Medical sterilization fiber dressing and preparation process thereof

Abstract

The present application relates to the technical field of medical materials, and discloses a medical sterilization fiber dressing and a preparation process thereof. The dressing comprises a functional substrate and an electrochemically active component. The functional substrate comprises cyclodextrin grafted chitosan and sodium alginate, and the electrochemically active component comprises zinc powder and copper powder. The dressing utilizes the zinc powder and copper powder to form a micro-battery in an electrolyte environment, releases zinc ions and generates a micro-electric field to kill bacteria. At the same time, the cavity structure of the cyclodextrin grafted chitosan specifically recognizes and includes wound infection markers, and then regulates the reaction rate of the micro-battery, so as to realize the on-demand release of sterilization activity. The preparation process comprises the following steps: mixing the components to prepare a spinning solution, forming in a calcium chloride solution through wet spinning, and then stretching and drying to obtain the fiber dressing. The dressing can respond to the wound infection state, realize on-demand sterilization, and has good biocompatibility.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical materials, in particular to a medical sterilization fiber dressing and a preparation process thereof. BACKGROUND

[0002] Bacterial infection in the process of wound healing is a common problem in clinical practice and needs to be solved urgently, which can significantly prolong the healing period and even cause serious systemic complications. In order to effectively prevent and control wound infection, various medical sterilization dressings have been developed and widely used.

[0003] Currently, the mainstream technical approach to achieve the sterilization function of the dressing is to load various sterilization active components, such as antibiotics, silver ions or quaternary ammonium salts, etc. However, there is an inherent technical contradiction in the practical application of such dressings. On the one hand, in order to achieve the ideal sterilization effect, the release concentration of the active component needs to be maintained above the effective threshold; on the other hand, while these sterilization components kill pathogenic microorganisms, they also exhibit varying degrees of cytotoxicity to normal human tissue cells (such as fibroblasts and keratinocytes), thereby inhibiting the normal healing process of the wound.

[0004] The release mode of the active component in the existing sterilization dressing is mostly passive and continuous diffusion. This uncontrollable release means that the dressing will continuously release high concentrations of sterilization substances regardless of whether the wound is infected or not or the degree of infection. This continuous chemical intervention not only may cause unnecessary damage to the newly formed tissue, but also may induce bacterial resistance due to long-term use. Therefore, the existing technical solution is difficult to achieve an ideal balance between high sterilization activity and good biocompatibility, and lacks a mechanism that can self-regulate according to the actual infection state of the wound and achieve on-demand sterilization. SUMMARY

[0005] The technical problem to be solved by the present application is that the existing medical sterilization dressing has a sustained and uncontrollable release of active components, making it difficult to balance high sterilization activity and biocompatibility to normal tissue cells, and lacking a regulation mechanism that responds to the infection state of the wound to achieve on-demand sterilization.

[0006] To solve the above problems, the present application provides the following technical solutions:

[0007] In a first aspect, the present application provides a medical sterilization fiber dressing, which adopts the following technical solutions:

[0008] A medical sterilization fiber dressing, comprising a functional substrate and an electrochemically active component;

[0009] The functional substrate comprises cyclodextrin grafted chitosan and sodium alginate;

[0010] The electrochemically active component comprises zinc powder and copper powder;

[0011] The amount of the cyclodextrin grafted chitosan is 33.3-50 parts by weight, the amount of the sodium alginate is 50-66.7 parts by weight, and the amount of the electrochemically active component is 2-4 parts by weight, based on 100 parts by weight of the total weight of the functional substrate;

[0012] The mass ratio of the zinc powder to the copper powder is (5-10):1.

[0013] By adopting the technical solution, the medical sterilization fiber dressing provided by the application is composed of specific components and has a specific structure design, and simultaneously integrates a micro-electrochemical sterilization system and a molecular recognition regulation system. The action mechanism is as follows.

[0014] First, in the composition of the electrochemically active component, the technical solution utilizes the inherent standard electrode potential difference of metal materials. The standard electrode potential (E°(Zn 2+ / Zn) of zinc is significantly lower than the standard electrode potential (E°(Cu 2+ / Cu) of copper. According to the electrochemical principle, when the two kinds of metal particles form an electrical contact in the functional substrate and are exposed to an electrolyte environment such as wound exudate, a micro galvanic cell (also known as a micro galvanic couple) will be spontaneously formed. In this galvanic system, the zinc with a lower potential must undergo an oxidation reaction (Zn→Zn 2+ +2e - ) of losing electrons as an anode, and the copper with a higher potential must act as a cathode. The electrons released from the anode (zinc) are conducted to the cathode (copper) surface through direct contact between particles or conductive media, where a reduction reaction of gaining electrons occurs, which is usually the reduction of dissolved oxygen (O2+2H2O+4e - →4OH - ) in the reduction environment. This process ensures the continuous and stable release of zinc ions and forms a local micro electric field between the separated zinc and copper particles. The released zinc ions can destroy the protein structure of bacteria and inhibit the activity of key enzymes, and the micro electric field formed can directly act on the bacterial cell membrane to change the transmembrane potential, thereby achieving the sterilization of bacteria.

