Evaluation of the sterilization effect on biphasic scaffold based on bioactive glass and polymer honeycomb membrane

The sterilization is a core preoccupation when it comes to implantable biomaterials. The most common in industry is the gamma sterilization; however, the radiation used in this method can induce modifications in the material properties. This study investigates the impact of such radiations on the physicochemical properties and biological toxicity of a new biomaterial based on a poly-l-co-d,l-lactide polymer honeycomb membrane and bioactive glass (BG), combined, to form an assembly (membrane/BG assembly). The investigated BGs are the S53P4, which is FDA approved and clinically used, and 13-93B20, a BG containing boron promising for bone regeneration. Infrared and photoluminescence measurements revealed that, upon irradiation, defects are created in the BGs molecular matrix. Defects were identified to be mainly non-bridging oxygen hole center and occur in higher proportion in the 13-93B20 making it more sensitive to irradiation compared to the S53P4. However, the irradiation does not significantly impact the structure of the BGs. On the membrane side, the molecular weight is divided by two resulting in a lower shear stress resistance. However, the membrane honeycomb topography does not seem to be impacted by the irradiation. In contact with cells, no toxicity effect was observed, and BGs keep their bioactive properties by releasing ions beneficial to the cell fate and with no influence on apatite precipitation speed. Overall, this study showed that, despite some impact on the physicochemical properties, the irradiation does not induce deleterious effect on the membrane/BG assemblies and is therefore a suitable method for the sterilization of this novel biomaterial.Peer reviewe

Dynamique structurale et conformationnelle de la fibronectine plasmatique humaine en solution (de ses propriétés d'organisation en solution à la régulation de ses fonctions biologiques)

Le travail présenté concerne l'études des propriétés de dynamique structurale et d'assemblage de la matrice extracellulaire (ECM) à travers l'étude d'une macromolécule particulière: la fibronectine (Fn).Dans un premier temps, la dynamique structurale de la Fn est abordée via l'étude du processus de dépliement-repliement induit soit par effet de température ou d'urée. Ces différentes études ont révélé l'existence de différents états structuraux stables de la Fn.Dans un second temps, le processus de repliement de la Fn, suite à un dépliement induit par effet d'urée, a été étudié. Cette étude a permis de mettre en évidence un processus de dépliement "pseudo-réversible" de la Fn.Dans un troisième temps, les propriétés d'auto-assemblage de l'état natif et replié de la Fn sont testées sous différentes condition de force ioniques. Nous avons montré à travers ce travail que l'état pré-initial de la molécule ainsi que les conditions de force ioniques en solution ont un effet sur la morphologie et la cinétique de formation des structures auto-assemblées de la molécule.The principle aim of this work is focused on extracellular matrix (ECM) structural dynamism and self assembly properties through study of fibronectin (Fn) which is an ECM essential component.First, we have studied influence of temperature and urea effect on fibronectin unfolding process to characterize protein structural dynamism. These different studies highlighted presence of different stable structural states of Fn.Second, a study concerning the renaturation process of fibronectin, after a denaturation induced by urea, has been developed. Different data obtained by spectroscopic and hydrodynamic approaches reveal that Fn denaturation process is "pseudo-reversible".Third, self association properties of these native and refolded states of fibronectin in solution have been investigated under different ionic strength conditions. This study indicates that pre-initial Fn state as well as ionic strength conditions have an effect on morphology and kinetic formation of Fn self-assembly.CERGY PONTOISE-BU Saint-Martin (951272103) / SudocSudocFranceF

Interactions surfaces-protéines-cellules (Adsorption de la fibronectine sur supports modèles et influence sur le comportement cellulaire)

In vivo, le comportement cellulaire dépend des interactions entre les cellules et leur environnement, la matrice extracellulaire (MEC). Classiquement, in vitro, une stratégie visant à améliorer la culture des cellules est de recouvrir le support de culture par une protéine de la MEC capable de favoriser l adhérence cellulaire, comme la fibronectine. L objectif de cette thèse est d analyser la relation surfaces-protéinescellules, et en particulier les propriétés de la fibronectine adsorbée sur des surfaces modèles et leur influence sur le comportement cellulaire. Différents supports modèles (verre, OTS, polystyrène) sont générés et caractérisés. Puis, à partir de concentrations protéiques variées, les cinétiques d adsorption sont suivies, et la quantité et les changements conformationnels de la fibronectine adsorbée sont déterminés de manière concomitante. Enfin, l adhérence et la morphologie de deux types cellulaires sont étudiées, dans différentes conditions d ensemencement.In living tissues, cell behaviors depend on close connections between cells and their environment, the extracellular matrix (ECM). For in vitro cell culture experiments, a classic strategy to improve cell culture is to coat cell culture supports by an ECM protein which is able to promote cell adhesion, like fibronectin. The aim of this thesis is to analyze the surfaces-proteins-cells relationship, and especially the properties of fibronectin adsorbed onto model surfaces and their influence on cell behavior. Different model supports (glass, OTS, polystyrene) are generated and characterized. Then, adsorption kinetics using various protein concentrations are followed, and the amount and the conformational changes of adsorbed fibronectin are concomitantly determined. Finally, cell adhesion and morphology are studied in different cell seeding conditions, and for two cell types.CERGY PONTOISE-BU Saint-Martin (951272103) / SudocSudocFranceF

