Abstract: Disclosed are adducts of boric acid and chitosan wherein the amino groups of the D-glucosamine units are bonded to residues of polyol or alditol oligosaccharides, the molar ratio between boric acid and the repeating chitosan unit ranging between 0.001 and 4.

Abstract: Disclosed are adducts of boric acid and chitosan wherein the amino groups of the D-glucosamine units are bonded to residues of polyol or alditol oligosaccharides, the molar ratio between boric acid and the repeating chitosan unit ranging between 0.001 and 4.

Abstract: The present invention concerns the preparation of chemically modified derivatives of chitosan with acrylic groups and their use in the field of enamel-dentin adhesives. Chitosan derivatives have physical-chemical features (hydrophilicity, presence of electrical charges on the chain) which allow them to interact with the organic part of the demineralized tooth. At the same time, the acrylic groups incorporated in the polymer chain allow the formation of a covalent bond with the restorative material used in the dental field that is typically composed of acrylic resins. By combining the adhesion to the tooth surface and the bond with the restorative material, the chemically modified chitosan described herein is able to increase the lifespan of the dental restoration and can thus find use in the field of adhesives, in particular enamel-dentin adhesives.

Abstract: The present invention concerns the preparation of chemically modified derivatives of chitosan with acrylic groups and their use in the field of enamel-dentin adhesives. Chitosan derivatives have physical-chemical features (hydrophilicity, presence of electrical charges on the chain) which allow them to interact with the organic part of the demineralized tooth. At the same time, the acrylic groups incorporated in the polymer chain allow the formation of a covalent bond with the restorative material used in the dental field that is typically composed of acrylic resins. By combining the adhesion to the tooth surface and the bond with the restorative material, the chemically modified chitosan described herein is able to increase the lifespan of the dental restoration and can thus find use in the field of adhesives, in particular enamel-dentin adhesives.

Abstract: Described in the present application are compositions comprising mixtures of polyanionic polysaccharides and polycationic polysaccharides consisting of oligosaccharide derivatives of chitosan. In the compositions of the invention said mixtures have proven to be soluble in aqueous environments, despite ionic complexes forming between the acid polysaccharides and chitosan derivatives. Said compositions have also demonstrated significant rheological behavior with an unexpected increase in viscosity and viscoelasticity, although the polysaccharides used have relatively low average molecular weights. The said solubility and rheological behavior renders the compositions of the invention particularly advantageous from the biomedical application viewpoint, in particular for viscosupplementation and particularly in the field of articular pathologies and of ophthalmic surgery.

Abstract: The present invention provides nanocomposite systems made of metallic nanoparticles stabilized with branched cationic polysaccharides, in particular alditolic or aldonic mono- and oligo-saccharidic derivatives of chitosan, and their preparation obtainable with aqueous solutions of these polysaccharides in the presence or absence of reducing agents. The peculiar chemical and physical-chemical features of these polysaccharides allow to form metallic nanoparticles homogeneously dispersed in the polysaccharidic matrix and an effective stabilization thereof. The properties associated with the nanometric dimensions and the presence of biological signals on polymeric chains may be exploited in applications with antimicrobial activities and of molecular biosensors.

Abstract: In the present invention nanocomposite materials in form of three-dimensional structure formed by a polymeric matrix consisting of a polysaccharidic composition of neutral or anionic polysaccharides and a branched cationic polysaccharides, in which metallic nanoparticles are uniformly dispersed and stabilized, are described. Using appropriate techniques of gelification or by means of an appropriate dehydration, the nanocomposite materials are three-dimensional matrices having different shapes in hydrated form as hydrogels, or in non-hydrated form. These nanocomposite materials have a broad-spectrum of strong bactericidal activity, but do not show any cytotoxicity.

Abstract: The present invention describes the preparation of hydrogels (or 3D matrices) obtainable from aqueous solutions of mixtures of acid polysaccharides and derivatives of basic polysaccharides, such as oligosaccharide derivatives of chitosan. Said solutions are suitably gelled with either chemical or physical gelling agents with the aim of encapsulating either cells, isolated or in multicellular associations, or pharmacologically active molecules, in solution or suspension, for use in the biomedical and pharmaceutical field.

Abstract: Described in the present application are compositions comprising mixtures of polyanionic polysaccharides and polycationic polysaccharides consisting of oligosaccharide derivatives of chitosan. In the compositions of the invention said mixtures have proven to be soluble in aqueous environments, despite ionic complexes forming between the acid polysaccharides and chitosan derivatives. Said compositions have also demonstrated significant rheological behaviour with an unexpected increase in viscosity and viscoelasticity, although the polysaccharides used have relatively low average molecular weights. The said solubility and rheological behaviour renders the compositions of the invention particularly advantageous from the biomedical application viewpoint, in particular for viscosupplementation and particularly in the field of articular pathologies and of ophthalmic surgery.

Abstract: Process for preparing a modified alginate polymers are disclosed. The processes comprise the steps of covalently attaching a modifying moiety to one or more unmodified monomeric subunits of an alginate polymer; and changing one or more unmodified mannuronic (M) monomeric subunits of the alginate polymer to one or more unmodified guluronic (G) monomeric sub-units by an enzymatic epimerization reaction performed in any order. Processes for preparing alginate gels, fiber, and compositions are also disclosed. Modified alginates in which only M monomeric subunits are modified, and alginate gels, fibers and compositions comprising the same, are disclosed.