Bacterial adhesion on cement: Effects of bioactive polymers

9 - Conference paper: eCM XII - Implant Infection, 22-24 juin 2011, Davos Platz (Suisse

Bioactive polymer coatings to improve bone repair

4 - Chapitre de livr

Synthesis and in vitro evaluation of gelatin/hydroxyapatite graft copolymers to form bionanocomposites

1 - ArticleThe combination of gelatin (Gel) with a bioactive component hydroxyapatite (HA) and cartilage powder (CP) to form biocomposites takes advantage of the osteoconductivity and osteoinductivity properties The studies on bionanocomposites containing HA. CP fillers and Gel are still being conducted In this present study, the bioactive fillers were loaded onto poly(hydroxylethylmethacrylate) and poly( hydroxylethylmethacrylate-co-methyl methacrylate) grafted gelatin copolymers to produce novel bionanocomposites having osteoconductive and osteoinductive properties The resulting bionanocomposites were assessed by ATR-IR and SEM-EDX techniques to prove the interaction between different matrices In vitro behavior of these bionanocomposites was performed in SBF for 21 days at pH 74 to verify formation of the apatite layer on the surfaces and its enhancement The results confirmed the formation of thick plentiful aggregated (hexagonal or spherical) nanoparticles with a bright color (apatite layer) containing carbonate ions onto the surface of composites especially these containing CP and P(HEMA-co-M MA) having bone cement formation in their structure. These novel bionanocomposites have unique bioactivity that can be applied in bone implants as scaffolds and tissue engineering in future

Bioactive polymer grafting onto titanium in order to prevent hip prosthesis infection

1 - ArticleDuring implantation of a total hip prosthesis (PTH), many interactions will develop at the interface bone-implant to achieve ultimately the healing of the host tissue. In a few cases (similar to 2%), a microbial colonization occurs, whose consequences are dramatic. The nature of the surface of materials can improve the host response and prevent infection. Studies in LBPS show that the "bioactive" polymers bearing sulfonate groups are able to inhibit bacterial adhesion. In this study, sodium styrene sulfonate, bearing sulfonate groups, was grafted on the surface of titanium alloys, which is the material of total hip replacement. It was shown that the TA6V grafted sodium styrene sulfonate, inhibits the adhesion of Staphylococcus aureus (methycillin-resistant strain)

Functionalization of biomaterials for joint implant application

1 - Articl

Feasibility Study of the Elaboration of a Biodegradable and Bioactive Ligament Made of Poly(ε-caprolactone)-pNaSS Grafted Fibers for the Reconstruction of Anterior Cruciate Ligament: In Vivo Experiment

International audienc

Évaluation clinique et biologique d'un ligament synthétique bioactif chez la brebis

1 - ArticleRésumé Le ligament croisé antérieur, qui joue un rôle majeur dans la stabilisation du genou, est le plus fréquemment rompu. Si la greffe autologue est la " technique " la plus utilisée, l'utilisation d'un ligament synthétique est réservée à des applications très précises. Le poly(éthylène téréphtalate) (PET) est le polymère de choix pour élaborer les prothèses ligamentaires mais sa biocompatibilité doit être améliorée. Le greffage du PET par un polymère bioactif poly(styrène sulfonate de sodium) (pNaSS) selon la technique du grafting from permet d'obtenir un taux de greffage parfaitement reproductible de l'ordre de 5 [mu]mol/g. Un groupe de sept brebis ont été implantées des ligaments non greffés alors qu'un second groupe de sept brebis ont été implantées des ligaments greffés du pNaSS pour une durée de trois mois. L'évaluation clinique et biologique du liquide synovial in vivo chez des brebis implantées avec un ligament en PET greffé ou non de pNaSS met en évidence une récupération fonctionnelle précoce et une excellente tolérance du pNaSS se traduisant par une absence d'inflammation articulaire significative. The anterior cruciate ligament, which plays a key role in the knee stabilization, is commonly injured mainly during sport practicing such as soccer or skiing. Although it seems that ligament replacement by a tendon autograft is a better solution, the reconstruction with an artificial ligament provides a shorter recovery time. Polyethylene terephthalate (PET) is the best polymer to fabricate ligament prosthesis but its biocompatibility still needs to be improved. Radical graft polymerization of sodium salt of styrene sulfonate (NaSS) on PET surface was performed using the "grafting from" technique. The grafting ratio is about 5 [mu]mol/g and found to be perfectly reproducible. Polymer grafted ligaments and non-grafted ligaments were implanted in sheep for a 3-month observation. The clinical and biological evaluation of the knee synovial liquid of implanted sheep evidenced an early functional recuperation and an excellent tolerance of pNaSS reflecting a significant absence of articular inflammation

Inhibition de l'adhérence de Porphyromonas gingivalis sur la surface de titane greffé de poly(styrène sulfonate de sodium)

