K Anselme

Institut de France, Lutetia Parisorum, Île-de-France, France

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Publications (106)306.07 Total impact

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    ABSTRACT: Highly controlled mixed molecular layers are crucial to study the role of material surface chemistry in biointerfaces, such as bacteria and subsequent biofilms interacting with biomaterials. Silanes with non-nucleophilic functional groups are promising to form self-assembled monolayers (SAMs) due to their low sensitivity to side-reactions. Nevertheless, the real control of surface chemistry, layer structure and organization has not been determined. Here, we report a comprehensive synthesis and analysis of undecyltrichlorosilane- and 11-bromoundecyltrichlorosilane-based mixed SAMs on silicon substrates. The impact of the experimental conditions on the control of surface chemistry, layer structure and organization was investigated by combining survey and high-resolution X-ray photoelectron spectroscopy analysis, wettability measurements and ellipsometry. The most appropriate conditions were first determined for elaborating highly reproducible, but easily made, pure 11-bromoundecyltrichlorosilane SAMs. We have demonstrated that the control is maintained on more complex surfaces i.e., surfaces revealing various chemical densities, which were obtained with different ratios of undecyltrichlorosilane and 11-bromoundecyltrichlorosilane. The control is also maintained after bromine to amine group conversion via SN2 bromine-to-azide reactions. The appropriateness of such highly controlled amino- and methyl-group revealing platforms (NH2-X%/CH3) for biointerface studies was shown by the higher reproducibility of bacterial adhesion on NH2-100%/CH3 SAMs compared to bacterial adhesion on molecular layers of overall similar surface chemistry, but less control at the molecular scale.
    ACS Applied Materials & Interfaces 10/2013; · 5.01 Impact Factor
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    ABSTRACT: Arrays of nanowires (NWs) are currently being established as vehicles for molecule delivery and electrical- and fluorescence-based platforms in the development of biosensors. It is conceivable that NW-based biosensors can be optimized through increased understanding of how the nanotopography influences the interfaced biological material. Using state-of-the-art homogenous NW arrays allows for a systematic investigation of how the broad range of NW densities used by the community influences cells. Here it is demonstrated that indium arsenide NW arrays provide a cell-promoting surface, which induces both increased cell proliferation and focal adhesion up-regulation. Furthermore, a systematic variation in NW spacing affects both the detailed cell morphology and adhesion properties, where the latter can be predicted based on changes in free-energy states using the proposed theoretical model. As the NW density influences cellular parameters, such as cell size and adhesion tightness, it will be important to take NW density into consideration in the continued development of NW-based platforms for cellular applications, such as molecule delivery and electrical measurements.
    ACS Applied Materials & Interfaces 09/2013; · 5.01 Impact Factor
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    ABSTRACT: This work describes the preparation and characterization of porous 3D-scaffolds based on chitosan (CHI), chitosan/silk fibroin (CHI/SF) and chitosan/silk fibroin/hydroxyapatite (CHI/SF/HA) by freeze drying. The biomaterials were characterized by X-ray diffraction, attenuated total reflection Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy and energy dispersive spectroscopy. In addition, studies of porosity, pore size, contact angle and biological response of SaOs-2osteoblastic cells were performed. The CHI scaffolds have a porosity of 94.2±0.9%, which is statistically higher than the one presented by CHI/SF/HA scaffolds, 89.7±2.6%. Although all scaffolds were able to promote adhesion, growth and maintenance of osteogenic differentiation of SaOs-2 cells, the new 3D-scaffold based on CHI/SF/HA showed a significantly higher cell growth at 7days and 21days and the level of alkaline phosphatase at 14 and 21days was statistically superior compared to other tested materials.
    Materials science & engineering. C, Materials for biological applications. 08/2013; 33(6):3389-3395.
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    ABSTRACT: Laser direct write techniques represent a prospective alternative for engineering a new generation of hybrid biomaterials via the creation of patterns consisting of biological proteins onto practically any type of substrate. In this paper we report on the characterization of fibronectin features obtained onto titanium substrates by UV nanosecond laser transfer. Fourier-transform infrared spectroscopy measurements evidenced no modification in the secondary structure of the post-transferred protein. The molecular weight of the transferred protein was identical to the initial fibronectin, no fragment bands being found in the transferred protein's Western blot migration profile. The presence of the cell-binding domain sequence and the mannose groups within the transferred molecules was revealed by anti-fibronectin monoclonal antibody immunolabelling and FITC-Concanavalin-A staining, respectively. The in vitro tests performed with MC3T3-E1 osteoblast-like cells and Swiss-3T3 fibroblasts showed that the cells' morphology and spreading were strongly influenced by the presence of the fibronectin spots.
