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Chevallier, Pascale

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Chevallier

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Pascale

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Université Laval. Département de génie des mines, de la métallurgie et des matériaux

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ncf11892659

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Voici les éléments 1 - 10 sur 15
  • PublicationAccès libre
    Evaluating poly(Acrylamide-co-Acrylic Acid) hydrogels stress relaxation to direct the osteogenic differentiation of mesenchymal stem cells
    (Wiley, 2021-04-19) Prouvé, Émilie; Drouin, Bernard; Laroche, Gaétan; Rémy-Zolghadri, Murielle; Chevallier, Pascale; Durrieu, Marie-Christine
    The aim of this study is to investigate polyacrylamide-based hydrogels stress relaxation and the subsequent impact on the osteogenic differentiation of human mesenchymal stem cells (hMSCs). Different hydrogels are synthesized by varying the amount of cross-linker and the ratio between the monomers (acrylamide and acrylic acid), and characterized by compression tests. It has been found that hydrogels containing 18% of acrylic acid exhibit an average relaxation of 70%, while pure polyacrylamide gels show an average relaxation of 15%. Subsequently, hMSCs are cultured on two different hydrogels functionalized with a mimetic peptide of the bone morphogenetic protein-2 to enable cell adhesion and favor their osteogenic differentiation. Phalloidin staining shows that for a constant stiffness of 55 kPa, a hydrogel with a low relaxation (15%) leads to star-shaped cells, which is typical of osteocytes, while a hydrogel with a high relaxation (70%) presents cells with a polygonal shape characteristic of osteoblasts. Immunofluorescence labeling of E11, strongly expressed in early osteocytes, also shows a dramatically higher expression for cells cultured on the hydrogel with low relaxation (15%). These results clearly demonstrate that, by fine-tuning hydrogels stress relaxation, hMSCs differentiation can be directed toward osteoblasts, and even osteocytes, which is particularly rare in vitro.
  • PublicationAccès libre
    Human saphenous vein endothelial cell adhesion and expansion on micropatterned polytetrafluoroethylene
    (Wiley, 2012-08-31) Boivin, Marie-Claude; Laroche, Gaétan; Hoesli, Corinne A.; Lagueux, Jean; Bareille, Reine; Rémy-Zolghadri, Murielle; Chevallier, Pascale; Bordenave, Laurence; Durrieu, Marie-Christine
    Intimal hyperplasia and thrombosis are responsible for the poor patency rates of small-diameter vascular grafts. These complications could be avoided by a rapid and strong adhesion of endothelial cells to the prosthetic surfaces, which typically consist of expanded polytetrafluoroethylene (PTFE) for small-diameter vessels. We have previously described two peptide micropatterning strategies that increase the endothelialization rates of PTFE. The micropatterns were generated either by inkjet printing 300 μm squares or by spraying 10.1 ± 0.1 μm diameter droplets of the CGRGDS cell adhesion peptide, while the remaining surface was functionalized using the CWQPPRARI cell migration peptide. We now directly compare these two micropatterning strategies and examine the effect of hydrodynamic stress on human saphenous vein endothelial cells grown on the patterned surfaces. No significant differences in cell adhesion were observed between the two micropatterning methods. When compared to unpatterned surfaces treated with a uniform mixture of the two peptides, the cell expansion was significantly higher on sprayed or printed surfaces after 9 days of static cell culture. In addition, after 6 h of exposure to hydrodynamic stress, the cell retention and cell cytoskeleton reorganization on the patterned surfaces was improved when compared to untreated or random treated surfaces. These results indicate that micropatterned surfaces lead to improved rates of PTFE endothelialization with higher resistance to hydrodynamic stress.
