Université de Fribourg

Shear stress-responsive polymersome nanoreactors inspired by the marine bioluminescence of dinoflagellates

Rifaie‐Graham, Omar ; Galensowske, Nikolas F. B. ; Dean, Charlie ; Pollard, Jonas ; Balog, Sandor ; Gouveia, Micael G. ; Chami, Mohamed ; Vian, Antoine ; Amstad, Esther ; Lattuada, Marco ; Bruns, Nico

In: Angewandte Chemie International Edition, 2020, vol. 60, no. 2, p. 904-909

Some marine plankton called dinoflagellates emit light in response to the movement of surrounding water, resulting in a phenomenon called milky seas or sea sparkle. The underlying concept, a shear-stress induced permeabilisation of biocatalytic reaction compartments, is transferred to polymer-based nanoreactors. Amphiphilic block copolymers that carry nucleobases in their hydrophobic block...

Université de Fribourg

Monolithic resorcinol–formaldehyde alcogels and their corresponding nitrogen-doped activated carbons

Civioc, Romain ; Lattuada, Marco ; Koebel, Matthias M. ; Galmarini, Sandra

In: Journal of Sol-Gel Science and Technology, 2020, vol. 95, no. 3, p. 719–732

Here we report the adaptation of formaldehyde crosslinked phenolic resin-based aerogel and xerogel synthesis to ethanol-based solvent systems. Three specific formulations, namely one resorcinol–formaldehyde (RF) and two resorcinol– melamine–formaldehyde (RMF) systems were studied. As-prepared resins were characterized in terms of envelope and skeletal density. Furthermore, resin samples ...

Université de Fribourg

Strong, machinable, and insulating chitosan–urea aerogels: toward ambient pressure drying of biopolymer aerogel monoliths

Guerrero-Alburquerque, Natalia ; Zhao, Shanyu ; Adilien, Nour ; Koebel, Matthias M. ; Lattuada, Marco ; Malfait, Wim J.

In: ACS Applied Materials & Interfaces, 2020, vol. 12, no. 19, p. 22037–22049

Biopolymer aerogels are an emerging class of materials with potential applications in drug delivery, thermal insulation, separation, and filtration. Chitosan is of particular interest as a sustainable, biocompatible, and abundant raw material. Here, we present urea-modified chitosan aerogels with a high surface area and excellent thermal and mechanical properties. The irreversible gelation of...

Université de Fribourg

One-step ring opening metathesis block-like copolymers and their compositional analysis by a novel retardation technique

Yasir, Mohammad ; Liu, Peng ; Markwart, Jens C. ; Suraeva, Oksana ; Wurm, Frederik R. ; Smart, Jansie ; Lattuada, Marco ; Kilbinger, Andreas F. M.

In: Angewandte Chemie International Edition, 2020, vol. 59, no. 32, p. 13597-13601

Using a one-step synthetic route for block copolymers avoids the repeated addition of monomers to the polymerization mixture, which can easily lead to contamination and, therefore, to the unwanted termination of chain growth. For this purpose, monomers (M1–M5) with different steric hindrances and different propagation rates are explored. Copolymerization of M1 (propagating rapidly) with M2...

Université de Fribourg

Characterization of the shape anisotropy of superparamagnetic iron oxide nanoparticles during thermal decomposition

Vanhecke, Dimitri ; Crippa, Federica ; Lattuada, Marco ; Balog, Sandor ; Rothen-Rutishauser, Barbara ; Petri-Fink, Alke

In: Materials, 2020, vol. 13, no. 9, p. 2018

Magnetosomes are near-perfect intracellular magnetite nanocrystals found in magnetotactic bacteria. Their synthetic imitation, known as superparamagnetic iron oxide nanoparticles (SPIONs), have found applications in a variety of (nano)medicinal fields such as magnetic resonance imaging contrast agents, multimodal imaging and drug carriers. In order to perform these functions in medicine,...

