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search.filters.applied.f.access: openAccess × Author: Kraegeloh, Annette × Author: Tavernaro, Isabella × Start date: 2000 × Has files: Yes × Type: Text × WGL Institute: INM ×

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Now showing 1 - 6 of 6
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    Bright fluorescent silica-nanoparticle probes for high-resolution STED and confocal microscopy
    (Frankfurt am Main : Beilstein-Institut, 2017) Tavernaro, Isabella; Cavelius, Christian; Peuschel, Henrike; Kraegeloh, Annette
    In recent years, fluorescent nanomaterials have gained high relevance in biological applications as probes for various fluorescencebased spectroscopy and imaging techniques. Among these materials, dye-doped silica nanoparticles have demonstrated a high potential to overcome the limitations presented by conventional organic dyes such as high photobleaching, low stability and limited fluorescence intensity. In the present work we describe an effective approach for the preparation of fluorescent silica nanoparticles in the size range between 15 and 80 nm based on L-arginine-controlled hydrolysis of tetraethoxysilane in a biphasic cyclohexane–water system. Commercially available far-red fluorescent dyes (Atto647N, Abberior STAR 635, Dy-647, Dy-648 and Dy-649) were embedded covalently into the particle matrix, which was achieved by aminosilane coupling. The physical particle attributes (particle size, dispersion, degree of agglomeration and stability) and the fluorescence properties of the obtained particles were compared to particles from commonly known synthesis methods. As a result, the spectroscopic characteristics of the presented monodisperse dye-doped silica nanoparticles were similar to those of the free uncoupled dyes, but indicate a much higher photostability and brightness. As revealed by dynamic light scattering and ζ-potential measurements, all particle suspensions were stable in water and cell culture medium. In addition, uptake studies on A549 cells were performed, using confocal and stimulated emission depletion (STED) microscopy. Our approach allows for a step-by-step formation of dye-doped silica nanoparticles in the form of dye-incorporated spheres, which can be used as versatile fluorescent probes in confocal and STED imaging.
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    Targeted T1 Magnetic Resonance Imaging Contrast Enhancement with Extraordinarily Small CoFe2O4 Nanoparticles
    (Washington, DC : American Chemical Society, 2019) Piché, Dominique; Tavernaro, Isabella; Fleddermann, Jana; Lozano, Juan G.; Varambhia, Aakash; Maguire, Mahon L.; Koch, Marcus; Ukai, Tomofumi; Hernández Rodríguez, Armando J.; Jones, Lewys; Dillon, Frank; Reyes Molina, Israel; Mitzutani, Mai; González Dalmau, Evelio R.; Maekawa, Toru; Nellist, Peter D.; Kraegeloh, Annette; Grobert, Nicole
    Extraordinarily small (2.4 nm) cobalt ferrite nanoparticles (ESCIoNs) were synthesized by a one-pot thermal decomposition approach to study their potential as magnetic resonance imaging (MRI) contrast agents. Fine size control was achieved using oleylamine alone, and annular dark-field scanning transmission electron microscopy revealed highly crystalline cubic spinel particles with atomic resolution. Ligand exchange with dimercaptosuccinic acid rendered the particles stable in physiological conditions with a hydrodynamic diameter of 12 nm. The particles displayed superparamagnetic properties and a low r2/r1 ratio suitable for a T1 contrast agent. The particles were functionalized with bile acid, which improved biocompatibility by significant reduction of reactive oxygen species generation and is a first step toward liver-targeted T1 MRI. Our study demonstrates the potential of ESCIoNs as T1 MRI contrast agents.
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    Silica nanoparticles for intracellular protein delivery: A novel synthesis approach using green fluorescent protein
    (London : BioMed Central, 2017) Schmidt, Sarah; Tavernaro, Isabella; Cavelius, Christian; Weber, Eva; Kümper, Alexander; Schmitz, Carmen; Fleddermann, Jana; Kraegeloh, Annette
    In this study, a novel approach for preparation of green fluorescent protein (GFP)-doped silica nanoparticles with a narrow size distribution is presented. GFP was chosen as a model protein due to its autofluorescence. Protein-doped nanoparticles have a high application potential in the field of intracellular protein delivery. In addition, fluorescently labelled particles can be used for bioimaging. The size of these protein-doped nanoparticles was adjusted from 15 to 35 nm using a multistep synthesis process, comprising the particle core synthesis followed by shell regrowth steps. GFP was selectively incorporated into the silica matrix of either the core or the shell or both by a one-pot reaction. The obtained nanoparticles were characterised by determination of particle size, hydrodynamic diameter, ζ-potential, fluorescence and quantum yield. The measurements showed that the fluorescence of GFP was maintained during particle synthesis. Cellular uptake experiments demonstrated that the GFP-doped nanoparticles can be used as stable and effective fluorescent probes. The study reveals the potential of the chosen approach for incorporation of functional biological macromolecules into silica nanoparticles, which opens novel application fields like intracellular protein delivery.
