Antibacterial nonwoven fabric composite material and method for manufacturing the same, and protective article

Abstract

The application relates to the technical field of antibacterial protective materials, and relates to an antibacterial non-woven fabric composite material and a preparation method thereof and protective articles. The composite material takes polypropylene non-woven fabric as a base material, and a gelatin layer and a polydopamine-copper ion chelating layer are sequentially constructed on the surface of the base material. During preparation, the base material is subjected to plasma surface activation treatment, then a gelatin solution is coated and dried in sequence, and a dopamine solution containing copper ions is immersed, so that a polydopamine-copper ion chelating layer is formed in situ through a dopamine self-polymerization reaction. Through three-step synergistic modification of plasma activation-gelatin interface bridging-polydopamine chelating copper, firm adhesion of the coating, stable chelation and slow release of copper ions are realized. The obtained material has the advantages of efficient antibacterial property, low release safety and excellent air permeability and filtering performance, and is suitable for masks, air filtering materials and medical protective articles.

Description

Technical Field

[0001] This invention relates to the technical field of antibacterial protective materials, specifically to an antibacterial nonwoven composite material, its preparation method, and protective products. Background Technology

[0002] As an essential respiratory protective device, face masks' core function is to filter airborne particulate matter and microorganisms through physical interception mechanisms. Traditional face masks typically use polypropylene meltblown nonwoven fabric as the filter layer. This material itself only provides passive physical barrier function and has no active killing or inhibition effect on trapped bacteria, fungi, and other pathogenic microorganisms. During actual wear, the warm and humid air exhaled by the human body creates a relatively closed microenvironment inside the mask. The temperature and humidity are suitable for microbial growth, and bacteria and fungi can accumulate and multiply on the fiber surface, not only reducing protective effectiveness but also increasing the risk of contact infection and secondary transmission. Therefore, endowing face mask materials with active antibacterial functions has become an important direction in the current research and development of protective equipment.

[0003] Currently, the main technical routes for preparing antibacterial mask materials include the following: (1) Physical blending method, in which antibacterial metal particles such as silver and copper are pre-dispersed into polymer raw materials, and then antibacterial nonwoven fabric is made by melt-blowing or spunbonding process. This method has a high degree of process integration, but most antibacterial particles are embedded in the fiber matrix, and the proportion of effective components exposed on the fiber surface is low, the antibacterial utilization efficiency is limited, and the particles that are not firmly embedded have the risk of falling off. (2) Surface finishing method, that is, by impregnation, spraying and other methods, an antibacterial functional layer is coated on the surface of the formed nonwoven fabric. This method makes the antibacterial components concentrated on the fiber surface, with a high effective utilization rate, but polypropylene has low surface energy and strong chemical inertness. The interaction between it and the polar antibacterial coating is mainly physical adsorption or weak van der Waals force, and the interfacial bonding force is weak. The coating is easily detached by friction, airflow impact or moisture in actual use, resulting in insufficient antibacterial durability. In addition, some of the metal-based antibacterial coatings mentioned above have the problem of uncontrollable metal ion release rate—if the release is too slow, the antibacterial activity is insufficient; if the release is too fast, it may cause cytotoxicity or skin irritation, making it difficult to achieve both high antibacterial efficiency and high biosafety.

[0004] Therefore, developing an antibacterial composite material that combines strong adhesion, long-lasting antibacterial activity, and high biocompatibility is of great significance for improving the overall protective efficacy of respiratory protective equipment such as masks and reducing the risk of cross-infection. Summary of the Invention

[0005] The purpose of this invention is to address the problem that existing polypropylene nonwoven fabric masks cannot simultaneously achieve coating adhesion, controllable metal ion release, and high-efficiency antibacterial activity. This invention provides an antibacterial nonwoven fabric composite material, its preparation method, and protective equipment. The composite material uses polypropylene nonwoven fabric as the substrate and undergoes a three-step synergistic modification process: plasma activation, gelatin interface bridging, and polydopamine chelation copper fixation. The coating adheres firmly to the substrate surface, with a copper ion release rate of less than 1 ppm / day. It exhibits a 94% inhibition rate against Staphylococcus aureus and an 87% inhibition rate against Escherichia coli, with a cell survival rate of no less than 90%. Simultaneously, it maintains the inherent breathability and filtration performance of the substrate, combining high-efficiency antibacterial activity, sustained release, and high biocompatibility.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] The first aspect of the present invention provides a method for preparing an antibacterial nonwoven composite material, comprising the following steps:

[0008] Step 1: Perform plasma surface activation treatment on the polypropylene nonwoven fabric substrate;

[0009] Step 2: Coat the activated substrate surface with gelatin solution and dry to form a gelatin layer;

[0010] Step 3: Immerse the material obtained in Step 2 in a dopamine solution containing copper ions. Through the self-polymerization reaction of dopamine, a polydopamine-copper ion chelate layer is formed in situ on the gelatin layer, thus obtaining the antibacterial nonwoven composite material.