[0015] Secondly, also the key of the technical scheme is that the cyclodextrin grafted chitosan in the functional base material gives the dressing the response ability to specific biomolecules. The β-cyclodextrin unit has a unique cavity structure of outer wall hydrophilic and inner cavity hydrophobic, and can specifically recognize and include specific hydrophobic biomolecules (such as bacterial metabolites or inflammatory markers) in the wound microenvironment with the concentration increased due to inflammation or bacterial infection through host-guest interaction. When the inclusion occurs, the specific mechanism is that the hydrophobic guest molecules will expel the water molecules with higher energy originally filled in the inner cavity of the β-cyclodextrin, and this process destroys the original local stable hydration layer around the cyclodextrin unit, thereby significantly enhancing the local hydrophobicity of the surface of the adjacent zinc and copper particles. In the electrochemical reaction, the metal ions (such as Zn 2+ ) need to overcome the energy barrier of a stable interfacial hydration shell when they are detached from the anode surface into the solution. The enhancement of local hydrophobicity just interferes with the stability of the hydration shell, reduces the energy barrier of ion detachment, which is equivalent to reducing the mass transfer resistance of the reaction product, thus significantly accelerating the electrochemical reaction rate of the microbattery. Therefore, the dressing can automatically increase the zinc ion release rate and the microelectric field intensity when the infection or inflammation signal is detected, so as to realize the on-demand and efficient bactericidal effect; and in the normal physiological environment, the active ion release is maintained at a low level, thereby reducing the toxicity to normal tissue cells and improving the biocompatibility.

[0016] Preferably, the amount of the cyclodextrin grafted chitosan is 33.3 parts by weight, the amount of the sodium alginate is 66.7 parts by weight, the amount of the electrochemically active component is 2 parts by weight, and the mass ratio of the zinc powder to the copper powder is 10:1, based on 100 parts by weight of the total weight of the functional base material. By adopting the above technical scheme, the components can obtain balanced performance under the above ratio, which not only ensures the fiber forming property and mechanical strength of the fiber dressing, but also realizes effective molecular recognition response and antibacterial activity.

[0017] Preferably, the cyclodextrin grafted chitosan is prepared by grafting β-cyclodextrin on chitosan with epichlorohydrin or glutaraldehyde as an activating agent. By adopting the above technical scheme, a stable covalent bond can be formed between chitosan and β-cyclodextrin by using the activating agent, which ensures the stability of the cyclodextrin functional unit in the structure of the dressing, which is the basis for realizing its molecular recognition and regulation function.

[0018] Further preferably, the specific preparation method of the cyclodextrin grafted chitosan is that β-cyclodextrin is grafted onto the molecular chain of chitosan by epichlorohydrin under alkaline conditions.

[0019] Further preferably, another specific preparation method of the cyclodextrin grafted chitosan is that the amino groups of β-cyclodextrin and chitosan are connected by glutaraldehyde, and are stabilized by sodium borohydride reduction.

[0020] In a second aspect, the application provides a preparation process of the medical sterilization fiber dressing, which adopts the following technical scheme:

[0021] A preparation process of a medical sterilization fiber dressing, comprising the following steps:

[0022] (a) Preparation of the spinning dope: cyclodextrin grafted chitosan and sodium alginate are dissolved in water to form a high molecular blend solution, and zinc powder and copper powder are dispersed into the high molecular blend solution, and after defoaming, a composite spinning dope is obtained;

[0023] (b) Wet spinning: the composite spinning dope is extruded through a spinneret and solidified and formed in a calcium chloride aqueous solution coagulation bath to obtain a nascent fiber;

[0024] (c) Post-treatment: the nascent fiber is stretched and dried to obtain the medical sterilization fiber dressing.

[0025] By adopting the above technical scheme, the preparation process is prepared by wet spinning, and the sodium ions in the sodium alginate and the calcium ions in the coagulation bath are ion exchanged to form a calcium alginate gel network insoluble in water. This process physically embeds and fixes the cyclodextrin grafted chitosan, zinc powder and copper powder in the three-dimensional fiber structure. The process ensures that the cyclodextrin grafted chitosan as a molecular recognition unit and the zinc and copper particles as electrochemically active units can realize structural integration and functional synergy on a single fiber carrier. The fiber prepared by this method makes the two functional components uniformly distributed on a microscale, providing a necessary structural basis for the formation of a microbattery and the realization of molecular recognition function.

[0026] Preferably, in step (a), the mass volume concentration of the high molecule in the high molecular blend solution is 4.5%.

[0027] By adopting the above technical scheme, the concentration value ensures that the spinning dope has a suitable viscosity, which not only ensures the fluidity of the solution to facilitate transportation and extrusion, but also maintains the continuity of the liquid flow in the spinning process to avoid broken filaments, thereby facilitating the formation of a uniform fiber structure.

