Silver alginate-containing fibres and dressings and methods of preparation

Abstract

This application discloses a silver alginate fiber, a dressing, and a preparation method. The preparation method of the silver alginate fiber includes: pretreating the alginate fiber by adding it to an alcohol-water reaction solution containing a silver source to pre-immobilize silver ions inside and on the surface of the fiber to obtain Ag. + / fiber, and keep it moist; keep the wet Ag + The fiber is irradiated to form nano-silver in situ inside and on the surface of the fiber, resulting in an Ag / fiber composite material. The Ag / fiber composite material is then washed and dried to obtain silver-containing alginate fibers. These silver-containing alginate fibers are then processed through nonwoven, woven, or knitted fabrics, slit, packaged, and terminally sterilized to obtain silver-containing alginate fiber dressings. This preparation method achieves uniform and stable immobilization of silver, controllable release behavior, long-lasting antibacterial effect, and stable product quality in the preparation of silver-containing alginate fibers and dressings.

Description

Technical Field

[0001] This application relates to the field of biomedical materials, and more specifically, to a silage-containing alginate fiber, a dressing, and a method for its preparation. Background Technology

[0002] In the field of high-end wound care, alginate fiber dressings have gradually become one of the important materials for wound repair due to their excellent "gelling" properties. After absorbing exudate, they form a hydrophilic gel, which not only creates an ideal moist healing environment for the wound but also avoids secondary damage during dressing changes. However, with the increasing complexity of bacterial biofilm infections in clinical practice and the need for long-lasting antibacterial capabilities in chronic, refractory wounds, the traditional alginate fiber dressing's single physical barrier and absorption functions are insufficient to meet the requirements of modern wound care.

[0003] To impart antibacterial properties to alginate fiber dressings, two main technological approaches are currently employed in industrial applications: post-processing with the addition of antibacterial agents and co-spinning with the original solution. While post-processing techniques (such as impregnation and spraying with silver halide solutions) are simple to operate, they have fundamental drawbacks. The silver ions loaded in this method primarily bind to the fiber matrix through physical adsorption, resulting in weak adhesion. Upon contact with wound exudate, silver ions are prone to burst release, which can lead to excessively high local silver concentrations in the initial stages of use, posing a potential risk of cytotoxicity. Furthermore, insufficient silver ion release concentrations in later stages may fail to maintain effective antibacterial levels, impacting treatment efficacy. In addition, this process is sensitive to the production environment and exhibits poor batch-to-batch stability, directly affecting the consistency and reliability of product performance.

[0004] While solution blending and spinning can improve the uniformity of silver distribution to some extent, it introduces new problems: silver compounds tend to agglomerate in the spinning solution, altering its rheological properties, leading to instability in the spinning process, difficulty in fiber formation, and affecting the fiber's mechanical properties. Furthermore, during wet spinning, when the silver-containing sodium alginate solution is injected into a coagulation bath containing calcium chloride, the silver ions in the solution react with chloride ions in the coagulation bath to form insoluble precipitates, resulting in silver loss. This further exacerbates a series of production process problems, such as spinneret blockage and uneven fiber structure. Additionally, this method often comes at the cost of sacrificing the inherent processing properties or gelation characteristics of alginate fibers.

[0005] Chinese patent CN 111118878 A discloses a silver ion alginate wound dressing and its preparation method. The method involves washing sodium alginate fibers four times: water washing, sodium chloride solution washing, ethanol washing, and amino silicone oil ethanol solution washing. Then, an antibacterial material is used to ultrasonically spray the nonwoven fabric, ensuring uniform distribution of the silver-containing antibacterial agent within the dressing and avoiding co-spinning with Ag. +While AgCl is lost, its high photosensitivity makes dressing products prone to photochromism during storage and use, affecting product quality stability.

[0006] Chinese patent CN 103170004 B discloses a method for preparing silver-containing fiber wound dressings. This method involves mixing silver nitrate solution with spinning solution to uniformly distribute silver within the fiber structure, thus preparing highly effective antibacterial fabrics and dressings for long-lasting antibacterial effects. As mentioned earlier, this technical approach inevitably faces the challenge of side reactions between silver ions and coagulation bath components during the wet spinning process. This can easily lead to problems such as precipitation and aggregation, decreased fiber mechanical properties, and spinneret blockage, affecting product performance.

[0007] Therefore, existing antibacterial fiber dressings suffer from the problem that silver elements are unstable in the alginate fibers, leading to uncontrollable release, potential toxicity in the early stages, and a decline in antibacterial performance in the later stages. Summary of the Invention

[0008] The main objective of this application is to provide a silver-containing alginate fiber, dressing, and preparation method to solve the technical problems of unstable silver element fixation and uncontrollable release in the existing technology, thereby achieving the technical effect of uniform and stable fixation of silver element and controllable release behavior.

