Université de Fribourg

Artificial lysosomal platform to study nanoparticle long-term stability

Milosevic, Ana ; Bourquin, Joël ; Burnand, David ; Lemal, Philipp ; Crippa, Federica ; Monnier, Christophe A. ; Rodriguez-Lorenzo, Laura ; Petri-Fink, Alke ; Rothen-Rutishauser, Barbara

In: CHIMIA International Journal for Chemistry, 2019, vol. 73, no. 1, p. 55–58

Nanoparticles (NPs) possess unique properties useful for designing specific functionalities for biomedi- cal applications. A prerequisite of a safe-by-design and effective use in any biomedical application is to study NP–cell interactions to gain a better understanding of cellular consequences upon exposure. Cellular uptake of NPs results mainly in the localization of NPs in the complex...

Université de Fribourg

Mimicking the chemistry of natural eumelanin synthesis: the ke sequence in polypeptides and in proteins allows for a specific control of nanosized functional polydopamine formation

Bergtold, Camille ; Hauser, Daniel ; Alain Chaumont ; El Yakhlifi, Salima ; Mateescu, Mihaela ; Meyer, Florent ; Metz-Boutigue, Marie-Hélène ; Benoît Frisch ; Schaaf, Pierre ; Ihiawakrim, Dris ; Ersen, Ovidiu ; Monnier, Christophe A. ; Petri-Fink, Alke ; Rothen-Rutishauser, Barbara ; Ball, Vincent

In: Biomacromolecules, 2018, vol. 19, no. 9, p. 3693–3704

The oxidation of dopamine and of other catecholamines leads to the formation of conformal films on the surface of all known materials and to the formation of a precipitate in solution. In some cases, it has been shown that the addition of additives in the dopamine solution, like certain surfactants or polymers, polyelectrolytes, and certain proteins, allows to get polydopamine nanoparticles...

Université de Fribourg

Lock-in thermography as an analytical tool for magnetic nanoparticles: measuring heating power and magnetic fields

Monnier, Christophe A. ; Crippa, Federica ; Geers, Christoph ; Knapp, Evelyne ; Rothen-Rutishauser, Barbara ; Bonmarin, Mathias ; Lattuada, Marco ; Petri-Fink, Alke

In: The Journal of Physical Chemistry C, 2017, vol. 121, no. 48, p. 27164–27175

Magnetic nanoparticles and their ability to convert electromagnetic energy into heat are of explicit interest for various applications. However, precise quantification of their heating efficiency is not always upfront, and several parameters render comparative studies challenging. This paper describes the theory behind lock-in thermography, a new technique for quantifying the heating...

Université de Fribourg

Lock-in thermography as a rapid and reproducible thermal characterization method for magnetic nanoparticles

Lemal, Philipp ; Geers, Christoph ; Monnier, Christophe A. ; Crippa, Federica ; Daum, Leopold ; Urban, Dominic A. ; Rothen-Rutishauser, Barbara ; Bonmarin, Mathias ; Petri-Fink, Alke

In: Journal of Magnetism and Magnetic Materials, 2017, vol. 427, p. 206–211

Lock-in thermography (LIT) is a sensitive imaging technique generally used in engineering and materials science (e.g. detecting defects in composite materials). However, it has recently been expanded for investigating the heating power of nanomaterials, such as superparamagnetic iron oxide nanoparticles (SPIONs). Here we implement LIT as a rapid and reproducible method that can evaluate the...

Université de Fribourg

A lock-in-based method to examine the thermal signatures of magnetic nanoparticles in the liquid, solid and aggregated states

Monnier, Christophe A. ; Lattuada, Marco ; Burnand, David ; Crippa, F. ; Martinez-Garcia, J. C. ; Hirt, A. M. ; Rothen-Rutishauser, B. ; Bonmarin, M. ; Petri-Fink, Alke

In: Nanoscale, 2016, vol. 8, no. 27, p. 13321–13332

We propose a new methodology based on lock-in thermography to study and quantify the heating power of magnetic nanoparticles. Superparamagnetic iron oxide nanoparticles exposed to a modulated alternating magnetic field were used as model materials to demonstrate the potency of the system. Both quantitative and qualitative information on their respective heating power was extracted at high...

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

Filling polymersomes with polymers by peroxidase-catalyzed atom transfer radical polymerization

Dinu, Maria Valentina ; Spulber, Mariana ; Renggli, Kasper ; Wu, Dalin ; Monnier, Christophe A. ; Petri-Fink, Alke ; Bruns, Nico

In: Macromolecular Rapid Communications, 2015, vol. 36, no. 6, p. 507–514

Polymersomes that encapsulate a hydrophilic polymer are prepared by conducting biocatalytic atom transfer radical polymerization (ATRP) in these hollow nanostructures. To this end, ATRPase horseradish peroxidase (HRP) is encapsulated into vesicles self-assembled from poly(dimethylsiloxane)-block-poly(2-methyl-2-oxazoline) (PDMS-b-PMOXA) diblock copolymers. The vesicles are turned into...

Université de Fribourg

Catechol-derivatized poly(vinyl alcohol) as a coating molecule for magnetic nanoclusters

Burnand, David ; Monnier, Christophe A. ; Redjem, Anthony ; Schaefer, Mark ; Rothen-Rutishauser, Barbara ; Kilbinger, Andreas ; Petri-Fink, Alke

In: Journal of Magnetism and Magnetic Materials, 2015, vol. 380, p. 157–162

Surface functionalization of superparamagnetic iron oxide nanoparticles (SPIONs) remains indispensable in promoting colloidal stability and biocompatibility. We propose a well-defined and characterized synthesis of a new catechol-functionalized RAFT (reversible addition–fragmentation chain transfer) poly(vinyl alcohol) polymer, which can be anchored onto hydrophobic SPIONs via a one-pot...

Université de Fribourg

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

Balog, Sandor ; Adolphe Merkle Institute, University of Fribourg, Switzerland ; Rodriguez-Lorenzo, Laura ; Monnier, Christophe A. ; Michen, Benjamin ; Obiols-Rabasa, Marc ; Casal-Dujat, Lucia ; Rothen-Rutishauser, Barbara ; Petri-Fink, Alke ; Schurtenberger, and 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 round...

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...