[0028] Preferably, in step (b), the mass volume concentration of the calcium chloride aqueous solution is 5.0-6.0%.

[0029] By adopting the above technical scheme, the coagulation bath with the concentration range can provide sufficient calcium ions to ensure that the sodium alginate undergoes a rapid and sufficient ion exchange reaction to form a dense and stable fiber network structure, thereby effectively solidifying the fiber morphology and coating the functional components.

[0030] Preferably, in step (c), the stretching ratio is 2.0-2.8; and the drying is performed under vacuum at 50℃.

[0031] By using the above technical solution, the polymer chains inside the fiber are effectively oriented at this stretching ratio, thereby improving the mechanical strength of the fiber and enabling it to meet the use requirements as a medical dressing. The vacuum drying condition at 50℃ can efficiently remove moisture without destroying the activity of the cyclodextrin structure.

[0032] Preferably, in step (a), the zinc powder and copper powder are subjected to ultrasonic dispersion treatment before being added to the polymer blend solution.

[0033] By using the above technical solution, ultrasonic treatment can effectively break the agglomerates of metal powder, enabling it to be dispersed in the spinning dope in a smaller particle size and more uniform state. This uniform dispersion is crucial for the density and distribution of the micro-battery in the final fiber and is a structural guarantee for ensuring uniform and stable antibacterial performance of the entire dressing.

[0034] In summary, the present application has the following at least one beneficial technical effect:

[0035] 1. The fiber dressing of the present application has the function of responding to specific biomolecules and adjusting the bactericidal activity accordingly. This function is achieved by covalently grafting cyclodextrin units with molecular recognition ability onto chitosan substrates and compounding with zinc-copper micro-electrochemical systems. When there are specific infection markers on the wound surface, the specific inclusion of cyclodextrin will change the microenvironment around the electrochemically active components, accelerate the micro-battery reaction, and thereby increase the release rate of active ions. This structural design enables the bactericidal intensity of the dressing to match the degree of infection on the wound surface, achieving on-demand bactericidal effect.

[0036] 2. The fiber dressing of the present application has high biocompatibility. Its bactericidal function mainly depends on the physical micro-electric field effect and the release of low-concentration zinc ions, avoiding the use of traditional chemical bactericides which have potential toxicity to normal tissue cells. In the absence of specific molecular stimulation, the release rate of its active components is maintained at a basic, low-cytotoxicity level. In vitro cytotoxicity test results show that the relative proliferation rate of cells cultured in its sample extract is more than 95%, and the toxicity classification is 0 or 1, which indicates that the dressing has little effect on the growth of normal cells while exerting bactericidal effect.

[0037] 3. The fiber dressing prepared by the present application has stable structure and the functional components are not easy to be lost. Through the wet spinning process, the cross-linking network is formed by the ion exchange of sodium alginate and calcium ions, and the functional components such as cyclodextrin grafted chitosan and zinc and copper particles are firmly embedded in the fiber matrix. This stable physical immobilization method, combined with stretching orientation in post-processing, not only gives the fiber dressing the mechanical strength required for use, but also ensures that the molecular recognition and electrochemical sterilization function can be continuously exerted during application. DETAILED DESCRIPTION

[0038] The main raw materials and reagents used in the following examples and comparative examples are as follows, and the reagents not specifically described are commercially available analytical pure or higher grade products.

[0039] Chitosan, CAS No. 9012-76-4. The deacetylation degree of the batch used in the examples of the present application is 90.5%, and the viscosity method is used to measure the viscosity average molecular weight of 3.5 x 10 5 Da.

[0040] Sodium alginate, CAS No. 9005-38-3, pharmaceutical grade. It is a block copolymer composed of β-D-mannuronic acid (M unit) and α-L-guluronic acid (G unit). The M to G unit ratio of the batch used in the examples of the present application is 1.2, and the apparent viscosity of its 1% (w / v) aqueous solution at 20°C is 350 mPa·s.

[0041] β-Cyclodextrin, CAS No. 7585-39-9. The purity is not less than 98.5%, and it is vacuum dried at 105°C for 12 hours before use.

[0042] Zinc powder, CAS No. 7440-66-6. The average particle size is 5.0 μm, and the purity is not less than 99.8%.

[0043] Copper powder, CAS No. 7440-50-8. The average particle size is 5.0 μm, and the purity is not less than 99.9%.

[0044] Glutaraldehyde, CAS No. 111-30-8, provided as a 25% (w / w) aqueous solution.

[0045] The cyclodextrin grafted chitosan used in the present application is a non-commercial substance, and its essence is a graft copolymer in which β-cyclodextrin molecules are grafted to the main chain of chitosan through chemical bonds. The specific preparation method is described in Preparation Example 1 and Preparation Example 2 described later.

