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Fabrication Of Metallic Patterns On PDMS Using Transfer Technology: Application To MRI Microcoils
M. Couty, S. Nazeer, C. Jelita, E. Martincic, M. Woytasik, J.C. Ginefri, L. Darrasse, M. Tatoulian, E. Dufour-Gergam
MICRO & NANO LETTERS - 7(6) :519-22 - DOI:10.1049/mnl.2012.0271 - 2012
Despite the large use of this material in the microsystem field, fabrication of metallic patterns on polydimethylsiloxane (PDMS) still remains a challenge. In this Letter, we present a new process based on the transfer principle and report its application to MRI microcoils. These double-side structures are well aligned and the transfer yield is higher than 90%. The limit of the working range for these flexible coils is a bending radius of 2 mm, similar to the radius of the coil. The developed process opens a wide range of further applications for flexible devices.
Stable modification of PDMS surface properties by plasma polymerization: Innovative process of allylamine PECVD deposition and microfluidic devices sealing
S. Massey, A. Duboin, D. Mantovani, P. Tabeling, M. Tatoulian
Surface & Coatings Technology - 206(19-20) :4303-9 - DOI:10.1016/j.surfcoat.2012.04.047 - 2012
This paper presents a new and innovative process of modification of wetting of open micro-channels involving a method to seal the microfluidic devices. Allylamine was polymerized on poly(dimethylsiloxane) (PDMS) by plasma-enhanced chemical vapour deposition (PECVD) to modify the wetting properties of open micro-channels. The sealing of the devices was done by thermal pressing. All the steps of the process were characterized by different analysis techniques to understand the mechanisms of the process and to assess the performance of the technique. Physicochemical analysis of the polymerized allylamine coatings (X-ray photoelectron spectroscopy and static water contact angle) showed that the coatings were resistant to the thermal pressing and were stable in ambient air and underwater up to 14 days of ageing, even if the water contact angle decreased during the underwater ageing. Parallel tests were undergone in microfluidic devices and the stability of ageing was tested by the production of the simple oil-in-water emulsions. All the experiments showed that this new PECVD/thermal press process is an effective way to modify the wetting properties of an open microfluidic device and includes a technique to seal effectively the system afterwards.
Electrografted nanostructured platforms for click chemistry
Cernat A., Griveau S., Martin S., Lacroix JC., Farcau M., Sandelescu R., Bedioui F.
Electrochemistry Communications - 23 :141-4 - DOI:10.1016/j.elecom.2012.07.014 - 2012
We report on the combination of nanosphere lithography, electrodeposition and click chemistry to produce nanostructured surfaces with improved number of anchored molecules. Our strategy was developed here for the immobilization of ferrocene at glassy carbon electrode, both used as models. The nanostructuration of the surface was obtained by adsorption of 900 nm-diameter polystyrene nanosphere followed either by electropolymerization of N-(10-azidodecyl)pyrrole or by electrografting of 4-azidobenzenediazonium. In the case of poly-N-(10-azidodecyl)pyrrole, the AFM analysis of the surface after electropolymerization and removal of the nanospheres show the formation of a patterned film with holes separated of ˜900 nm. In the case of 4-azidobenzenediazonium, the electrografting proceeds similarly to bare surfaces, but with a decrease of reduction peak intensity due to the partial coverage of the electrode surface with insulating nanospheres. For both modified surfaces, the immobilization of ferrocene by copper(I) catalyzed azide-alkyne cycloaddition was clearly evidenced by cyclic voltammetry. The evaluation of the surface coverage shows that the nanostructuration leads to larger specific area for the chemical anchorage of ferrocene. Finally this procedure produces versatile functionalization of conductive materials used in various applications.
Carbon nanotubes and metalloporphyrins and metallophthalocyanines-based materials for electroanalysis
Zagal JH., Griveau S., Santander-Nelli M., Gutierrez Granados S., Bedioui F.
J. Porph. Phthal. - 16 :713-40 - DOI:10.1142/S1088424612300054 - 2012
We discuss here the state of the art on hybrid materials made from single (SWCNT) or multi (MWCNT) walled carbon nanotubes and MN4 complexes such as metalloporphyrins and metallophthalocyanines. The hybrid materials have been characterized by several methods such as cyclic voltammetry (CV), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and scanning electrochemical microscropy (SECM). The materials are employed for electrocatalysis of reactions such as oxygen and hydrogen peroxide reduction, nitric oxide oxidation, oxidation of thiols and other pollutants.
Fine control of nuclear confinement identifies a threshold deformation leading to lamina rupture and induction of specific genes
Berre M, Aubertin J, Piel M
Integr Biol (Camb) - 4(11) :1406-14 - DOI:10.1039/c2ib20056b - 2012
The quest to understand how the mechanical and geometrical environment of cells impacts their behavior and fate has been a major force driving the recent development of new technologies in cell biology research. Despite rapid advances in this field, many challenges remain in order to bridge the gap between the classical and simple cell culture plate and the biological reality of actual tissue. In tissues, cells have their physical space constrained by neighboring cells and the extracellular matrix. Here, we propose a simple and versatile device to precisely and dynamically control this confinement parameter in cultured cells. We show that there is a precise threshold deformation above which the nuclear lamina breaks and reconstructs, whereas nuclear volume changes. We also show that different nuclear deformations correlate with the expression of specific sets of genes, including nuclear factors and classical mechanotransduction pathways. This versatile device thus enables the precise control of cell and nuclear deformation by confinement and the correlative study of the associated molecular events.
