Silver sulfate silver ion slow-release compound, preparation method and use thereof

Abstract

The application discloses a silver sulfate silver ion slow-release compound, a preparation method and application thereof, and belongs to the field of chemical materials and slow-release technology. The preparation method of the silver sulfate silver ion slow-release compound selects modified porous materials as a slow-release carrier, precisely loads silver sulfate through impregnation or co-precipitation, constructs a gradient density regulation layer by using a high molecular polymer, and can introduce an environmental response additive to dynamically adjust the silver ion release rate. The application solves the problems that the silver ion release of the existing silver sulfate solution is too fast, the concentration fluctuation is large, and the silver ion release cannot adapt to complex scene requirements, has the characteristics of strong release controllability, wide adaptation range and low cost, and is suitable for various fields such as medical antibiosis and water purification.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of chemical materials and slow-release technology, and particularly relates to a silver sulfate silver ion slow-release compound, a preparation method and an application thereof. BACKGROUND

[0002] In many fields, silver ions play an important role due to their unique chemical properties. For example, in the medical field, silver ions have antibacterial properties and can effectively inhibit the growth of various bacteria, helping to heal wounds and prevent infection. In the field of water purification, silver ions are widely used in drinking water disinfection, swimming pool water treatment and household water filter cartridges due to their high efficiency, broad-spectrum bactericidal ability and sustained disinfection effect, which can effectively inactivate bacteria and viruses in water and significantly improve the biological safety of the water. Silver sulfate is a common silver salt and is often used to prepare silver ion solutions. However, there are many problems with the release of silver ions in silver sulfate solutions. On the one hand, the release rate of silver ions is difficult to accurately control, and the initial release rate is too fast, resulting in rapid consumption of effective ingredients and the inability to maintain a stable effective concentration for a long time. On the other hand, traditional methods cannot flexibly adjust the release rate of silver ions according to actual needs, making it difficult to fully utilize the best performance of silver ions in different application scenarios. In the prior art, some methods add slow-release agents through simple physical mixing, but cannot accurately control the release of silver ions. Some methods use complex microcapsule technology, which is costly and complex, and is not suitable for large-scale application. Therefore, there is an urgent need for a silver sulfate silver ion slow-release compound and a preparation method thereof that can effectively maintain the slow release of silver ions in silver sulfate solutions, are accurately controllable, have low cost and are easy to implement on a large scale. SUMMARY

[0003] The purpose of the embodiments of the present application is to provide a preparation method of a silver sulfate silver ion slow-release compound, which aims to solve the problems of uncontrollable release rate of silver ions in existing silver sulfate solutions, poor environmental adaptability and insufficient carrier compatibility.

[0004] The embodiments of the present application are implemented as follows: a preparation method of a silver sulfate silver ion slow-release compound, comprising the following steps:

[0005] Selecting a porous material as a carrier material and pretreating the carrier material;

[0006] Loading silver sulfate onto the pretreated carrier material by using an impregnation method or a co-precipitation method;

[0007] Constructing a gradient density polymer as a control layer on the surface of the silver sulfate loaded carrier material;

[0008] According to the application scenario, introducing an environmental responsiveness additive on the surface of the control layer to adapt to the environment, and forming a final silver sulfate silver ion slow-release compound.

[0009] Further, the porous material is one or more of silica, hydroxyapatite, or chitosan microspheres; or, the porous material is one or more of silica, hydroxyapatite, or chitosan microspheres with a hierarchical pore structure.

[0010] Furthermore, the pretreatment of the carrier material is as follows: the carrier material is soaked in an acid or alkali solution, then rinsed with deionized water until neutral, and then dried.

[0011] Furthermore, the operating conditions for the impregnation method are as follows: silver sulfate solution concentration 0.1-1 mol / L, carrier material to solution mass-volume ratio 1:5-1:20, constant temperature shaking at 25-40℃ for 6-16 hours, shaking rate 150-300 r / min;

[0012] The operating conditions for the coprecipitation method are as follows: silver nitrate solution and ammonium sulfate solution are mixed at a molar ratio of silver ions to sulfate ions of 1:1-1:1.2, the pretreated carrier material is added, the pH is adjusted to 4-6, and the mixture is stirred at 30-50℃ for 2-4 hours.

