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  • 1
    In: Molecules, MDPI AG, Vol. 25, No. 3 ( 2020-01-29), p. 582-
    Kurzfassung: Recent advancements in biomedicine have focused on designing novel and stable interfaces that can drive a specific cellular response toward the requirements of medical devices or implants. Among these, in recent years, electroactive polymers (i.e., polyvinylidene fluoride or PVDF) have caught the attention within the biomedical applications sector, due to their insolubility, stability in biological media, in vitro and in vivo non-toxicity, or even piezoelectric properties. However, the main disadvantage of PVDF-based bio-interfaces is related to the absence of the functional groups on the fluoropolymer and their hydrophobic character leading to a deficiency of cell adhesion and proliferation. This work was aimed at obtaining hydrophilic functional PVDF polymer coatings by using, for the first time, the one-step, matrix-assisted pulsed evaporation (MAPLE) method, testing the need of a post-deposition thermal treatment and analyzing their preliminary capacity to support MC3T3-E1 pre-osteoblast cell survival. As osteoblast cells are known to prefer rough surfaces, MAPLE deposition parameters were studied for obtaining coatings with roughness of tens to hundreds of nm, while maintaining the chemical properties similar to those of the pristine material. The in vitro studies indicated that all surfaces supported the survival of viable osteoblasts with active metabolisms, similar to the “control” sample, with no major differences regarding the thermally treated materials; this eliminates the need to use a secondary step for obtaining hydrophilic PVDF coatings. The physical-chemical characteristics of the thin films, along with the in vitro analyses, suggest that MAPLE is an adequate technique for fabricating PVDF thin films for further bio-applications.
    Materialart: Online-Ressource
    ISSN: 1420-3049
    Sprache: Englisch
    Verlag: MDPI AG
    Publikationsdatum: 2020
    ZDB Id: 2008644-1
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 2
    In: Nanomaterials, MDPI AG, Vol. 11, No. 6 ( 2021-05-21), p. 1367-
    Kurzfassung: Properties such as large surface area, high pore volume, high chemical and thermal stability, and structural flexibility render zeolitic imidazolate frameworks (ZIFs) well-suited materials for gas separation, chemical sensors, and optical and electrical devices. For such applications, film processing is a prerequisite. Herein, matrix-assisted pulsed laser evaporation (MAPLE) was successfully used as a single-step deposition process to fabricate ZIF-8 films. By correlating laser fluency and controlling the specific transfer of lab-synthesized ZIF-8, films with user-controlled physical and chemical properties were obtained. Films’ characteristics were evaluated by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The analysis showed that frameworks of ZIF-8 can be deposited successfully and controllably to yield polycrystalline films. The deposited films maintained the integrity of the individual ZIF-8 framework, while undergoing minor crystalline and surface chemistry changes. No significant changes in particle size were observed. Our study demonstrated control over both the MAPLE deposition conditions and the outcome, as well as the suitability of the listed deposition method to create composite architectures that could potentially be used in applications ranging from selective membranes to gas sensors.
    Materialart: Online-Ressource
    ISSN: 2079-4991
    Sprache: Englisch
    Verlag: MDPI AG
    Publikationsdatum: 2021
    ZDB Id: 2662255-5
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 3
    In: Colloids and Surfaces B: Biointerfaces, Elsevier BV, Vol. 162 ( 2018-02), p. 98-107
    Materialart: Online-Ressource
    ISSN: 0927-7765
    Sprache: Englisch
    Verlag: Elsevier BV
    Publikationsdatum: 2018
    ZDB Id: 1500523-9
    SSG: 12
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 4
    In: Nanomaterials, MDPI AG, Vol. 13, No. 1 ( 2022-12-23), p. 64-
    Kurzfassung: Nowadays, using polymers with specific characteristics to coat the surface of a device to prevent undesired biological responses can represent an optimal strategy for developing new and more efficient implants for biomedical applications. Among them, zwitterionic phosphorylcholine-based polymers are of interest due to their properties to resist cell and bacterial adhesion. In this work, the Matrix-Assisted Laser Evaporation (MAPLE) technique was investigated as a new approach for functionalising Polydimethylsiloxane (PDMS) surfaces with zwitterionic poly(2-Methacryloyloxyethyl-Phosphorylcholine) (pMPC) polymer. Evaluation of the physical–chemical properties of the new coatings revealed that the technique proposed has the advantage of achieving uniform and homogeneous stable moderate hydrophilic pMPC thin layers onto hydrophobic PDMS without any pre-treatment, therefore avoiding the major disadvantage of hydrophobicity recovery. The capacity of modified PDMS surfaces to reduce bacterial adhesion and biofilm formation was tested for Gram-positive bacteria, Staphylococcus aureus (S. aureus), and Gram-negative bacteria, Escherichia coli (E. coli). Cell adhesion, proliferation and morphology of human THP-1 differentiated macrophages and human normal CCD-1070Sk fibroblasts on the different surfaces were also assessed. Biological in vitro investigation revealed a significantly reduced adherence on PDMS–pMPC of both E. coli (from 29 × 10 6 to 3 × 102 CFU/mL) and S. aureus (from 29 × 106 to 3 × 102 CFU/mL) bacterial strains. Additionally, coated surfaces induced a significant inhibition of biofilm formation, an effect observed mainly for E. coli. Moreover, the pMPC coatings improved the capacity of PDMS to reduce the adhesion and proliferation of human macrophages by 50% and of human fibroblast by 40% compared to unmodified scaffold, circumventing undesired cell responses such as inflammation and fibrosis. All these highlighted the potential for the new PDMS–pMPC interfaces obtained by MAPLE to be used in the biomedical field to design new PDMS-based implants exhibiting long-term hydrophilic profile stability and better mitigating foreign body response and microbial infection.
