2255 results about "Carboxymethyl-chitosan" patented technology

The invention relates to chitosan-based styptic sponge with a thrombin immobilization effect, and the chitosan-based styptic sponge is a porous sponge made from chitosan with the thrombin immobilization effect and hemostatic. The preparation method of the chitosan-based styptic sponge provided by the invention comprises the following steps: immobilizing thrombin with chitosan or carboxymethyl chitosan, and adding other styptics, cryoprotectants and crosslinking agents to prepare the porous styptic sponge, wherein the weight ratio of the chitosan or carboxymethyl chitosan to the thrombin is 100:(0.1-20); pre-freezing, lyophilizing in vacuum, casting, cutting, encapsulating and sterilizing to prepare the chitosan-based styptic sponge. According to the chitosan-based styptic sponge, the thrombin is immobilized through the chitosan or carboxymethyl chitosan, so that the stability and procoagulant activity of the thrombin can be improved, and the property of the prepared chitosan-based styptic sponge is more stable, the procoagulant and wound healing effects are remarkably improved, and the chitosan-based styptic sponge can be widely applied to wound or surgery hemostasis.

The invention provides a special organic-inorganic composite biological pesticide-fertilizer for flowers. The special organic-inorganic composite biological pesticide-fertilizer for flowers comprises the following raw materials in parts by weight: 80-90 parts of municipal sludge, 10-20 parts of fruit peel, 10-20 parts of fallen leaves, 10-15 parts of poultry manure, 10-14 parts of bagasse, 20-30 parts of iron ore slag, 10-12 parts of animal feathers, 10-15 parts of tree ash, 10-15 parts of monoammonium phosphate, 20-25 parts of urea, 10-12 parts of ammonia sulfate, 8-10 parts of ammonium hydrogen carbonate, 8-10 parts of potassium chloride, 5-7 parts of carboxymethyl chitosan, 20-30 parts of modified bentonite, 5-8 parts of lignite, 2-4 parts of black dye tree, 9-11 parts of celastrus angulatus, 9-11 parts of common carpesium fruit, 9-11 parts of radix sophorae flavescentis, 4-6 parts of lilac daphne flower bud, 3-5 parts of coptis root, 10-12 parts of powder of root of stellera chamaejasme, 2-4 parts of vegetable oil, 1-3 parts of zinc sulfate, 3-4 parts of ferrous sulfate, 0.8-1.2 parts of borax, 20-26 parts of potassium fulvate and 0.3-0.4 part of EM (effective microorganism) strain. The pesticide-fertilizer disclosed by the invention has the advantages of scientific ratio of nitrogen, phosphorus and potassium, easiness in absorption by crops, obvious yield-increasing benefit and the like. By applying the pesticide-fertilizer, the nutrient absorption of plants can be balanced, the quality of flowers can be effectively improved, plants are green in leaves and bright in flower, and the flowering phase is also prolonged.

The invention provides a specialized organic / inorganic composite biological medicine fertilizer for watermelon, and a preparation method thereof. The weight parts of composition raw materials are as follows: 50-70 parts of sludge produced by sewage treatment, 20-30 parts of tree ash, 30-40 parts of watermelon vines, 20-30 parts of cow manure, 15-20 parts of bagasse, 5-7 parts of fishbone dust, 8-10 parts of oil cakes, 10-15 parts of the tree ash, 10-15 parts of phosphorus slag, 8-10 parts of poultry feather, 8-10 parts of monoammonium phosphate, 10-12 parts of triple superphosphate, 12-15 parts of potassium chloride, 2-4 parts of carboxymethyl chitosan, 20-30 parts of modified bentonite, 10-12 parts of decomposed coal, 2-4 parts of seven leaf clover, 9-11 parts of angled bittersweet, 8-10 parts of capillary artemisia, 5-7 parts of fructus cnidii, 6-8 parts of fructus quisqualis, 3-5 parts of wormwood, 3-5 parts of litsea cubeba, 8-10 parts of daturae flower powder, 3-5 parts of paraffin, 1-1.25 parts of zinc sulfate, 2-3 parts of ferrous sulfate, 0.8-1.2 parts of borax, 10-12 parts of potassium fulvic acid, 3-4 parts of chili oil and 0.2-0.5 part of EM strains. A green organic fertilizer is obtained by mixing a plurality of organic wastes and fermenting the mixture, thereby reducing environment pollutions. The specialized organic / inorganic composite biological medicine fertilizer for the watermelon has the advantages of comprehensive nutrition and enhanced sterilizing effects by mixing the fermented organic materials and inorganic fertilizer and adding medicine juice of the Chinese herbal medicine having insectidical functions. With the application of the fertilizer, watermelon quality can be effectively increased; and the watermelon has green leaves, bright flower, prolonged flowering period and increased output.