[0009] To achieve the above objectives, the first aspect of this application provides a method for preparing alginate-containing fibers, comprising the following steps:

[0010] Alginate fibers were pretreated by adding them to an alcohol-water reaction solution containing a silver source to pre-immobilize silver ions inside and on the surface of the fibers to obtain Ag. + / fiber, and keep it moist; wet Ag + / Fibers are irradiated to form nano-silver in situ inside and on the surface of the fibers, resulting in Ag / fiber composite materials; The Ag / fiber composite material was washed and dried to obtain alginate-containing fibers.

[0011] In some embodiments of this disclosure, maintaining moisture includes: not applying moisture to the Ag after pretreatment. + The fibers are dehydrated or dried to allow the Ag to be removed from the liquid. + The fiber retains a portion of the alcohol-water reaction solution and is then encapsulated. Wherein, the Ag + The mass ratio of the fiber to the alcohol-water reaction solution it carries is 1:(0.5-8), preferably 1:(1-5).

[0012] In some embodiments of this disclosure, the silver-source-containing alcohol-water reaction solution comprises a silver compound, a complexing agent, and an aqueous alcohol-water solution; The silver compound is a soluble or slightly soluble silver compound selected from one or more of silver nitrate, silver sulfate, and silver hypochlorite. The concentration of the silver compound in the reaction solution is 0.1%-8%, preferably 0.2%-4%, by weight. The complexing agent is one or more of PVP K30, PVP K90, and EDTA, and its concentration in the reaction solution is 0.05%-2% by weight. The alcohol concentration in the aqueous alcohol solution is 5%-95%, preferably 20%-75%, and the alcohol is one or more of ethanol, isopropanol, and propylene glycol by weight, preferably ethanol.

[0013] In some embodiments of this disclosure, the irradiation treatment is performed using either cobalt-60 gamma ray irradiation or electron beam irradiation. The irradiation dose is 5 kGy-50 kGy, preferably 15 kGy-40 kGy.

[0014] In some embodiments of this disclosure, the mass ratio of the alginate fiber to the silver-sourced alcohol-water reaction solution is 1:(4-20); The pretreatment time is 3 min-480 min, preferably 5 min-120 min; The pretreatment temperature is 10 ℃-40 ℃.

[0015] In some embodiments of this disclosure, the alginate fiber is one or more of sodium alginate fiber and calcium alginate fiber, with a linear density of 1 dtex-6 dtex.

[0016] In some embodiments of this disclosure, the drying temperature is 25 ℃-55 ℃ and the drying time is 1 h-72 h.

[0017] In some embodiments of this disclosure, the elution is staged elution, and the number of elution cycles is 1-6. The eluent is an alcohol eluent, and the final alcohol eluent contains a surfactant; The alcohol eluent contains one or more of ethanol, isopropanol, and propylene glycol, with an alcohol concentration of 5%-98%, preferably 65%-95%, by weight. The surfactant is a nonionic surfactant, preferably a Tween series, a Span series, or a complex thereof.

[0018] A second aspect of this application provides a silver-containing alginate fiber comprising alginate fibers and in-situ loaded silver nanoparticles inside and on the surface of the alginate fibers.

[0019] A third aspect of this application provides a method for preparing a argylate fiber dressing, comprising the following steps: processing the argylate fiber prepared above into a fabric or nonwoven fabric through nonwoven, woven or knitted processes, and then slitting, packaging and sterilizing to obtain the argylate fiber dressing.

[0020] In a fourth aspect of this application, a silver alginate fiber dressing is provided, which is prepared by the above method.

[0021] In some embodiments of this disclosure, the silver content of the alginate-containing fiber dressing is 0.1%-8.0% (i.e., 1000ppm-80000ppm), preferably 1%-4% (i.e., 10000ppm-40000ppm), and the weight of the alginate-containing fiber dressing is 15 g / m². 2 -240 g / m 2 .

[0022] The technical solutions provided by the embodiments of this application may include the following beneficial effects: The method for preparing silver-containing alginate fibers provided in this application first involves pretreating the alginate fibers in an alcohol-water reaction solution containing a silver source to ensure that silver ions are present both on the fiber surface and inside through ion exchange and complexation pre-adsorption of silver ions. Then, the silver-loaded fibers are irradiated and reduced in a humid microenvironment. The irradiation energy generates strong reducing free radicals (such as hydrated electrons and H radicals) in the solution, which in turn remove the Ag pre-adsorbed on the fibers. + In situ restoration to Ag 0 This process allows silver ions to be uniformly reduced on and inside the fiber surface, and to aggregate and grow, ultimately forming firmly loaded silver nanoparticles. This results in the preparation of silver alginate fibers that are stable in their loading, controllable in their release, stable in their performance, highly absorbent, and efficient.

