143 results about "Cross linked chitosan" patented technology

The various embodiments herein provide an electro spun wound dressing comprising three nano fibrous layers and a method of synthesizing the same. The outer polymeric layer acts as a support layer for the other two layers and is hydrophilic in nature. The middle layer comprises a genipin cross linked reservoir layer loaded with a herbal extract of Melilotus officinalis and is hydrophobic or hydrophilic in nature. The second layer is cross-linked to control a release of the Melilotus officinalis extract in an aqueous environment. The third layer is a wound contacting inner layer comprising a non-cross-linked chitosan based nanofibrous layer that is hydrophilic in nature. Various additives are provided to enhance the mechanical or the chemical properties of the wound dressing and to control a release profile of the herbal extract.

The present invention discloses one kind of polyurethane base biological immobile carrier. The carrier has three kinds of structures: macroporous polyurethane network; polyurethane cross-linked chitosan and coated active carbon; and microporous network formed with chitosan and cross-linked glutaraldehyde, chloropropylene oxide or chloroacetic acid. These three kinds of network interpenetrate to form the polymer capable of fixing bioactive molecule. The carrier of the present invention has the features of coexisting macropores and micropores, coexisting hydrophilicity and reaction property, coexisting powerful adsorption and strong polarity, high biological bearing capacity, good compatibility, high physical, chemical and mechanical performance, etc., and is suitable for various bioreactors for treating sewage.

The invention discloses a new-typed heavy metal ion adsorbent of silica loading crosslinking chitosan in the environment-protection domain, which is characterized by the following: the metal ion adsorbent adapts gamma-epoxy propyl-trimethyl silane with epoxy group and soluble inorganic silane agent as chitosan crosslinking agent; the chitosan crosslinking action is accomplished by the reaction of chitosan and epoxy group and the silane agent hydrolysis and condensation course. The invention displays simple course without organic solvent and environmental pollution, which can dispose the waste water with heavy metal ion.

The invention discloses a composite frame of multi-aldehyde sodium alginate cross-linked polyethylene / chitosan for bone or cartilage repair and treatment, as well as preparation and application of the material of the framework. The framework is made from Calcium polyphosphate, chitosan and multi-aldehyde sodium alginate. As organic matrix multi-aldehyde sodium alginate cross-linked chitosan derived from nature which is the main component of the composite frameworks of the invention, therefore the composite framework is safe and non-toxic, has good biocompatibility and biodegradability, and cell identificaton signal existed on the surface provides physical support and the best chemical environment for bone or cartilage regeneration and reconstruction, the network structure makes the mechanical properties improved greatly. In addition, the components of the inorganic strengthened calcium polyphosphate are consistent with those of human bone tissue, has the property of activity which promotes bone or cartilage growth and the controllable degradation. The composite of the invention can be used as defect repair of bone or cartilage and tissue engineering, drug delivery carrier.

The invention discloses a multifunctional composite adsorbent. Cross-linked chitosan is used as a matrix and is formed by cross-linking heavy metal ion imprinting chitosan by using a cross-linking agent; the cross-linked chitosan matrix is filled with nano Fe3O4 and nano TiO2; and the surface of the multifunctional composite adsorbent is modified by thiocarbamide so as to form a large amount of free amino groups. The invention correspondingly discloses a preparation method for the multifunctional composite adsorbent. The preparation method comprises the following steps of: performing photocatalysis loading, performing heavy metal ion imprinting to ensure the metal imprinting ions are fully reacted with chitosan in the heavy metal imprinting ions to form complexes, and adding the cross-linking agent and reacting; and adding epichlorohydrin and an acetone solution containing thiocarbamide, and modifying and grafting, finally oscillating and desorbing, and regenerating by using an alkaline solution to prepare the multifunctional composite adsorbent. By using the multifunctional composite adsorbent, heavy metal can be selectively separated and/or organic pollutants can be degraded.

An ion-exchanging chitosan microsphere, especially a chitosan microsphere cross-linked with sulfuric acid, the preparation method and a medicinal carrier of the chitosan microsphere cross-linked withsulfuric acid. The method relates to preparing chitosan microspheres by phase separation, comprises: first adding the chitosan solution into a nontoxic oil phase, then adding an emulsifying agent anda dispersing agent, adding sulfuric acid solution for cross-linking, after reaction, washing the resultant product, drying by vacuum and getting chitosan microsphere cross-linked with sulfuric acid. The microspheres of the invention are smooth, have the sphere configuration, could be used for a medicinal controllable carrier.

