Entity

Time filter

Source Type


Meseck G.R.,University of Zurich | Kach A.,Center for Microscopy and Image Analysis | Seeger S.,University of Zurich
Journal of Physical Chemistry C | Year: 2014

One-dimensional (1D) nanostructures have been identified as key technology for future devices and integrated into surface-bound materials. The roughness of surface-bound 1D silicone nanofilaments (SNFs) has been used extensively to create surfaces with extreme wetting properties and as carrier material. Electron microscopy has shown that this material is made of individual filaments with diameters spanning tens of nanometers and a length of several micrometers which arrange into a highly entangled quasi-porous network. However, a comprehensive analysis of the three-dimensional (3D) superstructure has remained elusive so far. In this study, focused ion beam nanotomography (FIB-nt) is used to quantify the otherwise hardly accessible structural parameters roughness (12.68) and volume fraction (2.80). The volume fraction is anisotropic, and two major species of SNFs are quantified to contribute equally to the overall surface area. Spatial statistics reveals a self-avoiding growth pattern of SNFs over the substrate, and a 3D model of the data is rendered. The presented analysis therefore significantly advances the understanding of SNF surface coatings with regard to their structure at the nano- and microscale. Finally, the described procedure may serve as a useful tool to analyze other surface-bound 1D nanostructures of similar complex arrangement. © 2014 American Chemical Society. Source


Wild P.,Institute of Veterinar Anatomy | Wild P.,Institute of Virology | Leisinger S.,Institute of Veterinar Anatomy | de Oliveira A.P.,Institute of Virology | And 5 more authors.
Viruses | Year: 2015

Herpes simplex virus 1 (HSV-1) capsids are assembled in the nucleus bud at the inner nuclear membrane into the perinuclear space, acquiring envelope and tegument. In theory, these virions are de-enveloped by fusion of the envelope with the outer nuclear membrane and re-enveloped by Golgi membranes to become infective. Us3 enables the nucleus to cytoplasm capsid translocation. Nevertheless, Us3 is not essential for the production of infective progeny viruses. Determination of phenotype distribution by quantitative electron microscopy, and calculation per mean nuclear or cell volume revealed the following: (i) The number of R7041(ΔUS3) capsids budding at the inner nuclear membrane was significantly higher than that of wild type HSV-1; (ii) The mean number of R7041(ΔUS3) virions per mean cell volume was 2726, that of HSV-1 virions 1460 by 24 h post inoculation; (iii) 98% of R7041(ΔUS3) virions were in the perinuclear space; (iv) The number of R7041(ΔUS3) capsids in the cytoplasm, including those budding at Golgi membranes, was significantly reduced. Cell associated R7041(ΔUS3) yields were 2.37 × 108 and HSV-1 yields 1.57 × 108 PFU/mL by 24 h post inoculation. We thus conclude that R7041(ΔUS3) virions, which acquire envelope and tegument by budding at the inner nuclear membrane into the perinuclear space, are infective. © 2015 by the authors; licensee MDPI, Basel, Switzerland. Source


Meseck G.R.,University of Swaziland | Kach A.,Center for Microscopy and Image Analysis | Seeger S.,University of Swaziland
Journal of Physical Chemistry C | Year: 2014

One-dimensional (1D) nanostructures have been identified as key technology for future devices and integrated into surface-bound materials. The roughness of surface-bound 1D silicone nanofilaments (SNFs) has been used extensively to create surfaces with extreme wetting properties and as carrier material. Electron microscopy has shown that this material is made of individual filaments with diameters spanning tens of nanometers and a length of several micrometers which arrange into a highly entangled quasi-porous network. However, a comprehensive analysis of the three-dimensional (3D) superstructure has remained elusive so far. In this study, focused ion beam nanotomography (FIB-nt) is used to quantify the otherwise hardly accessible structural parameters roughness (12.68) and volume fraction (2.80). The volume fraction is anisotropic, and two major species of SNFs are quantified to contribute equally to the overall surface area. Spatial statistics reveals a self-avoiding growth pattern of SNFs over the substrate, and a 3D model of the data is rendered. The presented analysis therefore significantly advances the understanding of SNF surface coatings with regard to their structure at the nano- and microscale. Finally, the described procedure may serve as a useful tool to analyze other surface-bound 1D nanostructures of similar complex arrangement. © 2014 American Chemical Society. Source


Jacobson M.,University of Zurich | Roth Z'Graggen B.,University of Zurich | Graber S.M.,University of Zurich | Schumacher C.M.,ETH Zurich | And 9 more authors.
Nanomedicine | Year: 2015

Aim: Magnetic field guided drug targeting holds promise for more effective cancer treatment. Intravascular application of magnetic nanoparticles, however, bears the risk of potentially important, yet poorly understood side effects, such as off-Target accumulation in endothelial cells. Materials & methods: Here, we investigated the influence of shear stress (0-3.22 dyn/cm), exposure time (5-30 min) and endothelial activation on the uptake of ferromagnetic carbon-encapsulated iron carbide nanomagnets into endothelial cells in an in vitro flow cell model. Results: We found that even moderate shear stresses typically encountered in the venous system strongly reduce particle uptake compared with static conditions. Interestingly, a pronounced particle uptake was observed in inflamed endothelial cells. Conclusion: This study highlights the importance of relevant exposure scenarios accounting for physiological conditions when studying particle-cell interactions as, for example, shear stress and endothelial activation are major determinants of particle uptake. Such considerations are of particular importance with regard to successful translation of in vitro findings into (pre-)clinical end points. © 2015 Future Medicine Ltd. Source

Discover hidden collaborations