[0023] The preparation method of this application employs a synergistic technique combining "alcohol-water system ion exchange complexation" and "wet irradiation reduction". Through ion exchange and molecular complexation, silver ions (Ag) are... + Pre-fixed and uniformly distributed within and on the surface of alginate fibers to form a precursor; then, using irradiation as a green driving force, the generated strong reducing free radicals (such as hydrated electrons and H radicals) are used to ignite Ag. + In-situ restoration to Ag 0The alginate nanoparticles (AgNPs) are nucleated and grown. Due to spatial confinement and chemical anchoring effects, the in-situ reduced silver nanoparticles (AgNPs) are bound by the three-dimensional network structure of alginate, requiring them to overcome the spatial hindrance of the polymer chains to diffuse outwards, resulting in a low diffusion coefficient. Simultaneously, they coordinate with the fiber substrate, forming a stable "encapsulated" structure. Therefore, unlike traditional methods that only physically adsorb silver ions on the fiber surface or in shallow pores, this method embeds silver nanoparticles into the fiber network through in-situ reduction, achieving a three-dimensional, uniform, and robust loading within the alginate fiber, ensuring the stability of the Ag ions. + The reduction process is essentially complete, the product morphology is stable, and there are no chemical reducing agents remaining throughout the process. This fundamentally solves the problems of uneven silver distribution and easy shedding, significantly reduces the potential cytotoxicity caused by rapid silver release, easy shedding, and reducing agent residue, and improves the safety and effectiveness of the product.

[0024] The "impregnation-immobilization-wet irradiation" molecular complexation and reduction technology adopted in this application maximizes the stability and load-bearing strength of silver, has little impact on the performance of alginate fibers, and is simple, efficient, feasible, and suitable for industrial production.

[0025] Therefore, the preparation method of this application uses a controllable, green, and efficient process to stably and firmly load silver onto alginate fibers, giving them a highly efficient and long-lasting antibacterial effect.

[0026] In the preparation method of this application, alginate fiber, as a natural polyanionic electrolyte, has carboxyl groups (-COO) on its molecular chain. - These are natural metal ion chelating sites. Based on a chemical process of ion exchange, the inherent Na+ in the fiber is chelated... + or Ca² + With Ag in solution + A displacement reaction occurs, forming alginate—Ag + The complex. Preferably, an alcohol is used as the solvent, which has a low dielectric constant, reduces the hydration of silver ions, controls the exchange rate, and ensures the Ag... + Uniformly embedded in the fiber network. Preferably, at this stage, PVP is added, which can react with Ag via carbonyl groups. + Weak coordination occurs, serving as a "temporary stabilizer" and "transporter" for Ag. + The purpose is to prevent it from being reduced prematurely; preferably, at this stage, EDTA is added to complex trace amounts of active cations (such as Ca²⁺) present in the system. + ), to prevent Ag + Competing for exchange sites improves the selectivity of silver loading.

[0027] When irradiation reduction (such as gamma rays or electron beams) uses high-energy rays to pass through an alcohol-water solution, the rays interact with water molecules in the solvent, producing reducing particles H radicals (H·) and hydrated electrons (e·). - (aq), and oxidizing particles such as OH radicals (·OH), etc. Hydrated electrons (e - Ag(q) and H radicals (H·) have strong reducing power and can penetrate the interior of fibers, removing Ag previously fixed by ion exchange. + In-situ, deep, and uniform reduction to silver atoms (Ag) 0 They aggregate into silver microparticles, and the reaction is as follows: Ag + + e - aq → Ag 0 Ag + + H·+ H2O → Ag 0 +H3O + OH radicals (·OH) are strong oxidizing groups that can inhibit Ag. + Reduction of ions. Introducing an alcohol into the solvent acts as a free radical scavenger, removing oxidizing free radicals (·OH) and generating reducing organic free radicals. These reducing particles gradually reduce metal ions to metal atoms, which then aggregate into nuclei, forming silver microparticles. Taking ethanol as an example, the reaction is as follows: CH3CH2OH + ·OH → ·CH(CH3)OH + H2O Due to Ag + Through ion exchange, the reducing agent is uniformly distributed within the fiber's network structure. When the reducing agent generated by irradiation diffuses into the fiber's interior, the reduction reaction occurs in situ. Ag + It acts as a "seed" or "nucleation center," generating silver atoms (Ag). 0 Unstable, it will rapidly aggregate to form silver atom clusters, eventually forming silver nanoparticles. The generated silver nanoparticles will firmly attach to or embed in the fiber surface or interior, forming Ag / fiber composite materials. At the same time, the functional groups (such as -OH) on the fiber surface can, to a certain extent, encapsulate the newly formed silver nanoparticles, preventing them from growing excessively and agglomerating, thus playing a role in stabilizing the particles.

[0028] The preparation method of this application also includes preparing a high-performance silver-fiber composite material, and then processing it through processes such as washing, drying, non-woven or woven or knitted fabrication, slitting, encapsulation, and terminal sterilization to obtain a high-performance silver alginate fiber dressing.