The invention discloses a method for forming a simulated cell outer layer membrane structure on the surface of cross-linked chitosan. The method comprises the following steps that: firstly, the chitosan is cross-linked by glutaraldehyde; and secondly, the surface of the cross-linked chitosan is grafted with phosphinylideyne choline groups to construct the simulated cell membrane structure, the reaction of the grafted phosphinylideyne choline groups is carried out in an anhydrous non-protonic solvent, the reaction temperature is between 40 and 80 DEG C, and the concentration of phosphorylcholine dichloride is between 0.1 and 20mg/ml. The test results show that for the surface modified by the simulated cell outer layer membrane structure, the capabilities of adsorbing protein and blood platelet are obviously reduced, and the blood compatibility is obviously improved. The modified material with the simulated cell outer layer membrane structure has wide application prospect in fields such as blood purification, body implantation materials, tissue engineering, slow release of medicines, biological sensors, and the like.

The invention relates to the technical field of fine and deep processing and utilizing of medicines and aquatic products, and aims at providing a preparation method for preparing cross-linked chitosan microspheres with epoxy chloropropane as a cross-linking agent. The preparation method comprises the steps of: firstly preparing chitosan microspheres by an antiphase suspension method, making partial hydroxy on chitosan molecules to participate in cross-linking reaction with epoxy chloropropane as the cross-linking agent, thus converting linear chitosan molecules into reticular high polymer, and preparing cross-linked chitosan microspheres having a porous reticular structure with calcium carbonate as a pore-forming agent. The cross-linked chitosan microspheres prepared by the preparation method provided by the invention can be biodegraded, have good acid and base resistance, better adsorption effect on acid radical ions and proteins, and strong heavy metal ion loading capacity, and can be applied to foodstuff, medicine chemical industry and other fields.

The invention relates to a preparation method and application of a sulfhydryl chitosan/activated carbon composite functional membrane, belonging to the technical fields of novel functional membrane material preparation and arsenic-polluted water treatment. The preparation method comprises the following steps: compounding chitosan and activated carbon into a membrane, adding epoxy chloropropane to carry out cross-linking to obtain a cross-linked chitosan/activated carbon composite membrane, modifying the cross-linked chitosan/activated carbon composite membrane with 2,3-dimercaptosuccinic acid, and introducing sulfhydryl group onto the chitosan framework, thereby obtaining the functional membrane. The novel functional membrane prepared by the method provided by the invention can display multiple synergic functions of chitosan, activated carbon and sulfhydryl group, is used for treating arsenic-polluted water, is applicable to wide pH range, does not need the step of preoxidation, can effectively remove As (III) and As (V), is free from the influence of coexistent competitive anions, has the advantages of favorable mechanical strength and simple treatment technique, can be used repeatedly, can greatly lower the cost, and is a new material and method having industrial application prospects.

The invention relates to a method for efficiently removing bivalent copper ions in aqueous solution. The method comprises the following steps of: (1) synthesizing cross-linked chitosan chelated resin through graft copolymerization of chitosan and epoxy chloropropane; (2) performing intercalation treatment on cross-linked chitosan and polyhydroxy aluminum cross-linked bentonite; (3) absorbing bivalent copper ions in aqueous solution by using the modified bentonite intercalated with the cross-linked chitosan; and (4) measuring the removal rate of bivalent copper ions. The modified bentonite obtained by the method provided by the invention is high in chitosan intercalation quantity, efficient and quick in absorbing and treating copper ions in aqueous solution, wide in pH application range, low in cost and the like, and can be widely applied to treatment of copper-containing industrial sewage.

