Distribution of SiO2 nanoparticles in 3D liver microtissues

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

Silica nanoparticles for intracellular protein delivery: A novel synthesis approach using green fluorescent protein

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

Popularization of health in public television: the case of RTVE in 2016

La televisión es el principal medio al que los ciudadanos están expuestos para informarse sobre temas de ciencia y tecnología (FECYT, 2015). El servicio pú- blico radiotelevisivo es el ente, que, por ley, debe atender a las necesidades de información, cultura, educación y entretenimiento de la ciudadanía. Esta investigación tiene como objetivo conocer el tratamiento informativo y audiovisual de los programas especializados en salud de RTVE. La muestra cuenta con aquellos emitidos en 2016: La mañana (incluye Saber Vivir), Centro Médico, Esto es Vida y El Ojo Clínico. La metodología empleada es el estudio de caso: se elabora una triangulación a partir de una exploración descriptivo-analítica de los programas seleccionados, un cuestionario sobre la recepción informativa de los mismos y un análisis de contenido de una serie de episodios y, a su vez, de los tweets emitidos por sus respectivas cuentas durante el último mes. Las variables miden aspectos del tratamiento informativo y audiovisual de los programas, así como la funcionalidad, el tratamiento informativo de los tuits y el contenido extra que aportan. Los resultados presentan como rasgo común la conducción de la información a través de fuentes personales. Asimismo, destaca El Ojo Clínico y Esto es Vida por su tratamiento divulgativo, tanto en pantalla como en Twitter.Citizens inform themselves about science and technology mainly through television (FECYT, 2015) and the public broadcasting service is the entity that by law must offer the information, culture, education and entertainment that citizens need. This research aims to know the informative and audiovisual treatment of RTVE’s specialized health programs. The sample consists of the programmes broadcasted in 2016: La mañana (includes Saber Vivir), Centro Médico, Esto es Vida and El Ojo Clínico. A case study methodology will be implemented, a triangulation of methods is applied: a descriptive-analytical exploration of the selected programs, a content analysis of some episodes and of a sample of official tweets issued by the tv programmes accounts and a questionnaire on the informative reception by the audience. The variables analyse aspects of the informative and audiovisual treatment of the tv programmes, as well as tweet’s aims and reporting style. An overall result is the common usage of personal information as scientific sources. El Ojo Clínico and Esto es Vida need to be highlighted for their positive informative reporting, both on screen and on Twitter

Targeted T1 Magnetic Resonance Imaging Contrast Enhancement with Extraordinarily Small CoFe2O4 Nanoparticles

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

Kinetic and spectroscopic responses of pH-sensitive nanoparticles: influence of the silica matrix

Intracellular pH sensing with fluorescent nanoparticles is an emerging topic as pH plays several roles in physiology and pathologic processes. Here, nanoparticle-sized pH sensors (diameter far below 50 nm) for fluorescence imaging have been described. Consequently, a fluorescent derivative of pH-sensitive hydroxypyrene with pKa = 6.1 was synthesized and subsequently embedded in core and core–shell silica nanoparticles via a modified Stöber process. The detailed fluorescence spectroscopic characterization of the produced nanoparticles was carried out for retrieving information about the environment within the nanoparticle core. Several steady-state and time-resolved fluorescence spectroscopic methods hint to the screening of the probe molecule from the solvent, but it sustained interactions with hydrogen bonds similar to that of water. The incorporation of the indicator dye in the water-rich silica matrix neither changes the acidity constant nor dramatically slows down the protonation kinetics. However, cladding by another SiO2 shell leads to the partial substitution of water and decelerating the response of the probe molecule toward pH. The sensor is capable of monitoring pH changes in a physiological range by using ratiometric fluorescence excitation with λex = 405 nm and λex = 488 nm, as confirmed by the confocal fluorescence imaging of intracellular nanoparticle uptake.DFGDFG JU650/7-1 and DFG JUG650/8-

Silica Nanoparticles for Intracellular Protein Delivery: a Novel Synthesis Approach Using Green Fluorescent Protein

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

Additional file 3: Figure S3. of Silica Nanoparticles for Intracellular Protein Delivery: a Novel Synthesis Approach Using Green Fluorescent Protein

TEM images of GFP(ʟ-arginine)-doped particles; particles after the first regrowth step (core + shell) with an unlabelled shell (CFS1U, dTEM = 21.1 ± 1.6 nm) and particles after the second regrowth step (core + shell + shell) [CFS1FS2U (dTEM = 31.7 ± 1.6 nm), CFS1US2F (dTEM = 34.1 ± 1.6 nm), CFS1US2U (dTEM = 33.1 ± 1.7 nm)]. (JPEG 140 kb

Additional file 1: Figure S1. of Silica Nanoparticles for Intracellular Protein Delivery: a Novel Synthesis Approach Using Green Fluorescent Protein

TEM images of GFP(NaHCO3) modified particles; nanoparticles after the first regrowth step (core + shell) with a labelled shell (CFS1F, dTEM = 22.7 ± 2.1 nm) with an unlabelled shell (CFS1U, dTEM = 21.9 ± 1.7 nm). (JPEG 53 kb