[0029] The silver alginate fiber dressing prepared in this invention exhibits excellent comprehensive performance. Firstly, it solves the problems of traditional silver dressings, such as "short-acting and highly toxic" and unstable color, achieving controlled silver release for up to 168 hours (7 days). While ensuring long-lasting and potent antibacterial effects, it greatly reduces potential cytotoxicity caused by silver burst release or particle shedding. Secondly, this process retains the core functions of alginate fibers; their high absorbency and gelling properties remain unaffected. Upon contact with wound exudate, the dressing rapidly forms a physical barrier, optimizing the moist healing environment. Attached Figure Description

[0030] The accompanying drawings, which form part of this application, are used to provide a further understanding of the application and to make other features, objects, and advantages of the application more apparent. The illustrative embodiments and descriptions of this application are used to explain the application and do not constitute an undue limitation of the application. In the drawings: Figure 1 Infrared characteristic spectra of alginate-containing fibers and their raw material fibers provided in Examples 1 and 2 of this application. Detailed Implementation

[0031] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0032] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0033] All concentrations mentioned in the following examples and comparative examples are by weight.

[0034] Example 1: Preparation of silver-containing sodium alginate fiber dressing using silver nitrate as the silver source 10 kg of sodium alginate fiber (linear density 1.67 dtex) was added to 100 kg of an ethanol-water reaction solution containing a silver source (silver nitrate, concentration 0.5% in the reaction solution; PVP K30 complexing agent, concentration 0.5% in the reaction solution; ethanol concentration 30% in the ethanol-water solution), and soaked at 25 ℃ for 60 minutes to obtain Ag. + Remove the fiber and keep the liquid-to-fiber mass ratio at 1:2 (i.e., 10 kg of fiber and about 20 kg of liquid).

[0035] Light-proof encapsulation of wet Ag + / fibers were subjected to cobalt-60 gamma irradiation treatment at a dose of 15 kGy to obtain Ag / fiber composite materials.

[0036] The fibers were eluted twice with 95% ethanol solution, with the amount of eluent being 6 times the weight of the fibers (i.e., 60 kg each time). Tween 20 was added at a mass ratio of 0.1% of the eluent during the last elution. The fibers were then centrifuged after elution.

[0037] The washed fibers were dried at 40°C for 4 hours to obtain silver-containing sodium alginate fibers.

[0038] The dried silver-containing sodium alginate fibers were processed into a nonwoven fabric with a basis weight of 120 g / m² by carding and needle punching.

[0039] The nonwoven fabric was cut into 10 cm × 10 cm sheets, packaged in aluminum foil bags, and sterilized by cobalt-60 irradiation to obtain a cynomolgus fiber dressing.

[0040] Example 2: Preparation of Silver-Containing Calcium Alginate Fiber Dressing Using Silver Nitrate as the Silver Source 10 kg of calcium alginate fiber (linear density 1.67 dtex) was added to 100 kg of isopropanol-water reaction solution containing a silver source (silver nitrate, concentration 0.5% in the reaction solution; PVP K30 complexing agent, concentration 1.0% in the reaction solution; isopropanol concentration 30% in the isopropanol-water solution), and soaked at 25 ℃ for 5 minutes to obtain Ag. + Remove the fiber and keep the liquid-to-fiber mass ratio at 1:2 (i.e., 10 kg of fiber and about 20 kg of liquid).

[0041] Light-proof encapsulation of wet Ag + / fibers were subjected to cobalt-60 gamma irradiation treatment at a dose of 30 kGy to obtain Ag / fiber composite materials.

[0042] The fibers were eluted twice with 95% isopropanol solution, with the amount of eluent being 6 times the weight of the fibers (i.e., 60 kg each time). Tween 20 was added at a mass ratio of 0.1% of the eluent during the last elution. The fibers were then centrifuged after elution.

[0043] The washed fibers were dried at 40°C for 4 hours to obtain silver-containing calcium alginate fibers.

[0044] The dried silver-containing calcium alginate fibers are processed into a nonwoven fabric with a basis weight of 120 g / m² by carding and needle punching.

[0045] The nonwoven fabric was cut into 10 cm × 10 cm sheets, packaged in aluminum foil bags, and sterilized by cobalt-60 irradiation to obtain a cynomolgus fiber dressing.

[0046] Example 3: Preparation of a mixed fiber dressing containing alginate using silver nitrate as the silver source 10 kg of alginate fiber (sodium alginate fiber:calcium alginate fiber = 1:1, both with a linear density of 1.67 dtex) was added to 100 kg of an ethanol-water reaction solution containing a silver source (silver nitrate, concentration 1.0% in the reaction solution; PVP K30, concentration 0.5% in the reaction solution; ethanol-water solution concentration 30%), and the solution was soaked at 25 ℃ for 120 minutes to obtain Ag. + Remove the fiber and keep the liquid-to-fiber mass ratio at 1:2 (i.e., 10 kg of fiber and about 20 kg of liquid).

[0047] Light-proof encapsulation of wet Ag + / fibers were subjected to cobalt-60 gamma irradiation treatment at a dose of 45 kGy to obtain Ag / fiber composite materials.