    Journal of Materials Science Materials in Medicine 04/2013; · 2.14 Impact Factor
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    Doris M Campos, Gloria A Soares, Karine Anselme
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    ABSTRACT: We have recently developed new 3D hydroxyapatite/collagen (50/50 wt%) scaffolds using a biomimetic synthesis approach. The first in vitro tests performed in static culture showed a limited cell colonization and survival inside the scaffolds. The current study evaluated in dynamic culture the scaffold changes and colonization by human immortalized osteoprogenitor STRO-1A cells. The stability of our scaffolds in the different culture conditions (static, low flow, high flow) was validated by the maintenance of the pore diameter and interconnectivity over 21 d. The colonization and the viability of STRO-1A cells inside the scaffolds were further evaluated on histological sections. It was demonstrated that only the high flow-rate allowed cell survival after 7 d and a complete scaffold colonization. Moreover, the colonization and viability was different in function of the scaffold position inside the perfusion container. The differentiation markers (alkaline phosphatase activity, type I procollagen and osteocalcin synthesis) of STRO-1A cells were analyzed in the culture medium after 7, 14 and 21 d. The low flow-rate increased significantly the three markers compared with static conditions. In contrast, markers were reduced in high flow-rate compared with low flow-rate. To explain this surprising result, we hypothesized that the different molecules were actually adsorbed on the scaffold because of the closed circuit used in the high flow-rate conditions. In summary, this study provides original results on the influence of flow rate but mostly of the circuit used (open/closed) on the structural modifications and cell colonization of collagen-HA scaffolds.
    Biomatter. 04/2013; 3(2).
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    ABSTRACT: Chemo-mechanotransduction, the way by which mechanical forces are transformed into chemical signals, plays a fundamental role in many biological processes. The first step of mechanotransduction often relies on exposure, under stretching, of cryptic sites buried in adhesion proteins. Likewise, here we report the first example of synthetic surfaces allowing specific interactions with proteins or cells promoted by mechanical action in a fully reversible manner. Silicone sheets are first plasma treated and then functionalized by grafting sequentially under stretching poly(ethyleneglycol) (PEG) chains and biotin or arginine-glycine-aspartic acid (RGD) peptides. At rest position these ligands are not accessible for their receptors. Under stretching the surface becomes specifically interactive to streptavidin, biotin-antibodies or adherent for cells, the interactions being fully reversible by stretching/unstretching both for proteins and cells, revealing a reversible exposure process of the ligands. By changing the degree of stretching, the amount of interacting proteins can be varied continuously.
    ACS Nano 03/2013; 7:3457-3465. · 12.03 Impact Factor
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    ABSTRACT: a b s t r a c t We have recently demonstrated strong nuclear deformation of SaOs-2 osteosarcoma cells on poly-L-lactic acid (PLLA) micropillar substrates. In the present study, we first demonstrated that chemical and me-chanical properties of the micropillar substrates have no dominant effect on deformation. However, SaOs-2 nucleus deformation could be strongly modulated by varying the pillar size and spacing, high-lighting the importance of geometric constraints for shaping the nucleus. Furthermore, comparing the capacity for nuclear deformation in three different osteosarcoma cell lines (SaOs-2, MG-63 and OHS-4) revealed strong cell-type specific differences. Surprisingly, the highly-deformable SaOs-2 cell line dis-played the highest cell stiffness as assessed by AFM-based colloidal force spectroscopy and featured a more prominent array of actin fibres above the nucleus, suggesting a link between actin-mediated cell stiffness and cell nucleus deformation. In contrast, in MG-63 and OHS-4 cells dense microtubule and vimentin networks seem to facilitate some nuclear deformation even in the absence of a prominent actin cytoskeleton. Together these results suggest that an interaction of all three cytoskeletal elements is needed for efficient nuclear deformation. In conclusion, the dominant parameters influencing nuclear deformation on micropillar substrates are not their material properties but the substrate geometry together with cell phenotype and cytoskeleton organization.
