The disclosure relates to a method for separation and purification of N-acetyl-glucosamine, and belongs to the technical field of biological engineering. In the disclosure, a raw material solution containing N-acetyl-glucosamine is obtained by microbial fermentation or by hydrolyzing the chitin. The raw material solution is subjected to flocculation pretreatment, and continuous centrifugation or pressure filtration is performed to remove suspended solids such as microorganisms, proteins and polysaccharides to obtain clear liquid. Double-stage ion exchange chromatography is performed to remove impurities such as charged organic molecules and inorganic salts. Membrane concentration is performed to efficiently remove water to improve the concentration of the target product. Spray drying or further evaporation concentration and crystallization are performed. Finally drying is performed to obtain an N-acetyl-glucosamine crystal of which the purity is more than 99%.

The disclosure relates to a method for separation and purification of N-acetyl-glucosamine, and belongs to the technical field of biological engineering. In the disclosure, a raw material solution containing N-acetyl-glucosamine is obtained by microbial fermentation or by hydrolyzing the chitin. The raw material solution is subjected to flocculation pretreatment, and continuous centrifugation or pressure filtration is performed to remove suspended solids such as microorganisms, proteins and polysaccharides to obtain clear liquid. Double-stage ion exchange chromatography is performed to remove impurities such as charged organic molecules and inorganic salts. Membrane concentration is performed to efficiently remove water to improve the concentration of the target product. Spray drying or further evaporation concentration and crystallization are performed. Finally drying is performed to obtain an N-acetyl-glucosamine crystal of which the purity is more than 99%.

According to the present invention, a crystal of ammonium N-acetylneuraminate anhydrate, and a process for producing a crystal of ammonium N-acetylneuraminate anhydrate, comprising adding or adding dropwise a solvent selected from the group consisting of alcohols and ketones to an aqueous N-acetylneuraminic acid solution containing an ammonium-containing compound and having a pH of 3.0 to 9.0 to precipitate a crystal of ammonium N-acetylneuraminate anhydrate, and collecting the crystal of ammonium N-acetylneuraminate anhydrate from the aqueous solution, can be provided.

According to the present invention, a crystal of ammonium N-acetylneuraminate anhydrate, and a process for producing a crystal of ammonium N-acetylneuraminate anhydrate, comprising adding or adding dropwise a solvent selected from the group consisting of alcohols and ketones to an aqueous N-acetylneuraminic acid solution containing an ammonium-containing compound and having a pH of 3.0 to 9.0 to precipitate a crystal of ammonium N-acetylneuraminate anhydrate, and collecting the crystal of ammonium N-acetylneuraminate anhydrate from the aqueous solution, can be provided.

Provided herein is chitosan dually derivatized with arginine and gluconic acid; and methods of making and using the same, e.g., for gene delivery in vivo.

Provided herein is chitosan dually derivatized with arginine and gluconic acid; and methods of making and using the same, e.g., for gene delivery in vivo.

The present invention provides a mannose-based mRNA targeted delivery system and use thereof. The mRNA can encode one or more target polypeptides and contains at least one mannose modification. The technical solution of the present invention modifies the mRNA molecule with a mannose, so that the mRNA can be directly and efficiently coupled with the mannose, and the targeted delivery of the mRNA is realized without the need for a carrier.

The present invention provides a mannose-based mRNA targeted delivery system and use thereof. The mRNA can encode one or more target polypeptides and contains at least one mannose modification. The technical solution of the present invention modifies the mRNA molecule with a mannose, so that the mRNA can be directly and efficiently coupled with the mannose, and the targeted delivery of the mRNA is realized without the need for a carrier.

A fucosylated chondroitin sulfate oligosaccharide having the structure as shown in J, and further disclosed is a method for preparing the fucosylated chondroitin sulfate oligosaccharide: using a chondroitin sulfate A salt as a raw material, sequentially performing enzymolysis, a group protection operation, and glycosylation to synthesize the oligosaccharide compound; the certainty of the described structure allows said oligosaccharide to be applied to the medical field.

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A fucosylated chondroitin sulfate oligosaccharide having the structure as shown in J, and further disclosed is a method for preparing the fucosylated chondroitin sulfate oligosaccharide: using a chondroitin sulfate A salt as a raw material, sequentially performing enzymolysis, a group protection operation, and glycosylation to synthesize the oligosaccharide compound; the certainty of the described structure allows said oligosaccharide to be applied to the medical field.

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