The invention discloses a polydopamine-modified chitosan-based material and a preparation method thereof. The preparation method comprises the following concrete steps: (1) preparing a chitosan solution with a certain concentration from acetic acid, carrying out crosslinking by using glutaraldehyde as a cross-linking agent and casting the cross-linked chitosan solution into a die; (2) subjecting the chitosan solution obtained in the step (1) to gelating at first and natural air drying next so as to obtain a chitosan film; (3) dissolving dopamine in a buffer solution of tris(hydroxymethyl)aminomethane hydrochloride and adjusting the pH value of the obtained solution to 8.5 so as to obtain a polydopamine solution with a certain concentration; and (4) soaking the chitosan film prepared in the step (1) in the polydopamine solution obtained in the step (3), then taking the material out for cleaning and carrying out air drying again so as to obtain the surface polydopamine-modified chitosan film material. The method provided by the invention can improve surface hydrophilicity of the chitosan material, promotes deposition of a phosphate component on the surface of the material, provides a better coating material for a tissue-engineered bone repair scaffold, is simple in process and has good application prospects and scientific significance.

It is flow injection chemical radiation immune detection pool of silane cross-linking polyose film group which is the following: to combine the sensor and the chemical radiation flow pool to make flow injection chemical radiation immune measurement pool; the chemical radiation flow pool comprises the upper plastic board, down transparent board and silicon rubber cushion ring; to open two paths in the upper plastic board as the entrance and exit of the flow transportation; to etch a groove in its inside to embed immune sensor; the down board is glass or organic glass board with good transparency and directly lay them on the down end of electron-multiplier phototube; to adopt silicon rubber cushion ring in the middle as reaction pool where the immune reaction and radiation measurement happens; the immune sensor structure is to process chitose on the silane load surface and fix the antigen molecule and form the new immune sensor.

The invention discloses a preparation method of a chitosan-based dressing with a compact-loose double layer structure. The preparation method comprises the following steps: (1) preparing a chitosan solution with a certain concentration by acetic acid, cross linking with glutaraldehyde serving as a cross linking agent, casting a cross linked chitosan solution into a mould; (2) pre-freezing the chitosan gel obtained in the step (1) for 4h at 4 DEG C, then pre-freezing for 12h at (-20) DEG C, and then pre-freezing for 12h at (-80) DEG C, and finally vacuum freezing and drying for more than 24h, so as to obtain the chitosan material of the loose layer; and (3) bonding one side of the chitosan material of the loose layer with a certain amount of chitosan gel system containing a cross linking agent to form the compact layer, drying in air, so as to obtain the chitosan-based dressing with a compact-loose double layer structure. The material is applicable for recovering and healing of wound in medical field, the preparation process is simple and available, and the raw material is easy to get.

The invention discloses cross-linked chitosan microspheres, and a preparation method and application thereof, and belongs to the field of high polymer materials. The preparation method comprises the following steps: (1) dissolving chitosan powder in acetic acid solution to form an aqueous phase, adding an emulsifying agent into liquid paraffin, and mixing uniformly to form an oil phase; (2) injecting the aqueous phase into the oil phase, and stirring to form a water-in-oil type emulsion; (3) adding benzaldehyde into the water-in-oil type emulsion to generate Schiff alkali for protecting amino, adding a pore-foaming agent and stirring, adjusting the pH to be 9 to 10, and then adding epichlorohydrin and diethylenetriamine in sequence to perform cross-linking reaction; (4) after the cross-linking reaction is ended, separating to obtain a reaction product; (5) removing the oil phase and protecting groups from the reaction product, reducing to generate the amino, and washing and drying to obtain the cross-linked chitosan microspheres. The cross-linked chitosan microspheres prepared by the preparation method are small in particle size and high in dispersibility, and can be used as an adsorption agent for a dye, namely, Congo red; the chemical stability is improved.

The invention relates to citric acid cross-linked chitosan hydrogel and a preparation method thereof. The preparation method comprises the following steps of dissolving chitosan in an acetic acid solution, heating, then adding citric acid, subsequently, carrying out freezing and unfreezing, so that a preliminary hydrogel model is obtained, and afterwards, carrying out an amidation cross-linking reaction on the hydrogel model, so as to finally obtain the hydrogel which is porous and macroporous and is in different shapes. According to the preparation method, the chitosan is cross-linked by utilizing the citric acid; the hydrogel which is favorable in biocompatibility and is used for repairing spinal cord injury is obtained, and the hydrogel is used for the spinal cord injury, can be used for inhibiting the formation of a scar and can be used for lightening the inflammatory reaction of a secondary injury after the spinal cord injury.