[0048] The fibers were eluted twice with 95% ethanol solution, with the amount of eluent being 6 times the weight of the fibers (i.e., 60 kg each time). Tween 20 was added at a mass ratio of 0.1% of the eluent during the last elution. The fibers were then centrifuged after elution.

[0049] The washed fibers were dried at 40°C for 4 hours to obtain alginate-containing fibers.

[0050] The dried alginate-containing fibers are processed into a nonwoven fabric with a basis weight of 120 g / m² by carding and needle punching.

[0051] The nonwoven fabric was cut into 10 cm × 10 cm sheets, packaged in aluminum foil bags, and sterilized by cobalt-60 irradiation to obtain a cynomolgus fiber dressing.

[0052] Example 4: Preparation of a silver alginate-containing mixed fiber dressing using silver sulfate as the silver source 10 kg of alginate fiber (sodium alginate fiber:calcium alginate fiber = 1:1, both with a linear density of 1.67 dtex) was added to 100 kg of an ethanol solution containing a silver source (silver sulfate, concentration 0.5% in the reaction solution; PVPK30, concentration 0.5% in the reaction solution; ethanol-water solution concentration 30%), and the solution was soaked at 25 ℃ for 120 minutes to obtain Ag. + Remove the fiber and keep the liquid-to-fiber mass ratio at 1:2 (i.e., 10 kg of fiber and about 20 kg of liquid).

[0053] Light-proof encapsulation of wet Ag + / fibers were subjected to cobalt-60 gamma irradiation treatment at a dose of 45 kGy to obtain Ag / fiber composite materials.

[0054] The fibers were eluted twice with 95% ethanol solution, with the amount of eluent being 6 times the weight of the fibers (i.e., 60 kg each time). Tween 20 was added at a mass ratio of 0.1% of the eluent during the last elution. The fibers were then centrifuged after elution.

[0055] The washed fibers were dried at 40°C for 4 hours to obtain alginate-containing fibers.

[0056] The dried alginate-containing fibers are processed into a nonwoven fabric with a basis weight of 120 g / m² by carding and needle punching.

[0057] The nonwoven fabric was cut into 10 cm × 10 cm sheets, packaged in aluminum foil bags, and sterilized by cobalt-60 irradiation to obtain a cynomolgus fiber dressing.

[0058] Comparative Example 1: Preparation of Silver-Containing Sodium Alginate Fiber Dressings by Traditional Impregnation Method The difference between this comparative example and Example 1 is that after the silver source solution immersion treatment, it is not subjected to cobalt-60 γ-ray irradiation treatment, but is directly eluted and subsequently processed.

[0059] The specific steps are as follows: 10 kg of sodium alginate fiber (linear density 1.67 dtex) was added to 100 kg of an ethanol-water mixture containing a silver source (silver nitrate, concentration 0.5% in the reaction solution; PVP K30, concentration 0.5% in the reaction solution; ethanol-water mixture concentration 30%) and impregnated at 25 °C for 60 minutes to obtain Ag. + / Fiber, remove.

[0060] The fibers were eluted twice with 95% ethanol solution, with the amount of eluent being 6 times the weight of the fibers (i.e., 60 kg each time). Tween 20 was added at a mass ratio of 0.1% of the eluent during the last elution. The fibers were then centrifuged after elution.

[0061] The washed fibers were dried at 40°C for 4 hours to obtain silver-containing sodium alginate fibers.

[0062] The dried silver-containing sodium alginate fibers were processed into a nonwoven fabric with a basis weight of 120 g / m² by carding and needle punching.

[0063] The nonwoven fabric was cut into 10 cm × 10 cm sheets, packaged in aluminum foil bags, and sterilized by cobalt-60 irradiation to obtain a cynomolgus fiber dressing.

[0064] In this comparative example, silver was mainly in ionic form during preparation. It is extremely photosensitive and easily changes color during the preparation process, so it must be kept out of light throughout.

[0065] Comparative Example 2: Preparation of Silver-Containing Sodium Alginate Fiber Dressing by Reduction-Loading Method with Silver Source Solution The difference between this comparative example and Example 1 is that the silver source reaction solution is packaged in a light-proof manner, treated with cobalt-60 γ-ray irradiation, and then loaded with sodium alginate fiber. After loading, it is eluted and subsequently processed.

[0066] The specific steps are as follows: 100 kg of an ethanol-water reaction solution containing a silver source (silver nitrate, concentration 0.5% in the reaction solution; PVP K30 complexing agent, concentration 0.5% in the reaction solution; ethanol concentration 30% in the ethanol-water solution) was sealed in a light-proof container and irradiated with cobalt-60 gamma rays at a dose of 15 kGy to obtain a suspension containing elemental silver.

[0067] 10 kg of sodium alginate fiber (linear density 1.67 dtex) was added to the above-mentioned silver-containing suspension and soaked at 25 °C for 60 minutes to obtain Ag / fiber composite material, which was then removed.

