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

Comportement des nanoparticules de silice en milieu biologique : des cellules aux biomatériaux

Recent development of nanotechnologies, while promising great advances, in particular in the bio-medical field, rise several questions, e.g. what is the behaviour of these nano-objects in biological conditions? Among these materials, silica arise special interest for it is already used in cosmetics, with the associated question of dermal exposure, and is studied for intracellular drug delivery. This study aims at bringing some answers concerning the fate of different kind of silica nanoparticles in biological conditions by exploring the following phenomena: aggregation and dissolution in biological media, internalisation in 2D or 3D cell cultures, toxicity and intracellular fate. In the context of cutaneous exposure, human dermal cells were used, both in direct exposition and through diffusion of the nanoparticles in dermis-like collagen matrices immobilizing cells. It appears that dissolution is size-dependant, internalisation is influenced by diameter and composition of the particles, toxic effects are governed by number of exposed particles, more than weight concentration, and intracellular dissolution can be modulated by the size of the particles or incorporation of disulfide moieties, possibly inducing the release of encapsulated molecules. Thus characteristics of the nanoparticles (diameter, surface charge and composition) influence their behaviour in biological media and in presence of cellsLe développement des nanotechnologies, tout en promettant des progrès remarquables, notamment dans le domaine biomédical, soulève de nombreuses questions : en particulier quel est comportement de ces nano-objets en milieu biologique ? La silice a une place particulière parmi ces matériaux puisqu'elle est utilisée dans des produits cosmétiques, posant ainsi la question de l'exposition cutanée, et étudiée pour développer des vecteurs de libération intracellulaire. Cette étude a pour but d'apporter des éléments de réponses sur le comportement de différentes nanoparticules de silice en milieu biologique, à travers le suivi des phénomènes suivants : agrégation et dissolution en milieu biologique, internalisation dans des cellules en culture 2D ou 3D, toxicité et devenir intracellulaire des particules. Pour se placer dans le contexte d'une exposition cutanée, l'étude a été menée sur des cellules humaines du derme, en exposition directe ou immobilisées dans un matériau modèle du derme à travers lequel les nanoparticules diffusent. On constate ainsi que la cinétique de dissolution des particules en milieu biologique est fonction de leur taille, l'internalisation est influencée par le diamètre et la composition des particules, les effets toxiques sont liés au nombre de particules plutôt qu'à la concentration massique, et enfin la dissolution intracellulaire peut être modulée par la taille et l'insertion de fonctions disulfures et permettre la libération de molécules encapsulées dans les particules. Il apparaît donc que les caractéristiques des nanoparticules (taille, charge de surface et composition) influencent leur comportement en milieu biologique et en présence de cellule

Comportement des nanoparticules de silice en milieu biologique : des cellules aux biomatériaux

Recent development of nanotechnologies, while promising great advances, in particular in the bio-medical field, rise several questions, e.g. what is the behaviour of these nano-objects in biological conditions? Among these materials, silica arise special interest for it is already used in cosmetics, with the associated question of dermal exposure, and is studied for intracellular drug delivery. This study aims at bringing some answers concerning the fate of different kind of silica nanoparticles in biological conditions by exploring the following phenomena: aggregation and dissolution in biological media, internalisation in 2D or 3D cell cultures, toxicity and intracellular fate. In the context of cutaneous exposure, human dermal cells were used, both in direct exposition and through diffusion of the nanoparticles in dermis-like collagen matrices immobilizing cells. It appears that dissolution is size-dependant, internalisation is influenced by diameter and composition of the particles, toxic effects are governed by number of exposed particles, more than weight concentration, and intracellular dissolution can be modulated by the size of the particles or incorporation of disulfide moieties, possibly inducing the release of encapsulated molecules. Thus characteristics of the nanoparticles (diameter, surface charge and composition) influence their behaviour in biological media and in presence of cellsLe développement des nanotechnologies, tout en promettant des progrès remarquables, notamment dans le domaine biomédical, soulève de nombreuses questions : en particulier quel est comportement de ces nano-objets en milieu biologique ? La silice a une place particulière parmi ces matériaux puisqu'elle est utilisée dans des produits cosmétiques, posant ainsi la question de l'exposition cutanée, et étudiée pour développer des vecteurs de libération intracellulaire. Cette étude a pour but d'apporter des éléments de réponses sur le comportement de différentes nanoparticules de silice en milieu biologique, à travers le suivi des phénomènes suivants : agrégation et dissolution en milieu biologique, internalisation dans des cellules en culture 2D ou 3D, toxicité et devenir intracellulaire des particules. Pour se placer dans le contexte d'une exposition cutanée, l'étude a été menée sur des cellules humaines du derme, en exposition directe ou immobilisées dans un matériau modèle du derme à travers lequel les nanoparticules diffusent. On constate ainsi que la cinétique de dissolution des particules en milieu biologique est fonction de leur taille, l'internalisation est influencée par le diamètre et la composition des particules, les effets toxiques sont liés au nombre de particules plutôt qu'à la concentration massique, et enfin la dissolution intracellulaire peut être modulée par la taille et l'insertion de fonctions disulfures et permettre la libération de molécules encapsulées dans les particules. Il apparaît donc que les caractéristiques des nanoparticules (taille, charge de surface et composition) influencent leur comportement en milieu biologique et en présence de cellule