The invention relates to a preparation method of a biological preservative. As known to all, along with the rapid development of the society, chemical preservatives have been used in food, have strong impact on food safety and endanger the health of consumers, therefore, the use of preservatives causes great concern of government departments and consumers. According to the biological preservative, natural plants and microbial antibiotic substances are used as base materials, for example, the biological preservative is prepared by mixture of carboxymethyl chitosan, xylooligosaccharide, nisin from lactic streptococci, acetic acid, lactobacillus reuteri, pediococcus acidilactici, calcium citrate, ionized calcium, lactic acid, plant essential oil and water. The biological preservative can inhibit growth of harmful microorganisms by antagonistic and competitive inhibition effects among different microorganisms and produce extracted and separated components of antibacterial active ingredients having antifungal and antibacterial functions in normal growth and metabolism processes, thereby achieving antiseptic and fresh-keeping effects.

The invention discloses a tumor-targeted nanometer drug delivery system for cooperative chemotherapy and photodynamic therapy and a preparation method thereof. The drug delivery system is prepared from carboxymethyl chitosan, folate, a photosensitizer chlorine e6 and adriamycin, wherein the chlorine e6 and the folate are coupled to a carboxymethyl chitosan chain segment through an amido bond, and are loaded to polymer nanoparticles of the adriamycin through an ion exchange method. The nanometer material prepared by the method is high in yield, regular in shape and even in distribution. In-vivo and in-vitro experiments prove that the tumor targeting property of the nanometer preparation can be significantly improved by folate receptor mediation; enrichment on the tumor part is achieved and drug release is controlled. The photosensitizer is capable of effectively reversing the chemotherapy drug resistance and significantly inhibiting the growth of tumors after being irradiated by near-infrared light. Therefore, the related nanometer drug delivery system has good application prospect in the aspect of breast cancer treatment.

The invention relates to a preparation method of a grafting amphoteric chitosan flocculant, comprising the following steps: carrying out graft copolymerization between carboxymethyl chitosan and polyacrylamide to obtain the grafting amphoteric chitosan flocculant, wherein the substituted ratio of a carboxyl group is 5%-90%, and the mass of the polyacrylamide is 40%-80% of the grafting amphoteric chitosan flocculant. The carboxymethyl chitosan can be obtained by separation after carboxylation reaction between chitosan and chloroacetic acid. The chitosan can adopt various commercially available products, and preferably, molecular weight of the chitosan is not less than 50,000, more preferably 750,000-850,000. The carboxymethyl chitosan grafting polyacrylamide flocculant prepared by the method of the invention improves water solubility of the chitosan, is applicable to treating water with different electric charges, and has good salt tolerance; and the flocculant can be also widely applied to an acid medium and an alkaline medium, and has wide adaptability to the pH value range.