  • PublicationAccès libre
    Fibronectin grafting to enhance skin sealing around transcutaneous titanium implant
    (John Wiley & Sons, 2021-04-30) Bilem, Ibrahim; Ghadhab, Souhaila; Ruel, Jean; Laroche, Gaétan; Auger, François A.; Guay-Bégin, Andrée-Anne; Pauthe, Emmanuel; Chevallier, Pascale
    Intraosseous transcutaneous amputation prosthesis is a new approach in orthopedic implants that overcomes socket prosthesis problems. Its long-term performance requires a tight skin-implant seal to prevent infections. In this study, fibronectin (Fn), a widely used adhesion protein, was adsorbed or grafted onto titanium alloy. Fn grafting was performed using two different linking arms, dopamine/glutaric anhydride or phosphonate. The characterization of Fn-modified surfaces showed that Fn grating via phosphonate has led to the highest amount of Fn cell-binding site (RGD, arginine, glycine, and aspartate) available on the surface. Interestingly, cell culture studies revealed a strong correlation between the amount of available RGD ligands and cellular behavior, since enhanced proliferation and spreading of fibroblasts were noticed on Fn-grafted surfaces via phosphonate. In addition, an original in vitro mechanical test, inspired from the real situation, to better predict clinical outcomes after implant insertion, has been developed. Tensile test data showed that the adhesion strength of a bio-engineered dermal tissue was significantly higher around Fn-grafted surfaces via phosphonate, as compared to untreated surfaces. This study sheds light on the importance of an appropriate selection of the linking arm to tightly control the spatial conformation of biomolecules on the material surface, and consequently cell interactions at the interface tissue/implant.
  • PublicationAccès libre
    Milkweed scaffold : a new candidate for bone cell growth
    (Taylor & Francis Online, 2019-06-17) Bilem, Ibrahim; Laroche, Gaétan; Naudé, Nicolas; Elkoun, S.; Chevallier, Pascale; Robert, Mathieu; Soulié, Simon
    This study aims to evaluate the potential of milkweed as potential candidate to construct biodegradable scaffold for bone regeneration. A mat made of milkweed, polyethylene, and polypropylene was treated with an atmospheric pressure plasma to functionalize the surface of the polymer assembly with carboxylic acid groups, which enable to conjugate bioactive molecules, while accelerating the degradation of milkweed. Degradation tests demonstrated substantial decrease of the weight of the treated polymer mat as compared to untreated one. Biological assays revealed that the polymer assembly promoted preosteoblast MC3T3 cells recruitment with a significant enhancement observed on the RGD-grafted polymer mat.
  • PublicationAccès libre
    Fibronectin-modified surfaces for evaluating the influence of cell adhesion on sensitivity of leukemic cells to siRNA nanoparticles
    (London Future Medicine, 2016-04-13) Valencia-Serna, Juliana; Laroche, Gaétan; Chevallier, Pascale; Bahadur K.C., Remant; Uludağ, Hasan
    Aim: This study aimed to create fibronectin (FN)-grafted polymeric surfaces to investigate the influence of leukemic cell adhesion on siRNA treatment. Materials & methods: FN was grafted on plasma-treated PTFE surfaces using chemical crosslinkers. Adhesion and growth of chronic myeloid leukemia K562 cells on modified surfaces were investigated. The silencing effect of siRNA/lipid-polymers nanoparticles on cells grown on FN-grafted surfaces was evaluated. Results: Crosslinker-mediated immobilization showed significant FN grafting on surfaces, which provided K562 cell adhesion and growth advantage. siRNA nanoparticle silencing was similarly effective on FN-adhered and suspension-growing K562 cells. Conclusion: This study provided initial data to develop a cell-adhesive system to investigate therapeutic effects on leukemic cells. The response of chronic myeloid leukemia cells to siRNA nanoparticles was independent on cell attachment.
