15 research outputs found

    Modulation of Cellular Colonization of Porous Polyurethane Scaffolds via the Control of Pore Interconnection Size and Nanoscale Surface Modifications.

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    Full-scale cell penetration within porous scaffolds is required to obtain functional connective tissue components in tissue engineering applications. For this aim, we produced porous polyurethane structures with well-controlled pore and interconnection sizes. Although the influence of the pore size on cellular behavior is widely studied, we focused on the impact of the size of the interconnections on the colonization by NIH 3T3 fibroblasts and Wharton's jelly-derived mesenchymal stem cells (WJMSCs). To render the material hydrophilic and allow good material wettability, we treated the material either by plasma or by polydopamine (PDA) coating. We show that cells weakly adhere on these surfaces. Keeping the average pore diameter constant at 133 ÎĽm, we compare two structures, one with LARGE (52 ÎĽm) and one with SMALL (27 ÎĽm) interconnection diameters. DNA quantification and extracellular matrix (ECM) production reveal that larger interconnections is more suitable for cells to move across the scaffold and form a three-dimensional cellular network. We argue that LARGE interconnections favor cell communication between different pores, which then favors the production of the ECM. Moreover, PDA treatment shows a truly beneficial effect on fibroblast viability and on matrix production, whereas plasma treatment shows the same effect for WJMSCs. We, therefore, claim that both pore interconnection size and surface treatment play a significant role to improve the quality of integration of tissue engineering scaffolds.journal article2019 Jun 052019 05 24importe

    Greffage covalent de polymères bioactifs sur des surfaces en titane pour améliorer la réponse de cellules osseuses

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    L'objectif de cette étude a été d'améliorer l'ostéointégration d'implants en titane en greffant à leur surface des polymères porteurs de groupes ionique sulfonate et carboxylate, de manière covalente selon deux voies. uelle que soit la voie, la surface est oxydée chimiquement de façon à produire de l'hydroperoxyde de titane et Ti-OH. La première voie consiste a génerer des radicaux en surface qui amorcent la polymérisation radicalaire des monomères : styrène sulfonate de sodium NaSS et acide méthacrylique MA. La deuxième voie fait appel à une molécule gréffée au titane par silanisation, présentant à une extrémité une double liaison vinylique qui, dans une seconde étape, est copolymérisée avec MA et NaSS. La caractérisation des surfaces par différentes techniques (IR, XPS, angle de contact) a permis de montrer l'éficacité du greffage et de terminer les compositions des deux monomères. Le taux de greffage a étè évalué par dosage colorique et des valeurs comprises entre 1,0 ug/cm2 et 5, 0 ug/cm2 ont été obtenues selon la voie utilisée. L'étude in-vitro a été réalisée avec des pré-ostéoblastes MC3T3-E1 cultivé sur le titane gréffé et titane témoin. La comparaison des résultats a permis de montrer une amélioration de l'adhèsion des cellules, un accroisement de l'activité de la phosphatase alcaline ainsi qu'une augmentation de la production de phosphate de calcium pour la surface de titane gréffé présentant un rapport MA/NaSS proche de 1. La distribution aléatoire de ces groupements ioniques le long des chaînes macromoléculaires permettrait de créer des sites qui intéragiraient avec les protéines adhésives avec comme conséquence la modification de leur conformation.The goal of this study was to improve osseointegration of titanium implants by covalently grafting ionic polymers such as poly(sodium styrene sulfonate) and/or poly(metharcrylic acid) at their surface, according to two ways. Whatever the chosen way, surface was chemically oxidized in order to produce titanium hydroperoxide and Ti-OH. The first way consisted of producing radicals at the titanium surface which initited polymerization of monomers: sodium styrene sulfonate NaSS and methacrylic acid MA. The second way used a molecule with a vinyl bond at one end which was grafted to the titanium surface by silanization. Copolymerisation of MA and NaSS with the terminal double bond allowed the grafting of the ionic polymer. Surface characterization by various techniques (IR, XPS, contact angle) allowed to show the grafting efficiency and to determine the monomers compositions. Quantitative grafting is determined by a colorimetric method and evaluated between 1,0 ug/cm2 et 5,0 ug/cm2 according to the way chosen. In vitro study was performed with pre-osteoblast cells MC3T3-E1 cultured onto grafted titanium and native titanium as control. Comparison of results has shown an improvement of cellular adhesion, an increase of phosphatase alkaline activity and production of calcium phosphate for grafted surfacces having a ratio MA/NaSS equal to 1. Random distribution of these ionic groups along the macromolecular chains would allow creating active sites which could interact with adhesive proteins the conformation of which would be modifiedPARIS13-BU Sciences (930792102) / SudocSudocFranceF

    A new approach to graft bioactive polymer on titanium implants: Improvement of MG 63 cell differentiation onto this coating

