Frequency Doubling Nanocrystals for Cancer Theranostics

A novel bio-photonics approach based on the nonlinear optical process of second harmonic generation by non-centrosymmetric nanoparticles is presented and demonstrated on malignant human cell lines. The proposed method allows to directly interact with DNA in absence of photosensitizing molecules, to enable independent imaging and therapeutic modalities switching between the two modes of operation by simply tuning the excitation laser wavelength, and to avoid any risk of spontaneous activation by any natural or artificial light source.Comment: 16 pages, 7 figure

Assessing the dynamics of organic aerosols over the North Atlantic Ocean

© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 7 (2017): 45476, doi:10.1038/srep45476.The influence of aerosols on climate is highly dependent on the particle size distribution, concentration, and composition. In particular, the latter influences their ability to act as cloud condensation nuclei, whereby they impact cloud coverage and precipitation. Here, we simultaneously measured the concentration of aerosols from sea spray over the North Atlantic on board the exhaust-free solar-powered vessel “PlanetSolar”, and the sea surface physico-chemical parameters. We identified organic-bearing particles based on individual particle fluorescence spectra. Organic-bearing aerosols display specific spatio-temporal distributions as compared to total aerosols. We propose an empirical parameterization of the organic-bearing particle concentration, with a dependence on water salinity and sea-surface temperature only. We also show that a very rich mixture of organic aerosols is emitted from the sea surface. Such data will certainly contribute to providing further insight into the influence of aerosols on cloud formation, and be used as input for the improved modeling of aerosols and their role in global climate processes.We gratefully acknowledge the financial support by the H. Dudley Wright and the Henri Moser Foundations, the Rector’s Office and the Institute for Environmental Sciences at the University of Geneva, as well as a generous anonymous donator

Harmonic nanoparticles for biolabelling

The NAMDIATREAM FP7 program founded by the European Commission (acronym for Nanotechnological toolkits for multi-modal disease diagnostics and treatment monitoring) aims to develop tools based on nanotechnology to enable early detection and imaging of breast, lung and prostate cancers. This thesis reports on the use of hamonic nanoparticles (HNPs) as non-linear labels for multiphoton microscopy. HNPs are inorganic non-centrosymmetric nanoparticles (NPs) generating a second harmonic signal at any femtosecond excitation wavelength within their transparency range. They display a photostable signal and exert an excellent optical contrast with respect to a standard fluorescent cell dye under normal imaging conditions. The optical properties and biocompatibility of six different HNPs are evaluated to identify the best candidate for biological applications.Then HNPs are used for the first time as exogenous optical contrast agents for the study of the differentiation of embryonic stem cells in vitro. Finally, we propose an original approach to cancer theranostics based on the nonlinear optical properties of HNPs. Le projet européen FP7 NAMDIATREAM a pour objectif le développement de nouveaux outils de détection précoce du cancer du sein, du poumon et de la prostate basés sur les nanotechnologies. Cette thèse décrit l'utilisation de nanoparticules harmoniques (HNPs) en tant que marqueurs pour la microscopie à excitation multiphotonique. Les HNPs sont des nanoparticules inorganiques noncentrosymétriques qui génèrent un signal de seconde harmonique à n'importe quelle longueur d'onde d'excitation comprise dans leur plage de transparence. Elles émettent un signal photostable et exercent un excellent contraste optique par rapport à un marqueur cellulaire fluorescent sous des conditions d'imagerie normales. Les propriétés optiques et la bio-compatibilité de six différentes nanoparticules harmoniques seront évaluées pour identifier le meilleur candidat pour les applications biologiques. Puis les HNPs sont utilisées pour la première fois comme agent de contraste exogène pour l'étude de la différentiation in vitro de cellules souches embryonnaires. Finalement, nous proposons une aproche originale de théragnostic du cancer basée sur les propriétés non-linéaires des HNPs

Aminodextran-coated potassium niobate (KNbO3) nanocrystals for second harmonic bio-imaging

Matériaux et outils pour la santéInternational audiencePotassium niobate (KNbO3) nanocrystals exhibiting good second harmonic generation properties were coated with dextran derivatives containing primary amine groups. The surface modification results from attractive electrostatic interaction between the aminodextran molecules and the negatively charged surface of bare KNbO3 nanocrystals. To avoid flocculation, a suspension of KNbO3 nanocrystals was firstly prepared and then added drop-wise to an aqueous solution of aminodextran. The as-prepared hybrid (ADcoated KNbO3) nanoparticles were then characterized by using various techniques including transmission electron microscopy (TEM), infrared analysis (FTIR), dynamic light scattering (DLS) and zeta potential measurements as a function of pH of the dispersion medium. Then, the prepared AD- coated KNbO3 nanoparticles were evaluated in vitro diagnostic application as biomarker for non-tumor lung-derived