[0013] Furthermore, the construction of a polymer with a gradient density as a control layer on the surface of the silver sulfate-loaded carrier material is achieved through multilayer coating or in-situ polymerization; the specific polymer is one or more of polyethylene glycol, polyvinyl alcohol, polylactic acid, or polyacrylic acid.

[0014] Furthermore, a gradient-density polymer was constructed as a control layer by multilayer coating: a carrier material loaded with silver sulfate was sequentially immersed in a polymer solution with progressively increasing concentration, and each layer was dried between layers to construct a gradient-density control layer.

[0015] The concentration of the polymer increases by 3%-10% with each layer; the number of layers in the multilayer coating is 2-5, and each layer is dried at 60-80℃ for 1-2 hours after coating;

[0016] A gradient-density polymer was constructed as a control layer by in-situ polymerization: by successively increasing the monomer concentration or changing the polymerization conditions, multiple rounds of polymerization were carried out on a support loaded with silver sulfate, so that the monomers directly reacted inside and on the surface of the support material to generate polymers. Each round of polymerization was carried out on the polymer layer formed in the previous round, thus constructing a gradient structure with density from low to high.

[0017] The monomer concentration increases by 3%-10% in each round; the initiator dosage is 0.5%-2% of the monomer mass; the polymerization conditions are changed by altering the initiator concentration, polymerization temperature, or polymerization time.

[0018] Furthermore, the environmentally responsive additive is one or more of the following: pH-responsive carboxymethyl chitosan, temperature-responsive poly(N-isopropylacrylamide), or ion-responsive sodium alginate.

[0019] Furthermore, the environmental responsiveness adaptation to form the final silver sulfate silver ion sustained-release complex involves immersing the carrier material in a 0.5%-5% environmental responsive additive solution for 1-3 hours, followed by freeze-drying to form a composite regulatory structure.

[0020] Another objective of this invention is to provide a silver sulfate silver ion sustained-release complex, which is prepared according to the preparation method of the silver sulfate silver ion sustained-release complex described in any one of the above embodiments.

[0021] Another objective of this invention is to provide the use of a silver sulfate silver ion sustained-release complex in the preparation of medical wound antibacterial dressings or in the preparation of water purification materials, wherein the silver sulfate silver ion sustained-release complex is prepared according to any of the above-described methods for preparing the silver sulfate silver ion sustained-release complex.

[0022] Beneficial effects of the present invention

[0023] This invention discloses a silver sulfate-silver ion sustained-release complex, its preparation method, and its applications, belonging to the field of chemical materials and sustained-release technology. The preparation method of the silver sulfate-silver ion sustained-release complex of this invention uses a modified porous material as a sustained-release carrier, precisely loading silver sulfate through impregnation or co-precipitation methods, constructing a gradient density regulating layer using polymers, and dynamically adjusting the silver ion release rate by introducing environmentally responsive additives. This invention solves the problems of excessively rapid silver ion release, large concentration fluctuations, and inability to adapt to complex scenarios in existing silver sulfate solutions. It features strong release controllability, wide applicability, and low cost, making it suitable for various fields such as medical antibacterial and water purification. Attached Figure Description

[0024] Figure 1 This is a flowchart of a preferred embodiment of the preparation method of a silver sulfate silver ion sustained-release complex. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. For ease of explanation, only the parts related to the embodiments of this invention are shown. It should be understood that the specific embodiments described herein are merely for explaining this invention and are not intended to limit this invention.

[0026] This invention discloses a silver sulfate-silver ion sustained-release complex, its preparation method, and its applications, belonging to the field of chemical materials and sustained-release technology. The preparation method of the silver sulfate-silver ion sustained-release complex of this invention uses a modified porous material as a sustained-release carrier, precisely loading silver sulfate through impregnation or co-precipitation methods, constructing a gradient density regulating layer using polymers, and dynamically adjusting the silver ion release rate by introducing environmentally responsive additives. This invention solves the problems of excessively rapid silver ion release, large concentration fluctuations, and inability to adapt to complex scenarios in existing silver sulfate solutions. It features strong release controllability, wide applicability, and low cost, making it suitable for various fields such as medical antibacterial applications, environmental catalysis, and water purification.