    Biomaterials 01/2013; · 8.31 Impact Factor
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    ABSTRACT: Calcium phosphates, particularly hydroxyapatite Ca10(PO4)6(OH)2 (HA), arewidely used for bone regeneration due to their biocompatibility and good resorption properties. However, their performance upon implantation is improved when they are associated with bioactive molecules such as growth factors. Using mesoporous HA leads to improved protein adsorption and release kinetics because the diameter of the mesopores (2–50 nm) is in the same range as their size. We prepared this type of material by the nanocasting method using three different templates: a silica foam and two carbon templates derived fromit using propylene or sucrose as carbon source. We investigated the influence of the template, the calcination temperature and of the conditions during template removal. We obtained HA materials with a surface area of up to 90 m2 g-1 and with an intergranular mesopore volume of up to 0.4 cm3 g-1. In this paper,we showfor the first time that the synthesis of mesoporous HA from a mesoporous silica foam template allows eliminating the template at lower temperatures (in an alkaline medium), thus preventing the sintering of the HA. These materials have interesting properties for drug delivery applications. The protein adsorption and release capacities of these HAs were tested with two model proteins, bovine serum albumin (BSA), and Cytochrome C. These materials are an important milestone for future bone regeneration systems based on HA associated with human growth factor proteins.
    Journal of Materials Science 01/2013; 48:3722. · 2.16 Impact Factor
  • 01/2013: pages 469-489; , ISBN: 9783527649600
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    ABSTRACT: In order to design soft coatings, surface tethering of vesicular structures self-assembled from oligonucleotide-polymer hybrids is achieved through hybridization. Watson-Crick base-pairing occurs between the nucleotide sequences involved in the self-assembly and their surface-tethered complementary sequences. Combining the quartz crystal microbalance and in situ observations using confocal laser scanning microscopy, it is evidenced that the vesicles retain their morphology even under flow stress. Surprisingly, these soft surfaces prevent bacterial colonization.
    Advanced Functional Materials 12/2012; 22(23). · 9.77 Impact Factor
  • K Anselme, M Bigerelle
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    ABSTRACT: Surface characteristics of materials, whether their topography, chemistry, or surface energy, play an essential part in osteoblast adhesion on biomaterials. Thus, the quality of cell adhesion will influence the cell's capacity to proliferate and differentiate in contact with a biomaterial. We have developed for more than ten years numerous studies on the influence of topography and chemistry of metallic substrates on the response of primary human bone cells. The originality of our approach is that contrary to most of other authors, we quantified the adhesion of primary human bone cells on metallic substrates with perfectly characterized surface topography after some hours but also over 21 days. Moreover, we have developed original statistical approaches for characterizing the relation between surface roughness and cell-adhesion parameters. In this article, we will illustrate different studies we did these last ten years concerning the development of a new adhesion parameter, the adhesion power; the correlation between short-term adhesion, long-term adhesion, and proliferation; the influence of roughness organization on cell adhesion and the development of the order parameter; our modeling approach of cell adhesion on surface topography; the relative influence of surface chemistry and topography on cell adhesion and contact angle; the relation between surface features dimensions and cell adhesion. Further, some considerations will be given on the methods for scanning surface topography for cell-adhesion studies. Finally, perspectives will be given to elucidate these intracellular mechanotransduction mechanisms induced by the deformation of cells on model sinusoidal peaks-or-valleys surfaces. SCANNING 00: 1-10, 2012. © 2012 Wiley Periodicals, Inc.
    Scanning 11/2012; · 1.29 Impact Factor
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    ABSTRACT: In this study, two series of 11 samples of TiAl6V4 titanium alloy and 316L stainless steel have been polished in an isotropic manner at different levels in order to quantify the influence of biomaterial roughness on cell behavior. Topography was measured by a tactile profilometer and a multiscale analysis has been carried out. Human osteoblasts have been cultured on those samples. It appears that roughness has no reproducible effect on the cell behavior except an influence on cell orientation on the wider grooves. As a conclusion, biomaterial surface damage, in the roughness range between R(a) = 0.01 and 0.1 μm, has no influence on cell-adhesion mechanisms when roughness is isotropic and groove width is inferior to a critical value. SCANNING 00: 1-9, 2012. © 2012 Wiley Periodicals, Inc.