[0046] Preparation Example 1:

[0047] This preparation example provides a method for preparing cyclodextrin grafted chitosan using epichlorohydrin as an activating agent, which comprises the following steps:

[0048] 1. Disperse 10.0 g of chitosan powder in 500 mL of 1.0% (v / v) acetic acid aqueous solution, and stir magnetically at 50°C for 3 hours until completely dissolved to form a uniform transparent viscous solution. Transfer the solution to a 1000 mL three-necked flask, and protect with nitrogen for 20 minutes. Then, increase the temperature of the system to 60°C. Slowly add 28.0 g of epichlorohydrin dropwise through a constant pressure dropping funnel under continuous stirring, and continue the reaction at this temperature for 3 hours to activate the chitosan.

[0049] 2. Dissolve another 10.0 g of β-cyclodextrin in 100 mL of sodium hydroxide solution, and adjust the pH of the solution to 12. Slowly add the β-cyclodextrin solution dropwise through a constant pressure dropping funnel to the above activated chitosan reaction system. After the addition is completed, increase the temperature of the reaction system to 70°C, and continue the stirring reaction for 18 hours.

[0050] 3. After the reaction is completed, cool the system to room temperature, and slowly adjust the pH of the reaction solution to 7.0 using 1.0 mol / L hydrochloric acid solution. Transfer the neutralized solution to a dialysis bag with a molecular weight cut-off of 8000-14000 Da, and dialyze against deionized water as the dialysis medium for 4 days, with the deionized water being replaced every 6 hours. Freeze-dry the dialysis-purified solution under the conditions of -60°C and a vacuum degree lower than 10 Pa for 48 hours to obtain a white loose solid product, which is named as CD-g-CS-1.

[0051] To confirm the chemical structure of the product CD-g-CS-1, Fourier transform infrared spectroscopy and nuclear magnetic resonance hydrogen spectrum analysis were performed. The Fourier transform infrared spectroscopy results show that the product spectrum contains both characteristic absorption peaks (3400 cm -1 nearby O-H and N-H stretching vibration wide peak) from chitosan and characteristic absorption peaks (1028 cm -1 nearby C-O-C stretching vibration peak) from β-cyclodextrin. The nuclear magnetic resonance hydrogen spectrum analysis results show that, after sufficient dialysis purification, the product spectrum contains both signals belonging to the protons of the chitosan backbone (mainly distributed in the δ3.5-3.9 ppm region) and signals belonging to the protons of the cyclic structure of β-cyclodextrin (end group H1 proton signal near δ5.0 ppm). The above results confirm that the β-cyclodextrin units have been successfully grafted onto the molecular chain of chitosan through covalent bonds.

[0052] Preparation Example 2:

[0053] This preparation example provides a method for preparing cyclodextrin grafted chitosan using glutaraldehyde as an activating agent, which comprises the following steps:

[0054] 1. Dissolve 10.0 g of chitosan powder in 500 mL of 1.0% (v / v) acetic acid aqueous solution and stir at 50 °C for 3 hours to completely dissolve. Dissolve 10.0 g of β-cyclodextrin in 200 mL of deionized water. Mix the two solutions in a 1000 mL flask and adjust the pH of the mixed solution to 5.0 using 1.0 mol / L hydrochloric acid solution.

[0055] 2. Increase the temperature of the system to 40 °C and slowly add 0.5 mL of 25% glutaraldehyde aqueous solution under continuous stirring. Continue the reaction at this temperature for 6 hours. After the reaction is completed, cool the system to room temperature and slowly add 0.5 g of sodium borohydride solution dissolved in 20 mL of deionized water to reduce and stabilize the Schiff base structure formed, and continue stirring at room temperature for 12 hours.

[0056] 3. After the reaction is completed, adjust the pH of the reaction solution to 7.0 using 1.0 mol / L hydrochloric acid solution. The neutralized solution is also purified by dialysis using a dialysis bag with a molecular weight cut-off of 8000-14000 Da for 4 days. The purified solution is freeze-dried under the same conditions as in Preparation Example 1 to obtain a white loose solid product, which is named CD-g-CS-2.

[0057] To confirm the chemical structure of the product CD-g-CS-2, Fourier transform infrared spectroscopy analysis was performed. The results showed that the product spectrum also retained the characteristic peaks of the chitosan and β-cyclodextrin backbone. Compared with the raw material chitosan, the intensity of the characteristic absorption peak of the primary amine group (-NH2) in the product was weakened, and an absorption peak corresponding to the bending vibration of the secondary amine (C-N) appeared near 1560 cm -1 , and no obvious imine group (-C=N-) absorption peak was observed. This result indicates that after the reaction of glutaraldehyde as a crosslinking agent with the amino group of chitosan, it has been successfully reduced by sodium borohydride, thereby forming a stable C-N covalent bond between them, confirming the success of the grafting reaction.

[0058] Example 1:

[0059] The present application provides a preparation process for a medical sterilization fiber dressing, which comprises the following steps:

[0060] 1. Preparation of spinning dope:

[0061] Take 1.5 g of cyclodextrin grafted chitosan (CD-g-CS-1) prepared in Preparation Example 1 and 3.0 g of sodium alginate, add to 95.5 mL of deionized water, and mechanically stir at room temperature for 10 hours to form a uniform polymer blend solution, wherein the total solid content of the polymer is 4.5% (w / v).