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    1 - ArticleIntegration of titanium implants into bone is only passive and the resulting fixation is mainly mechanical in nature, with anchorage failure. Our objective, to increase the biointegration of the implant and the bone tissue, could be obtained by grafting a bioactive ionic polymer to the surface of the titanium by a covalent bond. In this paper, we report the grafting of an ionic polymer model poly(sodium styrene sulfonate) (polyNaSS), in a two-step reaction procedure. Treatment of the titanium surface by a mixture of sulfuric acid and hydrogen peroxide allows the formation of titanium hydroxide and titanium peroxide. In the second reaction step, heating of a metal implant, placed in a concentrated solution of sodium styrene sulfonate monomer (NaSS), induces the decomposition of titanium peroxides with the formation of radicals capable of initiating the polymerization of NaSS. Various parameters, such as temperature of polymerization and time of polymerization, were studied in order to optimize the yield of polyNaSS grafting. Colorimetry, Fourier-transformed infrared spectra recorded in an attenuated total reflection, X-ray photoelectron spectroscopy techniques and contact angle measurements were applied to characterize the surfaces. MG63 osteoblastic cell response was studied on polished, oxidized and grafted titanium samples. Cell adhesion, alkaline phosphatase activity and calcium nodules formation were significantly enhanced on grafted titanium samples compared to unmodified surfaces. (C) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved

    A bioactive polymer grafted on titanium oxide layer obtained by electrochemical oxidation. Improvement of cell response

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    1 - ArticleThe anchorage failure of titanium implants in human body is mainly due to biointegration problem. The proposed solution is to graft a bioactive polymer at the surface of the implant in order to improve and control the interactions with the living system. In this paper, we describe the grafting of poly sodium styrene sulfonate on titanium surface by using a silanization reaction. The key point is to increase the TiOH content at the surface of the implant which can react with methoxy silane groups of 3-methacryloxypropyltrimethoxysilane (MPS). Two procedures were used: chemical oxidation and electrochemical oxidation. The last oxidation procedure was carried out in two different electrolytes: oxalic acid and methanol. These different oxidation methods allow controlling the roughness and the depth of the oxide layer. The methacryloyl group of MPS grafted at the titanium surface by silanization reaction is copolymerized with sodium styrene sulfonate using a thermal initiator able to produce radicals by heating. Colorimetric method, ATR-FTIR, XPS techniques and contact angle measurements were applied to characterize the surfaces. MG63 osteoblastic cell response was studied on polished, oxidized and grafted titanium samples. Cell adhesion, Alkaline Phosphatase activity and calcium nodules formation were significantly enhanced on grafted titanium surfaces compared to un-modified surfaces

    Grafting of bioactive polymers onto titanium surfaces and human osteoblasts response

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    1 - ArticleTitanium is widely used in orthopedic and dental implants for its excellent resistance to corrosion and its biocompatibility. In order to improve the long-term osteointegration of titanium, bioactive polymers bearing ionics groups such as sulfonates (sodium polysytrene sulfonate, poly-NaSS) are grafted by a covalent way onto titanium surface. The surface is chemically modified and then bioactive polymers are grafted by radical polymerization. The chemical composition of grafted surfaces is given by ATR/FTIR and XPS which certified the presence of sulfonate groups at the surface of grafted titanium. Quantitative grafting of polyNaSS is determined by a colorimetric method and evaluated at 5 mu g/cm(2). In vitro study is performed in order to see the effect of these bioactive polymers on the mineralization of human osteoblast (line MG63). After 28 days of cultured cells on grafted titanium surfaces and non-grafted ones, the amount of calcium onto surfaces is quantified. The results show that the mineralization of these cells is improved with the presence of polyNaSS. The amount of calcium is increased on grafted surfaces compared to non-grafted ones. Cell adhesion was evaluated. Cells were seeded onto grafted and non-grafted titanium and then subjected to detachment forces. The results show that the attachment of human osteoblasts-like cells is increased for grafted titanium with polyNaSS. A study on titanium surface grafted by polymers bearing ionics groups such as carboxylate and phosphate is in progress. (C) 2007 Elsevier Masson SAS. Tons droits reserves

    Development of proteomic tools to study protein adsorption on a biomaterial, titanium grafted with poly(sodium styrene sulfonate)

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    1 - ArticleIt is known that protein adsorption is the initial interaction between implanted biomaterials and biological environment. Generally, a complex protein layer will be formed on material surfaces within a few minutes and the composition of this layer at the interface determines the biological response to the implanted material, and therefore the long-term compatibility of the biomaterial. Despite different techniques exist to observe protein adsorption on biomaterials, none of them led to the identification of adsorbed proteins. In this paper, we report a chromatographic technique coupled to proteomics to analyse and identify proteins from complex biological samples adsorbed on biomaterial surfaces. This approach is based on (1) elaboration of the chromatographic support containing the biomaterial (2) a chromatography step involving adsorption of proteins on the biomaterial (3) the high-resolution separation of eluted proteins by 2-DE gel and (4) the identification of proteins by mass spectrometry. Experiments were performed with proteins from platelets rich plasma (PRP) adsorbed on a biomaterial which consist in titanium bioactivated with PolyNaSS. Our results show that chromatographic approach combined to 2-DE gels and mass spectrometry provides a powerful tool for the analysis and identification of proteins adsorbed on various surfaces
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