[0027] Figure 1 This is a flowchart illustrating a preferred embodiment of the preparation method of a silver sulfate silver ion sustained-release complex according to the present invention; the present invention provides a method for preparing a silver sulfate silver ion sustained-release complex, comprising the following steps:

[0028] S101, Select porous materials as carrier materials and pretreat the carrier materials;

[0029] The porous material is one or more of silica, hydroxyapatite, or chitosan microspheres.

[0030] To suit high-end scenarios requiring long-term, stable, high-load, and intelligent response, in another embodiment of the present invention, the porous material is selected as a porous material with a hierarchical pore structure, wherein the hierarchical pore structure is a hierarchical pore structure with the synergistic effect of macropores and mesopores; more specifically, the porous material is one or more of silica, hydroxyapatite, or chitosan microspheres with a hierarchical pore structure.

[0031] In this embodiment of the invention, the preparation methods of silica, hydroxyapatite, and chitosan microspheres with hierarchical porosity can employ industry-standard techniques, which will not be elaborated here. In this embodiment, only porous materials with hierarchical porosity are selected as carrier materials; no porous materials with hierarchical porosity are prepared.

[0032] In this embodiment of the invention, the pretreatment of the carrier material involves soaking the carrier material in an acid or alkali solution, rinsing it with deionized water until neutral, and then drying it. Acid-alkali treatment adjusts the surface charge and pore size of the carrier material to optimize its loading performance on silver sulfate.

[0033] For example, in one embodiment of the present invention, the pretreatment of the carrier material is as follows: chitosan microspheres with hierarchical porosity are immersed in a silane coupling agent solution with a mass fraction of 5%-15% for 2-6 hours, rinsed with deionized water, and dried at 80-120°C for 3-5 hours.

[0034] For example, in another embodiment of the present invention, the pretreatment of the carrier material is as follows: silicon dioxide with a hierarchical porosity structure is soaked in dilute hydrochloric acid solution for 2-4 hours, then rinsed with deionized water until neutral, and then dried at 100-120°C for 4-6 hours to fully expose the silanol groups on its surface and increase the binding sites with silver sulfate.

[0035] S102, silver sulfate is loaded onto the pretreated carrier material using an impregnation method or a co-precipitation method;

[0036] The operating conditions for the impregnation method are as follows: silver sulfate solution concentration 0.1-1 mol / L, carrier material to solution mass-volume ratio 1:5-1:20, constant temperature oscillation at 25-40℃ for 6-16 hours, oscillation rate 150-300 r / min, so that silver sulfate can fully enter the pores of the carrier material.

[0037] The operating conditions for the co-precipitation method are as follows: silver nitrate solution and ammonium sulfate solution are mixed at a molar ratio of silver ions to sulfate ions of 1:1-1:1.2. After adding the pretreated carrier material, the pH is adjusted to 4-6, and the mixture is stirred at 30-50℃ for 2-4 hours to allow silver sulfate to precipitate on the surface and in the pores of the carrier material.

[0038] S103, a polymer with gradient density is constructed as a control layer on the surface of a carrier material loaded with silver sulfate;

[0039] The construction of a gradient-density polymer as a control layer on the surface of the silver sulfate-loaded carrier material is achieved through multilayer coating or in-situ polymerization; the specific polymer is one or more of polyethylene glycol, polyvinyl alcohol, polylactic acid, or polyacrylic acid.

[0040] A gradient-density polymer layer was constructed by multilayer coating: a carrier material loaded with silver sulfate was sequentially immersed in a polymer solution with progressively increasing concentration, and each layer was dried between layers to construct a gradient-density control layer.

[0041] In this embodiment of the invention, the concentration of the polymer increases by 3%-10% with each layer; the number of layers in the multilayer coating is 2-5, and each layer is dried at 60-80°C for 1-2 hours after coating;

[0042] A gradient-density polymer is constructed as a control layer through in-situ polymerization: by successively increasing the monomer concentration or changing the polymerization conditions, multiple rounds of polymerization are carried out on a support loaded with silver sulfate, so that the monomers directly undergo polymerization reactions inside and on the surface of the support material to generate polymers. Each round of polymerization is carried out on the polymer layer formed in the previous round, thereby constructing a gradient structure with density from low to high.

[0043] In this embodiment of the invention, the monomer concentration increases by 3%-10% in each round; the initiator dosage is 0.5%-2% of the monomer mass; and the polymerization conditions are changed by altering the initiator concentration, polymerization temperature, or polymerization time.