[0062] Another 0.09 g of zinc powder and copper powder with a mass ratio of 10:1 was added to the polymer solution. The mixture was stirred for 6 hours in a planetary stirring deaerator, and then deaerated under vacuum until no obvious bubbles were observed to obtain a composite spinning dope.

[0063] 2. Wet spinning and post-treatment:

[0064] The spinning dope was delivered to a spinneret (100 holes x 0.10 mm) at a flow rate of 10.0 ml / hour by a metering pump. The dope passed through a 30 mm air layer and entered a calcium chloride aqueous solution coagulation bath with a concentration of 5.0% (w / v) to form a nascent fiber. After washing with water, the nascent fiber was stretched by 2.0 times in a water bath at 70°C. Finally, the stretched fiber was dried under vacuum at 50°C for 12 hours to obtain the final product, designated as S1.

[0065] Example 2:

[0066] The preparation process of this example was basically the same as that of Example 1, the main difference being that the ratio of the electrochemically active components in the preparation of the spinning dope in step 1 was different.

[0067] The total mass of zinc powder and copper powder was 4.0% of the dry weight of the polymer (4.5 g), i.e. 0.18 g, and the mass ratio of zinc powder to copper powder was adjusted to 5:1.

[0068] All other preparation steps and process parameters were exactly the same as in Example 1. The final product obtained was designated as S2.

[0069] Example 3:

[0070] The preparation process of this example was basically the same as that of Example 1, the main difference being that the types and ratios of the functional substrates in the preparation of the spinning dope in step 1 were different.

[0071] 2.25 g of cyclodextrin grafted chitosan (CD-g-CS-2) prepared in Preparation Example 2 and 2.25 g of sodium alginate were weighed, i.e. the mass ratio of the two was 1:1. The total solid content of the polymer and the addition amount of the metal powder (2.0% of the dry weight of the polymer) and the ratio (mass ratio of zinc to copper 10:1) were consistent with Example 1.

[0072] All other preparation steps and process parameters were exactly the same as in Example 1. The final product obtained was designated as S3.

[0073] Example 4:

[0074] The preparation process of this example is basically the same as that of Example 1, the main difference is that the process parameters in the wet spinning and post-processing of step 2 are different:

[0075] The concentration of the calcium chloride aqueous solution in the coagulation bath was adjusted to 6.0% (w / v). The draw ratio in the fiber drawing step was adjusted to 2.8 times.

[0076] The components and proportions of the spinning dope in this example are exactly the same as those in Example 1. The final product obtained is named S4.

[0077] Comparative Example 1:

[0078] The difference compared with Example 1 is that it uses 1.5 grams of ungrafted chitosan instead of cyclodextrin grafted chitosan (CD-g-CS-1). The rest of the raw material proportions, preparation steps and process parameters are exactly the same as those in Example 1. The final product obtained is named D1.

[0079] Comparative Example 2:

[0080] The difference compared with Example 1 is that it does not add any zinc powder and copper powder when preparing the spinning dope. The rest of the raw materials, preparation steps and process parameters are exactly the same as those in Example 1. The final product obtained is named D2.

[0081] Comparative Example 3:

[0082] The difference compared with Example 1 is that it uses 1.5 grams of ungrafted chitosan and physically blends an equal amount of β-cyclodextrin used in Preparation Example 1 to replace the chemically grafted cyclodextrin grafted chitosan (CD-g-CS-1) when formulating the polymer blend solution. The rest of the raw material proportions, preparation steps and process parameters are exactly the same as those in Example 1. The final product obtained is named D3.

[0083] Comparative Example 4:

[0084] The difference compared with Example 1 is that it only uses 0.09 grams of zinc powder as the electrochemically active component, without adding copper powder. The rest of the raw material proportions, preparation steps and process parameters are exactly the same as those in Example 1. The final product obtained is named D4.

[0085] Comparative Example 5:

[0086] The difference compared with Example 1 is that it uses 1.5 grams of chitosan without graft modification and 3.0 grams of sodium alginate to prepare the blank fiber, and does not add any metal powder in the spinning dope. The prepared blank fiber is immersed in a 0.2% (w / v) polyhexamethylene biguanide (PHMB) solution for 1 hour in the post-treatment stage, and then dried to prepare a dressing using a conventional chemical sterilization agent. The rest of the preparation steps and process parameters are the same as Example 1. The final product is named D5.

[0087] Test Example 1

[0088] To evaluate the antibacterial performance of the medical sterilization fiber dressing prepared by the present application, the samples of Examples S1-S4 and Comparative Examples D1-D5 are tested by the shake flask method, and the specific experimental steps are as follows:

[0089] 1. Sample and strain preparation:

[0090] The fiber samples prepared in Examples S1-S4 and Comparative Examples D1-D5 are cut into small pieces and sterilized by ethylene oxide for standby.

