Christel Chanseau

Institut Européen De Chimie Et Biologie, Pessac, Aquitaine, France

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Publications (10)25.49 Total impact

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    ABSTRACT: The picosecond ultrasonics technique is used to investigate the viscoelastic properties of nucleus of fixed single osteoblast progenitor cells adhering on a titanium alloy substrate. A two-color probing picosecond ultrasonics and a fluorescence visualization setups were developed and combined to allow to distinguish subcomponents inside the cell under investigation. It opens the way for quantitative measurements of the viscoelastic properties of single cells and of their sub-micrometer thickness. It is shown that a blue probe, λ = 400 nm, is preferable to a red probe, λ = 800 nm, to perform these measurements with fixed sub-micrometer bone cells. 26 GHz acoustic frequencies are detected in cells as thin as 135 nm. A 1D analytical model of the acoustic generation and of the optical detection is used to describe the experimental results. The nucleus longitudinal elastic moduli (13-16 GPa) and dynamic viscosities (13-30 cP) are measured at high frequencies (GHz) from a time-frequency analysis of the experimental data of fixed single cells.
    The European Physical Journal Applied Physics 01/2013; 61(1):11201-. · 0.79 Impact Factor
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    ABSTRACT: How endothelial cells (ECs) express the particular filopodial or lamellipodial form of the actin machinery is critical to understanding EC functions such as angiogenesis and sprouting. It is not known how these mechanisms coordinately promote lumen formation of ECs. Here, adhesion molecules (RGD peptides) and inductor molecules (BMP-2 mimetic peptides) are micropatterned onto polymer surfaces by a photolithographic technique to induce filopodial and lamellipodial migration modes. Firstly, the effects of peptide microgeometrical distribution on EC adhesion, orientation and morphogenesis are evaluated. Large micropatterns (100 μm) promote EC orientation without lumen formation, whereas small micropatterns (10-50 μm) elicit a collective cell organization and induce EC lumen formation, in the case of RGD peptides. Secondly, the correlation between EC actin machinery expression and EC self-assembly into lumen formation is addressed. Only the filopodial migration mode (mimicked by RGD) but not lamellipodial migration mode (mimicked by BMP-2) promotes EC lumen formation. This work gives a new concept for the design of biomaterials for tissue engineering and may provide new insight for angiogenesis inhibition on tumors.
    Small 11/2012; · 7.51 Impact Factor
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    ABSTRACT: The differentiation of stem cells can be modulated by physical factors such as the micro- and nano-topography of the extracellular matrix. One important goal in stem cell research is to understand the concept that directs differentiation into a specific cell lineage in the nanoscale environment. Here, we demonstrate that such paths exist by controlling only the micro- and nano-topography of polymer surfaces. Altering the depth (on a nanometric scale) of micro-patterned surface structures allowed increased adhesion of human mesenchymal stem cells (hMSCs) with specific differentiation into osteoblasts, in the absence of osteogenic medium. Small (10 nm) depth patterns promoted cell adhesion without noticeable differentiation, whereas larger depth patterns (100 nm) elicited a collective cell organization, which induced selective differentiation into osteoblast-like cells. This latter response was dictated by stress through focal-adhesion-induced reorganization of F-actin filaments. The results have significant implications for understanding the architectural effects of the in vivo microenvironment and also for the therapeutic use of stem cells.
    Journal of Cell Science 02/2012; 125(Pt 5):1217-24. · 5.33 Impact Factor
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    ABSTRACT: The measurement of the mechanical properties of single biological cells with a nanometer depth resolution using only coherent light is proposed. A pump-probe set-up based on an ultrafast laser (100 fs pulses) is used to excite and detect acoustic frequencies in the GHz range. Experiments are performed on single fixed mouse MC3T3 cells adhering on titanium alloy substrate. Using two different probe wavelengths, the contributions to the optical detection resulting from the cell interface displacements and from interactions between acoustic waves and the laser light are identified. Semi-analytical calculations allow the determination of acoustic celerities and thicknesses in cells thinner than 150 nm.
    Journal of Physics Conference Series 03/2011; 278(1):012042.