The invention relates to a preparation method of a double-ion type crude oil desalting demulsifier. The preparation method specifically comprises the following steps: (1) carrying out esterification modification on polyethylene glycol monomethyl ether; (2) preparing glycidyl dimethyl alkyl ammonium chloride; (3) preparing quaternary ammonium carboxymethyl chitosan; (4) making the modified polyethylene glycol monomethyl ether react with the quaternary ammonium carboxymethyl chitosan to obtain a polyethylene glycol monomethyl ether grafted quaternary ammonium carboxymethyl chitosan. The double-ion type crude oil desalting demulsifier takes natural macromolecular compounds of chitosan as raw materials, thereby having many advantages of wide sources, naturalness, no toxicity, sustainability, good product bio-compatibility and degradation and the like. The prepared demulsifier is good in demulsification and dehydration effects, furthermore, demulsifier molecules contain a large number of carboxyl alkyl groups and quaternary ammonium salt groups, so that the demulsifier has a very strong binding capacity for negatively charged ions such as metal cations, naphthenic acid radicals and particles of which the surfaces are electronegative, thereby further having the removal ability for oil soluble salts while performing demulsification.

An antibacterial medical dressing for the operation wound is prepared from chitosan fibers through alkalizing to become alkaline chitosan fibers, and etherifying reaction on chloroacetic acid to become carboxymethyl chitosan fibers. When said fibers are encountered with water, it is swelling to become elastic gel. It is possible to add additive for higher curative effect.

The present invention discloses a method for the preparation of an anti-microbial wound dressing comprises alkalizing chitosan fiber to obtain alkalized chitosan fiber which is then etherified with chloroacetic acid to produce carboxymethyl chitosan fiber. Said fiber is made into dressing by fiber opening, web formation and needling. Alternatively chitosan fiber can be made into chitosan non-woven fabric by non-woven technique first which is then carboxylmethylated. The fabric is then made into wound dressing by cutting, packaging and sterilizing. The present invention also discloses the uses of the anti-microbial wound dressing made according to said method. The dressing according to the present invention can be applied in surgical wound, burn, and other chronic wound. Said dressing, when covering wound, is able to prevent moisture losses in body fluid, provide a favorable moist environment necessary for wound healing and maintain a fluid-free, maceration-free, germ-free wound surface. Said dressing is antiphlogistic, hemostatic and antalgic and promotes wound healing.

An antibacterial medical dressing is prepared from chitosan fibers through alkalizing, etherifying reaction on chloroacetic acid to obtain carboxymethyl chitosan fibers, opening, netting, needling, and cutting by needed sizes, packing and disinfecting. It can be used for preparing the surgical dressing for wound, bum and scald, the anti-inflammatory staltic fiberous ball, anti-inflammtory drainage sliver, and operation dressing.

The invention relates to a preparation method and application of an environment-friendly lithium ion battery, and in particular relates to a simulated mussel protein environment-friendly lithium ion battery adhesive. By simulating the molecular structure and action mechanism of mussel protein, histidine and dopamine are connected to polyacrylic acid, polymaleic acid, sodium alginate, sodium carboxymethylcellulose, carboxymethyl chitin, carboxymethyl chitosan, abietic acid and other natural or synthesized polymer to prepare a series of aqueous adhesives. The adhesive has a good adhering effect for various cathode materials such as carbon black, graphite and silicon. By adopting the adhesive provided by the invention, various properties of a lithium ion battery can be obviously improved, and especially cycle property of a silicon cathode material in a battery can be obviously improved.

The medical chitosan dressing is mixture of chitosan in 1 weight portion, Chinese medicine extract in 0.01-10 weight portions, chitosan derivative in 0.01-10 weight portions, and metal ion in 0.0001-0.05 weight portion. The Chinese medicine extract is bletilla tuber polysaccharide or natural indigo; and the chitosan derivative is one of hydroxypropyl chitin, hydroxypropyl chitosan, succinyl chitin, succinyl chitosan, carboxymethyl chitin and carboxymethyl chitosan. The medical chitosan dressing has the functions of promoting healing of the wound and stopping bleeding, inhibiting bacterial growth, and has excellent wound pasting performance.