[0011] Furthermore, in step 1, the atmosphere for plasma treatment is one or more of air, oxygen, nitrogen, or argon; the treatment power is 300-500 W, and the treatment time is 2-10 minutes.

[0012] Furthermore, in step 2, the concentration of the gelatin solution is 200-2000 mg / L.

[0013] Furthermore, in step 3, the concentration of dopamine monomer in the copper-containing dopamine solution is 0.5-10 g / L, and the mass ratio of the added dopamine monomer to the copper element in the copper salt is 1:2-6.

[0014] Furthermore, the areal density of the gelatin layer is 0.01-0.5 g / m².

[0015] Furthermore, the areal density of the polydopamine-copper ion chelate layer is 0.05-1 g / m².

[0016] Furthermore, the areal density ratio of the gelatin layer to the polydopamine-copper ion chelate layer is 1:1 to 1:20.

[0017] A second aspect of the present invention provides an antibacterial nonwoven composite material prepared by the preparation method described above, comprising:

[0018] Polypropylene nonwoven fabric substrate;

[0019] And, a gelatin layer and a polydopamine-copper ion chelate layer are sequentially constructed on the surface of the substrate.

[0020] A third aspect of the present invention provides a protective product comprising the above-described antibacterial nonwoven composite material.

[0021] Furthermore, the protective equipment is a mask, air filter material, or medical protective clothing.

[0022] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0023] 1. The preparation method of the antibacterial nonwoven composite material provided by this invention includes a three-step synergistic process of plasma activation, gelatin interface bridging, and polydopamine chelation for copper fixation. Plasma activation introduces polar groups on the polypropylene surface, providing chemical bonding sites for the uniform anchoring of the gelatin layer. The gelatin layer, as a biological interface layer, is firmly bonded to the activated substrate at one end, while the other end provides dense active anchoring sites for the polydopamine-copper ion chelate layer through abundant amino and carboxyl groups. Polydopamine forms a film in situ on the gelatin layer through self-polymerization, and achieves stable fixation and sustained release of copper ions through the strong chelating effect of its catechol groups. The coating adheres firmly to the substrate surface, with a copper ion release rate of less than 1 ppm / day. It exhibits a 94% inhibition rate against Staphylococcus aureus and an 87% inhibition rate against Escherichia coli, with a cell survival rate of not less than 90%. Simultaneously, it maintains the inherent air permeability and filtration performance of the substrate, combining high-efficiency antibacterial activity, sustained release, and high biocompatibility.

[0024] 2. The antibacterial nonwoven composite material obtained by the above preparation method provided by the present invention has an integrated three-layer structure consisting of a polypropylene substrate, a gelatin interface layer, and a polydopamine-copper ion chelating layer. The gelatin layer and the polydopamine-copper ion chelating layer are firmly constructed on the surface of the substrate in sequence. Copper ions are stably chelated in the polydopamine network, giving the material efficient and long-lasting antibacterial properties. At the same time, the copper ion release rate is low, resulting in high biocompatibility, while retaining the inherent air permeability and filtration properties of polypropylene nonwoven fabric, making it suitable for manufacturing various respiratory protective products.

[0025] 3. This invention provides a method for applying the above-mentioned antibacterial nonwoven composite material to protective products such as masks, air filter materials or medical protective clothing. Without sacrificing wearing comfort (breathability), it can endow the end product with active antibacterial function, effectively reduce the risk of microbial growth and cross-infection on the material surface during use, and improve the overall protective performance. Attached Figure Description

[0026] Figure 1 The results show the changes in contact angle of nonwoven fabrics after treatment with different low-temperature plasma power and time.

[0027] Figure 2 The image shows the diameter of polydopamine in its liquid state and its SEM image in its solid state.

[0028] Figure 3 SEM images of different doses of PDA:Cu=1:2 sprayed onto nonwoven fabrics modified with plasma-gelatin composite.

[0029] Figure 4 Mapping of the composite modified nonwoven fabric prepared in Example 1.

[0030] Figure 5 Results of biosafety experiments on HaCaT cells using PDA and the polydopamine-copper ion chelate (PDA@Cu-2) prepared in Example 1.

[0031] Figure 6 The results of cell necrosis staining for polydopamine-copper ion chelate (PDA@Cu-2).

[0032] Figure 7 The results show the quality changes of nonwoven fabric before and after high-temperature treatment, as well as the quantitative determination results of Cu²⁺ in the supernatant. Detailed Implementation

[0033] The present invention will now be described in detail with reference to the accompanying drawings.

