In vitro studies and preliminary in vivo evaluation of silicified concentrated collagen hydrogels

Hybrid and nanocomposite silicacollagen materials derived from concentrated collagen hydrogels were evaluated in vitro and in vivo to establish their potentialities for biological dressings. Silicification significantly improved the mechanical and thermal stability of the collagen network within the hybrid systems. Nanocomposites were found to favor the metabolic activity of immobilized human dermal fibroblastswhile decreasing the hydrogel contraction. Cell adhesion experiments suggested that in vitro cell behavior was dictated by mechanical properties and surface structure of the scaffold. First-to-date in vivo implantation of bulk hydrogels in subcutaneous sites of rats was performed over the vascular inflammatory period. These materials were colonized and vascularized without inducing strong inflammatory response. These data raise reasonable hope for the future application of silicacollagen biomaterials as biological dressings.Fil: Desimone, Martín Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; ArgentinaFil: Hélary, Christophe. Université Pierre et Marie Curie; FranciaFil: Quignard, Sandrine. Université Pierre et Marie Curie; FranciaFil: Rietveld, Ivo B. Universite de Paris; FranciaFil: Bataille, Clement. Université de Versailles Saint-quentin-en-yvelines.; FranciaFil: Copello, Guillermo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; ArgentinaFil: Mosser, Gervaise. Université Pierre et Marie Curie; FranciaFil: Giraud Guille, Marie-Madeleine. Université Pierre et Marie Curie; FranciaFil: Livage, Jacques. Université Pierre et Marie Curie; FranciaFil: Meddahi Pellé, Anne. Université de Versailles Saint-quentin-en-yvelines.; FranciaFil: Coradin, Thibaud. Université Pierre et Marie Curie; Franci

Bioactive polymer coatings to improve bone repair

4 - Chapitre de livr

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

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

Functionalization of biomaterials for joint implant application

1 - Articl

Polymer bacteriostatic: A new approach for orthopedic bone cement

1 - ArticleThe implantation of joint prostheses may lead to infection (about 2% of the cases) with more or less dramatic consequences as morbidity or even death. Several clinical and experimental studies showed the high interest of antibiotic prophylaxis to prevent such infections but also its relative inefficiency when the infection is established. Bioactive polymers bearing anionic groups have synthesized and showed to be able to inhibit bacterial adhesion. In this study, the bioactive polymers were mixed with commercial acrylic orthopaedic cement used in the surgery of total hip prosthesis. We demonstrated that mixtures cement/bioactive polymers may inhibit adhesion of Staphylococcus aureus (S. aureus) - strain resistant MRSA 88244) by diffusion process. Kinetics of diffusion of the bioactive polymers can be controlled by addition of hydrophobic units as methymethacrylate in the macromolecular chains of the polymers

New antitumor agent: In vitro activity on breast carcinoma cells

1 - ArticlePrevious work showed that established interactions between water-soluble polymers and cell membrane receptors can lead to modulate cell proliferation and differentiation in vitro. These polymers can be considered as bioactive. The aim of this work was to establish the consequences of the interactions between human breast cancer cells MCF7 and polymers of various chemical compositions regarding cell adhesion and proliferation onto tissue culture plate. Water soluble copolymers were synthesized by radical polymerization and are composed of methacrylic acid and sodium styrene sulphonate units. The modulation of the MCF7, biological-induced by these polymers of various compositions, was evaluated. The influence of the polymers chemical composition on the kinetics of cell proliferation, as well as cell morphology and spreading, were studied. A polymer concentration-dependent inhibition effect was observed. One hundred microgram per liter polymers solutions induced strong inhibition of cell proliferation, as well as a change of the MCF7 cells morphology, which can be related to an inhibition of cell spreading. The polymers/MCF7 cells interactions are modulated by the chemical composition of the copolymers and then the respective rate in sulphonate and carboxylate groups distributed along the macromolecular chain

The effect of polystyrene sodium sulfonate grafting on polyethylene terephthalate artificial ligaments on in vitro mineralisation and in vivo bone tissue integration

This study investigates the impact of polystyrene sodium sulfonate (PolyNaSS) grafting onto the osseointegration of a polyethylene terephthalate artificial ligament (Ligament Advanced Reinforcement System, LARS ) used for Anterior Cruciate Ligament (ACL). The performance of grafted and non-grafted ligaments was assessed in vitro by culturing human osteoblasts under osteogenic induction and this demonstrated that the surface modification was capable of up-regulating the secretion of ALP and induced higher level of mineralisation as measured 6 weeks post-seeding by Micro-Computed Tomography. Grafted and non-grafted LARS were subsequently implanted in an ovine model for ACL reconstruction and the ligament-to-bone interface was evaluated by histology and biomechanical testings 3 and 12 months post-implantation. The grafted ligaments exhibited more frequent direct ligament-tobone contact and bone formation in the core of the ligament at the later time point than the nongrafted specimens, the grafting also significantly reduced thefibrous encapsulation of the ligament 12 months post-implantation. However, this improved osseo-integration was not translated into a significant increase in the biomechanical pull-out loads. These results provide evidences that PolyNaSS grafting improved the osseo-integration of the artificial ligament within the bone tunnels. This might positively influence the outcome of the surgical reconstructions, as higher ligament stability is believed to limit micro-movement and therefore permits earlier and enhanced healing.Programme ANR LIGAR

Silica-collagen bionanocomposites as tree-dimensiam scaffolds for fibroblast immobilization

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