Université de Fribourg

Simple and fast evaluation of relaxation parameters of magnetic nanoparticles

Lemal, Philipp ; Balog, Sandor ; Ackermann-Hirschi, Liliane ; Taladriz-Blanco, Patricia ; Hirt, Ann M. ; Rothen-Rutishauser, Barbara ; Lattuada, Marco ; Petri-Fink, Alke

In: Journal of Magnetism and Magnetic Materials, 2020, vol. 499, p. 166176

The efficacy of magnetic hyperthermia treatment depends on the optimal available magnetic nanoparticles (MNPs) that are excited in a given alternating magnetic field and viscosity of the region of interest. In this regard, assessing the relevant relaxation parameters is of upmost importance and could improve the speed of development of efficient applications. Here, we demonstrate how to...

Université de Fribourg

Phase transformation of superparamagnetic iron oxide nanoparticles via thermal annealing: implications for hyperthermia applications

Crippa, Federica ; Rodriguez-Lorenzo, Laura ; Hua, Xiao ; Goris, Bart ; Bals, Sara ; Garitaonandia, José S. ; Balog, Sandor ; Burnand, David ; Hirt, Ann M. ; Haeni, Laetitia ; Lattuada, Marco ; Rothen-Rutishauser, Barbara ; Petri-Fink, Alke

In: ACS Applied Nano Materials, 2019, vol. 2, no. 7, p. 4462–4470

Magnetic hyperthermia has the potential to play an important role in cancer therapy and its efficacy relies on the nanomaterials selected. Superparamagnetic iron oxide nanoparticles (SPIONs) are excellent candidates due to the ability of producing enough heat to kill tumor cells by thermal ablation. However, their heating properties depend strongly on crystalline structure and size, which may...

Université de Fribourg

Functional polymers through mechanochemistry

Schrettl, Stephen ; Balkenendea, Diederik W. R. ; Calvino, Céline ; Karman, Marc ; Lavrenova, Anna ; Neumann, Laura N. ; Sagaraa, Yoshimitsu ; Verde-Sestoa, Ester ; Giannantonio, Michela di ; Simon, Yoan C. ; Fromm, Katharina M. ; Lattuada, Marco ; Weder, Christoph

In: CHIMIA International Journal for Chemistry, 2019, vol. 73, no. 1, p. 7–11

While coupling mechanical and chemical processes is widespread in living organisms, the idea to harness the mechanically induced dissociation of weak covalent and non- covalent bonds to create artificial materials that respond to mechanical stimulation has only recently gained attention. Here we summarize our activities that mainly revolve around the exploitation of non-covalent interactions...

Université de Fribourg

Effect of clustering on the heat generated by superparamagnetic iron oxide nanoparticles

Lattuada, Marco

In: CHIMIA International Journal for Chemistry, 2019, vol. 73, no. 1, p. 39–42

Magnetic nanoparticles have been the subject of enormous investigations for their potential use as cancer treatment via hyperthermia. This is due to their ability to generate heat when exposed to an external magnetic field oscillating at sufficiently high frequency. There are many different parameters that need to be considered when designing the optimal nanoparticle formulation for...

Université de Fribourg

Effect of aging on thermal conductivity of fiber-reinforced aerogel composites: An X-ray tomography study

Iswara, Subramaniam ; Griffa, Michele ; Kaufmann, Rolf ; Beltran, Mario ; Huber, Lukas ; Brunner, Samuel ; Lattuada, Marco ; M.Koebel, Matthias ; Malfait, Wim J.

In: Microporous and Mesoporous Materials, 2019, vol. 278, p. 289–296

Silica aerogels display an ultra-low thermal conductivity (λ) and are used as thermal superinsulators. Here, we study the influence of aging and drying processes on the microstructure and thermal conductivity of fiber-reinforced silica aerogel composites. Glass wool-silica gel composites were aged for variable times, hydrophobized, and dried either at ambient pressure or from supercritical...