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0035] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0036] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0037] To facilitate understanding of the invention, certain technical and scientific terms are specifically defined below. Unless otherwise expressly defined elsewhere in this document, all other technical and scientific terms used herein have the meanings commonly understood by one of ordinary skill in the art to which this invention pertains.

[0038] In this document, the terms “comprising” or “including” are open-ended expressions, meaning they include the contents specified in this invention but do not exclude other aspects.

[0039] In this document, the terms “optionally,” “optionally,” or “optionally” generally refer to an event or condition that may, but may not, occur, and the description includes both cases in which the event or condition occurs and cases in which the event or condition does not occur.

[0040] Existing polypropylene nonwoven fabric masks have the disadvantage of not being able to simultaneously achieve coating adhesion, controllable metal ion release, and high-efficiency antibacterial activity.

[0041] The first aspect of this embodiment provides a method for preparing an antibacterial nonwoven composite material, comprising the following steps:

[0042] Step 1: Perform plasma surface activation treatment on the polypropylene nonwoven fabric substrate;

[0043] Step 2: Coat the activated substrate surface with gelatin solution and dry to form a gelatin layer;

[0044] Step 3: Immerse the material obtained in Step 2 in a dopamine solution containing copper ions. Through the self-polymerization reaction of dopamine, a polydopamine-copper ion chelate layer is formed in situ on the gelatin layer, thus obtaining the antibacterial nonwoven composite material.

[0045] The preparation method provided by this invention effectively solves the problems of low utilization rate of antibacterial components in traditional physical blending methods, easy coating peeling in surface finishing methods, and complex processes and easy damage to the permeability of the substrate in chemical grafting methods through a three-step synergistic process of plasma activation, gelatin interface bridging, and polydopamine chelation and copper fixation. Plasma activation introduces polar groups on the polypropylene surface, providing chemical bonding sites for the uniform anchoring of the gelatin layer. The gelatin layer, as a biological interface layer, firmly bonds to the activated substrate at one end, while the other end provides dense active anchoring sites for the polydopamine-copper ion chelate layer through abundant amino and carboxyl groups. Polydopamine forms a film in situ on the gelatin layer through self-polymerization, and achieves stable fixation and sustained release of copper ions through the strong chelating effect of its catechol groups. This results in a final product that simultaneously achieves high antibacterial activity and low copper release safety.

[0046] Since the dopamine self-polymerization reaction in step 3 occurs in situ on the surface of the gelatin layer, some polydopamine oligomers and copper ions may penetrate into the surface microstructure of the gelatin layer, forming a micron- or nanometer-thick gelatin-polydopamine interpenetrating interface transition region between the gelatin layer and the polydopamine-copper ion chelate layer. The presence of this transition region further enhances the bonding force between the two layers, transforming the simple physical stacking of the polydopamine-copper ion chelate layer and the gelatin layer into a chemically interlocked structure.

[0047] In some embodiments, in step 1, the plasma treatment atmosphere is one or more of air, oxygen, nitrogen, or argon; the treatment power is 300-500 W, and the treatment time is 2-10 minutes. By limiting the appropriate plasma treatment power and time, polar groups (such as hydroxyl and carboxyl groups) can be fully introduced onto the surface of polypropylene fibers, significantly reducing the contact angle and improving hydrophilicity, thus providing an ideal interface for the uniform coating and firm anchoring of the subsequent gelatin layer.

[0048] In some embodiments, in step 2, the concentration of the gelatin solution is 200-2000 mg / L. A suitable gelatin solution concentration can form a uniform and continuous gelatin film layer on the substrate surface with a moderate thickness, providing sufficient active sites to efficiently anchor the subsequent polydopamine-copper ion chelating layer, while avoiding excessive coating thickness that clogs the pores between fibers, thus balancing antibacterial load and breathability.

[0049] In some embodiments, in step 3, the concentration of dopamine monomer in the copper-containing dopamine solution is 0.5-10 g / L, and the mass ratio of the added dopamine monomer to the copper element in the copper salt is 1:2-6. A suitable concentration of dopamine monomer and the appropriate mass ratio of dopamine monomer to copper element allow for a good balance between the self-polymerization rate of polydopamine and the chelating loading of copper ions. Under these conditions, the polydopamine-copper ion chelate layer has a moderate particle size, uniform dispersion, and stable zeta potential, enabling efficient loading and slow release of copper ions for long-lasting antibacterial effects while maintaining coating density and controlling the copper ion release rate within a safe range. Preferably, the mass ratio of the added dopamine monomer to the copper element in the copper salt is 1:2-4.

[0050] In some embodiments, the areal density of the gelatin layer is 0.01-0.5 g / m².

[0051] In some embodiments, the areal density of the polydopamine-copper ion chelate layer is 0.05-1 g / m².