[0091] Staphylococcus aureus (ATCC 6538) and Escherichia coli (ATCC 8739) are inoculated in nutrient broth medium respectively, and cultured in a constant temperature shaking incubator at 37°C, 150 rpm for 12 hours to the logarithmic growth phase. The bacterial suspension is diluted with phosphate buffer solution (PBS, pH 7.2-7.4) to adjust the final concentration to 1.0 x 10 5 ~1.0 x 10 6 CFU / mL.

[0092] 2. Contact culture and detection:

[0093] Under sterile operating conditions, 0.1 grams of each sterilized sample is weighed and placed in a sterile conical flask containing 10 milliliters of the above diluted bacterial suspension. At the same time, a conical flask without any sample is set as a blank control group. After sealing all the conical flasks, they are placed in a constant temperature shaking incubator at 37°C, 150 rpm for 24 hours.

[0094] 3. Viable bacteria count and antibacterial rate calculation:

[0095] After the culture is completed, 1 milliliter of culture solution is taken from each conical flask and diluted by 10 times gradient with sterile PBS. 100 microliters of bacterial solution of appropriate dilution are taken and evenly spread on nutrient agar plates. After 24 hours of culture in a constant temperature incubator at 37°C, viable bacterial colony counting is performed. Three parallel samples are set for each sample, and the results are averaged. The antibacterial rate is calculated according to the following formula:

[0096] Antibacterial rate (%) = [(number of viable bacteria in blank control group - number of viable bacteria in sample group) / number of viable bacteria in blank control group] x 100%;

[0097] The test results are recorded in Table 1 below.

[0098] Table 1: Test results of antibacterial performance of various samples

[0099] Sample No. Antibacterial rate (%) against Staphylococcus aureus Antibacterial rate (%) against Escherichia coli S1 99.97 99.98 S2 99.99 99.99 S3 99.96 99.97 S4 99.98 99.99 D1 99.85 99.91 D2 15.7 12.4 D3 98.54 97.89 D4 75.3 70.1 D5 99.99 99.99

[0100] The test results of Table 1 show that the fiber dressings prepared in Examples S1-S4 exhibit high antibacterial activity against both S. aureus and E. coli. Comparative Example D2, which does not contain zinc powder and copper powder in its components, has a significantly lower antibacterial rate than Examples S1-S4, which confirms that the electrochemically active components are the structural basis for achieving high antibacterial activity.

[0101] The antibacterial effect is generated from the structural design of the fiber dressing. When the dressing comes into contact with the bacterial suspension containing electrolytes, a large number of micro-batteries are formed between the zinc particles and copper particles dispersed in the fiber substrate. In this system, zinc with a lower electrochemical potential acts as an anode to undergo oxidation reaction (Zn→ Zn ２＋ +2e － ), releasing zinc ions and electrons; while copper with a higher potential acts as a cathode. This process produces two synergistic antibacterial effects: first, the continuously released zinc ions can destroy the protein structure of bacteria and inhibit the activity of their enzyme system; second, the local micro-electric field formed between zinc and copper particles can directly act on the bacterial cell membrane, changing its transmembrane potential and leading to damage to the membrane structure integrity.

[0102] The sample of Comparative Example D4 contains only zinc powder without copper powder, and its antibacterial rate is much lower than that of Examples S1-S4, which indicates that a single metal component cannot effectively form a micro-battery system, thereby confirming the necessity of the synergistic effect of zinc-copper particle pairs for generating a strong micro-electric field and driving efficient release of ions. Examples S1-S4 and Comparative Example D1 both exhibit high antibacterial activity, indicating that the basic antibacterial function of the dressing is mainly provided by the electrochemically active components inside it. The cyclodextrin grafted chitosan provides a stable dispersion carrier for the electrochemically active components in this antibacterial mechanism, and its regulatory effect on the antibacterial rate will be further elucidated in subsequent tests.

[0103] Test Example 2:

[0104] To verify the response capability of the fiber dressing prepared in the present application to specific biomolecules, the amount of zinc ions released in different solution environments is determined to evaluate it. The specific experimental steps are as follows:

[0105] 1. Solution preparation:

[0106] Two test solutions were prepared. Solution A: a basic simulated body fluid with an ion concentration similar to human blood plasma. Solution B: an activation solution, prepared by dissolving and adding cholesterol to Solution A to achieve a final concentration of 50 mg / L.

[0107] 2. Incubation process:

[0108] Under aseptic conditions, 0.1 g of sterile samples from Examples S1-S4 and Comparative Examples D1 and D3 were weighed and placed into sterile centrifuge tubes containing 10 mL of solution A and solution B, respectively. After sealing all centrifuge tubes, they were placed in a 37°C constant temperature water bath shaker and incubated at 50 rpm for 24 hours.

