摘要:
The invention relates to an enzyme which is able to degrade hyaluronic acid and which is produced by fungi of the genus Fistulina (especially Fistulina hepatica). The degradation proceeds by lyase mechanism in which double bonds between C4 and C5 of glucuronic acid are formed. The invention also includes the process of preparation and purification of the enzyme and a possible practical use thereof for the preparation of low-molecular hyaluronan or of cosmetic or pharmaceutical devices. Further, the invention relates to the method of preparation of low-molecular hyaluronan.
摘要:
The present invention relates to the preparation of textile processable endless monofilaments and multifilaments on the basis of hyaluronan which has been selectively oxidized to aldehyde in the position 6 of its/V-acetyl-D-glucosamine group and to the subsequent modification of such filaments with low molecular dihydrazides. The fibres as well as the fabrics, which are subsequently prepared from the former, exhibit a time-varying solubility in saline depending on the external modification of the fibres. After having been externally modified, the fibres as well as the fabrics exhibit a prolong period of transition into an evenly distributed gel layer. The externally modified fibrous materials retain their full biocompatibility.
摘要:
The invention relates to the preparation and use of α,β-unsaturated aldehyde of hyaluronan having a double bond in the positions 4 and 5 and an aldehydic group in the position 6 of the glucosamine part of the polysaccharide. The method of preparation is based on dehydration of hyaluronan having an aldehydic group in the position 6 of the glucosamine part of the polysaccharide. Two methods have been described, which are dehydration in a solution or heating in solid state in absence of solvents, bases or other additives. This derivative allows stabilization of conjugates of hyaluronan with amino compounds by means of a multiple bond from the aldehyde side, and therefore, it is possible to effectively immobilize practically any compound containing an amino group to such modified hyaluronan in physiological conditions. In case of using a diamine or compounds or polymers containing three or more amino groups, it is possible to prepare crosslinked hyaluronan derivatives. The described solution brings along a significant advantage not only in the field of carriers of biologically active substances, but also in tissue engineering where crosslinking with biologically acceptable amino compounds in physiological conditions is very much demanded.
摘要:
Spinning nozzle for production of nanofibrous and microfibrous materials comprises: a first plate (1) provided with at least one continuous groove (2) for directing a first material to an outlet mouth portion (3) of the continuous groove (2) in a face (4) of the first plate (1); a second plate (5) provided with at least one continuous groove (6) for directing a second material to an outlet mouth portion (7) of the continuous groove (6) of the second plate (5), the outlet mouth portion (7) being arranged adjacent to the outlet mouth portion (3) of the first plate (1); and a separating plate (8) arranged between the first plate (1) and the second plate (5) for separating the continuous grooves (2) of the first plate (1) from the continuous grooves (6) of the second plate (5), while the face (9) of the separating plate (8) forms with the face (4) of the first plate (1) and/or the face (10) of the second plate (5) a continuous surface in the region of the outlet mouth portions (3; 7) of the continuous grooves (2; 6).
摘要:
The invention relates to a method of preparation hydrophobized hyaluronic acid (Formula I) and further to a method of encapsulating biologically active substances into the nanomicelles of hydrophobized hyaluronan serving as carriers of biologically active hydrophobic substances. The hydrophobization of hyaluronan is carried out through an esterification reaction of hyaluronan with long-chain carboxylic acids, the latter being activated by a halogenide derivative of 2,4,6-trichlorobenzoic acid or by another organic chloride. In an aqueous environment, water-soluble hydrophobized derivatives can form nanomicelles in which nonpolar substances can be bound by means of non-covalent physical interactions. The core of a nanomicelle is formed by hydrophobic acyl functional groups while the shell of a nanomicelle is formed by hyaluronic acid. The encapsulation of the substances into nanomicelles can be performed by means of the solvent exchange method or by means of sonication. Hyaluronic nanomicelles support the penetration of bound substances in topical applications and enable the bound substances to be transferred into the individual cells. The nanomicelles obtained from hydrophobized hyaluronan derivatives are usable in cosmetic and pharmaceutical applications.
摘要:
The invention related to hyaluronic derivative according to formula (I), methods of preparation thereof and a hydrogel prepared obtained from the derivative and methods of preparation thereof. The hydrogel can be used in tissue engineering, cosmetics, medicine or regenerative medicine such as the forming of scaffolds for the treatment of articular cartilage or bone tissue defects.
摘要:
The invention relates to a crosslinked hyaluronan derivative in the form of a hydrogel or microfibers, and to a method of preparation thereof, consisting in a C—C coupling reaction. The C—C coupling reaction is performed via reaction of a hyaluronan derivative carrying a terminal aryl-halide and/or aryl-borate group, and a hyaluronan derivative carrying an alkenyl or alkynyl group, in water, phosphates buffer or a mixture of an organic acid and an alcohol, and in the presence of a palladium active catalyst. The palladium active catalyst may be e.g. a complex of palladium (II) acetate and an inorganic or organic base, or a complex of palladium (II) and 2-amino-4,6-dihydroxypyrimidine.
摘要:
The combined spinning nozzle for the production of nanofibrous or microfibrous materials comprises a thin-walled electrode (1) and a first non-conductive body (2) adjoining the first wall of said thin-walled electrode, said first body having its wall, which faces the thin-walled electrode (1), provided with an array of grooves (5) formed therein, said grooves leading to the distal end (6) of the combined spinning nozzle and having their proximal ends connected to a supply of spinning mixture. The thin-walled electrode (1) and the first non-conductive body (2) may assume either plate-like or cylindrical shapes. The combined spinning nozzle may further comprise a second non-conductive body (4) adjoining a second wall of the thin-walled electrode (1) and directing the air from the proximal end towards the distal end (6) of the nozzle.
摘要:
The invention relates to the biodegradable fibres which are based on hydrophobic derivatives of hylauronan, specifically on the base of the hyaluronan derivative C11-C18-acylated on hydroxyl groups of hyaluronic acid, and use thereof. Further the invention relates to the preparation of these fibres which is performed with the use of the wet spinning method in a coagulation bath comprising water solution of organic acid, with the production of continuous monofiles which can be thereafter processed to threads and further to textiles, knitted textiles, or nonwoven textiles. These textiles, knitted textiles or nonwoven textiles can be used for example for the production of implantable surgical material for human and veterinary medicine.
摘要:
The subject-matter of the invention is a photoreactive derivative of hyaluronic acid (formula I) and the method of preparation thereof, where first an aldehyde derivative of hyaluronic acid is prepared, oxidized in the position 6 of the glucosamine cycle and then the oxidized derivative reacts with an amine carrying a photoreactive species, for example 1-(2-aminoethyl)pyridine-2(1H)-one, in the presence of a reducing agent, forming a photoreactive derivative. The prepared photoreactive derivative may be then photocrosslinked, wherein the reaction is based on [4+4] photocycloaddition. Moreover, the invention relates to a 3D-crosslinked derivative of hyaluronic acid (formula II) which exhibits an increased hydrolytic stability and improved sorption properties, with the possibility of a further design of the physical properties thereof according to the requirements of the final applications, and moreover, to the use thereof in tissue engineering, regenerative medicine, medical agents or formulations or cosmetics.