[0052] In some embodiments, the areal density ratio of the gelatin layer to the polydopamine-copper ion chelate layer is 1:1 to 1:20. The gelatin layer is thin and uniform, providing sufficient anchoring points without clogging fiber pores; the polydopamine-copper ion layer has sufficient copper ion loading to ensure efficient antibacterial activity, while the dense coating allows for slow and sustained release of copper ions. This areal density ratio ensures optimal synergistic effect of the two layers, balancing antibacterial activity, adhesion, and breathability. Preferably, the areal density ratio of the gelatin layer to the polydopamine-copper ion chelate layer is 1:2 to 1:10.

[0053] The second aspect of this embodiment provides an antibacterial nonwoven composite material prepared by the preparation method described above, comprising:

[0054] Polypropylene nonwoven fabric substrate;

[0055] And, a gelatin layer and a polydopamine-copper ion chelate layer are sequentially constructed on the surface of the substrate.

[0056] The antibacterial nonwoven composite material obtained by the preparation method of the present invention has an integrated three-layer structure consisting of a polypropylene substrate, a gelatin interface layer, and a polydopamine-copper ion chelating layer. The gelatin layer and the polydopamine-copper ion chelating layer are firmly constructed on the surface of the substrate in sequence, and copper ions are stably chelated in the polydopamine network, giving the material efficient and long-lasting antibacterial properties. At the same time, the copper ion release rate is low, resulting in high biocompatibility, while retaining the inherent air permeability and filtration properties of polypropylene nonwoven fabric, making it suitable for manufacturing various respiratory protective products.

[0057] The third aspect of this embodiment provides a protective product comprising the aforementioned antibacterial nonwoven composite material.

[0058] Applying the antibacterial nonwoven composite material of the present invention to protective products such as masks, air filter materials or medical protective clothing can endow the end products with active antibacterial function without sacrificing wearing comfort (breathability), effectively reducing the risk of microbial growth and cross-infection on the material surface during use, and improving the overall protective effectiveness.

[0059] In some embodiments, the protective equipment is a mask, air filter material, or medical protective clothing.

[0060] To better understand the technical solutions of the above embodiments, the following more detailed experimental examples are provided for further explanation. Those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of this disclosure. Where specific techniques or conditions are not specified in the examples, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0061] Example 1

[0062] (1) Plasma treatment: Polypropylene meltblown nonwoven fabric (25 g / m²) was placed in a low-temperature plasma treatment instrument with an air atmosphere, a power of 400 W, and a treatment time of 3 minutes. After treatment, the contact angle decreased from approximately 120° to approximately 25°, and the hydrophilicity was significantly improved (e.g., Figure 1 (As shown).

[0063] (2) Gelatin coating: The nonwoven fabric treated in step (1) is immersed in a gelatin solution with a concentration of 400 mg / L, and then dried at 60°C for 30 minutes to form a gelatin layer. Under these conditions, the gelatin film is uniform and the contact angle is further reduced to about 15°.

[0064] (3) PDA-Cu loading: Prepare a dopamine solution containing copper ions, with a dopamine monomer concentration of 2 g / L. Add copper sulfate (CuSO4·5H2O) at a mass ratio of 1:2 between dopamine monomer and copper element, and dissolve it in Tris-HCl buffer (pH 8.5, 10 mM). Immerse the material obtained in step (2) in this solution and react at room temperature in the dark for 12 hours. After removal, rinse with deionized water and dry to obtain the antibacterial nonwoven composite material.

[0065] During the preparation process, the areal density of the gelatin layer and the PDA-Cu layer was also tested.

[0066] Precision electronic balance (accuracy 0.01 mg); constant temperature and humidity chamber (temperature 23±1℃, relative humidity 50±2%); desiccator.

[0067] Test procedure: Cut 10 square samples of polypropylene meltblown nonwoven fabric substrate into 10 cm × 10 cm (area S = 0.01 m²), place them in a constant temperature and humidity chamber for at least 24 hours to equilibrate, until the difference between two consecutive weighings does not exceed 0.02 mg. After removal, weigh them quickly and record the average value of the 10 samples as W0.

[0068] After plasma treatment according to step (1) of Example 1, the sample was coated with gelatin solution (400 mg / L) according to step (2) and dried at 60°C for 30 minutes. The dried sample was equilibrated in a constant temperature and humidity chamber for 24 hours, and the average value was weighed in the same way and recorded as W1.

[0069] The density of the gelatin layer was calculated as (W1 - W0) / 0.01, in g / m². Ten parallel measurements showed that the density of the gelatin layer in this embodiment was 0.08 ± 0.01 g / m².

[0070] Continue impregnating the PDA-Cu solution according to step (3). After reaction, rinsing, and drying, maintain constant temperature and humidity equilibrium, weigh, and record as W2. Calculate the density of the PDA-Cu layer using the same method, which is 0.21±0.03 g / m².