The invention discloses multi-core adhesive microspheres capable of loading a water soluble low molecular medicament. The microspheres are ionic cross-linked chitosan/gelatin microspheres, wherein acrylic resin microspheres for wrapping and controlling the releasing of the water soluble low molecular medicament are dispersed in the microspheres. A preparation method comprises the following steps of: dispersing or dissolving the medicament into solution of acrylic resin-containing organic solvent; preparing medicament-loading microsphere cores by an emulsification solvent volatilization method; dispersing the cores in the solution of chitosan and gelatin; preparing W/O type mixture from the mixture and oily ingredients; solidifying the gelatin at a low temperature and separating the microspheres from the oil phase; and finally performing cross linking with ionic cross-linking aqueous solution. The chitosan medicament-loading microspheres have the advantages of controllable particle size distribution, good release control effect of water soluble medicament, adjustable releasing rate, high biological adhesion, simple preparation method, and mild condition.

The invention discloses a sustained/controlled release microsphere of a chitosan coated stilbene compound using a biological extract Genipin as a cross-linking agent and a preparation method thereof. In the microsphere, a cross-linked condensation compound layer of the chitosan and the Genipin serves as a capsule shell and is used for coating a medicament 3,5-dihydroxyl-4-isopropyl stilbene, resveratrol, pterostilbene, oxidized resveratrol or piceatannol; the medicament stability of the product is improved; the sustained/controlled release of the medicament is realized; and the released Genipin after in vivo metabolism of the capsule shell has the characteristics of biocompatibility, no cytotoxicity and the like. The invention is applicable to the sustained/controlled release microspheresof Genipin cross-linked chitosan coated 3,5-dihydroxyl-4-isopropyl stilbene, resveratrol, pterostilbene, oxidized resveratrol, piceatannol and other stilbene compounds and a preparation method thereof. The preparation method is low in requirements on the control condition and easy to operate. In the microspheres, the quality is uniform; the grain size is 0.1 to 100 mu m; the surface of the microsphere has a multiporous structure; and the entrapment rate of the capsule shell to the medicament is 30 to 90 percent.

The invention provides a phase change microcapsule, which comprises a capsule wall and a capsule core wrapped in the capsule wall, the capsule wall is chitosan cross-linked by glutaraldehyde, and the capsule core is fatty alcohol. The present invention also provides a preparation method of phase change microcapsules, comprising the following steps: dissolving chitosan in an aqueous acetic acid solution to obtain an aqueous solution of chitosan; adding molten fatty alcohol to the aqueous solution of chitosan, emulsifying After that, the first emulsion is obtained; the first emulsion is added into the liquid paraffin, and the double emulsion is obtained after stirring; glutaraldehyde is added to the double emulsion, and the phase change microcapsules are obtained after reaction. The phase-change microcapsule provided by the present invention uses fatty alcohol as the capsule core, and the phase-change microcapsules prepared by different fatty alcohols have different phase-transition temperatures. Therefore, the phase-change temperature of the phase-change microcapsules provided by the present invention is adjustable, It can meet the use requirements of phase change microcapsules at different temperatures.

The invention discloses an application of glutaraldehyde cross-linked chitosan for inhibiting growth of a burkholderia cepacia complex. The glutaradehyde cross-linked chitosan is prepared by the following steps of: adding chitosan into acetic acid solution, and stirring to be uniform, so as to obtain chitosan solution; mixing the chitosan solution with glutaradehyde solution, and stirring and reacting for 12-36h, so as to obtain hydrogel; and washing and drying the hydrogel, so as to obtain the glutaraldehyde cross-linked chitosan. The glutaraldehyde cross-linked chitosan prepared by the invention has appropriate crosslinking degree, has good inhibiting effect on the burkholderia cepacia complex when being used for plant cultivation, and has good high temperature stability and anti-bacteria durability; and the glutaraldehyde cross-linked chitosan prepared by the invention is used for preparing a plant preservative film or preservative coating applied to fruit vegetable transportation or stock preservation, thus postharvest diseases can be effectively prevented, and water retention and fresh keeping effects can be realized.