1 - ArticleRésumé Les infections péri-implantaires représentent l'une des causes majeures d'échec de l'ostéo-intégration des implants dentaires en titane. Ces infections sont induites par des bactéries de la flore buccale comme Porphyromonas gingivalis, dont l'adhérence sur l'implant dépend des propriétés physico-chimiques et topographiques de surface de celui-ci. À titre d'exemple, nous avons montré que la modification chimique de surfaces implantaires en titane par greffage d'un polymère " bioactif " tel que le poly(styrène sulfonate de sodium) permet de diminuer sensiblement (> 40 %) l'adhérence de Staphyloccocus aureus. L'objectif de cette étude est d'évaluer l'adhérence de Porphyromonas gingivalis sur des surfaces de titane greffées de poly(styrène sulfonate de sodium) afin d'obtenir des surfaces implantaires dotées de propriétés inhibitrices de l'adhérence de bactéries pathogènes de la flore buccale. Le greffage du poly(styrène sulfonate de sodium) sur le titane est réalisé en deux étapes : oxydation chimique du titane pour créer des espèces actives, puis greffage du poly(styrène sulfonate de sodium) par voie radicalaire. La caractérisation chimique des surfaces est réalisée par spectroscopie infrarouge à transformée de Fourier. L'adhérence bactérienne a été étudiée sur les surfaces de titane greffées et non greffées (titane contrôle), préadsorbées ou non de protéines plasmatiques. L'adsorption protéique et le comptage des bactéries sont suivis par marquage des protéines et des bactéries à la fluorescéine puis quantification par analyse d'images. Les résultats montrent que l'adsorption protéique est plus importante (~3 fois) et l'adhérence de P. gingivalis est fortement inhibée (~73 %) sur les surfaces greffées de poly(styrène sulfonate de sodium) par comparaison au titane témoin non greffé. De plus, l'inhibition de l'adhérence bactérienne observée sur les surfaces greffées et préadsorbées de protéines du plasma est comparable à celle observée sur les surfaces préadsorbées de fibronectine. En conclusion, les résultats obtenus montrent que la modification de la surface du titane par greffage poly(styrène sulfonate de sodium) conduit à une inhibition significative de l'adhérence de P. gingivalis et que cette activité inhibitrice de l'adhérence bactérienne implique l'adsorption protéique. Ces surfaces de titane greffées présentent un intérêt évident en application clinique dentaire pour le revêtement des implants. Dental implant-associated infections as peri-implantitis represent one of the major causes of osteointegration failures of oral implants. Adhesion of Porphyromonas gingivalis, one of the bacterial strains mainly involved in such infections, is tightly dependent on the topographical and/or physico-chemical properties of the implant surfaces. As a matter of fact, we showed that the grafting of one bioactive polymer such as poly(sodium styrene sulfonate) onto titanium implant surfaces allowed a sensitive decrease of Staphylococcus aureus adhesion (> 40%). The aim of the study consists in evaluating the adhesion of P. gingivalis onto titanium surfaces grafted with poly(sodium stryrene sulfonate) in order to elaborate implants exhibiting appropriate inhibiting properties towards the adhesion of periodontal pathogens. The grafting of poly(sodium stryrene sulfonate) onto titanium surfaces is carried out in two steps: chemical oxydation of titanium to initiate radical species then grafting of poly(sodium stryrene sulfonate) by radical polymerization. Chemical characterization of the surfaces is achieved by Fourier transformed infrared spectroscopy (FTIR). Bacterial adhesion was studied on grafted and non grafted (control) titanium surfaces, preadsorbed or not by plasmatic proteins. Protein adsorption as well as bacteria adhesion is followed by fluorescence spectroscopy by using proteins or bacteria previously labelled with fluorescence probes; the quantification of adsorption and bacteria adhesion are performed by image analysis. Results showed that protein adsorption is more important (~3 times) and that P. gingivalis adhesion is strongly inhibited (~73%) onto poly(sodium styrene sulfonate) grafted surfaces when compared to titanium control. Moreover, the inhibition of bacterial adhesion on grafted surfaces preadsorbed with plasma proteins is comparable to that observed on grafted surfaces preadsorbed with fibronectin. In conclusion, the obtained results evidenced that the grafting of titanium surface by poly(sodium styrene sulfonate) led to significant inhibition of P. gingivalis adhesion and that this inhibitory activity involved adsorbed proteins. Poly(sodium styrene sulfonate) grafted titanium surfaces present a high interest for the elaboration of oral implants in various clinical dental applications

Resin composite blocks via high-pressure high-temperature polymerization

1 - ArticleObjectives. The aim of this study was to thermo-polymerize under high pressure four commercially available dental resin composites to obtain and characterize composite blocks suitable for CAD/CAM procedures. Methods. Gradia (GC, Japan), Vita VM LC (Vita Zahnfabrik, Germany), Grandio (VOCO, Germany), and EsthetX (Dentsply, Germany), were selected for this study. Paradigm (3 M ESPE, USA), a CAD/CAM composite block, was included for comparison. Composite blocks were obtained through polymerization at high-temperature high-pressure (HT/HP). Samples for mechanical/physical characterizations were cut from Paradigm and HT/HP composite blocks while control samples were obtained by photo-polymerizing (PP) the materials in molds. Flexural strength (sigma(f)), fracture toughness (K-IC), hardness, and density (rho) were determined and compared by pairwise t-tests (alpha = 0.05). Fractured surfaces were characterized under a scanning electron microscope. Results. The results have shown that HT/HP polymerization resulted in a significant (p < 0.05) increase in sigma(f), hardness, and rho for all composites investigated. Even if K-IC of all materials was increased by HT/HP polymerization, significant increases were detected only for Gradia and EsthetX. The Weibull modulus of HT/HP polymerized composites was higher than that of PP counterparts. HT/HP materials had higher sigma(f), Weibull modulus, and K-IC compared to Paradigm. The most significant SEM observation of fractured K-IC specimens from all the materials tested was the presence of fewer and smaller voids in HT/HP polymerized composites. Significance. The results of this study suggest that HT/HP polymerization could be used to obtain dental resin composite blocks with superior mechanical properties, suitable for CAD/CAM processing. (C) 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved

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