  • PublicationAccès libre
    Grafting of a model protein on lactide and caprolactone based biodegradable films for biomedical applications
    (Taylor & Francis, 2014-01-23) Larrañaga, Aitor; Laroche, Gaétan; Guay-Bégin, Andrée-Anne; Chevallier, Pascale; Sabbatier, Gad; Fernández, Jorge; Sarasua, José-Ramón
    Thermoplastic biodegradable polymers displaying elastomeric behavior and mechanical consistency are greatly appreciated for the regeneration of soft tissues and for various medical devices. However, while the selection of a suitable base material is determined by mechanical and biodegradation considerations, it is the surface properties of the biomaterial that are responsible for the biological response. In order to improve the interaction with cells and modulate their behavior, biologically active molecules can be incorporated onto the surface of the material. With this aim, the surface of a lactide and caprolactone based biodegradable elastomeric terpolymer was modified in two stages. First, the biodegradable polymer surface was aminated by atmospheric pressure plasma treatment and second a crosslinker was grafted in order to covalently bind the biomolecule. In this study, albumin was used as a model protein. According to X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), albumin was efficiently immobilized on the surface of the terpolymer, the degree of albumin surface coverage (ΓBSA) reached ~35%. Moreover, gel permeation chromatography (GPC) studies showed that the hydrolytic degradation kinetic of the synthesized polymer was slightly delayed when albumin was grafted. However, the degradation process in the bulk of the material was unaffected, as demonstrated by Fourier transform infrared (FTIR) analyses. Furthermore, XPS analyses showed that the protein was still present on the surface after 28 days of degradation, meaning that the surface modification was stable, and that there had been enough time for the biological environment to interact with the modified material.
  • PublicationAccès libre
    Effect of linking arm hydrophilic/hydrophobic nature, length and end-group on the conformation and the RGD accessibility of surface-immobilized fibronectin
    (Elsevier, 2019-10-30) Laroche, Gaétan; Vanslambrouck, Stéphanie; Guay-Bégin, Andrée-Anne; Chevallier, Pascale
    In order to stimulate the cellular response to implant materials, extracellular matrix (ECM) proteins, such as collagen and fibronectin (FN), are immobilized on the implant surface. Amongst all ECM proteins used for biomimetic materials for medical applications, FN is one of the most investigated proteins thanks to its ability to promote cell adhesion and its contribution to important physiological processes. However, its conformation and hence its bioactivity strongly depend on the hydrophilic/hydrophobic nature of the surface as well as on immobilization strategies. This work investigates the effect of these two parameters, as well as the effect of the crosslinker length. FN was grafted onto silicon wafers using eights different linking arms presenting different lengths, hydrophilic/hydrophobic characters and binding sites. The protein was linked through either its amino groups (lysine amino acids) or sulfhydryl functionalities (cysteine amino acids). The grafting of each crosslinker and subsequent FN conjugation onto the surfaces was evidenced by X-ray photoelectron spectroscopy, while the surface hydrophilicity was determined by contact angle measurements. Moreover, atomic force microscopy images revealed that the conformation of surface conjugated FN only depends on the hydrophilicity of the linking arm. The FN conformation was also probed by enzyme-linked immunosorbent assays (ELISA). ELISA data demonstrated that all of the three investigated parameters linking arm parameter (length, hydrophobic/hydrophilic character, and terminal end-group) somewhat influence the RGD accessibility.
  • PublicationAccès libre
    Atmospheric pressure cold plasma versus wet-chemical surface treatments for carboxyl functionalization of polylactic acid : a first step toward the immobilization of bioactive molecules
    (Elsevier, 2020-02-08) Laroche, Gaétan; Rodríguez Durán, Iván; Vanslambrouck, Stéphanie; Chevallier, Pascale
    The use of polylactic acid (PLA) has attracted growing interest, particularly in recent years, for biomedical applications because of its mechanical properties, biocompatibility, and biodegradability. Despite this, features such as surface hydrophobicity and the absence of suitable functional groups for covalent immobilization of bioactive molecules, make it challenging to endow PLA-based medical devices with additional features and thus broaden their range of applicability. In the present study, we demonstrate the suitability of atmospheric pressure dielectric barrier discharges operating in the Townsend regime as a promising alternative to other surface treatments, such as diazonium and alkali hydrolytic treatments, for carboxyl functionalization of PLA. Chemical changes in PLA surfaces are evaluated by contact angle measurements and by X-ray photoelectron spectroscopy while physical changes are investigated by scanning electron microscopy and atomic force microscopy. The amount of carboxyl groups generated on PLA surfaces is assessed by toluidine blue O assay and substantiated by grafting, through carboxyl groups, a fluorescent probe containing amino functionalities. All of the surface treatments have proven to be very effective in generating carboxylic groups on the PLA surface. Nevertheless, plasma treatment is shown to not degrade the PLA surface, in sharp contrast with diazonium and alkali hydrolytic treatments.