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    ABSTRACT: We use femtosecond laser pulses absorbed in a metallic transducer, namely the picosecond ultrasonics technique, for the remote optical generation and detection of GHz acoustic frequencies in single cells by pump-probe sampling. Samples are MC3T3 cells adhering on a TiAl4V alloy substrate. Both pump and probe beams are focused at the cell/transducer interface. The pump absorption yields a temperature rise in the absorbing substrate and a picosecond acoustic pulse is generated through the thermoelastic effect. The probe beam is partially reflected from the metallic interface and partially scattered by the acoustic wavefront propagating in the transparent cell. The change of reflectivity of the cell is measured as a function of the pump-probe time delay. Interferences arise from the two probe contributions causing the so-called Brillouin oscillations. Optical phase variations due to acoustic-induced changes in cell thickness are simultaneously measured. The result of a semi-analytical calculation is fitted to the experimental data. Acoustic frequencies are detected at 30 GHz in the nucleus of single osteoblast cells.
    Proc SPIE 02/2011;
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    ABSTRACT: Objective The aim of this work was to synthesize and to characterize chemically and biologically (in vitro and in vivo) a nano-sized hydroxyapatite (nHA).Materials and methodsWet chemical precipitation at room temperature was performed, then chemical structure was explored using transmission electron microscopy, X-ray diffraction and Fourier transformed infrared spectroscopy. In vitro biological characterization was done using MG63 osteoblastic cell line cultured onto the material, and characterization was done for morphology (scanning electron microscopy), viability (live/dead assay) and proliferation (MTT test). Finally, nHA powder was tested in vivo in a study involving C57 Black mice for bone repair in a calvarial bone critical sized defect.ResultsMorphological, physico-chemical and cristallographic analyses revealed specific features of hydroxyapatite. Biological in vitro experiments revealed high affinity and proliferative ability of MG63 cells cultured onto the material. In vivo study displayed that in this model, the material allowed to repair bone continuity after 1 month healing.Discussion and conclusionsThe different ways of nHA synthesis are discussed regarding the potential application of the material. The obtained material should find applications in bone tissue engineering experiments.RésuméObjectifL’objectif de cette étude était de synthétiser et de caractériser au niveau chimique et biologique (in vitro and in vivo) une hydroxyapatite nano-cristalline.Matériels et méthodesLe matériau a été synthétisé par précipitation humide, puis sa structure a été étudiée par microscopie électronique à transmission, par spectroscopie infrarouge à transformée de Fourier et par diffraction des rayons X. La caractérisation biologique in vitro a été faite en utilisant des ostéoblastes de lignée MG63 cultivés en présence du matériau : la morphologie, la viabilité et la prolifération des cellules ont été évaluées par microscope électronique à balayage, par le test de Live/Dead et par des tests au MTT, respectivement. Enfin, une étude in vivo de la réparation osseuse a été réalisée en utilisant le matériau pour combler un défaut osseux critique sur la calvaria de souris C57 Black.RésultatsL’analyse morphologique, physico-chimique et cristallographique a permis de retrouver des caractéristiques spécifiques des cristaux d’hydroxyapatite. L’étude biologique in vitro a montré une forte affinité et une prolifération des cellules MG63 sur le matériau. Enfin, l’utilisation in vivo du matériau a permis d’obtenir une restauration de la continuité osseuse complète après un mois.Discussion et conclusionsLes différentes méthodes de synthèse de l’hydroxyapatite ont été discutées en fonction de leur application. Ce matériau pourrait trouver des applications en ingénierie tissulaire osseuse.
    IRBM 09/2010; 31(4):226–233. · 0.38 Impact Factor
  • X-ray Structure Analysis Online. 01/2009; 25:55-56.
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    ABSTRACT: Hybrid materials combining polyethylene terephthalate and different types of cells (endothelial and osteoblastic cells) have been developed thanks to the covalent grafting of different densities of RGD containing peptides onto the polymer surface. Biomimetic modifications were performed by means of a three-step reaction procedure: creation of COOH functions, coupling agent grafting and the immobilization of the RGDC peptides. High resolution mu-imager was used to evaluate RGD densities (varying between 0.6 and 2.4 pmol/mm(2)) and has exhibited the stability of the surface grafted peptides when treated in harsh conditions. The efficiency of this route for biomimetic modification of a PET surface was demonstrated by measuring the adhesion of MC3T3 and HSVEC cells and by focal adhesion observation. Results obtained prove that a minimal RGDC density of 1 pmol/mm(2) is required to improve MC3T3 and HSVEC cells responses. Indeed, cells seeded onto a RGDC-modified PET with a density higher than 1 pmol/mm(2) were able to establish focal adhesion as visualized by fluorescence microscope compared to cells immobilized onto unmodified PET and RGDC-modified PET with densities lower than 1 pmol/mm(2). Moreover, the number of focal contacts was enhanced by the increase of RGDC peptide densities grafted onto the material surface. With this study we proved that the density of peptides immobilized on the surface is a very important parameter influencing osteoblast or endothelial cell adhesion and focal contact formation.