Aminodextran-coated potassium niobate (KNbO3) nanocrystals for second harmonic bio-imaging

Matériaux et outils pour la santéInternational audiencePotassium niobate (KNbO3) nanocrystals exhibiting good second harmonic generation properties were coated with dextran derivatives containing primary amine groups. The surface modification results from attractive electrostatic interaction between the aminodextran molecules and the negatively charged surface of bare KNbO3 nanocrystals. To avoid flocculation, a suspension of KNbO3 nanocrystals was firstly prepared and then added drop-wise to an aqueous solution of aminodextran. The as-prepared hybrid (ADcoated KNbO3) nanoparticles were then characterized by using various techniques including transmission electron microscopy (TEM), infrared analysis (FTIR), dynamic light scattering (DLS) and zeta potential measurements as a function of pH of the dispersion medium. Then, the prepared AD- coated KNbO3 nanoparticles were evaluated in vitro diagnostic application as biomarker for non-tumor lung-derived

Functionalized bismuth ferrite harmonic nanoparticles for cancer cells labeling and imaging

Bismuth ferrite (BFO) harmonic nanoparticles (NPs) display high nonlinear optical efficiency and excellent biocompatibility profile which make them attractive for the development of diagnostic applications as contrast agents. In this study, we present a general method for the functionalization of this material with chemical ligands targeting cancer molecular biomarkers. In particular, a conjugation protocol based on click reaction between alkynyl-containing targeting ligands and poly(ethylene glycol)-coated BFO NPs (67.7 nm) displaying surface reactive azido groups was developed. Copper-free click reaction allowed fast and efficient conjugation of a covalent inhibitor of prolyl-specific endopeptidases to coated BFO NPs. The ability of these functionalized nanomaterials (134.2 nm) to act as imaging probes for cancer cells was demonstrated by the selective labeling of human lung cancer cells

Functionalized bismuth ferrite harmonic nanoparticles for cancer cells labeling and imaging

Bismuth ferrite (BFO) harmonic nanoparticles (NPs) display high nonlinear optical efficiency and excellent biocompatibility profile which make them attractive for the development of diagnostic applications as contrast agents. In this study, we present a general method for the functionalization of this material with chemical ligands targeting cancer molecular biomarkers. In particular, a conjugation protocol based on click reaction between alkynyl-containing targeting ligands and poly(ethylene glycol)-coated BFO NPs (67.7nm) displaying surface reactive azido groups was developed. Copper-free click reaction allowed fast and efficient conjugation of a covalent inhibitor of prolyl-specific endopeptidases to coated BFO NPs. The ability of these functionalized nanomaterials (134.2nm) to act as imaging probes for cancer cells was demonstrated by the selective labeling of human lung cancer cells

High-speed tracking of murine cardiac stem cells by harmonic nanodoublers

Potassium niobate nonlinear nanoparticles are used for the first time to monitor the evolution of embryonic stem cells (ESC) by second harmonic microscopy. These particles feature the complete absence of photo-bleaching and unlimited excitation wavelength flexibility. The potential of this approach is made evident for tissue-regeneration studies and applications, by capturing a high-speed movie of ESC-derived cardiomyocytes autonomously beating within a cluster. Time-resolved data are analyzed to retrieve 3D information of the contraction pattern at the cellular level

Harmonic nanoparticles for regenerative research

In this visualized experiment, protocol details are provided for in vitro labeling of human embryonic stem cells (hESC) with second harmonic generation nanoparticles (HNPs). The latter are a new family of probes recently introduced for labeling biological samples for multi-photon imaging. HNPs are capable of doubling the frequency of excitation light by the nonlinear optical process of second harmonic generation with no restriction on the excitation wavelength. Multi-photon based methodologies for hESC differentiation into cardiac clusters (maintained as long term air-liquid cultures) are presented in detail. In particular, evidence on how to maximize the intense second harmonic (SH) emission of isolated HNPs during 3D monitoring of beating cardiac tissue in 3D is shown. The analysis of the resulting images to retrieve 3D displacement patterns is also detailed