Comportement des nanoparticules de silice en milieu biologique (des cellules aux biomatériaux)

PARIS-BIUSJ-Biologie recherche (751052107) / SudocSudocFranceF

Silica-Based Nanoparticles for Intracellular Drug Delivery

International audienceSilica-based nanoparticles have recently raised a great deal of attention as possible drug carriers. Such an interest is driven by the possibility to control their size, the chemical composition and the porous structure as well as to easily modify their surface with a wide range of biologically-relevant functionalities, favoring colloidal stability, long-time blood circulation and even specific targeting. Drug loading can be performed during particle formation but, at this time, the most popular method relies on the impregnation of pre-formed mesoporous colloids. Strategies to control drug delivery via bio-responsive pore capping are also developed. However, despite an increasing number of in vitro and in vivo studies related to the interaction of silica particles with cells and animals, their biocompatibility is still an issue, especially if applications in intracellular drug delivery are foreseen

Long-term fate of silica nanoparticles interacting with human dermal fibroblasts

International audienceThe long-term fate of fluorescent non-porous FITC-SiO2 nanoparticles of various sizes (10-200 nm) and charge is studied in the presence of human dermal fibroblasts. Particle aggregates are formed in the culture medium and uptaken, at least partially, by macropinocytosis. The smallest particles have a strong impact on cell viability and genotoxic effects can be observed for negatively-charged colloids 10 nm in size. Largest particles do not impact on cellular activity and can be monitored in cellulo via fluorescence and transmission electron microscopy studies over two weeks. These observations reveal a significant decrease in the size of silica particles located in endocytic vesicles. The dissolution process is confirmed by monitoring the cell culture medium that contains both colloidal and soluble silica species. Such dissolution can be explained on the sole basis of silica solubility and has great implication for the use of non-porous silica particles as intra-cellular drug release systems

Introduction of disulfide bridges within silica nanoparticles to control their intra-cellular degradation

International audienceIncorporation of disulfide bridges in the core structure of silica nanoparticles modifies their intracellular fate within dermal fibroblasts, especially influencing their degradation pathway

Silica nanoparticles as sources of silicic acid favoring wound healing in vitro.

There is good evidence that certain silicon-containing materials promote would healing and their common feature is the delivery of orthosilicic acid (Si(OH)4) either directly or following metabolism. In this respect, amorphous silica nanoparticles (NP), which dissolve in aqueous environments releasing up to 2mM orthosilicic acid, may be appropriate 'slow release' vehicles for bioactive silicon. Here we studied the impact of silica NP suspensions (primary particles∼10nm) in undersaturated conditions (below 2mM Si) with differing degrees of surface charge and dissolution rate on human dermal fibroblasts (CCD-25SK cells) viability, proliferation and migration in a cellular wound model. Silica was shown to be non-toxic for all forms and concentrations tested and whilst the anticipated stimulatory effect of orthosilicic acid was observed, the silica NPs also stimulated fibroblast proliferation and migration. In particular, the amine-functionalized particles promoted wound closure more rapidly than soluble orthosilicic acid alone. We suggest that this effect is related to easy cellular internalization of these particles followed by their intracellular dissolution releasing silicic acid at a faster rate than its direct uptake from the medium. Our findings indicate that amorphous silica-based NPs may favour the delivery and release of bioactive silicic acid to cells, promoting wound healing

Silica nanoparticles as sources of silicic acid favoring wound healing in vitro

International audienceThere is good evidence that certain silicon-containing materials promote would healing and their common feature is the delivery of orthosilicic acid (Si(OH)4) either directly or following metabolism. In this respect, amorphous silica nanoparticles (NP), which dissolve in aqueous environments releasing up to 2 mM orthosilicic acid, may be appropriate ‘slow release’ vehicles for bioactive silicon. Here we studied the impact of silica NP suspensions (primary particles ∼ 10 nm) in undersaturated conditions (below 2 mM Si) with differing degrees of surface charge and dissolution rate on human dermal fibroblasts (CCD-25SK cells) viability, proliferation and migration in a cellular wound model. Silica was shown to be non-toxic for all forms and concentrations tested and whilst the anticipated stimulatory effect of orthosilicic acid was observed, the silica NPs also stimulated fibroblast proliferation and migration. In particular, the amine-functionalized particles promoted wound closure more rapidly than soluble orthosilicic acid alone. We suggest that this effect is related to easy cellular internalization of these particles followed by their intracellular dissolution releasing silicic acid at a faster rate than its direct uptake from the medium. Our findings indicate that amorphous silica-based NPs may favour the delivery and release of bioactive silicic acid to cells, promoting wound healing