[0109] 3. Ion concentration determination:

[0110] After incubation, centrifuge the tubes at 4000 rpm for 5 minutes and collect the supernatant. Filter the supernatant through a 0.22-micron filter membrane to remove impurities. Inductively coupled plasma mass spectrometry (ICP-MS) was used to analyze the zinc ions (Zn) in the filtrate. 2 + The concentration was determined. Three parallel samples were prepared for each sample, and the average value of the results was taken.

[0111] The test results are recorded in Table 2 below.

[0112] Table 2. Concentration of zinc ions released by each sample in different solutions:

[0113] Sample No. Zinc ion release concentration in A solution (μg / mL) Zinc ion release concentration in B solution (μg / mL) S1 1.12 3.82 S2 1.35 5.15 S3 0.98 3.59 S4 1.17 4.97 D1 1.25 1.31 D3 1.03 1.09

[0114] Table 2 shows that the zinc ion release concentration of samples S1–S4 in the activating solution (solution B) was significantly higher than that in the baseline simulated body fluid (solution A). In contrast, there was no significant difference in the zinc ion release concentration of samples D1 and D3 in the two solutions. This result indicates that the fiber dressing prepared in the examples can respond to the presence of specific biomolecules (cholesterol) in the solution and correspondingly increase the release rate of its active ions.

[0115] This responsiveness stems from the structural characteristics of cyclodextrin-grafted chitosan in the fiber substrate. β-Cyclodextrin possesses a cavity structure that is hydrophilic on the outside and hydrophobic on the inside, enabling it to specifically encapsulate hydrophobic molecules, such as cholesterol, through host-guest interactions. When cholesterol molecules in the activating solution enter the cavity of β-cyclodextrin, they cause a change in the local conformation of the grafted polymer, displacing water molecules that might have previously partially occupied the cavity or adsorbed around it. This enhanced hydrophobicity of the microenvironment reduces the mass transfer resistance on the surfaces of zinc and copper particles, thereby accelerating the electrochemical reaction rate of the micro-battery and leading to an increase in the release of zinc ions.

[0116] Comparative Example D1 does not contain β-cyclodextrin cavity in its structure, and thus cannot form specific inclusion complex with cholesterol molecules. Its ion release rate is not affected by the presence or absence of cholesterol. Comparative Example D3 physically added β-cyclodextrin, but it cannot effectively convert molecular recognition events into local environmental regulation of the microbattery system because it is not covalently connected to the chitosan backbone. The above comparisons confirm that covalently grafting β-cyclodextrin units to the chitosan backbone is the key structural basis for achieving response to specific molecules and regulating electrochemical activity.

[0117] Test Example 3:

[0118] To evaluate the in vitro cytotoxicity of the fibrous dressing prepared by the present application, the MTT colorimetric method was used to detect the extract, and the specific experimental steps were as follows:

[0119] 1. Preparation of extract:

[0120] Under sterile conditions, the sterilized samples of Examples S1-S4 and Comparative Examples D1 and D5 were weighed, and then immersed in DMEM cell culture medium containing 10% fetal bovine serum at a ratio of 0.1 g / mL. The mixture was incubated in a 37°C, 5% CO2 incubator for 24 hours. After incubation, the mixture was centrifuged at 4000 rpm for 10 minutes, and the supernatant was filtered with a 0.22 micron filter to prepare a 100% concentration of sample extract.

[0121] 2. Cell culture and treatment:

[0122] L929 fibroblasts in the logarithmic growth phase were inoculated in a 96-well cell culture plate at a density of 1×10 4 cells / well, and cultured for 24 hours until the cells were completely adherent. The original culture medium was discarded, and 100 microliters of the prepared sample extract were added to each well. A negative control group (containing only cell culture medium) and a positive control group (containing 0.64% phenol cell culture medium) were also set up.

[0123] 3. MTT detection and data collection:

[0124] The culture plate was placed in a 37°C, 5% CO2 incubator for further incubation for 24 hours. After incubation, 10 microliters of MTT solution with a concentration of 5 mg / mL was added to each well, and incubated for another 4 hours. Then, the liquid in the wells was carefully aspirated, and 100 microliters of dimethyl sulfoxide (DMSO) was added to each well. The wells were shaken at low speed on a shaker for 10 minutes to completely dissolve the MTT crystals. The absorbance (OD value) of each well was measured at 490 nm using a microplate reader.

[0125] 4. Relative cell proliferation rate and toxicity classification:

[0126] The relative growth rate (RGR) of cells was calculated according to the following formula:

[0127] RGR (%) = [(OD value of sample group - OD value of blank well) / (OD value of negative control group - OD value of blank well)] x 100%;

[0128] According to the RGR value, the cytotoxicity of the material was graded (0-5 grades).

[0129] The test results are recorded in Table 3 below.

[0130] Table 3: Test results of in vitro cytotoxicity of each sample

[0131] Sample No. Relative growth rate of cells (RGR, %) Cytotoxicity grade S1 98.6 1 S2 95.3 1 S3 99.1 0 S4 97.5 1 D1 96.2 1 D5 45.8 3

[0132] The test results in Table 3 show that the cell relative growth rates of the sample leaching liquor of Examples S1-S4 are all above 95%, and the cytotoxicity grades are 0 or 1. The cell relative growth rate of the sample leaching liquor of Comparative Example D5 is significantly reduced, and the cytotoxicity grade is 3. This result shows that the fiber dressings prepared in the examples have no obvious in vitro cytotoxicity, while the comparative example D5 using a conventional chemical sterilizing agent shows moderate cytotoxicity.