[0044] In this embodiment of the invention, the in-situ polymerization method can make the polymer chains inside the carrier material relatively sparse, while the polymer chains outside are more dense and cross-linked. This gradient structure increases the diffusion resistance of silver ions layer by layer, thus achieving precise slow-release control.

[0045] For example, in a preferred embodiment of the present invention (Example 1), a three-layer coating is performed using a polyethylene glycol (PEG) solution:

[0046] First layer: 5% polyethylene glycol (PEG) solution, forming a porous and loose film;

[0047] The second layer consists of a 10% polyethylene glycol (PEG) solution, forming a relatively dense intermediate layer.

[0048] The third layer: a 15% concentration of polyethylene glycol (PEG) solution, forming a very dense outer layer;

[0049] In this way, the density and thickness of the polymer network increase gradually from the inside out, forming a gradient.

[0050] For example, in another embodiment of the present invention, the specific method for constructing a gradient density regulating layer using acrylic monomers through in-situ polymerization is as follows:

[0051] Step 1: Vector preparation and pretreatment:

[0052] The carrier material (such as aminated silica) that has been loaded with silver sulfate is vacuum dried to remove internal moisture and ensure that the monomer solution can fully penetrate it.

[0053] The carrier material is dispersed in an inert organic solvent (such as toluene or ethanol), and nitrogen gas is introduced to remove oxygen (oxygen inhibits free radical polymerization).

[0054] Step 2: First round of in-situ polymerization (forming a low-density inner layer):

[0055] Preparation of the first reaction solution: Add the first portion of acrylic acid monomer to the above system, making its concentration in the system 3% (v / v). At the same time, add an initiator (such as azobisisobutyronitrile, AIBN) accounting for 1.0% of the mass of this monomer.

[0056] Initiating polymerization: Slowly heat the system to 65-70℃ and maintain this temperature with stirring for 2 hours. During this time, the acrylic monomers polymerize inside and on the surface of the carrier pores, forming the first layer of polyacrylic acid film with a lower molecular weight and a more porous structure.

[0057] Washing and initial stabilization: After the reaction is complete, the mixture is centrifuged, rapidly washed with the inert organic solvent to remove unreacted monomers and homopolymers, and then briefly dried at low temperature (e.g., 40°C) to stabilize the structure.

[0058] Step 3: Second round of in-situ polymerization (forming a medium-density middle layer):

[0059] Change the reaction medium and add a second round of monomers: Redisperse the material from the first round of polymerization in a fresh, inert organic solvent (such as toluene or ethanol). Add a second portion of acrylic monomer, increasing its concentration to 6% (v / v), and add the appropriate amount of initiator;

[0060] Continue polymerization: A second round of polymerization is carried out under the same reaction conditions;

[0061] The newly added acrylic monomers not only polymerize in the blank areas on the carrier surface, but also continue to grow and graft onto the existing first layer of polyacrylic acid (PAA), forming a thicker, more cross-linked second polymer network. Due to the higher monomer concentration, the density of this layer increases significantly.

[0062] Step 4: Third round of in-situ polymerization (forming a high-density outer layer):

[0063] Add a third round of high-concentration monomers: Separate the material again and disperse it in a fresh inert organic solvent (such as toluene or ethanol), wherein the concentration of acrylic monomers is further increased to 9% (v / v), and the corresponding amount of initiator is added;

[0064] Final polymerization: The final polymerization is completed under the same conditions. At this point, a high molecular weight, highly crosslinked, and structurally dense polyacrylic acid "sealing layer" is formed on the outermost layer.

[0065] Step 5: Post-processing and functionalization:

[0066] Thorough cleaning and drying: After polymerization, the material is repeatedly cleaned with solvent to thoroughly remove all unreacted monomers and impurities;

[0067] pH adjustment and activation: The obtained composite material is immersed in a dilute alkaline solution (such as NaOH) to convert the carboxyl groups (-COOH) on the PAA chain into carboxylate groups (-COO⁻).

[0068] This step causes the polymer chains to extend due to electrostatic repulsion and fully exposes their ion exchange sites, preparing for the subsequent controlled release of silver ions.

[0069] S104, depending on the application scenario, introduces environmentally responsive additives on the surface of the control layer to form the final silver sulfate silver ion slow-release complex.