  • PublicationAccès libre
    Rapid nucleation of iron oxide nanoclusters in aqueous solution by plasma electrochemistry
    (ACS Publications, 2015-06-18) Turgeon, Stéphane; Fortin, Marc-André; Laroche, Gaétan; Sarra-Bournet, Christian; Lagueux, Jean; Létourneau, Mathieu; Chevallier, Pascale; Laprise-Pelletier, Myriam; Bouchard, Mathieu
    Progresses in cold atmospheric plasma technologies have made possible the synthesis of nanoparticles in aqueous solutions using plasma electrochemistry principles. In this contribution, a reactor based on microhollow cathodes and operating at atmospheric pressure was developed to synthesize iron-based nanoclusters (nanoparticles). Argon plasma discharges are generated at the tip of the microhollow cathodes, which are placed near the surface of an aqueous solution containing iron salts (FeCl₂ and FeCl₃) and surfactants (biocompatible dextran). Upon reaction at the plasma−liquid interface, reduction processes occur and lead to the nucleation of ultrasmall iron-based nanoclusters (IONCs). The purified IONCs were investigated by XPS and FTIR, which confirmed that the nucleated clusters contain a highly hydrated form of iron oxide, close to the stoichiometric constituents of α-FeOOH (goethite) or Fe₅O₃(OH)₉ (ferrihydrite). Relaxivity values of r₁ = 0.40 mM−¹ s−¹ and r₂/r₁ = 1.35 were measured (at 1.41 T); these are intermediate values between the relaxometric properties of superparamagnetic iron oxide nanoparticles used in medicine (USPIO) and those of ferritin, an endogenous contrast agent. Plasma-synthesized IONCs were injected into the mouse model and provided positive vascular signal enhancement in T₁-w. MRI for a period of 10−20 min. Indications of rapid and strong elimination through the urinary and gastrointestinal tracts were also found. This study is the first to report on the development of a compact reactor suitable for the synthesis of MRI iron-based contrast media solutions, on site and upon demand.
  • PublicationAccès libre
    A fluorophore-tagged RGD peptide to control endothelial cell adhesion to micropatterned surfaces
    (ScienceDirect, 2013-10-31) Hoesli, Corinne A.; Duchesne, Carl; Juneau, Pierre-Marc; Laroche, Gaétan; Chevallier, Pascale
    The long-term patency rates of vascular grafts and stents are limited by the lack of surface endothelialisation of the implanted materials. We have previously reported that GRGDS and WQPPRARI peptide micropatterns increase the endothelialisation of prosthetic materials in vitro. To investigate the mechanisms by which the peptide micropatterns affect endothelial cell adhesion and proliferation, a TAMRA fluorophore-tagged RGD peptide was designed. Live cell imaging revealed that the micropatterned surfaces led to directional cell spreading dependent on the location of the RGD-TAMRA spots. Focal adhesions formed within 3 h on the micropatterned surfaces near RGD-TAMRA spot edges, as expected for cell regions experiencing high tension. Similar levels of focal adhesion kinase phosphorylation were observed after 3 h on the micropatterned surfaces and on surfaces treated with RGD-TAMRA alone, suggesting that partial RGD surface coverage is sufficient to elicit integrin signaling. Lastly, endothelial cell expansion was achieved in serum-free conditions on gelatin-coated, RGD-TAMRA treated or micropatterned surfaces. These results show that these peptide micropatterns mainly impacted cell adhesion kinetics rather than cell proliferation. This insight will be useful for the optimization of micropatterning strategies to improve vascular biomaterials.