    Biomaterials 12/2008; 30(5):711-20. · 8.31 Impact Factor
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    ABSTRACT: The aim of this study was to graft RGD peptides with well controlled densities onto poly(ethylene terephthalate) (PET) film surfaces. Biomimetic modifications were performed by means of a four-step reaction procedure: surface modification in order to create -COOH groups onto polymer surface, coupling agent grafting and finally immobilization of peptides. The originality of this work is to evaluate several grafted densities peptides. Toluidine blue and high-resolution mu-imager (using [(3)H]-Lys) were used to evaluate densities. Moreover, mu-imager has exhibited the stability of peptides grafted onto the surface when treated under harsh conditions. Benefits of the as-proposed method were related to the different concentrations of peptides grafted onto the surface as well as the capacity of RGD peptide to interact with integrin receptors.
    Biomolecular Engineering 12/2007; 24(5):477-82. · 3.17 Impact Factor
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    ABSTRACT: Introduction Le poly(ethylene térephthalate) (PET) est un matériau très utilisé comme implant biomédical grâce à ses propriétés telles que, son module d'Young ou sa biocompatibilité. Les nombreux progrès survenus au cours de ces dernières années dans le domaine des biomatériaux ont contribué à une nouvelle orientation des recherches portant sur la conception de matériaux implantables biologiquement actifs. La conception de matériaux biomimétiques a pour but non seulement, de restituer à un organe sa biofonctionnalité mais également d'induire des réactions biologiques contrôlées dans l'environnement de l'implant L'objectif principal de cette étude est donc d'optimiser la biointégration d'un biomatériau (le PET) par la fonctionnalisation de ce dernier, par greffage de peptides d'adhésion de type RGD (Arg – Gly – Asp) susceptibles d'améliorer l'adhésion des cellules au biomatériau [1, 2][3-5]. Dans le but d'augmenter l'adhésion des ostéoblastes sur le PET, notre travail a consisté à greffer des peptides RGD à la surface du polymère. Des études précédentes ont d'ores et déjà démontré que la répartition et la densité de biomolécules à la surface des biomatériaux influencent l'attachement cellulaire [6]. Le but de ce travail a été d'étudier l'impact d'un greffage de peptides RGD répartis en microdomaines à la surface du PET sur l'attachement des ostéoblastes. Matériels et méthodes: Le PET obtenu est un film commercial obtenu chez Good Fellow, il s'agit d'un film biorienté d'épaisseur 75µm.1-(3-Dimethylaminopropyl)-3-EthylCarboiimide hydrochloride (EDC) et N-HydroxySuccinimide (NHS) sont fournis par Aldrich, France. Les peptides RGDC sont obtenus chez Bachem, France. La solution de 3 H-Lysine, ayant une activité de 1mCi/ml a été commanée chez Amersham, France. La résine photosensible et le développeur proviennent de Shipley. Avant utilisation, le film de PET est nettoyé aux ultrasons dans de l'isopropanol. La première étape de modification est une hydrolyse de la surface du Pet afin de créer des functions –COOH en surface. Greffage des peptides RGDC: les quatre étapes de Greffage sont: Hydrolyse du PET dans une solution NaOH + eau/acétonitrile; Oxydation avec KMnO 4 dans H 2 SO 4 ; greffage de NHS et EDC ; greffage des peptides RGDC. Obtention des micros domaines: L'ablation est obtenue par traitement laser sur la surface greffée. Il s'agit d'un laser à excimère KrF (Lambda Physik LPX 220i) qui émet à 248nm. De plus, des microdomaines de peptides RGD ont été obtenus en utilisant des méthodes classiques de photolithographie. Caractérisation Physico-chimique: La spectroscopie de photoélectron X (XPS), le bleu de toluidine, les techniques de radiomarquage, le MEB et la profilomètre optique sont utilisés pour caractériser les surfaces. La quantité de molécules radiomarquées greffées à la surface du PET a été évaluée par imagerie béta haute résolution (Biospace) et nous pouvons également contrôler la distribution des acides aminés à la surface du matériau [7]. Résultats et discussion Le Greffage de la 3 H-Lysine à la surface du PET permet de quantifier la densité d'acides aminés greffés à la surface et de confirmer la stabilité de la liaison chimique sous contrainte. De plus, cet outil permet de visualiser les microdomaines (Figures 1 et 2). Les microdomaines obtenus par ablation laser ont également été observés par profilomètrie optique (Figure 3). Cette technique nous a permis également de corréler la profondeur d'ablation avec le nombre d'impulsions laser appliquées à la surface du matériau.

Publication Stats

98 Citations
25.49 Total Impact Points


  • 2012
    • Institut Européen De Chimie Et Biologie
      Pessac, Aquitaine, France
  • 2011–2012
    • Unité Inserm U1077
      Caen, Lower Normandy, France
  • 2010–2012
    • Université Victor Segalen Bordeaux 2
      Burdeos, Aquitaine, France
  • 2007
    • French Institute of Health and Medical Research
      Lutetia Parisorum, Île-de-France, France