[0071] PDA nanoparticles exhibit a regular spherical structure with a particle size of approximately 100 nm, and most particles exist in a monodisperse state, such as... Figure 2 As shown, when PDA:Cu=1:2, the composite particle size is about 106 nm, the Zeta potential is -14.3 mV, and the PDI is as low as 0.11, which is the best level of dispersibility and uniformity in this experimental gradient.

[0072] SEM images of the PDA-Cu-2 loaded fiber show that the coating is uniformly applied to the fiber surface, with well-maintained inter-fiber porosity, a slight increase in the apparent fiber diameter, and no obvious coating agglomeration. Figure 3 As shown in the figure. Elemental mapping analysis indicates that C, O, N, and Cu are uniformly distributed in the fiber region, proving that the plasma-gelatin-PDA-Cu-2 composite modification process can construct a functional coating with uniform composition on the surface of nonwoven fabrics. Figure 4 As shown.

[0073] Performance testing

[0074] Testing process:

[0075] test

[0076] (1) Antibacterial rate test

[0077] Bacterial strains: Staphylococcus aureus (ATCC 6538), Escherichia coli (ATCC 25922).

[0078] Preparation of bacterial culture: Streaking of frozen bacterial culture onto nutrient agar plates and incubating at 37℃±1℃ for 24 hours. Select typical single colonies and inoculate into nutrient broth, incubating with shaking at 37℃±1℃ for 18-24 hours to obtain the inoculated bacterial culture. Determine the bacterial concentration using a spectrophotometer and dilute to 1×10⁻⁶ with PBS buffer (pH 7.0). 5 -4×10 5 CFU / mL was used as the bacterial suspension for the test.

[0079] Test Procedure: Cut the sample into approximately 5 mm × 5 mm fragments. Weigh 0.75 g ± 0.05 g of sample and place it into a sterile Erlenmeyer flask. Add 5 mL of the test bacterial suspension and 70 mL of PBS buffer (0.03 mol / L, pH 7.0), and seal the flask. Simultaneously prepare a control sample (containing no sample, only an equal volume of bacterial suspension and PBS buffer). Place the Erlenmeyer flask in a constant temperature shaking incubator at 37℃ ± 2℃ and shake at 150 r / min for 18 hours. After incubation, serially dilute with PBS buffer. Pipette 1 mL of the diluted solution into a sterile Petri dish, add approximately 15 mL of nutrient agar medium cooled to 46℃ ± 1℃, and mix thoroughly. After the plates solidify, invert them and incubate at 37℃ ± 1℃ for 24-48 hours, then count the colonies.

[0080] Calculation formula: Antibacterial rate (%) = [(C0 - C) / C0] × 100%

[0081] Where: C0—the concentration of viable bacteria (CFU / mL) after 18 hours of shaking contact with the control sample; C—the concentration of viable bacteria (CFU / mL) after 18 hours of shaking contact with the test sample.

[0082] (2) Copper ion release rate test

[0083] Reagents and instruments: Phosphate buffer (PBS, pH 7.4); Inductively coupled plasma atomic emission spectrometer (PerkinElmer ICP 2100 or equivalent); Copper standard solution (1000 μg / mL, national standard substance).

[0084] Test Procedure: Cut a 5 cm × 5 cm sample (25 cm² area), immerse it in 50 mL of PBS buffer (pH 7.4), and incubate at 37℃±1℃ for 24 hours. After soaking, remove the sample, collect all supernatant, and filter through a 0.45 μm aqueous microporous membrane. ICP-OES Measurement Conditions: RF power 1300 W, plasma gas flow rate 15 L / min, auxiliary gas flow rate 1.5 L / min, nebulizer gas flow rate 0.8 L / min, and the analytical wavelength selected is Cu 324.754 nm. Prepare a series of standard working solutions (0, 0.1, 0.5, 1.0, 5.0, and 10.0 mg / L) using copper standard solutions to establish a standard curve. Measure the Cu²⁺ concentration in the supernatant and calculate the daily copper ion release rate in ppm / day.

[0085] (3) Cytotoxicity test

[0086] Cell line: Human immortalized keratinocytes (HaCaT) were cultured in DMEM high glucose medium containing 10% fetal bovine serum and routinely passaged at 37°C and 5% CO2.

[0087] Preparation of extract: The sample was cut into small pieces and added to serum-free DMEM medium at a surface area to extraction medium volume ratio of 3 cm² / mL. Extraction was carried out at 37℃±1℃ for 24 hours. After extraction, the supernatant was filtered through a 0.22 μm sterile filter membrane to obtain the stock extract. The stock extract was diluted to the required concentration (0.01-1 μg / mL, calculated as PDA or PDA@Cu) with serum-free DMEM medium.