The invention relates to a medical compound micropore polysaccharide and application in hemostasis on wound surface bleeding areas of various wounds and operation tissues. The medical compound micropore polysaccharide is prepared by adopting a method with the following steps: (1) preparing starch fluid; (2) preparing carboxymethyl chitosan solution; (3) mixing the starch fluid and the carboxymethyl chitosan solution, and adding dispersant and emulsifier into the mixture; (4) emulsifying, crosslinking and co-polymerizing; and (5) refining, drying, packing and sterile treatment. The invention also discloses application of the medical compound micropore polysaccharide in preparing a hemostasis medicament used for the wound surface bleeding areas of wounds and operation tissues. The medical compound micropore polysaccharide of the invention has the following characteristics: 1, the hemostasis time is short, namely the hemostasis is generally finished in 3 to 5 minutes; 2, the medical compound micropore polysaccharide has no antigenicity, has polysaccharide components, and has no protein or immune reaction; 3, the medical compound micropore polysaccharide can be fully degraded and absorbed in vivo; 4, the medical compound micropore polysaccharide is a sterile product and is convenient to use by opening; and 5, the tissue reaction is light. Therefore, the medical compound micropore polysaccharide is a comparatively ideal surgical hemostasis product.

The invention discloses a biological fertilizer special for flowers. The biological fertilizer special for flowers comprises the following materials in parts by weight: 30-40 parts of chicken manure, 15-20 parts of peat soil, 12-15 parts of rice chaff, 10-13 parts of wheat bran, 8-15 parts of fallen leaves, 20-30 parts of mushroom residue, 12-15 parts of feather, 10-16 parts of straw, 12-17 parts of monoammonium phosphate, 15-25 parts of urea, 10-15 parts of potassium sulphate, 12-15 parts of ammonium sulfate, 11-12 parts of ammonium bicarbonate, 6-8 parts of carboxymethyl chitosan, 4-6 parts of azadirachtin, 2-4 parts of zinc sulfate, 4-6 parts of ferrous sulfate, 1.1-1.3 parts of borax, 25-28 parts of potassium fulvic acid and 0.5-0.8 part of microorganism yeast. The invention also discloses a preparation method of the biological fertilizer. The biological fertilizer special for flowers has the advantages that the ecological environment and farmland soil can be protected, nitrogen, phosphorus and potassium are blended scientifically, crops are easy to absorb, the production increasing is obvious, double functions of fertilizing and killing insects are realized, and environmental protection is achieved.

The invention relates to a super absorbent polymer for physiology, in particular to an anti-compression and anti-bacterial super absorbent polymer still with high water absorbency under compression and with natural anti-bacterial property. The super absorbent polymer adopts the following technical scheme: taking polyvinyl alcohol with the polymer long chain rich in hydroxy as the interpenetrating polymer network (IPN), carboxymethyl chitosan with bioactivity and natural antibacterial property as the graft polymer and acrylate as the main comonomer, being combined with a cross-linking agent with molecular chains different in length, adopting the three-stage complex initiation system and realizing interpenetrating of polyvinyl alcohol and grafting of carboxymethyl chitosan by way of aqueous solution radical copolymerization to prepare the super absorbent resins with regular granularity, uniform crosslinking and less residual monomers. The invention develops multi-component composite surface treatment solution to carry out surface treatment on the super absorbent resins, thus further reducing the residual monomers, forming gradient crosslinking on the surfaces of the super absorbent resins and finally preparing the anti-compression and anti-bacterial super absorbent polymer for physiology. The super absorbent polymer is white without yellow spots, has regular granularity, inadherent surface, good liquidity, high absorption rate and absorption, excellent filtration property and less residual monomers and is against compression and tolerant to salt and free of gel plugging.

A water-soluble chitosan based fiber material for stopping hemorrhage and promoting healing of wound is made of carboxymethyl chitosan fibers, or hydroxypropyl chitosan fibers, hydroxyethyl chitosan fibers, or carboxymethyl hydroxyethyl chitosan fibers. Its preparing process is also disclosed.

