phosphatidylglycerol (DOPG)/monoolein (MO) vesicles to bicontinuous cubic phases at equilibrium conditions. In the present study, the combination of rapid mixing and time-resolved synchrotron small-angle X-ray scattering (SAXS) was applied for the in-situ investigations of fast structural transitions of diluted DOPG/MO vesicles into well-ordered nanostructures by the addition of low concentrated Ca(2+) solutions.Under static conditions and the in absence of the divalent cations, the DOPG/MO system forms large vesicles composed of weakly correlated bilayers with a d-spacing of approximately 140 A (L(alpha)-phase). The utilization of a stopped-flow apparatus allowed mixing these DOPG/MO vesicles with a solution of Ca(2+) ions within 10 milliseconds (ms). In such a way the dynamics of negatively charged PG to divalent cation interactions, and the kinetics of the induced structural transitions were studied. Ca(2+) ions have a very strong impact on the lipidic nanostructures. Intriguingly, already at low salt concentrations (DOPG/Ca(2+)>2), Ca(2+) ions trigger the transformation from bilayers to monolayer nanotubes (inverted hexagonal phase, H(2)). Our results reveal that a binding ratio of 1 Ca(2+) per 8 DOPG is sufficient for the formation of the H(2) phase. At 50 degrees C a direct transition from the vesicles to the H(2) phase was observed, whereas at ambient temperature (20 degrees C) a short lived intermediate phase (possibly the cubic Pn3m phase) coexisting with the H(2) phase was detected.The strong binding of the divalent cations to the negatively charged DOPG molecules enhances the negative spontaneous curvature of the monolayers and causes a rapid collapsing of the vesicles. The rapid loss of the bilayer stability and the reorganization of the lipid molecules within ms support the argument that the transition mechanism is based on a leaky fusion of the vesicles.
    Keywords Medicine ; R ; Science ; Q
    Subject code 540
    Language English
    Publishing date 2008-04-01T00:00:00Z
    Publisher Public Library of Science (PLoS)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article ; Online: Cantilever bending based on humidity-actuated mesoporous silica/silicon bilayers

    Christian Ganser / Gerhard Fritz-Popovski / Roland Morak / Parvin Sharifi / Benedetta Marmiroli / Barbara Sartori / Heinz Amenitsch / Thomas Griesser / Christian Teichert / Oskar Paris

    Beilstein Journal of Nanotechnology, Vol 7, Iss 1, Pp 637-

    2016  Volume 644

    Abstract: We use a soft templating approach in combination with evaporation induced self-assembly to prepare mesoporous films containing cylindrical pores with elliptical cross-section on an ordered pore lattice. The film is deposited on silicon-based commercial ... ...

    Abstract We use a soft templating approach in combination with evaporation induced self-assembly to prepare mesoporous films containing cylindrical pores with elliptical cross-section on an ordered pore lattice. The film is deposited on silicon-based commercial atomic force microscope (AFM) cantilevers using dip coating. This bilayer cantilever is mounted in a humidity controlled AFM, and its deflection is measured as a function of relative humidity. We also investigate a similar film on bulk silicon substrate using grazing-incidence small-angle X-ray scattering (GISAXS), in order to determine nanostructural parameters of the film as well as the water-sorption-induced deformation of the ordered mesopore lattice. The strain of the mesoporous layer is related to the cantilever deflection using simple bilayer bending theory. We also develop a simple quantitative model for cantilever deflection which only requires cantilever geometry and nanostructural parameters of the porous layer as input parameters.
    Keywords AFM cantilever ; bilayer bending ; grazing incidence small-angle X-ray scattering (GISAXS) ; mesoporous film ; sorption-induced deformation ; Technology ; T ; Chemical technology ; TP1-1185 ; Science ; Q ; Physics ; QC1-999
    Subject code 530
    Language English
    Publishing date 2016-04-01T00:00:00Z
    Publisher Beilstein-Institut
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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