[0068] The fibers were eluted twice with 95% ethanol solution, with the amount of eluent being 6 times the weight of the fibers (i.e., 60 kg each time). Tween 20 was added at a mass ratio of 0.1% of the eluent during the last elution. The fibers were then centrifuged after elution.

[0069] The washed fibers were dried at 40°C for 4 hours to obtain silver-containing sodium alginate fibers.

[0070] The dried silver-containing sodium alginate fibers were processed into a nonwoven fabric with a basis weight of 120 g / m² by carding and needle punching.

[0071] The nonwoven fabric was cut into 10 cm × 10 cm sheets, packaged in aluminum foil bags, and sterilized by cobalt-60 irradiation to obtain a cynomolgus fiber dressing.

[0072] Comparative Example 3: Preparation of silver-containing sodium alginate fiber dressings by irradiation under dry conditions. The difference between this comparative example and Example 1 is that after the silver source solution impregnation treatment, the fiber was taken out, dehydrated and dried, and then subjected to cobalt-60 γ-ray irradiation treatment, elution and subsequent treatment.

[0073] The specific steps are as follows: 10 kg of sodium alginate fiber (linear density 1.67 dtex) was added to 100 kg of an ethanol-water reaction solution containing a silver source (silver nitrate, concentration 0.5% in the reaction solution; PVP K30 complexing agent, concentration 0.5% in the reaction solution; ethanol concentration 30% in the ethanol-water solution), and soaked at 25 ℃ for 60 minutes to obtain Ag. + / Fiber, take it out, dehydrate it and place it in a drying room, dry it at 40℃ for 4 hours.

[0074] Light-shielded dry state Ag + / fibers are subjected to cobalt-60 gamma irradiation treatment with an irradiation dose of 15 kGy.

[0075] The fibers were eluted twice with 95% ethanol solution, with the amount of eluent being 6 times the weight of the fibers (i.e., 60 kg each time). Tween 20 was added at a mass ratio of 0.1% of the eluent during the last elution. The fibers were then centrifuged after elution.

[0076] The washed fibers were dried at 40°C for 4 hours to obtain silver-containing sodium alginate fibers.

[0077] The dried silver-containing sodium alginate fibers were processed into a nonwoven fabric with a basis weight of 120 g / m² by carding and needle punching.

[0078] The nonwoven fabric was cut into 10 cm × 10 cm sheets, packaged in aluminum foil bags, and sterilized by cobalt-60 irradiation to obtain a cynomolgus fiber dressing.

[0079] The following tests were conducted on the dressing performance indicators of the embodiments and comparative examples.

[0080] I. Infrared spectrum Infrared spectroscopy scans were performed on the sodium alginate fiber raw material and the silver-containing sodium alginate fiber prepared in Example 1, and on the calcium alginate fiber raw material and the silver-containing calcium alginate fiber prepared in Example 2. The comparative infrared spectra are shown below. Figure 1 As shown, the spectrum is at 3210 cm⁻¹ -1 A broad and strong absorption peak appears nearby, attributed to stretching vibrations of intermolecular and intramolecular OH bonds; at 1585 cm⁻¹ -1 and 1410 cm -1Two distinct characteristic absorption peaks appeared nearby, which were attributed to the antisymmetric and symmetric stretching vibrations of the carboxylate ion (—COO-) in alginate, respectively. These characteristic peaks have structural features consistent with alginate, and the characteristic peaks of the four material spectra are consistent, indicating that the main structure and functional groups of the guluronic acid and mannuronic acid units of the alginate-containing fiber prepared by this method have not been destroyed.

[0081] II. Silver content According to GB / T 14233.1-2022 standard, the silver content of the alginate fiber dressings prepared in the above examples and comparative examples was determined by wet digestion combined with atomic absorption spectrophotometry. 1g to 2g of sample was accurately weighed and cut into approximately 5mm × 5mm fragments, placed in an Erlenmeyer flask, and 30mL of nitric acid and 1.25mL of sulfuric acid were added. After shaking well, the mixture was allowed to stand overnight, then heated on a hot plate until the solution became clear. Water was added to evaporate the solution until white sulfuric acid fumes were emitted. After cooling, the contents were transferred to a 50mL volumetric flask and diluted to volume to obtain the test solution. A blank control solution was prepared using the same method. Using an atomic absorption spectrophotometer and the standard curve method, the absorbance of the series of standard solutions, test solutions, and blank control solutions was measured sequentially. The silver content in the sample was calculated based on the standard curve.