    Materialart: Online-Ressource
    ISSN: 2079-4991
    Sprache: Englisch
    Verlag: MDPI AG
    Publikationsdatum: 2022
    ZDB Id: 2662255-5
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 5
    In: Applied Sciences, MDPI AG, Vol. 10, No. 18 ( 2020-09-10), p. 6299-
    Kurzfassung: Current trends in designing medical and tissue engineering systems rely on the incorporation of micro- and nano-topographies for inducing a specific cellular response within the context of an aimed application. As such, dedicated studies have recently focused on understanding the possible effects of high and low density packed topographies on the behavior of epithelial cells, especially when considering their long-term viability and functionality. We proposed to use stair-like designed topographies with three different degrees of distribution, all created in polydimethylsiloxane (PDMS) as active means to monitor cell behavior. Our model cellular system was human bronchial epithelial cells (BEAS-2B), a reference line in the quality control of mesenchymal stem cells (MSCs). PDMS microtextured substrates of 4 µm square unit topographies were created using a mold design implemented by a KrF Excimer laser. Varying the spacing between surface features and their multiscale level distribution led to irregular stairs/lines in low, medium and high densities, respectively. Profilometry, scanning electron and atomic force microscopy, contact angle and surface energy measurements were performed to evaluate the topographical and interface characteristics of the designed surfaces, while density-induced cellular effects were investigated using traditional cell-based assays. Our analysis showed that microstructure topographical distribution influences the adhesion profiles of epithelial cells. Our analysis hint that epithelial organoid formation might be initiated by the restriction of cell spreading and migration when using user-designed, controlled micro-topographies on engineered surfaces.
    Materialart: Online-Ressource
    ISSN: 2076-3417
    Sprache: Englisch
    Verlag: MDPI AG
    Publikationsdatum: 2020
    ZDB Id: 2704225-X
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 6
    In: Coatings, MDPI AG, Vol. 13, No. 3 ( 2023-02-24), p. 503-
    Kurzfassung: In this paper, results concerning hydrogen and deuterium plasma (RF, 13.56 MHz) interactions with tungsten surfaces, were reported. We used the Hollow-Cathode (HC) configuration for plasma–tungsten surface interaction experiments, along with the collection of tungsten dust, at different distances. Further on, the plasma-exposed tungsten surfaces and the collected dust were morphologically analyzed by contact profilometry, scanning electron microscopy, and energy dispersive spectroscopy measurements, along with chemical investigations by the X-ray photoelectron spectroscopy technique. The results showed that exposing the tungsten surfaces to the hydrogen plasma induces surface erosion phenomena along with the formation of dust and interconnected W structures. Herein, the mean ejected material volume was ~1.1 × 105 µm3. Deuterium plasma facilitated the formation of blisters at the surface level. For this case, the mean ejected material volume was ~3.3 × 104 µm3. For both plasma types, tungsten dust within nano- and micrometer sizes could be collected. The current study offers a perspective of lab-scaled plasma systems, which are capable of producing tungsten fusion-like surfaces and dust.