[0070] The environmentally responsive additive is one or more of the following: pH-responsive carboxymethyl chitosan, temperature-responsive poly(N-isopropylacrylamide), or ion-responsive sodium alginate.

[0071] The environmental responsiveness adaptation is carried out by immersing the carrier material in a 0.5%-5% environmental responsive additive solution for 1-3 hours, followed by freeze-drying to form a silver sulfate silver ion slow-release complex.

[0072] In specific implementations, when the ambient pH or temperature changes, the structure of the environmentally responsive additive alters, thereby affecting the permeability of the control layer and achieving dynamic adjustment of the silver ion release rate. For example, in wound healing applications, since the pH at the wound site is usually acidic, the introduced pH-responsive carboxymethyl chitosan is protonated in an acidic environment, increasing the porosity of the control layer and accelerating the release of silver ions to enhance the antibacterial effect.

[0073] For example, in preferred embodiment 1 of the present invention, a method for preparing a silver sulfate silver ion sustained-release complex is as follows:

[0074] 1. Selection and pretreatment of carrier materials:

[0075] Selected material: Macroporous-mesoporous hierarchical silica, a special type prepared by a dual-template method. Its structure simultaneously possesses interconnected macropores (50-200 nm) and ordered mesopores (approximately 8 nm, >600 m² / g);

[0076] The function of this hierarchical structure is that macropores ensure low mass transfer resistance during loading and release, while mesopores provide high loading capacity and primary sustained-release effect. Together, they lay the physical foundation for long-lasting sustained release.

[0077] Preprocessing steps:

[0078] Acid washing and activation: Take 5.0 g of the above-described hierarchical silica and place it in 250 mL of 0.1 mol / L dilute hydrochloric acid solution. Shake and soak at room temperature for 3 hours. This step aims to clean the surface, remove impurities, and fully expose the silanol groups (-Si-OH) on the surface.

[0079] Rinsing and drying: Rinse the material repeatedly with deionized water until the filtrate is neutral, and then dry it in an oven at 110°C for 4 hours to obtain activated silica carrier material;

[0080] Surface amination: The activated silica was immersed in 100 mL of a 10% (w / w) ethanol solution of (3-aminopropyl)triethoxysilane (APTES) and shaken at room temperature for 4 hours to allow APTES to be fully grafted onto the support surface. After the reaction, the surface was repeatedly rinsed with deionized water until neutral to remove the physically adsorbed coupling agent.

[0081] Finally, the carrier material was dried in an oven at 100°C for 4 hours to obtain a modified carrier with amino functional groups (-NH2) on its surface. The introduction of amino groups provides more sites for subsequent electrostatic binding with silver sulfate.

[0082] 2. Silver sulfate loading:

[0083] Loading method: Impregnation method is adopted, and the specific operation is as follows:

[0084] Prepare 100 mL of a 0.5 mol / L silver sulfate aqueous solution. Add 5.0 g of the pretreated aminated hierarchical silica to the silver sulfate solution (carrier to solution mass-volume ratio of 1:20). Place the mixture in a constant temperature shaker and shake at 200 r / min for 10 hours at 30 °C to ensure that the silver sulfate fully diffuses and adsorbs into the hierarchical channels.

[0085] After loading, the solid product was obtained by centrifugation and washed 2-3 times with a small amount of deionized water to remove surface salts. The washed material was then vacuum dried at 60°C for 2 hours to obtain the "silver sulfate-hierarchical silica" composite.

[0086] 3. Constructing a gradient density polymer control layer:

[0087] Method: A multilayer coating method was used to construct a gradient density. The polymer used was polyethylene glycol (PEG-4000). The specific operation was as follows:

[0088] Prepare three PEG aqueous solutions with increasing concentrations:

[0089] First layer solution: 5% (w / w) polyethylene glycol (PEG) solution;

[0090] Second layer solution: 10% (w / w) polyethylene glycol (PEG) solution (concentration increases by 5%).

[0091] The third layer solution: a 15% (by mass) polyethylene glycol (PEG) solution (concentration then increased by 5%).

[0092] The "silver sulfate-hierarchical silica" complex was divided into three equal parts;

[0093] First coating: Immerse one portion of the composite in a 5% PEG solution for 30 minutes with slow stirring. After removal, dry at 70°C for 1.5 hours;

[0094] Second coating: Take out the material after the first coating, immerse it in a 10% PEG solution for 30 minutes, and then dry it at 70°C for 1.5 hours.