The invention discloses a finishing method for a textile with ultraviolet-resisting and antibacterial functions. The finishing method comprises the following steps: step (10), preparing a zinc oxide / carboxymethyl chitosan nano compound; step (20), pre-treating the textile with a cold plasma method; and step (30), preparing the zinc oxide / carboxymethyl chitosan nano compound prepared by the step (10) into a zinc oxide / carboxymethyl chitosan nano compound solution, and immersing the textile pre-treated by the step (20) with the solution; and adding an acrylic ester binding agent and adopting a rolling baking process to obtain the treated textile. The textile prepared by the finishing method has good ultraviolet-resisting and antibacterial functions.

The invention discloses a dressing composition used for inhibiting scars and accelerating wound healing and application thereof. The dressing composition consists of chitosan, acidic polysaccharide and panax notoginseng saponins in a weight proportion of 100:10-50:10-100, wherein the chitosan is selected from chitosan, chitosan lactate, acetate and hydrochloride; the acidic polysaccharide is selected from sodium carboxymethyl chitosan, sodium hyaluronate, zinc hyaluronate, sodium alginate and sodium carboxymethyl cellulose; and the panax notoginseng saponins accounts for no less than 40.0 percent of the total weight of ginsenosides Rg1 and Rb1. The formulations of the dressing composition are xerogel powder, capsules, gel membranes, hydrogels and fiber coatings. The dressing composition is used for wounds, burns, scalds, crush injuries, skin ulcers, gastroenteric ulcers and no healing of the wounds, has the advantages of rapid hemostasis, exudate reduction, moisturizing, air permeability, bacteriostasis, inflammation diminishing, itch relieving, no adhesion, effective inhibition of scarring, remarkable reduction of wound healing time and no need of replacing dressings, so that thedressing composition basically meets requirements of perfect functional external dressings.

The invention discloses a medical dressing containing nano silver and carboxymethyl chitosan and a preparation method thereof, which belong to the technical field of the preparation of biological materials for medical dressings. The preparation method comprises the following steps of: making water-soluble carboxymethyl chitosan form gel through biological activity crosslinking agent carbodiimide; preparing a porous carboxymethyl chitosan membrane by a freeze drying technology; soaking the porous carboxymethyl chitosan membrane in silver nitrate solution, and making silver ions adsorbed on the porous membrane; and making the silver ions form nano silver in the porous membrane in situ through ultraviolet illumination. The medical dressing containing the nano silver and the carboxymethyl chitosan has controllable permeability and mechanical properties and high and durable antibacterial properties.

The invention discloses the preparation method and uses of carboxymethyl chitosan and sodium alginate blend microcapsule wherein the method comprises, using water as solvent to blend the water solution of carboxymethyl chitosan and sodium alginate into blending liquid I, dissolving the contained medicament bovine serum albumin into the blended solvent I and mixing homogeneously, obtaining blended liquid II, dispersing the blended liquid II into fluid wax containing emulsifying agent, dropping CaCl2 coagulated liquid into the system, charging 10-30 mL alcohol isopropylicum and hardening to obtain micro-encapsulation, which exhibits sensitive response function to the pH changes.

The present invention is chitin-based biomembrane finishing agent for fabric and its preparation process and application process. The present invention features that the biomembrane finishing agent has chitin derivative as the main antiseptic component, and may includes chitin, chitinamine, chitosan, carboxymethyl chitosan and quaternarized chitosan. The biomembrane finishing agent has water or alcohol as solvent and has concentration of 0.02-20 wt%. The preparation process includes dissolving chitin or its derivative in water with acidifying agent or alcohol to form flowable colloid, adding assistants via stirring and maturing. The treated fabric has chitin-based biomembrane formed and thus has antiseptic, water-absorbing and moist maintaining functions.