The invention provides a sulfonated cross-linked chitosan resin type solid acid catalyst and a preparation method thereof, which belong to the technical field of solid acid catalysts of organic reaction. According to the invention, the catalyst is a sulfonated cross-linked chitosan polymer; and according to the method, the method comprises the steps of first preparing cross-linked chitosan by using commercial chitosan as raw material, carrying out sulfonation reaction on the cross-linked chitosan, washing the cross-linked chitosan by using distilled water and drying the cross-linked chitosan to obtain the product. The sulfonated cross-linked chitosan resin type solid acid catalyst provided by the invention has the advantages of simple method, mild reaction condition, low energy consumption and low cost and is beneficial for environmental protection; the prepared product has the advantages of acid capacity of high up to 4.05-4.38 mmol/g, use temperature of high up to 130-150 DEG C, higher catalytic activity and capability of being recycled for multiple times; the method provided by the invention can be widely applied to the preparation of the chitosan resin type solid acid catalyst; and the product prepared by the method provided by the invention can be widely used for the petrochemical industry and the fine chemical industry.

The invention provides chitosan microspheres as well as a preparation method and application thereof to reduction of dielectric loss of mineral oil and belongs to the field of modified chitosan. The preparation method of the chitosan microspheres comprises the following steps: after dissolving chitosan into acid, spraying the mixture into a sodium polyphosphate water solution and carrying out cross-linking reaction to obtain primarily cross-linked chitosan microspheres; washing the primarily cross-linked chitosan microspheres with water; after filtering and draining, adding the primarily cross-linked chitosan microspheres into a sodium hydroxide solution and stirring; then adding epichlorohydrin and reacting to obtain secondarily cross-linked chitosan microspheres; after washing the secondarily cross-linked chitosan microspheres with water, filtering and draining; then carrying out gradient elution and leaching by utilizing organic solvents with the volume percent of 10 percent to 20 percent, 30 percent to 40 percent, 70 percent to 80 percent and 90 percent to 95 percent; then freezing and drying. According to the preparation method of the chitosan microspheres, provided by the invention, the modified chitosan microspheres with a stable structure and good adsorption performance can be obtained. The invention further provides the application of the chitosan microspheres to the reduction of the dielectric loss of the mineral oil.

The invention relates to the application of cross-linked chitosan porous microspheres in cigarette filter tips. During the filter stick forming process, the cross-linked chitosan porous microspheres are uniformly sprayed into tobacco shreds, paper filter elements or non-woven filter cloth or added into the cavities of three-element hollow filter sticks. The cross-linked chitosan porous microspheres are porous spherical particles with a specific surface area of 35-300 m2/g. The microspheres particle size distribution range of the cross-linked chitosan porous microsphere is 10-500 Mum, and the pore size is 5-100 nm. The additional amount of the cross-linked chitosan porous microspheres is 10-260 mg/cigarette. The volume of natural stack of the cross-linked chitosan porous microspheres is 0.6-3.0 cm3/g. the cross-linked chitosan porous microspheres provided by the invention can satisfy the need for filter stick forming process. The release of crotonaldehyde in the main stream smoke of cigarettes can be effectively reduced by adding the cross-linked chitosan porous microspheres into the filter sticks.

The invention discloses a method capable of being used for preparing novel chitosan-casein phosphopeptide nanoparticles in the food industry. At present, the chitosan nanoparticles are generally prepared by a method using sodium tripolyphosphate cross-linked chitosan. However, as oral delivery carriers, the chitosan nanoparticles are not resistant to strong acid and cause that delivered nutriments are damaged in gastric acid and cannot be delivered to intestinal tracts in a targeted mode for absorption. In the method, a product obtained by using trypsase to hydrolyze casein is separated and purified to obtain casein phosphopeptide, and the casein phosphopeptide and chitosan are cross-linked with each other to from a 'core-shell' nanoparticle structure through condition optimization. Underthe action of negative charges of a surface phosphate group, the chitosan-casein phosphopeptide nanoparticles can avoid acidic and enzymatic degradations in vivo to have very strong stability, have certain targeting and controlled-release characteristics, and solve the problem that the current chitosan-sodium tripolyphosphate nanoparticles serving as the oral delivery carriers can be degraded by the gastric acid easily.