[0095] Third coating: Repeat the above operation, using a 15% PEG solution for coating and drying;

[0096] Finally, the three carrier materials, each with a three-layer gradient coating, were mixed to obtain a "PEG gradient-coated silver sulfate-hierarchical silica" composite. This gradient density structure means that the density of the polymer network gradually increases from the inside out, thereby achieving stepwise precise control over the diffusion rate of silver ions.

[0097] 4. Environmental responsiveness adaptation:

[0098] Application scenarios: Medical wound antibacterial dressings; The wound environment is usually weakly acidic (pH value decreases) during infection. Therefore, pH-responsive materials are introduced to accelerate the release of silver ions during infection (low pH) and stabilize their release during the healing period (neutral pH).

[0099] Responsive additive: Carboxymethyl chitosan (CMCS), which undergoes carboxylation under acidic conditions, resulting in molecular chain contraction, increased pore size, and accelerated release.

[0100] Specific procedures: Prepare a 2% (w / w) aqueous solution of carboxymethyl chitosan. Immerse the "PEG gradient-coated silver sulfate-hierarchical silica" composite in this solution and gently agitate for 2 hours. Remove the material, rapidly freeze it in liquid nitrogen, and then freeze-dry it for 24 hours to form the final environmentally responsive silver sulfate ion slow-release composite.

[0101] Performance verification:

[0102] Test method: The prepared silver sulfate silver ion sustained-release complex was placed in phosphate buffered solution (PBS) simulating wound exudate, and the mixture was shaken at a constant temperature of 37°C. Samples were taken periodically and the concentration of silver ions was detected by atomic absorption spectrometry.

[0103] Verification results:

[0104] Release period: Silver ion release can last for more than 21 days, fully covering the high-risk period for wound infection;

[0105] Release stability: The daily silver ion release fluctuates by ≤12% throughout the entire release cycle, demonstrating excellent stability and effectively avoiding the initial "sudden release" and the later "cliff-like" drop.

[0106] Environmental responsiveness: When the ambient pH drops from 7.4 (normal) to 6.0 (infection), the daily release rate of silver ions can increase by about 40%, demonstrating its excellent intelligent responsive bactericidal ability.

[0107] For example, in a preferred embodiment (Example 2) of the present invention, a method for preparing a silver sulfate silver ion sustained-release complex is as follows:

[0108] 1. Selection and pretreatment of carrier materials:

[0109] Weigh 10g of mesoporous silica (particle size 50-100μm, specific surface area 800m² / g), place it in a 500mL beaker, add 200mL of ethanol solution of 10% silane coupling agent (γ-aminopropyltriethoxysilane), seal and soak at room temperature for 4 hours, stirring once every 30 minutes during the soaking period; after soaking, rinse the mesoporous silica repeatedly with deionized water until the pH of the rinsing solution is neutral (pH=7.0), filter and collect the solid; place the collected mesoporous silica in a vacuum drying oven and dry at 100℃ for 4 hours, cool to room temperature and use for later use, and designate it as "modified mesoporous silica carrier".

[0110] 2. Directional loading of silver sulfate:

[0111] To prepare a 0.5 mol / L silver sulfate solution: Weigh 24.9 g of silver sulfate, add 200 mL of deionized water, stir in a 30 °C water bath until completely dissolved, cool and then bring the volume to 200 mL.

[0112] Add 10g of "modified mesoporous silica support" to a 250mL conical flask, and then add 100mL of the above 0.5mol / L silver sulfate solution (the mass-volume ratio of support to solution is 1:10, g:mL).

[0113] Place the conical flask in a constant temperature shaker, set the temperature to 30℃ and the shaking rate to 200r / min, and shake for 12 hours.

[0114] After oscillation, the solid was collected by filtration, and the unloaded silver sulfate on the surface was quickly rinsed with a small amount of deionized water. Then it was dried in a vacuum drying oven at 60°C for 2 hours and labeled as "silver sulfate-carrier complex".

