Centre National De La Recherche Scientifique

Université Claude Bernard Lyon I

Laboratoire Tetra Medical

Institut National De La Sante Et De La Recherche Medicale

Université Pierre Et Marie Curie (Paris 6)

Institut National Des Sciences Appliquees De Lyon

Université Jean Monnet Saint-Étienne

Université Pierre Et Marie Curie

Inserm (institut National De La Sante Et De La Recherche Medicale)

Université Jean Monnet De Saint-etienne

Alexandra Montembault

Laurent David

Mylène Desorme

Alain Domard

Fatiha Nothias

Sylvia Soares

The present invention relates to chitosan hydrogel microparticles of a median size d50 comprised between 1 and 500 &#x3bc;m (obtained from a number distribution), the chitosan having a degree of acetylation of less than equal to 20% and its concentration in the hydrogel being comprised between 0.25 and 5% by weight based on a total weight of the hydrogel, for use in neuron regeneration and/or in the repair of the nervous system, advantageously of the central nervous system, and/or in the grafting of neurons and/or in the treatment of neurodegenerative diseases and/or in the treatment of paralyses. It also relates to an implant comprising an aqueous suspension of microparticles mixed with Schwann cells and/or stem cells and/or trophic factors.

Chitosan hydrogel for repairing nerve tissue

A method for obtaining an elongate polysaccharide element, in particular a chitosan thread, includes extruding a hydroalcoholic extrusible solution containing a polyalcohol of said polysaccharide through an extrusion die, coagulating the extruded solution by neutralization, and at least one operation of removing the polyalcohol. The ratio of water to polyalcohol in the extrusible solution is determined such as to obtain in the elongate element a polysaccharide with the crystalline structure thereof mainly in the form of an anhydrous allomorph. Since the polysaccharide used to prepare the extrusible solution has a weight-average molar mass Mw, the polysaccharide in the elongate element obtained preferably has a weight-average molar mass Mwcomprised between Mwand 0.7 Mw. Since the purpose is to obtain a chitosan thread, the latter has properties of mechanical strength and flexibility that allow the thread to be tied into overhand knots and to be woven without breaking.

Method for obtaining an elongate polysaccharide element, in particular a chitosan thread

The invention relates to a method for producing an elongate polysaccharide element, in particular a chitosan thread, comprising an operation of extruding an extrusible solution of said polysaccharide through an extrusion die and an operation of coagulating the extruded solution. The extrusible solution is a hydroalcoholic solution containing an alcohol that does not form an azeotrope with water and which has a boiling point of more than 150&#xb0; C. at atmospheric pressure. The coagulation operation includes a step of evaporating the water, preferably over the alcohol, producing a gelled extruded elongate element in the form of a mainly alcoholic gel, in particular by subjecting the extruded solution to a hot air flow. At least one operation of eliminating the alcohol contained in said gel makes it possible to obtain the elongate polysaccharide element. The chitosan thread has a crystalline structure corresponding to the anhydrous allomorph and a rupture stress of at least 150 MPa after being immersed in demineralized water for fifteen hours. The apparatus (1) for the wet extrusion of polysaccharide thread () includes an extruder () with at least one extrusion die (), an evaporation enclosure () placed immediately after the output () of the extrusion die () and supplied with a hot air flow, a neutralization unit (), a washing unit (), a drying unit () and a winding unit ().

Chitosan yarn having a crystal structure corresponding to the anhydrous allomorph and a tensile strength, after immersion in demineralized water for fifteen hours, of at least 150 MPA

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Saint Etienne, France

Alexandra Montembault