The first World Cell Race
Maiuri P, Terriac E, Paul-Gilloteaux P, Vignaud T, McNally K, Onuffer J, Thorn K, Nguyen PA, Georgoulia N, Soong D, Jayo A, Beil N, Beneke J, Hong Lim JC, Pei-Ying Sim C, Chu YS; WCR participants, Jiménez-Dalmaroni A, Joanny JF, Thiery JP, Erfle H, Parson
Curr Biol. - 22(17) :R673-5 - DOI:10.1016/j.cub.2012.07.052 - 2012
Motility is a common property of animal cells. Cell motility is required for embryogenesis [1], tissue morphogenesis [2] and the immune response [3] but is also involved in disease processes, such as metastasis of cancer cells [4]. Analysis of cell migration in native tissue in vivo has yet to be fully explored, but motility can be relatively easily studied in vitro in isolated cells. Recent evidence suggests that cells plated in vitro on thin lines of adhesive proteins printed onto culture dishes can recapitulate many features of in vivo migration on collagen fibers [5,6]. However, even with controlled in vitro measurements, the characteristics of motility are diverse and are dependent on the cell type, origin and external cues. One objective of the first World Cell Race was to perform a large-scale comparison of motility across many different adherent cell types under standardized conditions. To achieve a diverse selection, we enlisted the help of many international laboratories, who submitted cells for analysis. The large-scale analysis, made feasible by this competition-oriented collaboration, demonstrated that higher cell speed correlates with the persistence of movement in the same direction irrespective of cell origin.
Predicting division plane position and orientation
Minc N, Piel M.
Trends Cell Biol. - 22(4) :193-200 - DOI:10.1016/j.tcb.2012.01.003 - 2012
Predicting cellular behavior is a major challenge in cell and developmental biology. Since the late nineteenth century, empirical rules have been formulated to predict the position and orientation of mitotic cleavage planes in plant and animal cells. Here, we review the history of division plane orientation rules and discuss recent experimental and theoretical studies that refine these rules and provide mechanistic insights into how division can be predicted. We describe why some of these rules may better apply to certain cell types and developmental contexts and discuss how they could be integrated in the future to allow the prediction of division positioning in tissues.
Anthrax receptors position the spindle
Minc N, Piel M
Nat. Cell Biol. - 15(1) :11-3 - DOI:10.1038/ncb2664 - 2012
Oriented mitosis is essential during tissue morphogenesis. The Wnt/planar cell polarity (Wnt/PCP) pathway orients mitosis in a number of developmental systems, including dorsal epiblast cell divisions along the animal-vegetal (A-V) axis during zebrafish gastrulation. How Wnt signalling orients the mitotic plane is, however, unknown. Here we show that, in dorsal epiblast cells, anthrax toxin receptor 2a (Antxr2a) accumulates in a polarized cortical cap, which is aligned with the embryonic A-V axis and forecasts the division plane. Filamentous actin (F-actin) also forms an A-V polarized cap, which depends on Wnt/PCP and its effectors RhoA and Rock2. Antxr2a is recruited to the cap by interacting with actin. Antxr2a also interacts with RhoA and together they activate the diaphanous-related formin zDia2. Mechanistically, Antxr2a functions as a Wnt-dependent polarized determinant, which, through the action of RhoA and zDia2, exerts torque on the spindle to align it with the A-V axis.
Microfabricated devices for cell biology: all for one and one for all
Lautenschläger F, Piel M
Curr Opin Cell Biol - 25(1) :116-24 - DOI:10.1016/j.ceb.2012.10.017 - 2012
Individual cells in their native physiological states face a dynamic multi-factorial environment. This is true of both single-celled and multi-cellular organisms. A key challenge in cell biology is the design of experimental methods and specific assays to disentangle the contribution of each of the parameters governing cell behavior. After decades of studying cells cultured in Petri dishes or on glass coverslips, researchers can now benefit from a range of recent technological developments that allow them to study cells in a variety of contexts, with different levels of complexity and control over a range of environmental parameters. These technologies include new types of microscopy for detailed imaging of large cell aggregates or even whole tissues, and the development of cell culture substrates, such as 3D matrices. Here we will review the contribution of a third type of tool, collectively known as microfabricated tools. Derived from techniques originally developed for microelectronics, these tools range in size from hundreds of microns to hundreds of nanometers.
Differential RNA-binding activity of the hnRNP G protein correlated with the sex genotype in the amphibian oocyte
Kanhoush, R; Praseuth, D; Perrin, C; Chardard, D; Vinh, J; Penrad-Mobayed, M.
Nucleic Acids Res. - 39(10) :4109-21 - DOI:10.1093/nar/gkq1315 - 2011
A proteomic approach has enabled the identification of an orthologue of the splicing factor hnRNP G in the amphibians Xenopus tropicalis, Ambystoma mexicanum, Notophthalmus viridescens and Pleurodeles walt, which shows a specific RNA-binding affinity similar to that of the human hnRN G protein. Three isoforms of this protein with a differential binding affinity for a specific RNA probe were identified in the P. walt oocyte. In situ hybridization to lampbrush chromosomes of P. waltl revealed the presence of a family of hnRNP G genes, which were mapped on the Z and W chromosomes and one autosome. This indicates that the isoforms identified in this study are possibly encoded by a gene family linked to the evolution of sex chromosomes similarly to the hnRNP G/RBMX gene family in mammals.

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579 publications.