[0115] 3. Construction of the gradient control layer:

[0116] Prepare gradient concentration polyethylene glycol solutions: Prepare 100 mL each of 5%, 10%, and 15% (mass fraction) polyethylene glycol aqueous solutions, and stir until completely dissolved;

[0117] The silver sulfate-carrier complex was evenly spread in a petri dish (approximately 2 mm thick), and a 5% polyethylene glycol solution was evenly sprayed on using a sprayer at a rate of 5 mL / g of the complex. After spraying, the mixture was placed in a 70°C forced-air drying oven and dried for 1.5 hours.

[0118] After drying, repeat the above spraying operation: spray 10% polyethylene glycol solution (spraying amount 5mL / g composite, dry at 70℃ for 1.5 hours) and 15% polyethylene glycol solution (spraying amount 5mL / g composite, dry at 70℃ for 1.5 hours) in sequence to form 3 gradient control layers, which are referred to as "gradient control type composite".

[0119] 4. Environmental responsiveness adaptation:

[0120] Application scenario: Water purification;

[0121] Responsive additive: Carboxymethyl chitosan;

[0122] Specific procedures: Prepare a 2% (mass fraction) carboxymethyl chitosan aqueous solution: Weigh 2g of carboxymethyl chitosan, add 100mL of deionized water, stir in a 40℃ water bath until completely dissolved, and cool to room temperature; add the "gradient-regulated complex" to the above carboxymethyl chitosan solution, soak at room temperature for 2 hours, stirring gently once every 20 minutes during the soaking period; after soaking, filter and collect the solid, transfer it to a freeze dryer, and freeze dry at -50℃ and a vacuum of 10Pa for 8 hours to obtain the final product "silver sulfate silver ion sustained-release complex".

[0123] Performance verification:

[0124] Test method: Weigh 1g of silver sulfate silver ion sustained-release complex and place it in 500mL of deionized water (simulating water environment). Static soaking at 25℃, replace all soaking solution once a day, and use inductively coupled plasma optical emission spectrometry (ICP-OES) to determine the concentration of silver ions in the soaking solution daily and calculate the daily release amount.

[0125] Test results: Silver ion release cycle: 21 days (the release is considered to have ended when the silver ion release concentration drops below 0.1 mg / L on the 21st day).

[0126] Daily release: 1.2 mg / g on day 1, 1.1 mg / g on day 7, 1.0 mg / g on day 14, and 0.1 mg / g on day 21. The daily release fluctuation range is ≤12%.

[0127] A preferred embodiment of the present invention also provides a silver sulfate silver ion sustained-release complex, which is prepared according to the preparation method of the silver sulfate silver ion sustained-release complex in any of the above embodiments.

[0128] A preferred embodiment of the present invention also provides the use of a silver sulfate silver ion sustained-release complex in the preparation of antibacterial dressings for medical wounds; the silver sulfate silver ion sustained-release complex is prepared according to the preparation method of the silver sulfate silver ion sustained-release complex in any of the above embodiments.

[0129] For example, the silver sulfate silver ion sustained-release complex prepared in Example 1 of the present invention can be used in the field of medical wound antibacterial dressings;

[0130] Performance verification:

[0131] Test method: The prepared silver sulfate silver ion sustained-release complex was placed in phosphate buffered solution (PBS) simulating wound exudate, and the mixture was shaken at a constant temperature of 37°C. Samples were taken periodically and the concentration of silver ions was detected by atomic absorption spectrometry.

[0132] Verification results: Release cycle: Silver ion release can last for more than 21 days, fully covering the high-risk period for wound infection.

[0133] Release stability: The daily silver ion release fluctuates by ≤12% throughout the entire release cycle, demonstrating excellent stability and effectively avoiding the initial "sudden release" and the later "cliff-like" drop.

[0134] Environmental responsiveness: When the ambient pH drops from 7.4 (normal) to 6.0 (infection), the daily release rate of silver ions can increase by about 40%, demonstrating its excellent intelligent responsive bactericidal ability.

[0135] A preferred embodiment of the present invention also provides the use of a silver sulfate ion slow-release complex in the preparation of water purification materials. The silver sulfate ion slow-release complex is prepared according to the preparation method of the silver sulfate ion slow-release complex in any of the above embodiments.

[0136] For example, the silver sulfate silver ion slow-release complex prepared in Example 2 of the present invention can be used in the field of environmental water purification;

[0137] Performance verification:

[0138] Test method: Weigh 1g of silver sulfate silver ion sustained-release complex and place it in 500mL of deionized water (simulating water environment). Static soaking at 25℃, replace all soaking solution once a day, and use inductively coupled plasma optical emission spectrometry (ICP-OES) to determine the concentration of silver ions in the soaking solution daily and calculate the daily release amount.