The invention discloses a preparation method for medical hydrocolloid dressing. The preparation method comprises the following steps:,1, dissolving styrene-butadiene-styrene block copolymer, then adding aliphatic series petroleum resins, carrying out the reaction, slowly adding cyclane oil, raising the temperature, then adding N.N-dibutyl dithio amido formic acid, and keeping the temperature to form a component A; 2, mixing anhydrosorbitol fatty acid ester and a polyoxyethylene sorbitan fatty ester condensation compound at normal temperature to form a liquid state component B; 3, taking sodium carboxymethyl cellulose, carboxymethyl chitosan, calcium alginate fibers and solid silver corpuscles, crushing the calcium alginate fibers into short fibers, mixing the substances at normal temperature to form a component C; and 4, adding the component B into the component A, raising the temperature, slowly stirring the mixture evenly and then adding the component C, stirring and cooling down the mixture, carrying out the debubbling in the vacuum, reducing the temperature, forming the dressing onto antiseize paper through injection moulding, and covering a PU film on the surface of the hydrocolloid to form a finished product.

The invention discloses a tea tree oil antibacterial microcapsule and a preparation method and application thereof. The method comprises the following steps of mixing a stabilizer and aqueous solution of carboxymethyl chitosan, and stirring the mixture to dissolve the stabilizer to obtain solution I; adding an emulsifier and a grease into the aqueous solution of carboxymethyl chitosan, and homogenizing to obtain solution II; adding the solution II into the solution I, under stirring at the constant temperature of 40 to 60 DEG C, adjusting the pH value of the solution to be between 5.0 to 6.5, and reacting to obtain re-coagulating solution, wherein the using amount of the solution II and the solution I is determined according to the carboxymethyl chitosan, and the proportion by mass of the carboxymethyl chitosan is 1:1.5; and cooling the re-coagulating solution, adjusting the pH value to be between 6.5 to 8.0, adding a curing agent to react and cure to obtain a tea tree oil microcapsule emulsion, and cooling and drying the tea tree oil microcapsule emulsion to obtain the tea tree oil antibacterial microcapsule. The preparation method is simple, the particle size is controllable, and the obtained microcapsule is regular in shape, high in yield and relatively high in packaging rate and medicine loading capacity. When the microcapsule is applied to a water-based formula, the stability is greatly improved.

The present invention belongs to the field of medical material science. The post-operation stick preventing carboxymethyl chitosan / carboxymethyl cellulose film is prepared through the process including compounding water solution of carboxymethyl chitosan and carboxymethyl cellulose separately with pure water, filtering, forming film with mixed water solution of carboxymethyl chitosan and carboxymethyl cellulose, drying, crosslinking the film in water solution of Ca ion and / or Fe ion, or Ca ion and Al ions to prepare the post-operation stick preventing film. The film is biocompatible, biodegradable inside body, wide applicable, high in antisticking effect and favorable to post-operation restore, and the preparation process is simple.

The invention relates to the field of well drilling in petroleum industry, in particular to a drilling fluid additive composition application thereof and a water-based drilling fluid suitable for high-bearing-pressure plugging while drilling and application thereof. The composition contains a plugging agent, a nano blocking agent, a shear strength improving agent, a bionic wall fixing agent and a bionic shale inhibitor, wherein the plugging agent is a weak crosslinking copolymer, the content of a crosslinking structure in the weak crosslinking copolymer is 0.1-1% by weight, the nano blocking agent is modified silicon dioxide nano-particles, the shear strength improving agent is a dimer acid-organic amine copolymer, and the bionic wall fixing agent is carboxymethyl chitosan grafted with groups deviated from dopamine on main chains. The composition can make a water-based drilling fluid added with the composition as an additive produce an excellent plugging effect in the process of plugging while drilling through the matching effect of the plugging agent, the nano blocking agent, the shear strength improving agent, the bionic wall fixing agent and the bionic shale inhibitor.