Bioconjugaison de la fibronectine à des sondes exogènes (du fluorophore organique à la nanoparticule hybride)

La fibronectine (Fn) est une protéine structurante de la matrice extracellulaire (MEC) et est impliquée dans de nombreux comportements cellulaires. Le suivi du devenir d une protéine de la MEC telle que la Fn n est possible que par l intermédiaire de sondes détectables par imagerie. L objectif de ce travail de thèse est de conjuguer la Fn à différentes sondes exogènes : un fluorophore organique et deux types de nanoparticules hybrides. L étude ce concentre sur l impact de la bioconjugaison sur la structure et les fonctionnalités biologiques de la Fn. L ensemble de ce travail met en évidence l importance du contrôle des conditions de bioconjugaison (stœchiométrie de greffage, pH, solvant). L obtention d un complexe Fn-FITC fonctionnel rend possible le suivi au cours du temps du remodelage de la Fn simultanément à la migration cellulaire. L élaboration d un complexe Fn/nanoparticule de conformation globale correcte met en évidence des interactions spécifiques Fn/ cellules.Fibronectin (Fn) is a structural protein of extracellular matrix (ECM) and is implicated into many cellular behavior (adhesion, migration ). Follow the becoming of an ECM protein as Fn is possible only via imaging dyes. The aim of this PhD work is to conjugate Fn to different exogenic dyes : organic fluorophore (and two sorts of double detection hybrid nanoparticles. The study focuses on bioconjugation impact onto Fn structure and biological functionalities. This work put in evidence the importance of controlling bioconjugation conditions particularly bioconjugation stœchiometry, pH value and solvent condition. Getting functional Fn-FITC complex make possible the following of Fn matrix remodeling simultaneously of cellular migration. The Fn/nanoparticles conjugate presents a correct global conformation and specific interaction with cells.CERGY PONTOISE-BU Saint-Martin (951272103) / SudocSudocFranceF

Fibronectin-Enriched Biomaterials, Biofunctionalization, and Proactivity: A Review

Modern innovation in reconstructive medicine implies the proposition of material-based strategies suitable for tissue repair and regeneration. The development of such systems necessitates the design of advanced materials and the control of their interactions with their surrounding cellular and molecular microenvironments. Biomaterials must actively engage cellular matter to direct and modulate biological responses at implant sites and beyond. Indeed, it is essential that a true dialogue exists between the implanted device and the cells. Biomaterial engineering implies the knowledge and control of cell fate considering the globality of the adhesion process, from initial cell attachment to differentiation. The extracellular matrix (ECM) represents a complex microenvironment able to meet these essential needs to establish a relationship between the material and the contacting cells. The ECM exhibits specific physical, chemical, and biochemical characteristics. Considering the complexity, heterogeneity, and versatility of ECM actors, fibronectin (Fn) has emerged among the ECM protagonists as the most pertinent representative key actor. The following review focuses on and synthesizes the research supporting the potential to use Fn in biomaterial functionalization to mimic the ECM and enhance cell–material interactions

DEVELOPMENT OF ANTIBIOFILM DRESSINGS WITH NATURAL ACTIVE INGREDIENTS FOR THE TREATMENT OF INFECTED WOUNDS

International audienc

DEVELOPMENT OF ANTIBIOFILM DRESSINGS WITH NATURAL ACTIVE INGREDIENTS FOR THE TREATMENT OF INFECTED WOUNDS

International audienc

Towards an Embedded Integrated Measurement System for the In Vitro Monitoring ofBiomedical Impedance Related to Fibrosis Phenomenon

International audienceIn this article a full wireless integrated measurement system of biomedical impedance is presented with main objective to characterize fibrosis phenomenon using impedance monitoring. It has further scope to make it secure and accurate by transferring measured data wirelessly using a Zigbee protocol This microcontroller-based system acquires the impedance by exciting an electrode and processes data in order to get clear values of real and imaginary data separately. The communication between master and slave is done with I2C protocol. Change in impedance can give a proper idea to reveal an intensity of fibrosis by correlated it to cell abnormal proliferation rate. In this article, as a proof of feasibility, we demonstrate on low and medium range resistors that our system is able to make reliable wireless transfer of impedance data, in accordance with the constraint of future in vitro experiments