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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

Quantification of gold nanoparticle cell uptake under controlled biological conditions and adequate resolution

Rothen-Rutishauser, Barbara ; Kuhn, Dagmar A ; Ali, Zulqurnain ; Gasser, Michael ; Amin, Faheem ; Parak, Wolfgang J ; Vanhecke, Dimitri ; Fink, Alke ; Gehr, Peter ; Brandenberger, Christina

In: Nanomedicine, 2014, vol. 9, no. 5, p. 607–621

Aim: We examined cellular uptake mechanisms of fluorescently labeled polymer-coated gold nanoparticles (NPs) under different biological conditions by two quantitative, microscopic approaches. Materials & methods: Uptake mechanisms were evaluated using endocytotic inhibitors that were tested for specificity and cytotoxicity. Cellular uptake of gold NPs was analyzed either by laser scanning...

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

Preparation and characterization of functional silica hybrid magnetic nanoparticles

Digigow, Reinaldo G. ; Dechézelles, Jean-François ; Dietsch, Hervé ; Geissbühler, Isabelle ; Vanhecke, Dimitri ; Geers, Christoph ; Hirt, Ann M. ; Rothen-Rutishauser, Barbara ; Petri-Fink, Alke

In: Journal of Magnetism and Magnetic Materials, 2014, vol. 362, p. 72–79

We report on the synthesis and characterization of functional silica hybrid magnetic nanoparticles (SHMNPs). The co-condensation of 3-aminopropyltriethoxysilane (APTES) and tetraethyl orthosilicate (TEOS) in presence of superparamagnetic iron oxide nanoparticles (SPIONs) leads to hybrid magnetic silica particles that are surface-functionalized with primary amino groups. In this work, a...

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

Test-methods on the test-bench: a comparison of complete exhaust and exhaust particle extracts for genotoxicity/mutagenicity assessment

Steiner, Sandro ; Heeb, Norbert V. ; Czerwinski, Jan ; Comte, Pierre ; Mayer, Andreas ; Petri-Fink, Alke ; Rothen-Rutishauser, Barbara

In: Environmental Science & Technology, 2014, vol. 48, no. 9, p. 5237–5244

With the growing number of new exhaust after-treatment systems, fuels and fuel additives for internal combustion engines, efficient and reliable methods for detecting exhaust genotoxicity and mutagenicity are needed to avoid the widespread application of technologies with undesirable effects toward public health. In a commonly used approach, organic extracts of particulates rather than complete...

Université de Fribourg

Modeling nanoparticle–alveolar epithelial cell interactions under breathing conditions using captive bubble surfactometry

Schürch, David ; Vanhecke, Dimitri ; Clift, Martin J. D. ; Raemy, David ; Aberasturi, Dorleta Jimenez de ; Parak, Wolfgang J. ; Gehr, Peter ; Petri-Fink, Alke ; Rothen-Rutishauser, Barbara

In: Langmuir, 2014, vol. 30, no. 17, p. 4924–4932

Many advances have been made in recent years in cell culture models of the epithelial barrier of the lung from simple monolayers to complex 3-D systems employing different cell types. However, the vast majority of these models still present a static air–liquid interface which is unrealistic given the dynamic nature of breathing. We present here a method where epithelial lung cells are...

Université de Fribourg

Magnetic microreactors for efficient and reliable magnetic nanoparticle surface functionalization

Digigow, Reinaldo G. ; Dechézelles, Jean-François ; Kaufmann, J. ; Vanhecke, Dimitri ; Knapp, H. ; Lattuada, Marco ; Rothen-Rutishauser, Barbara ; Petri-Fink, Alke

In: Lab on a Chip, 2014, p. -

Microreactors have attracted wide attention in the nano- and biotechnology fields because they offer many advantages over standard liquid phase reactions. We report the development of a magnetic microreactor for reliable, fast and efficient surface functionalization of superparamagnetic iron oxide nanoparticles (SPIONs). A comprehensive study of the development process in terms of setup, loading...

Université de Fribourg

Insertion of Nanoparticle Clusters into Vesicle Bilayers

Bonnaud, Cécile ; Monnier, Christophe A. ; Demurtas, Davide ; Jud, Corinne ; Vanhecke, Dimitri ; Montet, Xavier ; Hovius, Ruud ; Lattuada, Marco ; Rothen-Rutishauser, Barbara ; Petri-Fink, Alke

In: ACS Nano, 2014, vol. 8, no. 4, p. 3451–3460

A major contemporary concern in developing effective liposome–nanoparticle hybrids is the present inclusion size limitation of nanoparticles between vesicle bilayers, which is considered to be around 6.5 nm in diameter. In this article, we present experimental observations backed by theoretical considerations which show that greater structures can be incorporated within vesicle membranes by...