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Université de Fribourg

Nanostructure generation during milk digestion in presence of a cell culture model simulating the small intestine

Hempt, Claudia ; Gontsarik, Mark ; Buerki-Thurnherr, Tina ; Hirsch, Cordula ; Salentinig, Stefan

In: Journal of Colloid and Interface Science, 2020, vol. 574, p. 430–440

Hypothesis: The development of advanced oral delivery systems for bioactive compounds requires the fundamental understanding of the digestion process within the gastrointestinal tract. Towards this goal, dynamic invitro digestion models, capable of characterising the molecular as well as colloidal aspects of food, together with their biological interactions with relevant invitro cell culture...

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, p. -

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

A nano-rattle SnO2@carbon composite anode material for high-energy Li-ion batteries by melt diffusion impregnation

Maharajan, Sivarajakumar ; Kwon, Nam Hee ; Brodard, Pierre ; Fromm, Katharina M.

In: Nanomaterials, 2020, vol. 10, no. 4, p. 804

The huge volume expansion in Sn-based alloy anode materials (up to 360%) leads to a dramatic mechanical stress and breaking of particles, resulting in the loss of conductivity and thereby capacity fading. To overcome this issue, SnO2@C nano- rattle composites based on < 10 nm SnO2 nanoparticles in and on porous amorphous carbon spheres were synthesized using a silica template and tin melting...

Université de Fribourg

Metal nanoparticle–microbe interactions: synthesis and antimicrobial effects

Khan, Mujeebur R. ; Fromm, Katharina M. ; Rizvi, Tanveer F. ; Giese, Bernd ; Ahamad, Faheem ; Turner, Raymond J. ; Füeg, Michael ; Marsili, Enrico

In: Particle & Particle Systems Characterization, 2020, vol. 37, no. 5, p. 1900419

Metal nanoparticles (NPs), chalcogenides, and carbon quantum dots can be easily synthesized from whole microorganisms (fungi and bacteria) and cell‐free sterile filtered spent medium. The particle size distribution and the biosynthesis time can be somewhat controlled through the biomass/metal solution ratio. The biosynthetic mechanism can be explained through the ion‐reduction theory and...

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

A three‐dimensional porous organic semiconductor based on fully sp 2 ‐hybridized graphitic polymer

Byun, Yearin ; Xie, Lilia S. ; Fritz, Patrick ; Ashirov, Timur ; Dincă, Mircea ; Coskun, Ali

In: Angewandte Chemie International Edition, 2020, p. -

Dimensionality plays an important role in the charge transport properties of organic semiconductors. Although three‐dimensional semiconductors, such as Si, are common in inorganic materials, imparting electrical conductivity to covalent three‐ dimensional organic polymers is challenging. Now, the synthesis of a three‐ dimensional π‐conjugated porous organic polymer (3D p‐POP) using...

Université de Fribourg

Stereospecific hydrogenolysis of benzylic alcohols over Pd/C

Harvey, Freya M. ; Bochet, Christian G.

In: The Journal of Organic Chemistry, 2020, vol. 85, no. 11, p. 7611–7619

Hydrogenolysis of tertiary benzylic alcohols on palladium on carbon (Pd/C) generally proceeds with inversion of configuration. However, little is known about the hydrogenolysis mechanism of primary and secondary benzylic alcohols. Literature precedents suggest that these substrates may interact differently with the catalyst. To study the mechanism, we synthesized a pair of deuterated...

Université de Fribourg

Metal nanoparticle–microbe interactions: synthesis and antimicrobial effects

Khan, Mujeebur R. ; Fromm, Katharina M. ; Rizvi, Tanveer F. ; Giese, Bernd ; Ahamad, Faheem ; Turner, Raymond J. ; Füeg, Michael ; Marsili, Enrico

In: Particle & Particle Systems Characterization, 2020, vol. 37, no. 5, p. 1900419

Metal nanoparticles (NPs), chalcogenides, and carbon quantum dots can be easily synthesized from whole microorganisms (fungi and bacteria) and cell‐free sterile filtered spent medium. The particle size distribution and the biosynthesis time can be somewhat controlled through the biomass/metal solution ratio. The biosynthetic mechanism can be explained through the ion‐reduction theory and...

Université de Fribourg

Indirect solvent assisted tautomerism in 4-substituted phthalimide 2-hydroxy-Schiff bases

Yordanov, Dancho ; Deneva, Vera ; Georgiev, Anton ; Crochet, Aurelien ; Fromm, Katharina M. ; Antonova, Liudmil

In: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2020, vol. 237, p. 118416

The paper presents the synthesis and characterization of two 4-substituted phthalimide 2-hydroxy-Schiff bases containing salicylic (4) and 2-hydroxy-1-naphthyl (5) moieties. The structural differences of 2-hydroxyaryl substituents, resulting in different enol/keto tautomeric behaviour, depending on the solvent environment were studied by absorption UV–Vis spectroscopy. Compound 5 is...