    Scanning 11/2012; · 1.29 Impact Factor
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    ABSTRACT: This work evaluates the thermal reactivity and the biological reactivity of an amorphous calcium phosphate thin film produced by radio frequency (RF) magnetron sputtering onto titanium substrates. The analyses showed that the sputtering conditions used in this work led to the deposition of an amorphous calcium phosphate. The thermal treatment of this amorphous coating in the presence of H2O and CO2 promoted the formation of a carbonated HA crystalline coating with the entrance of CO32 − ions into the hydroxyl HA lattice. When immersed in culture medium, the amorphous and carbonated coatings exhibited a remarkable instability. The presence of proteins increased the dissolution process, which was confirmed by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses. Moreover, the carbonated HA coating induced precipitation independently of the presence of proteins under dynamic conditions. Despite this surface instability, this reactive calcium phosphate significantly improved the cellular behavior. The cell proliferation was higher on the Ticp than on the calcium phosphate coatings, but the two coatings increased cellular spreading and stress fiber formation. In this sense, the presence of reactive calcium phosphate coatings can stimulate cellular behavior.
    Materials Science and Engineering: C. 10/2012; 32(7):2086–2095.
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    ABSTRACT: Two types of completely densified β-TCP tablets were synthesized from a stoichiometric β-TCP powder. The first ones (TCP) were conventionally sintered, while the second ones (TCP-T) were sintered and treated by hot isostatic process (HIP). The HIP produced completely densified materials with relative densities greater than 99.9% and a transparent appearance of tablets. Samples were immersed in culture medium with (CM) or without serum (NCM) in static and dynamic conditions for a biomimetic evaluation. Similarly, SaOs-2 cells were cultured on samples in a static or dynamic flow perfusion system. The results of surface transformation in absence of cells showed that the dynamic condition increased the speed of calcium phosphate precipitations compared with the static condition. The morphology of precipitates was different with nature of tablets. The immersion in CM did impede this precipitation. XPS analysis of TCP-T tablets showed the presence of hydroxyapatite (HA) precipitates after incubation in NCM while octacalcium phosphate (OCP) precipitates were formed after incubation in CM. The analysis of the response of SaOs-2 cells on surfaces showed that the two types of materials are biocompatible. However, the dynamic mode of culture stimulated the differentiation of cells. Finally, it appears that the HIP treatment of TCP produces highly densified and transparent samples that display a good in vitro biocompatibility in static and dynamic culture conditions. Moreover, an interesting result of this work is the relationship between the presence of proteins in the immersion medium and the quality of precipitates formed on hipped TCP surface.
    Biomatter. 07/2012; 2(3):103-113.
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    Karine Anselme, Lydie Ploux, Arnaud Ponche
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    ABSTRACT: The need to control the adhesion of cells to material surfaces plays an important role in determining the design of biomaterial substrates for biotechnology and tissue-engineering applications. As a the first step in a cascade of cellular events, adhesion affects many aspects of cell function, including spreading, migration, proliferation and differentiation. After a short description of cell adhesion and essential molecules involved in, the present knowledge on the influence of surface topography on cell behavior will be described by considering not only the amplitude of the surface topography but also its organization at all scales (micro- and nano-scale). The biological mechanisms underlying the cell response to topography will be evoked. Secondly, the influence of surface chemistry as well as surface energy on cell adhesion will be described. Thirdly, as the cells never interact with a bare material but with materials on which the proteins from biological fluids have adsorbed, some studies on the role of proteins in cell adhesion will be used to illustrate this point. Finally, the influence of substrate mechanics on cell differentiation will be described.
    Journal of Adhesion Science and Technology 04/2012; 24(5):831-852. · 0.90 Impact Factor
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    ABSTRACT: In a previous paper, we proposed new silver nanoparticles (SNPs) based antibacterial coatings able to protect eukaryotic cells from SNPs related toxic effects, while preserving antibacterial efficiency. A SNPs containing n-heptylamine (HA) polymer matrix was deposited by plasma polymerization and coated by a second HA layer. In this paper, we elucidate the antibacterial action of these new coatings. We demonstrated that SNPs-loaded material can be covered by thin HA polymer layer without losing the antibacterial activity to planktonic bacteria living in the near surroundings of the material. SNPs-containing materials also revealed antibacterial effect on adhered bacteria. Adhered bacteria number was significantly reduced compared to pure HA plasma polymer and the physiology of the bacteria was affected. The number of adhered bacteria directly decreased with thickness of the second HA layer. Surprisingly, the quantity of cultivable bacteria harvested by transfer to nutritive agar decreased not only with the presence of SNPs, but also in relation to the covering HA layer thickness, that is, oppositely to the increase in adhered bacteria number. Two hypotheses are proposed for this surprising result (stronger attachment or weaker vitality), which raises the question of the diverse potential ways of action of SNPs entrapped in a polymer matrix.