[0088] CCK-8 assay: HaCaT cells in logarithmic growth phase were used, and 1×10⁻⁶ cells were used as the assay result. 4 Cells were seeded at a density of 100 μL per well in 96-well plates and cultured at 37°C and 5% CO2 for 24 hours to allow cell adhesion. The original culture medium was discarded, and 100 μL of culture medium containing different concentrations of extract was added to each well, with six parallel wells for each concentration. A negative control group (culture medium only, no extract) and a blank control group (culture medium only, no cells) were also set up. After another 24 hours of culture, 10 μL of CCK-8 reagent was added to each well, and the plates were incubated at 37°C in the dark for 2 hours. The absorbance (OD value) of each well was measured at 450 nm using a microplate reader.

[0089] Calculation formula: Cell survival rate (%) = [(OD experimental group - OD blank group) / (OD negative control group - OD blank group)] × 100%.

[0090] Example 1: Product Performance Testing

[0091] Antibacterial rate: 94% inhibition rate against Staphylococcus aureus and 87% inhibition rate against Escherichia coli.

[0092] Copper ion release rate: ≤1 ppm / day, in compliance with WHO / EPA safety standards.

[0093] Cytotoxicity: The in vitro cytotoxicity of polydopamine (PDA) and its copper ion chelate (PDA@Cu-2) to human immortalized keratinocytes (HaCaT) was evaluated using the CCK-8 cell proliferation assay. Figure 5 and Figure 6 It can be seen that within the experimental concentration range of 0–1 μg / mL, neither PDA nor PDA@Cu-2 showed significant cytotoxicity to HaCaT cells. For the PDA-treated group, cell viability remained above 95% at all concentration gradients, indicating that PDA has excellent biocompatibility within the experimental concentration range. The cell viability in the PDA@Cu-2-treated group was also consistently above 90%, indicating that the composite material also possesses good biocompatibility. Figure 5 The results of the biosafety experiment of PDA and the polydopamine-copper ion chelate (PDA@Cu-2) prepared in Example 1 on HaCaT cells are shown. Figure 6 The results show the staining results for cell necrosis.

[0094] Copper bonding stability:

[0095] To investigate the bonding stability of the plasma-gelatin-PDA@Cu-2 complex with the surface of PP nonwoven fabric, this embodiment employs a high-temperature water bath treatment method combined with a PerkinElmer ICP 2100 inductively coupled plasma optical emission spectrometer (ICP-OES). The evaluation was conducted from two dimensions: changes in the mass of the nonwoven fabric and the amount of Cu²⁺ released from the supernatant. The results of the mass change of the nonwoven fabric before and after high-temperature treatment and the quantitative determination results of Cu²⁺ in the supernatant are shown in [the table below]. Figure 7 Therefore, it can be seen that the quality change of the nonwoven fabric after high-temperature water bath treatment is minimal, the Cu²⁺ concentration in the supernatant is low, and copper ions are firmly attached to the nonwoven fabric.

[0096] Filtration performance: Meets the performance requirements of EN 14683 and ASTM F2100 for face masks.

[0097] Example 2

[0098] Compared to Example 1, Example 2 only changed the mass ratio of the added dopamine monomer to the copper element in the copper salt.

[0099] The other preparation processes and parameters are the same as in Example 1.

[0100] In Example 2-1, the mass ratio of the added dopamine monomer to the copper element in the copper salt was 1:0.5.

[0101] In Example 2-2, the mass ratio of the added dopamine monomer to the copper element in the copper salt was 1:1.

[0102] In Examples 2-3, the mass ratio of the added dopamine monomer to the copper element in the copper salt was 1:3.

[0103] In Examples 2-4, the mass ratio of the added dopamine monomer to the copper element in the copper salt was 1:4.

[0104] In Examples 2-5, the mass ratio of the added dopamine monomer to the copper element in the copper salt was 1:6.

[0105] In Examples 2-6, the mass ratio of the added dopamine monomer to the copper element in the copper salt was 1:8.

[0106] Using the same testing procedure as in Example 1, the performance of each group of products in Example 2 was tested, and the test results are shown in Table 1.

[0107] Table 1 Product Performance Test in Example 2

[0108] Group Copper ion release rate (ppm / day) Staphylococcus aureus inhibition rate (%) Escherichia coli inhibition rate (%) Cell viability (%) Example 1 0.8 94 87 94 Example 2-1 0.4 85 78 96 Example 2-2 0.6 90 84 95 Example 2-3 0.85 95 88 93 Examples 2-4 0.9 95 88 93 Examples 2-5 1.0 96 89 92 Examples 2-6 1.2 96 89 90

[0109] Example 3

[0110] This embodiment investigates the effect of the areal density ratio of the gelatin layer to the polydopamine-copper ion chelate layer on the overall properties of the composite material. By adjusting the gelatin solution concentration and / or the mass ratio of dopamine monomer to copper (gelatin solution concentration 200-2000 mg / L, mass ratio of added dopamine monomer to copper in the copper salt 1:2-6), a series of samples with different areal density ratios were obtained. Apart from this, the remaining preparation process and parameters were the same as in Example 1.

