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Université de Fribourg

A guide to investigating colloidal nanoparticles by cryogenic transmission electron microscopy: pitfalls and benefits

Monnier, Christophe A. ; Thévenaz, David C. ; Balog, Sandor ; Fiore, Gina L. ; Vanhecke, Dimitri ; Rothen-Rutishauser, Barbara ; Petri-Fink, Alke

In: AIMS Biophysics, 2015, vol. 2, no. 3, p. 245–258

Synthetic colloidal nanoparticles are nowadays omnipresent. Nonetheless, adequately characterizing them and interpreting the data is challenging, as their surrounding environment, e.g. the medium they are dispersed in, is often an active contributor to their size, morphology and structural integrity. In this regard, cryo-transmission electron microscopy (cryo-TEM) is an ideal methodology. This...

Université de Fribourg

Uptake efficiency of surface modified gold nanoparticles does not correlate with functional changes and cytokine secretion in human dendritic cells in vitro

Fytianos, Kleanthis ; Rodriguez-Lorenzo, Laura ; Clift, Martin J.D. ; Blank, Fabian ; Vanhecke, Dimitri ; Garnier, Christophe von ; Petri-Fink, Alke ; Rothen-Rutishauser, Barbara

In: Nanomedicine: Nanotechnology, Biology and Medicine, 2015, vol. 11, no. 3, p. 633–644

Engineering nanoparticles (NPs) for immune modulation require a thorough understanding of their interaction(s) with cells. Gold NPs (AuNPs) were coated with polyethylene glycol (PEG), polyvinyl alcohol (PVA) or a mixture of both with either positive or negative surface charge to investigate uptake and cell response in monocyte-derived dendritic cells (MDDCs). Inductively coupled plasma optical...

Université de Fribourg

Fate of cellulose nanocrystal aerosols deposited on the lung cell surface in vitro

Endes, Carola ; Mueller, Silvana ; Kinnear, Calum ; Vanhecke, Dimitri ; Foster, E. Johan ; Petri-Fink, Alke ; Weder, Christoph ; Clift, Martin J. D. ; Rothen-Rutishauser, Barbara

In: Biomacromolecules, 2015, vol. 16, no. 4, p. 1267–1275

When considering the inhalation of high-aspect ratio nanoparticles (HARN), the characterization of their specific interaction with lung cells is of fundamental importance to help categorize their potential hazard. The aim of the present study was to assess the interaction of cellulose nanocrystals (CNCs) with a multicellular in vitro model of the epithelial airway barrier following realistic...

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

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

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

Risk assessment of released cellulose nanocrystals – mimicking inhalatory exposure

Endes, Carola ; Müller, S. ; Schmid, O. ; Vanhecke, Dimitri ; Foster, E. Johan ; Petri-Fink, Alke ; Rothen-Rutishauser, Barbara ; Weder, Christoph ; Clift, Martin J. D.

In: Journal of Physics: Conference Series, 2013, vol. 429, no. 1, p. 012008

Cellulose nanocrystals (CNCs) exhibit advantageous chemical and mechanical properties that render them attractive for a wide range of applications. During the life-cycle of CNC containing materials the nanocrystals could be released and become airborne, posing a potential inhalatory exposure risk towards humans. Absent reliable and dose-controlled models that mimic this exposure in situ is a...

Université de Fribourg

Spatial SPION localization in liposome membranes

Bonnaud, Cécile ; Vanhecke, Dimitri ; Demurtas, Davide ; Rothen-Rutishauser, Barbara ; Petri-Fink, Alke

In: IEEE Transactions on Magnetics, 2012, vol. 49, no. 1, p. 166-171

Nanocarriers, including liposomes, offer great opportunities for targeted and controlled therapy. The development in this field has led to a large panel of drug delivery systems, which can be classified into 3 different nanovector generations. However, the success of such smart materials requires the control of a large variety of properties and parameters. Unfortunately, characterization at the...

Université de Fribourg

Investigating the interaction of cellulose nanofibers derived from cotton with a sophisticated 3D human lung cell coculture

Clift, Martin J. D. ; Foster, E. Johan ; Vanhecke, Dimitri ; Studer, Daniel ; Wick, Peter ; Gehr, Peter ; Rothen-Rutishauser, Barbara ; Weder, Christoph

In: Biomacromolecules, 2011, vol. 12, no. 10, p. 3666–3673

Cellulose nanofibers are an attractive component of a broad range of nanomaterials. Their intriguing mechanical properties and low cost, as well as the renewable nature of cellulose make them an appealing alternative to carbon nanotubes (CNTs), which may pose a considerable health risk when inhaled. Little is known, however, concerning the potential toxicity of aerosolized cellulose nanofibers....