[0133] The fiber dressings of Examples S1-S4 show low cytotoxicity, which is determined by their material composition and mechanism of action. The base material of the dressing, i.e. cyclodextrin grafted chitosan and sodium alginate, are both polysaccharide derivatives with known good biocompatibility. The antibacterial functional component releases zinc ions through a micro-battery system, and the results in Test Example 2 have shown that the basic ion release concentration of this system in a simulated body fluid environment is at a relatively low level. This concentration is sufficient to inhibit bacteria, but is lower than the threshold value for toxic effects on mammalian fibroblasts.

[0134] The sample of Comparative Example D5 achieves antibacterial function by releasing the chemical sterilizing agent polyhexamethylene biguanide (PHMB). The mechanism of action of PHMB is non-specific damage to cell membranes, which does not distinguish between prokaryotic cells (bacteria) and eukaryotic cells (animal cells), so while killing bacteria, it also causes damage to the L929 fibroblasts in contact, resulting in a significant decrease in their proliferation activity. Through comparison with Comparative Example D5, it is confirmed that the antibacterial method achieved by constructing a micro-electrochemical system in the present application has higher biological safety while ensuring antibacterial activity.

[0135] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and adaptions can be effected without departing from the spirit and scope of the present application, which is not limited to the exact construction and arrangement described. It is intended, therefore, to cover all modifications and adaptions that fall within the scope of the claims and their equivalents.

Claims

1. A process for the preparation of a medical antiseptic fibrous dressing, characterized in that, The medical sterilization fiber dressing comprises a functional substrate and an electrochemically active component; The functional substrate comprises cyclodextrin grafted chitosan and sodium alginate; The electrochemically active component comprises zinc powder and copper powder; The amount of the cyclodextrin grafted chitosan is 33.3-50 parts by weight, the amount of the sodium alginate is 50-66.7 parts by weight, and the amount of the electrochemically active component is 2-4 parts by weight, based on 100 parts by weight of the total weight of the functional substrate; The mass ratio of the zinc powder to the copper powder is (5-10):1; The preparation process of the medical sterilization fiber dressing comprises the following steps: (a) Preparation of a spinning dope: cyclodextrin grafted chitosan and sodium alginate are dissolved in water to form a high polymer blend solution, and zinc powder and copper powder are dispersed into the high polymer blend solution to obtain a composite spinning dope after degassing; (b) Wet spinning: the composite spinning dope is extruded through a spinneret and solidified in a calcium chloride aqueous solution coagulation bath to obtain a nascent fiber; (c) Post-treatment: the nascent fiber is stretched and dried to obtain the medical sterilization fiber dressing.

2. The process for producing a medical sterilizing fiber dressing according to claim 1, characterized by, The amount of the cyclodextrin grafted chitosan is 33.3 parts by weight, the amount of the sodium alginate is 66.7 parts by weight, and the amount of the electrochemically active component is 2 parts by weight, based on 100 parts by weight of the total weight of the functional substrate; and the mass ratio of the zinc powder to the copper powder is 10:

1.

3. The process for producing a medical sterilizing fiber dressing according to claim 1, wherein The cyclodextrin grafted chitosan is prepared by grafting β-cyclodextrin onto chitosan using epichlorohydrin or glutaraldehyde as an activating agent.

4. The process for producing a medical sterilizing fiber dressing according to claim 3, characterized by, The cyclodextrin grafted chitosan is prepared by grafting β-cyclodextrin onto chitosan using epichlorohydrin as an activating agent. The cyclodextrin grafted chitosan is prepared by grafting β-cyclodextrin onto chitosan using glutaraldehyde as an activating agent.

5. The process for producing a medical sterilizing fiber dressing according to claim 3, wherein The cyclodextrin grafted chitosan is prepared by grafting β-cyclodextrin onto chitosan using glutaraldehyde as an activating agent. In step (a), the mass-volume concentration of the high polymer in the high polymer blend solution is 4.5%.

6. The process for producing a medical sterilizing fiber dressing according to claim 1, wherein In step (b), the mass-volume concentration of the calcium chloride aqueous solution is 5.0-6.0%.

7. The process for producing a medical sterilizing fiber dressing according to claim 1, wherein In step (c), the stretching multiple of the stretching is 2.0-2.8 times; and the drying is performed under vacuum at 50°C.

8. The process for producing a medical sterilizing fiber dressing according to claim 1, wherein In step (a), the zinc powder and the copper powder are subjected to ultrasonic dispersion treatment before being added into the high polymer blend solution.

9. The process for producing a medical sterilizing fiber dressing according to claim 1, wherein ​