[0139] Test results: Silver ion release cycle: 21 days (the release is considered to have ended when the silver ion release concentration drops below 0.1 mg / L on the 21st day).

[0140] Daily release: 1.2 mg / g on day 1, 1.1 mg / g on day 7, 1.0 mg / g on day 14, and 0.1 mg / g on day 21. The daily release fluctuation range is ≤12%.

[0141] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a silver sulfate silver ion sustained-release complex, characterized in that, Includes the following steps: Porous materials were selected as carrier materials, and the carrier materials were pretreated. Silver sulfate was loaded onto the pretreated carrier material using either impregnation or co-precipitation methods. A polymer with gradient density was constructed as a control layer on the surface of a silver sulfate-loaded carrier material; Depending on the application scenario, environmentally responsive additives are introduced onto the surface of the control layer to adapt to environmental responsiveness and form the final silver sulfate silver ion slow-release complex. The porous material is one or more of silica, hydroxyapatite, or chitosan microspheres; or, the porous material is one or more of silica, hydroxyapatite, or chitosan microspheres with a hierarchical pore structure. The pretreatment of the carrier material is as follows: soak the carrier material in an acid or alkali solution, then rinse it with deionized water until neutral, and then dry it. The operating conditions for the impregnation method are as follows: silver sulfate solution concentration 0.1-1 mol / L, carrier material to solution mass-volume ratio 1:5-1:20, constant temperature shaking at 25-40℃ for 6-16 hours, shaking rate 150-300 r / min; The operating conditions for the coprecipitation method are as follows: silver nitrate solution and ammonium sulfate solution are mixed at a silver ion to sulfate ion molar ratio of 1:1 to 1:1.2, the pretreated carrier material is added, the pH is adjusted to 4-6, and the mixture is stirred at 30-50℃ for 2-4 hours. The construction of a gradient-density polymer as a control layer on the surface of the silver sulfate-loaded carrier material is achieved through multilayer coating or in-situ polymerization; the polymer is one or more of polyethylene glycol, polyvinyl alcohol, polylactic acid, or polyacrylic acid. The process of constructing a gradient density polymer as a control layer by multilayer coating involves immersing a carrier material loaded with silver sulfate sequentially in a polymer solution with progressively increasing concentration, and drying between each layer to construct a gradient density control layer. The concentration of the polymer increases by 3%-10% with each layer; the number of layers in the multilayer coating is 2-5, and each layer is dried at 60-80℃ for 1-2 hours after coating; The process of constructing a gradient-density polymer as a control layer by in-situ polymerization involves: gradually increasing the monomer concentration or changing the polymerization conditions, and carrying out multiple rounds of polymerization on a support loaded with silver sulfate, so that the monomers directly undergo polymerization reactions inside and on the surface of the support material to generate polymers. Each round of polymerization is carried out on the polymer layer formed in the previous round, thereby constructing a gradient structure with density from low to high. The monomer concentration increases by 3%-10% in each round; the initiator dosage is 0.5%-2% of the monomer mass; the polymerization conditions are changed by altering the initiator concentration, polymerization temperature, or polymerization time.

2. The method for preparing the silver sulfate-silver ion sustained-release complex according to claim 1, characterized in that, The environmentally responsive additive is one or more of the following: pH-responsive carboxymethyl chitosan, temperature-responsive poly(N-isopropylacrylamide), or ion-responsive sodium alginate.

3. The method for preparing the silver sulfate silver ion sustained-release complex according to claim 1, characterized in that, The process of adapting the material to environmental responsiveness to form the final silver sulfate silver ion sustained-release complex involves immersing the carrier material in a 0.5%-5% solution of environmentally responsive additives for 1-3 hours, followed by freeze-drying to form a composite regulatory structure.

4. A silver sulfate silver ion sustained-release complex, prepared according to the method for preparing the silver sulfate silver ion sustained-release complex according to any one of claims 1-3.

5. The use of the silver sulfate silver ion sustained-release complex according to claim 4 in the preparation of medical wound antibacterial dressings or in the preparation of water purification materials.

Images