    Materialart: Online-Ressource
    ISSN: 2079-6412
    Sprache: Englisch
    Verlag: MDPI AG
    Publikationsdatum: 2023
    ZDB Id: 2662314-6
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 7
    Online-Ressource
    Online-Ressource
    Wiley ; 2018
    In:  Plasma Processes and Polymers Vol. 15, No. 1 ( 2018-01)
    In: Plasma Processes and Polymers, Wiley, Vol. 15, No. 1 ( 2018-01)
    Kurzfassung: Copper particles, generated using an atmospheric pressure plasma jet (APPJ), are characterized and their generation is studied. The particle synthesis is based on the vaporization/condensation process. In our study, we used a radiofrequency (RF) plasma jet operating in an inert gas and copper bulk metal as source material. The RF power effects on the plasma characteristics are investigated. Correlating the information obtained by optical emission spectroscopy (OES), with visual investigations and with the profilometric electrode surface analyses we identify a RF power threshold when particles starts to be formed. Moreover, the metal vaporization stabilized after a couple of minutes of discharge operation. The influences of RF power over the particles shape, mean size and size distributions are studied.
    Materialart: Online-Ressource
    ISSN: 1612-8850 , 1612-8869
    URL: Issue
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2018
    ZDB Id: 2159694-3
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 8
    In: Molecules, MDPI AG, Vol. 25, No. 18 ( 2020-09-08), p. 4097-
    Kurzfassung: We report on the investigation of stearic acid-layered double hydroxide (LDH) composite films, with controlled wettability capabilities, deposited by a combined pulsed laser deposition (PLD)-matrix-assisted pulsed laser evaporation (MAPLE) system. Two pulsed lasers working in IR or UV were used for experiments, allowing the use of proper deposition parameters (wavelength, laser fluence, repetition rate) for each organic and inorganic component material. We have studied the time stability and wettability properties of the films and we have seen that the morphology of the surface has a low effect on the wettability of the surfaces. The obtained composite films consist in stearic acid aggregates in LDH structure, exhibiting a shift to hydrophobicity after 36 months of storage.
    Materialart: Online-Ressource
    ISSN: 1420-3049
    Sprache: Englisch
    Verlag: MDPI AG
    Publikationsdatum: 2020
    ZDB Id: 2008644-1
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 9
    Online-Ressource
    Online-Ressource
    MDPI AG ; 2018
    In:  Coatings Vol. 8, No. 8 ( 2018-08-07), p. 275-
    In: Coatings, MDPI AG, Vol. 8, No. 8 ( 2018-08-07), p. 275-
    Kurzfassung: We report on the fabrication of shellac thin films on silicon substrates by matrix-assisted pulsed laser evaporation (MAPLE) using methanol as matrix. Very adherent, dense, and smooth films were obtained by MAPLE with optimized deposition parameters, such as laser wavelength and laser fluence. Films with a root mean square (RMS) roughness of 11 nm measured on 40 × 40 µm2 were obtained for a 2000-nm-thick shellac film deposited with 0.6 J/cm2 fluence at a laser wavelength of 266 nm. The MAPLE films were tested in simulated gastric fluid in order to assess their capabilities as an enteric coating. The chemical, morphological, and optical properties of shellac samples were investigated by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM).
    Materialart: Online-Ressource
    ISSN: 2079-6412
    Sprache: Englisch
    Verlag: MDPI AG
    Publikationsdatum: 2018
    ZDB Id: 2662314-6
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 10
    In: Polymers, MDPI AG, Vol. 12, No. 8 ( 2020-07-23), p. 1640-
    Kurzfassung: Polymer-based nanocomposites have recently received considerable attention due to their unique properties, which makes them feasible for applications in optics, sensors, energy, life sciences, etc. The present work focuses on the synthesis of nanocomposites consisting of a polytetrafluorethylene-like matrix in which metallic nano-silver are embedded, by using multiple magnetron plasmas. By successively exposing the substrate to separate RF magnetrons using as combination of target materials polytetrafluorethylene (PTFE) and silver, individual control of each deposition process is insured, allowing obtaining of structures in which silver nanoparticles are entrapped in-between two PTFE layers with given thicknesses. The topographical and morphological characteristics investigated by means of Scanning Electron Microscopy and Atomic Force Microscopy techniques evidenced the very presence of Ag nanoparticles with typical dimension 7 nm. The chemical composition at various depositing steps was evaluated through X-ray Photoelectron Spectroscopy. We show that the presence of the top PTFE layer prevents silver oxidation, while its thickness allows the tailoring of optical properties, as evidenced by spectroellipsometry. The appearance of chemical bonds between silver atoms and PTFE atoms at interfaces is observed, pointing out that despite of pure physical deposition processes, a chemical interaction between the polymeric matrix and metal is promoted by plasma.
    Materialart: Online-Ressource
    ISSN: 2073-4360
    Sprache: Englisch
    Verlag: MDPI AG
    Publikationsdatum: 2020
    ZDB Id: 2527146-5
    Standort Signatur Einschränkungen Verfügbarkeit
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