    Journal of Nanomaterials 01/2012; 2012. · 1.55 Impact Factor
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    ABSTRACT: Knowing that a surface or profile can be characterized by numerous roughness parameters, the objective of this investigation was to present a methodology which aims to determine quantitatively and without preconceived opinion the most relevant pair of roughness parameters that describe an abraded surface. The methodology was firstly validated on simulated fractal profiles having different amplitudes and Hölder exponents and it was secondly applied to characterise different worn regions of a retrieved metallic femoral head articulated against an ultra-high molecular weight polyethylene (UHMWPE) acetabular cup containing an embedded metallic fibber into its surface. The methodology consists in combining the recent Bootstrap method with the usual discriminant analysis. It was validated on simulated fractal profiles showing that, among more than 3000 pairs tested, the total amplitude Rt and the fractal dimension Δ is the most relevant pair of roughness parameters; parameters corresponding to the variables modulated in the analytical expression of the fractal function. The application of this methodology on a retrieved metallic femoral head shows that the most relevant pair of parameters for discriminating the different investigated worn regions is the arithmetic roughness parameter Ra paired with the mean peak height Rpm. This methodology finally helps in a better understanding of the scratch mechanism of this orthopedic bearing component.
    Tribology International 01/2012; · 1.54 Impact Factor
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    ABSTRACT: Pure titanium samples were obtained using electrical discharge machining (EDM) on a spark erosion machine. Twenty-two titanium samples were obtained exhibiting a wide range of arithmetic roughness (Ra) varying from 1 to more than 20.9 µm. The surfaces present an isotropic structure formed by successive peaks and valleys. No specific direction or periodical structure is visible on surfaces. It is shown that the surfaces present similar morphological structures since the surfaces appear like a zoom of the surface at a lower grade while the grade rises. It is shown that it exists a bandwidth in the amplitude roughness where surfaces lost significantly their biocompatibility. However, electro-erosion is an appropriate tool-machining process to increase the biocompatibility of titanium implants when creating a relevant roughness.
    International Journal of Mechatronics and Manufacturing Systems 01/2012; 5(5):419-430.
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    ABSTRACT: Hydroxyapatite-collagen (HA/Col) composites are potential scaffolds for bone tissue engineering. In this work, three-dimensional (3-D) HA/Col (50/50 wt. (%)) scaffolds were synthesized using a self-assembly method and cross-linked with a 0.125% glutaraldehyde solution. Scaffolds were evaluated in vitro by cytotoxicity testing using MC3T3 cells; proliferation and differentiation were studied using STRO-1A human stromal cells for up to 21 days. Morphological and histological examinations showed a fibrous structure with a good distribution and homogeneous HA particles distribution. By thermogravimetric analysis, a ratio of 1.2 between inorganic and organic phase was found. The scaffolds presented no cytotoxicity when evaluated using three different parameters of cell survival and integrity: 2,3-bis[2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide (XTT), Neutral Red (NR) and Crystal Violet Dye Elution (CVDE). STRO-1A cells were found to adhere, proliferate and differentiate on the 3-D scaffold, but limited cell penetration was observed.
    Materials Research 12/2011; 15(1):151. · 0.52 Impact Factor

Publication Stats

3k Citations
306.07 Total Impact Points

Institutions

  • 2013
    • Institut de France
      Lutetia Parisorum, Île-de-France, France
  • 2006–2013
    • Université de Haute-Alsace
      • • Institut de Science des Matériaux de Mulhouse : IS2M
      • • Laboratoire de Physique et Mécanique Textiles (LPMT)
      Mulhouse, Alsace, France
  • 2011
    • Université de Technologie de Compiègne
      • Laboratoire Roberval
      Compiègne, Picardie, France
    • National Institute for Laser, Plasma and Radiation Physics
      Bucureşti, Bucureşti, Romania
  • 2010
    • French National Centre for Scientific Research
      Lutetia Parisorum, Île-de-France, France
  • 2000–2006
    • Université du Littoral Côte d'Opale (ULCO)
      Dunkirk, Nord-Pas-de-Calais, France
  • 1996–2002
    • Institut Calot
      Berck-sur-Mer, Nord-Pas-de-Calais, France