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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

An in vitro testing strategy towards mimicking the inhalation of high aspect ratio nanoparticles

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

In: Particle and Fibre Toxicology, 2015, vol. 11, no. 1, p. 40

The challenge remains to reliably mimic human exposure to high aspect ratio nanoparticles (HARN) via inhalation. Sophisticated, multi-cellular in vitro models are a particular advantageous solution to this issue, especially when considering the need to provide realistic and efficient alternatives to invasive animal experimentation for HARN hazard assessment. By incorporating a systematic test-bed...

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

Stress transfer in cellulose nanowhisker composites—Influence of whisker aspect ratio and surface charge

Rusli, Rafeadah ; Shanmuganathan, Kadhiravan ; Rowan, Stuart J. ; Weder, Christoph ; Eichhorn, Stephen J.

In: Biomacromolecules, 2011, vol. 12, no. 4, p. 1363–1369

The mechanically induced molecular deformation of cellulose nanowhiskers embedded in subpercolation concentration in an epoxy resin matrix was monitored through Raman spectroscopy. Cellulose nanowhiskers isolated by sulfuric acid hydrolysis from tunicates and by sulfuric acid hydrolysis and hydrochloric acid hydrolysis from cotton were used to study how the aspect ratio (ca. 76 for tunicate and...

Université de Fribourg

Optically healable supramolecular polymers

Burnworth, Mark ; Tang, Liming ; Kumpfer, Justin R. ; Duncan, Andrew J. ; Beyer, Frederick L. ; Fiore, Gina L. ; Rowan, Stuart J. ; Weder, Christoph

In: Nature, 2011, vol. 472, p. 334–337

Polymers with the ability to repair themselves after sustaining damage could extend the lifetimes of materials used in many applications. Most approaches to healable materials require heating the damaged area. Here we present metallosupramolecular polymers that can be mended through exposure to light. They consist of telechelic, rubbery, low-molecular-mass polymers with ligand end groups that are...

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....

Université de Fribourg

In vivo deployment of mechanically adaptive nanocomposites for intracortical microelectrodes

Harris, J. P. ; Hess, Andreas E. ; Rowan, Stuart J. ; Weder, Christoph ; Zorman, C. A. ; Tyler, D. J. ; Capadona, Jeffrey R.

In: Journal of Neural Engineering, 2011, vol. 8, no. 4, p. 046010

We recently introduced a series of stimuli-responsive, mechanically adaptive polymer nanocomposites. Here, we report the first application of these bio-inspired materials as substrates for intracortical microelectrodes. Our hypothesis is that the ideal electrode should be initially stiff to facilitate minimal trauma during insertion into the cortex, yet become mechanically compliant to match the...

Université de Fribourg

Bioinspired mechanically adaptive polymer nanocomposites with water-activated shape-memory effect

Mendez, Julie ; Annamalai, Pratheep K. ; Eichhorn, Stephen J. ; Rusli, Rafeadah ; Rowan, Stuart J. ; Foster, E. Johan ; Weder, Christoph

In: Macromolecules, 2011, vol. 44, no. 17, p. 6827–6835

New biomimetic, stimuli-responsive mechanically adaptive nanocomposites, which change their mechanical properties upon exposure to water and display a water-activated shape-memory effect, were investigated. These materials were produced by introducing rigid cotton cellulose nanowhiskers (CNWs) into a rubbery polyurethane (PU) matrix. A series of materials with CNW concentrations of 2–20% v/v...

Université de Fribourg

Biologically inspired hierarchical design of nanocomposites based on poly(ethylene oxide) and cellulose nanofibers

Changsarn, Sutheerat ; Mendez, James D. ; Shanmuganathan, Kadhiravan ; Foster, E. Johan ; Weder, Christoph ; Supaphol, Pitt

In: Macromolecular Rapid Communications, 2011, vol. 32, no. 17, p. 1367–1372

Attempts to create hierarchically structured, uniaxially oriented nanocomposites comprising cellulose nanowhiskers (CNWs), which promise anisotropic mechanical properties, are exceedingly rare. We report here the fabrication of uniaxially-oriented arrays of microfibers based on poly(ethylene oxide) (PEO) and CNWs by electrospinning. Compared with the neat PEO fibers, the incorporation of CNWs...

Université de Fribourg

Two-photon 3d optical data storage via aggregate switching of excimer-forming dyes

Lott, Joseph ; Ryan, Christopher ; Valle, Brent ; Johnson, Jack R. III ; Schiraldi, David A. ; Shan, Jie ; Singer, Kenneth D. ; Weder, Christoph

In: Advanced Materials, 2011, vol. 23, no. 21, p. 2425–2429

A novel optical data storage (ODS) system that relies on the optically-induced switching of the aggregation state and fluorescence of a two-photon absorption dye in a polymer matrix is reported. Well-defined, -3 × 3 × 6 μm large voxels are written with single focused laser pulses and read by confocal laser scanning microscopy.