ISIC - Gestion Valais

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Publications associées (83)

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The aggregation-induced emission properties of tetraarylethenes (TAEs) have led to numerous applications in chemistry, biology, and materials science. Herein, we describe two fluorinated tetraarylethenes, which can be employed as universal tags for the synthesis of solid state luminogens. The tags are accessible in one or two steps from commercially available starting materials. Facile coupling reactions with ubiquitous substrates such as thiols, alcohols, amines, phosphines, aldehydes, and enamines allow preparing a wide range of TAE conjugates, including tagged amino acids, peptides, carbohydrates, steroids, and commercial polymers.

2022

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High-Throughput Sizing, Counting, and Elemental Analysis of Anisotropic Multimetallic Nanoparticles with Single-Particle Inductively Coupled Plasma Mass Spectrometry

Ayush Agarwal, Natalia Gasilova, Cedric David Koolen, Mo Li, Wen Luo, Andreas Züttel

Nanoparticles (NPs) have wide applications in physical and chemical processes, and their individual properties (e.g., shape, size, and composition) and ensemble properties (e.g., distribution and homogeneity) can significantly affect the performance. However, the extrapolation of information from a single particle to the ensemble remains a challenge due to the lack of suitable techniques. Herein, we report a high-throughput single-particle inductively coupled plasma mass spectrometry (SP-ICP-MS)-based protocol to simultaneously determine the size, count, and elemental makeup of several thousands of (an)isotropic NPs independent of composition, size, shape, and dispersing medium with atomistic precision in a matter of minutes. By introducing highly diluted nebulized aqueous dispersions of NPs directly into the plasma torch of an ICP-MS instrument, individual NPs are atomized and ionized, resulting in ion plumes that can be registered by the mass analyzer. Our proposed protocol includes a phase transfer step for NPs synthesized in organic media, which are otherwise incompatible with ICP-MS instruments, and a modeling tool that extends the measurement of particle morphologies beyond spherical to include cubes, truncated octahedra, and tetrahedra, exemplified by anisotropic Cu NPs. Finally, we demonstrate the versatility of our method by studying the doping of bulk-dilute (

2022

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Core-shell Structured Chitosan-polyethylenimine Nanoparticles for Gene Delivery: Improved Stability, Cellular Uptake, and Transfection Efficiency

Sandrine Gerber, Laura Camille Louise Nicolle, Perrine Agnes Edith Robin

Gene therapy emerged as a promising treatment option for acquired and inherited diseases. The delivery of nucleic acids relies on vectors that condense and encapsulate their cargo. Especially non-viral gene delivery systems are of increasing interest. However, accomplishing therapeutic transgene expression levels and limited tolerability of these systems remain a challenge. Therefore, we investigate in the improvement of nucleic acid delivery using depolymerized chitosan – polyethylenimine DNA complexes (dCS-PEI/DNA). These core complexes are further entrapped into chitosan-based shells, functionalized with polyethylene glycol and cell penetrating peptides. This modular approach allows to evaluate the effect of functional shell components on physico-chemical particle characteristics and biological effects. The optimized ternary complex combines a core-dCS-LPEI/DNA complex with a shell consisting of dCS-PEG-COOH, which resulted in improved nucleic acid encapsulation, cellular uptake, transfection efficiency, and transfection potency in human hepatoma HuH-7 cells and murine primary hepatocytes. Effects on transgene expression are confirmed in wild-type mice following retrograde intrabiliary infusion. After administration of only 100 ng complexed DNA, ternary complexes induce a high reporter gene signal for three days. We conclude that ternary core-shell structured particles comprising functionalized chitosan are a promising gene delivery technology for both in vitro as well as in vivo applications.

2022

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