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    Distribution of SiO2 nanoparticles in 3D liver microtissues
    (Macclesfield : Dove Medical Press, 2019) Fleddermann, Jana; Susewind, Julia; Peuschel, Henrike; Koch, Marcus; Tavernaro, Isabella; Kraegeloh, Annette
    Introduction: Nanoparticles (NPs) are used in numerous products in technical fields and biomedicine; their potential adverse effects have to be considered in order to achieve safe applications. Besides their distribution in tissues, organs, and cellular localization, their impact and penetration during the process of tissue formation occurring in vivo during liver regeneration are critical steps for establishment of safe nanomaterials. Materials and methods: In this study, 3D cell culture of human hepatocarcinoma cells (HepG2) was used to generate cellular spheroids, serving as in vitro liver microtissues. In order to determine their differential distribution and penetration depth in HepG2 spheroids, SiO2 NPs were applied either during or after spheroid formation. The NP penetration was comprehensively studied using confocal laser scanning microscopy and scanning electron microscopy. Results: Spheroids were exposed to 100 µg mL-1 SiO2 NPs either at the beginning of spheroid formation, or during or after formation of spheroids. Microscopy analyses revealed that NP penetration into the spheroid is limited. During and after spheroid formation, SiO2 NPs penetrated about 20 µm into the spheroids, corresponding to about three cell layers. In contrast, because of the addition of SiO2 NPs simultaneously to cell seeding, NP agglomerates were located also in the spheroid center. Application of SiO2 NPs during the process of spheroid formation had no impact on final spheroid size. Conclusion: Understanding the distribution of NPs in tissues is essential for biomedical applications. The obtained results indicate that NPs show only limited penetration into already formed tissue, which is probably caused by the alteration of the tissue structure and cell packing density during the process of spheroid formation.
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    Safe-by-Design part II: A strategy for balancing safety and functionality in the different stages of the innovation process
    (Amsterdam : Elsevier, 2021) Tavernaro, Isabella; Dekkers, Susan; Soeteman-Hernández, Lya G.; Herbeck-Engel, Petra; Noorlander, Cornelle; Kraegeloh, Annette
    Manufactured nanomaterials have the potential to impact an exceedingly wide number of industries and markets ranging from energy storage, electronic and optical devices, light-weight construction to innovative medical approaches for diagnostics and therapy. In order to foster the development of safer nanomaterial-containing products, two main aspects are of major interest: their functional performance as well as their safety towards human health and the environment. In this paper a first proposal for a strategy is presented to link the functionality of nanomaterials with safety aspects. This strategy first combines information on the functionality and safety early during the innovation process and onwards, and then identifies Safe-by-Design (SbD) actions that allow for optimisation of both aspects throughout the innovation process. The strategy encompasses suggestions for the type of information needed to balance functionality and safety to support decision making in the innovation process. The applicability of the strategy is illustrated using a literature-based case study on carbon nanotube-based transparent conductive films. This is a first attempt to identify information that can be used for balancing functionality and safety in a structured way during innovation processes.
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    High-dose intranasal application of titanium dioxide nanoparticles induces the systemic uptakes and allergic airway inflammation in asthmatic mice
    (London : BioMed Central, 2020) Harfoush, Shaza Abdulnasser; Hannig, Matthias; Le, Duc Dung; Heck, Sebastian; Leitner, Maximilian; Omlor, Albert Joachim; Tavernaro, Isabella; Kraegeloh, Annette; Kautenburger, Ralf; Kickelbick, Guido; Beilhack, Andreas; Bischoff, Markus; Nguyen, Juliane; Sester, Martina; Bals, Robert; Dinh, Quoc Thai
    Background Titanium dioxide nanoparticles (TiO2 NPs) have a wide range of applications in several industrial and biomedical domains. Based on the evidence, the workers exposed to inhaled nanosized TiO2 powder are more susceptible to the risks of developing respiratory diseases. Accordingly, this issue has increasingly attracted the researchers’ interest in understanding the consequences of TiO2 NPs exposure. Regarding this, the present study was conducted to analyze the local effects of TiO2 NPs on allergic airway inflammation and their uptake in a mouse model of ovalbumin (OVA)-induced allergic airway inflammation. Methods For the purpose of the study, female BALB/c mice with or without asthma were intranasally administered with TiO2 NPs. The mice were subjected to histological assessment, lung function testing, scanning electron microscopy (SEM), inductively coupled plasma mass spectrometry (ICP-MS), and NP uptake measurement. In addition, T helper (Th) 1/Th2 cytokines were evaluated in the lung homogenate using the enzyme-linked immunosorbent assay. Results According to the results, the mice receiving OVA alone or OVA plus TiO2 NPs showed eosinophilic infiltrates and mucus overproduction in the lung tissues, compared to the controls. Furthermore, a significant elevation was observed in the circulating Th2 cytokines, including interleukin (IL)-4, IL-5, and IL-13 after NP exposure. The TiO2 NPs were taken up by alveolar macrophages at different time points. As the results of the SEM and ICP-MS indicated, TiO2 NPs were present in most of the organs in both asthmatic and non-asthmatic mice. Conclusion Based on the findings of the current study, intranasally or inhalation exposure to high-dose nanosized TiO2 particles appears to exacerbate the allergic airway inflammation and lead to systemic uptake in extrapulmonary organs. These results indicate the very important need to investigate the upper limit of intranasally or inhalation exposure to nanosized TiO2 particles in occupational and environmental health policy.