[0082] Table 1. Silver content test results

[0083] As shown in Table 1, Comparative Example 1 was unirradiated, and Comparative Example 3 had low dry irradiation reduction efficiency. In both, silver was mainly in ionic form, which easily dissolved in the eluent during elution, resulting in significant silver loss. Consequently, the silver content of the prepared silver-containing alginate fiber dressing was significantly lower than that of Examples 1-4. Comparative Example 2 was prepared using a method of silver source reduction followed by loading. During irradiation, silver ions were basically reduced, and elemental silver could not react with Na in the alginate fiber. + Ca 2+ Ion exchange cannot embed silver ions into the fiber interior; they can only be adsorbed onto the fiber surface through physical action. They cannot be stably immobilized within the fiber, resulting in weak adsorption and easy silver loss during elution. Consequently, the silver content of the prepared silver-containing alginate fiber dressing is significantly lower than that of Examples 1-4. In contrast, the preparation methods of Examples 1-4 employ a synergistic technique combining "alcohol-water system ion exchange complexation" and "wet irradiation reduction," enabling uniform in-situ reduction of silver ions on and within the fiber surface, where they aggregate, nucleate, and grow, ultimately forming firmly loaded silver nanoparticles that are less prone to loss during elution.

[0084] Therefore, compared with the preparation methods in the comparative examples, the preparation scheme adopted in this embodiment has stable silver immobilization, less silver loss, controllable product quality, and lower preparation cost.

[0085] III. Silver Release Performance To compare the silver release characteristics of the dressings, the silver alginate fiber dressings prepared in the above examples and comparative examples were placed in wide-mouth bottles containing 100 mL of wound simulation solution in a 10 cm × 10 cm size and incubated in a 37°C incubator. At 24 h, 72 h, and 168 h, the mixture was shaken and 10 mL of the extract was taken out. The silver content was determined by atomic absorption spectrophotometry. The silver content values ​​at the corresponding time points represent the amount of silver released.

[0086] Table 2. Results of Silver Emission Test

[0087] As shown in Table 2, the silver release of the silver-containing fiber dressings in Examples 1-4 showed a slow upward trend over 7 days (168 h), indicating that the silver-containing fiber dressings under these time conditions have sustained-release properties. In contrast, the silver release of Comparative Examples 1-3 did not have sustained-release properties, and Comparative Examples 1 and 3 exhibited burst release effects, which may lead to excessively high local concentrations and increased cytotoxicity.

[0088] IV. Silver's Antibacterial Properties According to the AATCC TM100-2019 standard and with appropriate adjustments, the long-term antibacterial performance of the samples against Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans was tested at 24h, 72h, and 168h. After cutting the samples, they were placed in sterile containers, inoculated with a specific concentration of bacterial suspension, and ensured complete immersion. Independent parallel sample groups were prepared for each bacterial species and each predetermined time point (0h, 24h, 72h, 168h). After inoculation, the "0h" group was immediately neutralized and eluted, while the other groups were incubated at suitable temperatures to the corresponding time points and then subjected to the same operation. All eluents were diluted and plated on corresponding agar plates for colony counting, with a positive control group simultaneously set up. The bactericidal rate or log reduction value of the test group compared to the positive control group at each time point was quantified. A log reduction value (R) greater than 3.0 (i.e., bactericidal rate > 99.9%) effectively proves its antibacterial activity. The calculation formula is as follows: R = lgB - lgA B represents the concentration of test bacteria surviving after a "0-hour" contact time, in CFU / mL; A represents the concentration of test bacteria surviving at the corresponding contact time, in CFU / mL; R represents the reduction in bacteria in the test sample.

[0089] Table 3. Results of Staphylococcus aureus antibacterial test

[0090] Table 4. Results of antibacterial test for Pseudomonas aeruginosa

[0091] Table 5. Results of Candida albicans antibacterial test

[0092] As shown in Tables 3-5, the silver-containing fiber dressings prepared in Examples 1-4 all exhibited a logarithmic reduction (R) value (i.e., bactericidal rate > 99.9%) in inhibiting the growth of Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans at the three specified test time points, indicating that the silver-containing fiber dressings prepared in the examples all possess long-lasting antibacterial properties. The silver-containing fiber dressings prepared in Comparative Examples 1-3 all passed the antibacterial activity test at the 24-hour test point; at the 72-hour test point, only Comparative Example 3 passed the antibacterial activity test against Staphylococcus aureus; at the 168-hour test point, all three comparative examples failed the antibacterial activity test against the three bacteria. With the passage of test time, the antibacterial activity of Comparative Examples 1-3 all showed varying degrees of decline.

[0093] V. Lightfastness Several pieces of the alginate fiber dressings prepared in the above examples and comparative examples were taken in 10 cm × 10 cm sizes and placed under normal laboratory lighting for 24 h, 72 h, and 168 h, respectively. Control samples were also prepared, and the color changes of the test samples at each stage were observed.