The invention discloses 3D-printed hydrogel wound dressing with a long-acting antibacterial effect. Raw materials for nanosilver reduction include sodium alginate and silver nitrate; raw materials forhydrogel construction include polyvinyl alcohol, carboxymethyl chitosan / chitosan, sodium alginate and deionized water; calcium chloride is adopted as a raw material for hydrogel cross linking. A preparation process includes: (1) preparing nanosilver-sodium alginate solution; (2) preparing polyvinyl alcohol / carboxymethyl chitosan / sodium alginate solution; (3) preparing to-be-printed solution; (4)performing 3D printing of hydrogel on a nonwoven fabric; (5) subjecting a sample prepared in the step 4 to cross linking (freezing-unfreezing and soaking in calcium chloride) to obtain the sodium alginate antibacterial hydrogel wound dressing. The sodium alginate antibacterial hydrogel wound dressing meets requirements of ideal dressing.

The invention discloses a novel chitosan hemostatic sponge and a preparation method thereof. The preparation method comprises the following steps of: stirring 5-20 percent of water-soluble chitosan carboxylate or carboxymethyl chitosan and 0.1-5 percent of 407 or 188 poloxamer in water at a low speed to fully dissolving state; adding 0-10 percent of glycerol, stirring at a high speed, foaming for 30 minutes to one hour, and performing injection molding; rapidly refrigerating at the temperature 40 DEG C below zero; demolding; refrigerating and drying till the water content is below 3 percent; and cutting, sterilizing and packing to obtain the novel chitosan hemostatic sponge.

The invention relates to a method for producing a water-absorbing swellable carboxymethyl chitosan sponge and its application, which comprises: adding a little chitosan powder or chitosan powder into the carboxymethyl chitosan solution with a quantitation of glycerin as the elasticizer, making every 100 ml solution with carboxymethyl chitosan of 1-5 g, chitosan powder or chitosan powder of 0.5-2 g and glycer of 1-5 g, stirring to foam and adding the environment-friendly ion-cross linker to cross-linking completely, cooling and drying to get the production. In the invention, using water-soluble materials as raw materials to avoid contamination, and using non-aldehyde group ion-cross linker to avoid residual toxicity of aldehyde group.

The invention discloses carboxymethyl chitosan quaternary ammonium salt / PAMAM(Polyamidoamine) core-shell nanoparticles and a preparation method. The nanoparticles are chitosan derivatives which are formed in a way that amino-terminated polyamidoamine dendritic macromolecule is grafted with carboxymethyl chitosan quaternary ammonium salt, and the chitosan derivatives are self-aggregated to form core-shell nanoparticles in water solution. The preparation method comprises the following steps: performing quaterisation decoration to amino at a second position of chitosan by CTA (3-Chloro-2-hydroxypropyltrimethyl ammonium chloride); performing carboxymethyl decoration to hydroxy at a sixth position of chitosan quaternary ammonium salt to synthetize carboxymethyl chitosan quaternary ammonium salt; activating carboxyl of the carboxymethyl chitosan quaternary ammonium salt by using NHS(N-Hydroxysuccinimide) / EDC(carbodiimide) to link the amino-terminated polyamidoamine dendritic macromolecule to synthetize the dendritic chitosan derivatives. The preparation process condition is simple and mild, and the product is easy to purify; and the core-shell nanoparticles of the prepared dendritic chitosan derivatives have the advantages of excellent water-solubility and functionality and has the attractive application prospect in the fields of antibiosis, gene transfer and drug controlled release.

The invention relates to the technical field of litchi preservation, and particularly discloses a room-temperature litchi storage preservative, and a preparation method and an application of the preservative. The preservative mainly comprises carboxymethyl-chitosan, nisin, natamycin, tea polyphenol, epsilon-polylysine, citric acid and phytic acid; litchi fruit is soaked in a preservation solution, and then aired, so that the litchi fruit can be stored at a room temperature; the quality and low level browning of the litchi fruit can be kept for a long time at the room temperature. Litchi treated by the preservative has the characteristics that the preservative is good in preservation effect, safe, environment-friendly, simple to operate and convenient to use; the preservative is extensive in source, low in cost, edible, and easy to degrade; no pesticide residue risk exists; short-term preservation during room-temperature storage and room-temperature logistics can be achieved; the preservative is a novel preservation material with a great development potential.