Ergebnisse einschränken






Université de Fribourg

Nanoparticle colloidal stability in cell culture media and impact on cellular interactions

Moore, Thomas L. ; Rodriguez-Lorenzo, Laura ; Hirsch, Vera ; Balog, Sandor ; Urban, Dominic ; Jud, Corinne ; Rothen-Rutishauser, Barbara ; Lattuada, Marco ; Petri-Fink, Alke

In: Chemical Society Reviews, 2015, vol. 44, no. 17, p. 6287–6305

Nanomaterials are finding increasing use for biomedical applications such as imaging, diagnostics, and drug delivery. While it is well understood that nanoparticle (NP) physico-chemical properties can dictate biological responses and interactions, it has been difficult to outline a unifying framework to directly link NP properties to expected in vitro and in vivo outcomes. When introduced to...

Université de Fribourg

Nanoparticle polydispersity can strongly affect in vitro dose

Rodriguez-Lorenzo, Laura ; Rothen-Rutishauser, Barbara ; Petri-Fink, Alke ; Balog, Sandor

In: Particle & Particle Systems Characterization, 2015, vol. 32, no. 3, p. 321–333

When nanomaterials meet the biological world, the cellular interaction of nanoparticles is routinely assessed in in vitro systems. Establishing dose–response relationships requires that the dose of nanoparticles delivered to the cell is accurate and precise. Nanoparticles as such or coated with high molecular-weight compounds are rarely uniform and the influence of heterogeneity, including...

Université de Fribourg

Avoiding drying-artifacts in transmission electron microscopy: Characterizing the size and colloidal state of nanoparticles

Michen, Benjamin ; Geers, Christoph ; Vanhecke, Dimitri ; Endes, Carola ; Rothen-Rutishauser, Barbara ; Balog, Sandor ; Petri-Fink, Alke

In: Scientific Reports, 2015, vol. 5, p. 9793

Standard transmission electron microscopy nanoparticle sample preparation generally requires the complete removal of the suspending liquid. Drying often introduces artifacts, which can obscure the state of the dispersion prior to drying and preclude automated image analysis typically used to obtain number-weighted particle size distribution. Here we present a straightforward protocol for...

Université de Fribourg

Characterizing nanoparticles in complex biological media and physiological fluids with depolarized dynamic light scattering

Balog, Sandor ; Rodriguez-Lorenzo, Laura ; Monnier, Christophe A. ; Obiols-Rabas, Marc ; Rothen-Rutishauser, Barbara ; Schurtenberger, Peter ; Petri-Fink, Alke

In: Nanoscale, 2015, p. -

Light scattering is one of the few techniques available to adequately characterize suspended nanoparticles (NPs) in real time and in situ. However, when it comes to NPs in multicomponent and optically complex aqueous matrices – such as biological media and physiological fluids – light scattering suffers from lack of selectivity, as distinguishing the relevant optical signals from the...

Université de Fribourg

Thermally reversible self-assembly of nanoparticles via polymer crystallization

Kinnear, Calum ; Balog, Sandor ; Rothen-Rutishauser, Barbara ; Petri-Fink, Alke

In: Macromolecular Rapid Communications, 2014, vol. 35, no. 23, p. 2012–2017

The directed self-assembly of gold nanoparticles through the crystallization of surface-grafted polyethylene oxide (PEO) in ethanol–water mixtures is described. This process is fully reversible and tunable through either the size of the core or the polymeric coating. Characterization by X-ray scattering and electron microscopy of the self-assembled structures reveals order at the nanoscale,...

Université de Fribourg

Size-dependent accumulation of particles in lysosomes modulates dendritic cell function through impaired antigen degradation

Seydoux, Emilie ; Rothen-Rutishauser, Barbara ; Nita, Izabela M ; Balog, Sandor ; Gazdhar, Amiq ; Stumbles, Philip A ; Petri-Fink, Alke ; Blank, Fabian ; Garnier, Christophe von

In: International Journal of Nanomedicine, 2014, p. 3885

Introduction: Nanosized particles may enable therapeutic modulation of immune responses by targeting dendritic cell (DC) networks in accessible organs such as the lung. To date, however, the effects of nanoparticles on DC function and downstream immune responses remain poorly understood. Methods: Bone marrow–derived DCs (BMDCs) were exposed in vitro to 20 or...

Université de Fribourg

Dynamic depolarized light scattering of small round plasmonic nanoparticles: When imperfection is only perfect

Balog, Sandor ; Rodriguez-Lorenzo, Laura ; Monnier, Christophe A. ; Michen, Benjamin ; Obiols-Rabasa, Marc ; Casal-Dujat, Lucia ; Rothen-Rutishauser, Barbara ; Petri-Fink, Alke ; Schurtenberger, Peter

In: The Journal of Physical Chemistry C, 2014, vol. 118, no. 31, p. 17968–17974

Although small round gold nanoparticles (Au NPs) possess only a small degree of shape anisotropy, they support localized surface plasmon resonances and exhibit intrinsic optical anisotropy. These inherent features promote depolarized light scattering, whose temporal fluctuations carry information about rotational Brownian dynamics, and thus can be used to describe the size distribution of...

Université de Fribourg

In Vitro dosimetry of agglomerates

Hirsch, Vera ; Kinnear, Calum ; Rodriguez-Lorenzo, Laura ; Monnier, Christophe A. ; Rothen-Rutishauser, Barbara ; Balog, Sandor ; Petri-Fink, Alke

In: Nanoscale, 2014, p. -

Agglomeration of nanoparticles in biological fluids is a pervasive phenomenon that leads to difficulty in the interpretation of results from in vitro exposures, primarily due to the differing particokinetics of agglomerates to nanoparticles. Therefore, well-defined small agglomerates were designed that possessed different particokinetics profiles, and their cellular uptake was compared to a...

Université de Fribourg

Correlation between morphology, water uptake, and proton conductivity in radiation-grafted proton-exchange membranes

Balog, Sandor ; Gasser, Urs ; Mortensen, Kell ; Gubler, Lorenz ; Scherer, Guenther G. ; youcef, Hicham Ben

In: Macromolecular Chemistry and Physics, 2010, vol. 211, no. 6, p. 635-643

An SANS investigation of hydrated proton exchange membranes is presented. Our membranes were synthesized by radiation-induced grafting of ETFE with styrene in the presence of a crosslinker, followed by sulfonation of the styrene. The contrast variation method was used to understand the relationship between morphology, water uptake, and proton conductivity. The membranes are separated into two...

Université de Fribourg

Photocount statistics in mesoscopic optics

Balog, Sandor ; Zakharov, Pavel ; Scheffold, Frank ; Skipetrov, S. E.

In: Physical Review Letters, 2006, vol. 97, p. 103901

We report the first observation of the impact of mesoscopic fluctuations on the photocount statistics of coherent light scattered in a random medium. A Poisson photocount distribution of the incident light widens and gains additional asymmetry upon transmission through a suspension of small dielectric spheres. The effect is only appreciable when the average number of photocounts becomes...