[0094] Table 6. Results of lightfastness test

[0095] As shown in Table 6, the silver-containing fiber dressings prepared in Examples 1-4, after irradiation reduction, exhibited silver primarily in a zero valence state, making them less prone to discoloration during subsequent storage and use. In Comparative Example 1, the silver in the silver-containing fiber dressing mainly existed in an ionic state, exhibiting strong photosensitivity and easily undergoing reduction and discoloration upon exposure to light, showing different degrees of reduction over time, resulting in unstable color. In Comparative Example 2, the silver source was essentially completely reduced during irradiation reduction, thus the silver-containing alginate fiber dressing possessed a relatively stable color. Comparative Example 3, irradiated under dry conditions with extremely low levels of reducing medium, primarily existed in the form of silver ions, still exhibiting strong photosensitivity, unstable color, and uncontrollable appearance. The inconsistent color of the silver-containing alginate fiber dressings prepared by different methods may be related to the silver particle size, distribution, or binding state with the fiber.

[0096] In summary, the silver-containing fiber dressings in Comparative Examples 1-3 did not exhibit sustained-release silver release, and their antibacterial activity decreased to varying degrees in the later stages. Furthermore, the colors of Comparative Examples 1 and 3 were unstable. The silver-containing alginate fiber dressings prepared in Examples 1-4 of this application achieved in-situ reduction, embedding silver nanoparticles into the alginate fiber network. This resulted in a three-dimensional, uniform, and robust loading within the fiber. The silver-containing fiber dressings exhibited sustained-release and long-lasting antibacterial properties for up to 168 hours and did not easily discolor during storage and use.

[0097] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing alginate-containing fibers, characterized in that, Includes the following steps: Alginate fibers were pretreated by adding them to an alcohol-water reaction solution containing a silver source to pre-immobilize silver ions inside and on the surface of the fibers to obtain Ag. + / fiber, and keep it moist; wet Ag + / Fibers are irradiated to form nano-silver in situ inside and on the surface of the fibers, resulting in Ag / fiber composite materials; The Ag / fiber composite material was washed and dried to obtain alginate-containing fibers.

2. The preparation method according to claim 1, characterized in that, The method of maintaining moisture includes: not applying moisture to the Ag after pretreatment. + The fibers are dehydrated or dried to allow the Ag to be removed from the liquid. + The fiber retains a portion of the alcohol-water reaction solution and is then encapsulated. Wherein, the Ag + The mass ratio of the fiber to the alcohol-water reaction solution it carries is 1:(0.5-8), preferably 1:(1-5).

3. The preparation method according to claim 1, characterized in that, The silver-source-containing alcohol-water reaction solution includes a silver compound, a complexing agent, and an aqueous alcohol solution; The silver compound is a soluble or slightly soluble silver compound selected from one or more of silver nitrate, silver sulfate, and silver hypochlorite. The concentration of the silver compound in the reaction solution is 0.1%-8%, preferably 0.2%-4%, by weight. The complexing agent is one or more of PVP K30, PVP K90, and EDTA, and its concentration in the reaction solution is 0.05%-2% by weight. The alcohol concentration in the aqueous alcohol solution is 5%-95%, preferably 20%-75%, and the alcohol is one or more of ethanol, isopropanol, and propylene glycol by weight, preferably ethanol.

4. The preparation method according to claim 1, characterized in that, The irradiation treatment is performed using either cobalt-60 gamma ray irradiation or electron beam irradiation. The irradiation dose is 5 kGy-50 kGy, preferably 15 kGy-40 kGy.

5. The preparation method according to claim 1, characterized in that, The mass ratio of the alginate fiber to the silver-containing alcohol-water reaction solution is 1:(4-20); And / or, the pretreatment time is 3 min-480 min, preferably 5 min-120 min; And / or, the pretreatment temperature is 10 ℃-40 ℃; And / or, the alginate fiber is one or more of sodium alginate fiber and calcium alginate fiber, with a linear density of 1 dtex-6 dtex; And / or, the drying temperature is 25 ℃-55 ℃, and the drying time is 1 h-72 h.

6. The preparation method according to claim 1, characterized in that, The elution is a graded elution, with elution times ranging from 1 to 6. The eluent is an alcohol eluent, and the final alcohol eluent contains a surfactant; The alcohol eluent contains one or more of ethanol, isopropanol, and propylene glycol, with an alcohol concentration of 5%-98%, preferably 65%-95%, by weight. The surfactant is a nonionic surfactant, preferably a Tween series, a Span series, or a complex thereof.

7. A fiber containing alginate, characterized in that, The preparation method according to any one of claims 1-6 is used to obtain alginate fibers and in-situ silver nanoparticles loaded inside and on the surface of the alginate fibers.

8. A method for preparing a argylenate fiber dressing, characterized in that, The procedure includes the following steps: processing the alginate-containing fiber as described in claim 7 into a fabric or nonwoven cloth through nonwoven, woven or knitted processes, followed by slitting, packaging and sterilization to obtain alginate-containing fiber dressing.

9. A silage-containing alginate fiber dressing, characterized in that, It is obtained by the preparation method described in claim 8.

10. The alginate fiber dressing according to claim 9, characterized in that, The silver content in the alginate fiber dressing is 0.1%-8.0%, preferably 1%-4%, by weight; And / or, the alginate fiber dressing has a basis weight of 15 g / m². 2 -240 g / m 2 .

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