[0111] The areal density settings are shown in Table 2.

[0112] Table 2

[0113] Example 3-1 0.50±0.03 0.25±0.03 1:0.5 Example 3-2 0.45±0.03 0.45±0.03 1:1 Example 3-3 0.20±0.02 0.40±0.03 1:2 Examples 3-4 0.08±0.01 0.40±0.03 1:5 Examples 3-5 0.04±0.01 0.40±0.03 1:10 Examples 3-6 0.03±0.01 0.45±0.03 1:15 Examples 3-7 0.02±0.01 0.40±0.03 1:20 Examples 3-8 0.02±0.01 0.50±0.03 1:25

[0114] Using the same testing process as in Example 1, the performance of each group of products in Example 3 was tested, and the test results are shown in Table 3.

[0115] Table 3 Performance Tests

[0116] Group Copper ion release rate (ppm / day) Staphylococcus aureus inhibition rate (%) Escherichia coli inhibition rate (%) Cell viability (%) Example 3-1 0.6 84 76 95 Example 3-2 0.7 90 84 94 Example 3-3 0.8 94 87 94 Examples 3-4 0.9 95 88 93 Examples 3-5 1.0 95 88 92 Examples 3-6 1.1 96 89 91 Examples 3-7 1.3 96 89 89 Examples 3-8 1.5 97 90 86

[0117] Example 4

[0118] (1) Plasma treatment: Take polypropylene meltblown nonwoven fabric (25 g / m²) and place it in a low-temperature plasma treatment instrument. The atmosphere is air, the power is 300 W, and the treatment time is 2 minutes.

[0119] (2) Gelatin coating: The nonwoven fabric treated in step (1) is immersed in a gelatin solution with a concentration of 200 mg / L, and then dried at 50°C for 30 minutes to form a gelatin layer. The density of the gelatin layer is 0.02 g / m².

[0120] (3) PDA-Cu loading: Prepare a dopamine solution containing copper ions, with a dopamine monomer concentration of 2 g / L. Add copper sulfate at a mass ratio of dopamine monomer to copper of 1:2 and dissolve it in Tris-HCl buffer (pH 8.5, 10 mM). Immerse the material obtained in step (2) in this solution and react at room temperature in the dark for 12 hours. After removal, rinse with deionized water and dry to obtain the antibacterial nonwoven composite material. The PDA-Cu layer density is 0.18 g / m².

[0121] Example 5

[0122] (1) Plasma treatment: Take polypropylene meltblown nonwoven fabric (25 g / m²) and place it in a low-temperature plasma treatment instrument. The atmosphere is air, the power is 400 W, and the treatment time is 3 minutes.

[0123] (2) Gelatin coating: The nonwoven fabric treated in step (1) is immersed in a gelatin solution with a concentration of 2000 mg / L, and then dried at 80°C for 30 minutes to form a gelatin layer. The density of the gelatin layer is 0.50 g / m².

[0124] (3) PDA-Cu loading: Prepare a dopamine solution containing copper ions, with a dopamine monomer concentration of 0.5 g / L. Add copper sulfate at a mass ratio of dopamine monomer to copper element of 1:6 and dissolve it in Tris-HCl buffer (pH 8.5, 10 mM). Immerse the material obtained in step (2) in this solution and react at room temperature in the dark for 12 hours. After removal, rinse with deionized water and dry to obtain the antibacterial nonwoven composite material. The PDA-Cu layer density is 0.18 g / m².

[0125] Example 6

[0126] (1) Plasma treatment: Take polypropylene meltblown nonwoven fabric (25 g / m²) and place it in a low-temperature plasma treatment instrument. The atmosphere is air, the power is 500 W, and the treatment time is 10 minutes.

[0127] (2) Gelatin coating: The nonwoven fabric treated in step (1) is immersed in a gelatin solution with a concentration of 400 mg / L, and then dried at 60°C for 30 minutes to form a gelatin layer. The density of the gelatin layer is 0.09 g / m².

[0128] (3) PDA-Cu loading: Prepare a dopamine solution containing copper ions, with a dopamine monomer concentration of 10 g / L. Add copper sulfate at a mass ratio of dopamine monomer to copper element of 1:6 and dissolve it in Tris-HCl buffer (pH 8.5, 10 mM). Immerse the material obtained in step (2) in this solution and react at room temperature in the dark for 12 hours. After removal, rinse with deionized water and dry to obtain the antibacterial nonwoven composite material. The PDA-Cu layer density is 0.58 g / m².

