Personne :
Sabbatier, Gad

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Sabbatier
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Gad
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Département de génie des mines, de la métallurgie et des matériaux, Faculté des sciences et de génie, Université Laval
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ncf11882388
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Voici les éléments 1 - 6 sur 6
  • Publication
    Accès libre
    Evaluation of an air spinning process to produce tailored biosynthetic nanofiber scaffolds
    (Elsevier Science, 2013-11-14) Abadie, Pierre; Laroche, Gaétan; Dieval, Florence; Sabbatier, Gad; Durand, Bernard
    We optimised the working parameters of an innovative air spinning device to produce nanofibrous polymer scaffolds for tissue engineering applications. Scanning electron microscopy was performed on the fibre scaffolds which were then used to identify various scaffold morphologies based on the ratio of surface occupied by the polymer fibres on that covered by the entire polymer scaffold assembly. Scaffolds were then produced with the spinning experimental parameters, resulting in 90% of fibres in the overall polymer construct, and were subsequently used to perform a multiple linear regression analysis to highlight the relationship between nanofibre diameter and the air spinning parameters. Polymer solution concentration was deemed as the most significant parameter to control fibre diameter during the spinning process, despite interactions between experimental parameters. Based on these findings, viscosity measurements were performed to clarify the effect of the polymer solution property on scaffold morphology.
  • Publication
    Accès libre
    Design, degradation mechanism and long-term cytotoxicity of poly(L-lactide) and poly(lactide-co-ε-caprolactone) terpolymer film and air-spun nanofiber scaffold
    (Wiley Online Library, 2015-06-08) Laroche, Gaétan; Larrañaga, Aitor; Guay-Bégin, Andrée-Anne; Sabbatier, Gad; Fernandez, Jorge; Diéval, Florence; Durand, Bernard; Sarasua, Jose-Ramon
    Degradable nanofiber scaffold is known to provide a suitable, versatile and temporary structure for tissue regeneration. However, synthetic nanofiber scaffold must be properly designed to display appropriate tissue response during the degradation process. In this context, this publication focuses on the design of a finely-tuned poly(lactide-co-e-caprolactone) terpolymer (PLCL) that may be appropriate for vascular biomaterials applications and its comparison with well-known semi-crystalline poly(L-lactide) (PLLA). The degradation mechanism of polymer film and nanofiber scaffold and endothelial cells behavior cultured with degradation products is elucidated. The results highlight benefits of using PLCL terpolymer as vascular biomaterial compared to PLLA.
  • Publication
    Accès libre
    Conception et élaboration d'échafaudages de nanofibres à dégradation contrôlée pour des applications en médecine régénératrice vasculaire
    (2015) Sabbatier, Gad; Laroche, Gaétan; Durand, Bernard; Dieval, Florence
    L’absence de croissance en monocouche des cellules endothéliales sur la paroi des prothèses vasculaires est une des causes d’échec de leur implantation chez l’humain. Des études précédentes ont montré que le recouvrement de ces prothèses par un échafaudage de nanofibres d’acide polylactique (PLA), fabriqué par un système de filage par jet d’air innovant, peut être utilisé pour promouvoir la croissance des cellules endothéliales de façon adéquate. Ainsi, le caractère dégradable d’un matériau comme le PLA permettrait son remplacement graduel par la matrice extra-cellulaire produite par les cellules. D’autre part, la réussite d’une transition entre les nanofibres dégradables et la matrice extra-cellulaire nécessite un remplacement contrôlé et approprié. Or, la dégradation des nanofibres de PLA, dépendant de ses séquences stéréochimiques, est généralement trop longue et peut induire une cytotoxicité relative pendant sa dégradation. Dans ce contexte, les études de cette thèse ont pour objectifs de mieux comprendre la formation des fibres lors du filage, d’optimiser la fabrication des échafaudages permettant ainsi la création de nanofibres d’autres polymères, puis, de concevoir des nanofibres provenant d’un polymère mieux adapté à nos besoins, d’évaluer leur mécanisme de dégradation et sa cytotoxicité durant sa dégradation. Les travaux d’optimisation du système de filage ont démontré que la concentration avec un effet prépondérant. Ainsi, la mesure de la viscosité permet de trouver les paramètres adéquats pour le filage de polymère. Ensuite, un poly(L-lactide) semi-cristallin (PLLA) et un terpolymère de poly(lactide-co-ε-caprolactone) (PLCL) dédié pour des applications vasculaires ont été synthétisés et filés par jet d’air. Ces échantillons ont été dégradés en solution aqueuse et caractérisés par des méthodes physico-chimiques afin de mieux comprendre leurs mécanismes de dégradation et mis en présence de cellules endothéliales pour évaluer leur cytotoxicité. La comparaison entre les échafaudages des deux polymères a montré des comportements singuliers en dégradation, dépendants des caractéristiques thermiques des polymères. De plus, ces mécanismes de dégradation des nanofibres ont une influence directe sur la sensibilité des cellules endothéliales face aux produits de dégradation. En conclusion, ces travaux de doctorat présentent une solution prometteuse pour améliorer les prothèses vasculaires et qui pourrait être appliquée pour résoudre plusieurs problématiques en médecine régénératrice.
  • Publication
    Restreint
    Atmospheric pressure plasma polymer of ethyl lactate: In vitro degradation and cell viability studies
    (Wiley, 2016-03-29) Laroche, Gaétan; Koehler, Julia; Hoesli, Corinne A.; Laurent, Morgane; Sabbatier, Gad; Ghérardi, Nicolas
    Ethyl lactate is injected into a dielectric barrier discharge (DBD) to build up a degradable plasma polymer (PP) to be used as a drug delivery system. Plasma power, deposition time, and type of carrier gas (Ar, N2) are correlated to the coating in vitro degradation rate. PPs are characterized by AFM, SEM, IR spectroscopy, XPS, and SEC, while surface profilometry is used to monitor the degradation kinetics. PPs deposited under N2 are mainly composed of hydrophilic functionalities, which explain their fast degradation upon exposure to an aqueous environment. In contrast, PPs synthesized under Ar lead to a slower degradation rate due to their hydrocarbon structure containing some hydrolyzable moieties. The potential of the PPs for vascular applications is verified
  • Publication
    Accès libre
    Air-spun PLA nanofibers modified with reductively-sheddable hydrophilic surfaces for vascular tissue engineering : synthesis and surface modification
    (John Wiley & Sons, 2013-09-23) Na, Re Ko; Laroche, Gaétan; Sabbatier, Gad; Cunningham, Alexander J.; Oh, Jung Kwon
    Polylactide (PLA) is a class of promising biomaterials that hold great promise for various biological and biomedical applications, particularly in the field of vascular tissue engineering where it can be used as a fibrous mesh to coat the inside of vascular prostheses. However, its hydrophobic surface providing nonspecific interactions and its limited ability to further modifications are challenges that need to be overcome. Here, the development of new air-spun PLA nanofibers modified with hydrophilic surfaces exhibiting reduction response is reported. Surface-initiated atom transfer radical polymerization allows for grafting pendant oligo(ethylene oxide)-containing polymethacrylate (POEOMA) from PLA air-spun fibers labeled with disulfide linkages. The resulting PLA-ss-POEOMA fibers exhibit enhanced thermal stability and improved surface properties, as well as thiol-responsive shedding of hydrophilic POEOMA by the cleavage of its disulfide linkages in response to reductive reactions, thus tuning the surface properties.
  • Publication
    Accès 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.