[0129] Comparative Example 1

[0130] The only difference from Example 1 is that step (1) is omitted, and the polypropylene meltblown nonwoven fabric is not subjected to plasma treatment. All other conditions are exactly the same.

[0131] Comparative Example 2

[0132] The only difference from Example 1 is that step (2) is omitted, and the plasma-treated nonwoven fabric is not coated with gelatin solution but directly immersed in a dopamine solution containing copper ions for PDA-Cu loading. All other conditions are exactly the same.

[0133] Comparative Example 3

[0134] The only difference from Example 1 is that step (3) is modified. Dopamine monomer is not added to the solution. Instead, the material coated with gelatin layer obtained in step (2) is immersed in Tris-HCl buffer containing only copper sulfate (the copper ion concentration is the same as the copper ion concentration of the copper-containing dopamine solution in Example 1, pH 8.5) for 12 hours at room temperature. After immersion, it is rinsed with deionized water and dried. All other conditions are exactly the same.

[0135] Comparative Example 4

[0136] The only difference from Example 1 is that step (3) is modified. No copper salt is added to the solution. Only a Tris-HCl buffer solution (pH 8.5) of dopamine monomer (2 g / L) is prepared. The material obtained in step (2) is immersed in this solution and reacted at room temperature in the dark for 12 hours. After removal, it is rinsed with deionized water and dried. All other conditions are exactly the same.

[0137] Comparative Example 5

[0138] The difference from Example 1 is that steps (1) and (2) are omitted, the polypropylene meltblown nonwoven fabric is not subjected to plasma treatment, and it is not coated with gelatin solution. The original nonwoven fabric is directly immersed in a dopamine solution containing copper ions (dopamine monomer concentration 2 g / L, PDA:Cu=1:2, Tris-HCl buffer pH 8.5), reacted at room temperature in the dark for 12 hours, and then rinsed with deionized water and dried.

[0139] Table 4 Performance tests of products prepared in Examples 4-6 and comparative examples

[0140] Copper ion release rate (ppm / day) Inhibition rate of Staphylococcus aureus (%) Inhibition rate of Escherichia coli (%) Cell viability (%) Example 4 0.7 91 85 95 Example 5 0.6 92 86 95 Example 6 1.0 96 89 92 Comparative Example 1 3.5 72 65 / Comparative Example 2 2.8 75 68 / Comparative Example 3 (Initial 24h) 15 85 80 72 Comparative Example 3 (after 48h solution change) 0.3 18 12 / Comparative Example 4 0 5 3 96

[0141] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," "some implementations," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0142] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing an antibacterial nonwoven composite material, characterized in that, Includes the following steps: Step 1: Perform plasma surface activation treatment on the polypropylene nonwoven fabric substrate; Step 2: Coat the activated substrate surface with gelatin solution and dry to form a gelatin layer; Step 3: Immerse the material obtained in Step 2 in a dopamine solution containing copper ions to form a polydopamine-copper ion chelate layer in situ on the gelatin layer, thereby obtaining the antibacterial nonwoven composite material.

2. The preparation method according to claim 1, characterized in that, In step 1, the plasma treatment atmosphere is one or more of air, oxygen, nitrogen, or argon; the treatment power is 300-500 W, and the treatment time is 2-10 minutes.

3. The preparation method according to claim 1, characterized in that, In step 2, the concentration of the gelatin solution is 200-2000 mg / L.

4. The preparation method according to claim 1, characterized in that, In step 3, the concentration of dopamine monomer in the copper-containing dopamine solution is 0.5-10 g / L, and the mass ratio of the added dopamine monomer to the copper element in the copper salt is 1:2-6.

5. The preparation method according to any one of claims 1-4, characterized in that, The areal density of the gelatin layer is 0.01-0.5 g / m².

6. The preparation method according to claim 5, characterized in that, The areal density of the polydopamine-copper ion chelate layer is 0.05-1 g / m².

7. The preparation method according to claim 6, characterized in that, The areal density ratio of the gelatin layer to the polydopamine-copper ion chelate layer is 1:1 to 1:

20.

8. An antibacterial nonwoven composite material prepared by the preparation method according to any one of claims 1-7, characterized in that, include: Polypropylene nonwoven fabric substrate; And, a gelatin layer and a polydopamine-copper ion chelate layer are sequentially constructed on the surface of the substrate.

9. A protective product, characterized in that, It includes the antibacterial nonwoven composite material as described in claim 8.

10. The protective equipment according to claim 9, characterized in that, The protective equipment mentioned includes masks, air filter materials, or medical protective clothing.

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