A non-sterilization type mildewproof and bacteriostatic material dynamically responding to bacterial proliferation, and a preparation method and application thereof

Abstract

The application discloses a kind of dynamic response bacteria proliferation non-sterilization type mildewproof bacteriostatic material and preparation method and application thereof.The material includes: polyvinyl alcohol, carboxymethyl cellulose or its salt, and metal ion, polyvinyl alcohol, carboxymethyl cellulose or its salt is bridged by metal ion;Metal ion includes Li + The material of the application releases Na + As signal medium by bacteria proliferation, through coordination-dissociation process, release Li + According to demand, further through the metabolic demand of sodium discharge and potassium absorption in the process of bacteria proliferation, utilize Li + With K + Similar hydrated radius, to occupy the "metabolic deception" of potassium ion channel, induce bacteria cell to actively absorb Li + On the one hand, lead to bacteria cell replication lack essential nutrient K + , finally gradually decline;On the other hand, by taking water molecules of intracellular protein, lead to protein spatial conformation change and inactivation, two aspects synergistic effect, realized Li + At low concentration, can high-efficiency mildewproof antibacterial, and the effect is durable.

Description

Technical Field

[0001] This invention relates to the field of functional materials technology, specifically to a non-bactericidal antifungal and antimicrobial material that dynamically responds to bacterial proliferation, its preparation method, and its application. Background Technology

[0002] Mold is a widespread and serious pollution problem in human settlements in hot and humid regions around the world, causing significant health damage and enormous economic losses of food and resources every year. Mold is characterized by rapid reproduction, strong adaptability, long latency, and wide distribution, which poses a severe challenge to effectively curbing mold growth and achieving long-term mold prevention.

[0003] Traditional anti-mildew and antibacterial technologies typically employ strong oxidizing agents for environmental surface treatment, such as those containing hypochlorite ions (ClO). — Hypochlorite or hydrogen peroxide containing hydroxyl radicals (·OH), these materials pass through ClO - The vigorous chemical reactions of strong oxidizing groups such as ·OH can indiscriminately and rapidly destroy the structure of microbial cells, achieving immediate sterilization. However, while this vigorous chemical reaction achieves immediate sterilization, it also presents problems such as being unfriendly to the human body and the rapid depletion of effective antibacterial components. Specifically, strong oxidants generally react with air to produce volatile, irritating gases—commonly known as the "bleach smell"—which not only irritate and damage the human respiratory system but also lead to the unnecessary loss of effective antibacterial components. In addition, the reaction between strong oxidants and microbial cells is very rapid, and ordinary users cannot control it after spraying. This results in the rapid depletion of effective components after the initial action, failing to provide continuous protection against subsequently settled mold spores. Ultimately, the material exhibits an anti-mold effect that is "effective when used, but ineffective afterward," causing repeated mold contamination and failing to meet the need for long-term mold prevention. This is precisely the fundamental reason why mold contamination continues to cause health problems and huge economic losses worldwide to this day.

[0004] With the development of technology, Ag + Metal ions, primarily composed of Ag, are gradually becoming the mainstream of current environmental surface antibacterial technologies. Studies have found that Ag... + Sterilization can be achieved through interactions with cell membranes, interference with enzyme activity, and the generation of free radicals, but this technology still has the following drawbacks: Ag + Easily reacts with Cl in the environment - It fails due to the formation of precipitates, and its dependence on precious metals makes it expensive. Even when combined with photocatalytic technology (such as titanium dioxide photocatalysis) to reduce the required Ag content... + While concentration and cost are important factors, photocatalytic activity is limited in typical environments where mold is prevalent, such as dark and humid conditions. This leads to a significant decrease in antibacterial effect, resulting in problems such as incomplete antibacterial action, short duration of action, and easy recurrence. Consequently, it is still difficult to meet the demand for long-lasting mold prevention.

[0005] Therefore, there is an urgent need in this field to develop materials and technologies that can exert long-lasting antibacterial and antifungal effects in complex environments (especially dark and humid environments) in order to solve the problem of recurring mold contamination.

[0006] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art. Summary of the Invention

[0007] The purpose of this invention is to provide a non-sterilizing antifungal and antimicrobial material that dynamically responds to bacterial proliferation, along with its preparation method and application, to solve the problems of incomplete antimicrobial action, short duration of action, and easy recurrence in existing antifungal and antimicrobial technologies, thereby avoiding repeated occurrences of mold contamination.

[0008] Based on the above, the present invention first provides a non-sterilizing antifungal and antimicrobial material that dynamically responds to bacterial proliferation. The material comprises: polyvinyl alcohol, carboxymethyl cellulose or its salts, and metal ions, wherein the polyvinyl alcohol, carboxymethyl cellulose or its salts are bridged by the metal ions; wherein the metal ions include: Li + .

[0009] Optionally, the metal ion reacts with the carboxylate group (-COO) of carboxymethyl cellulose or its salt. - The metal ions are connected by electrostatic interaction, and the hydroxyl groups (-OH) of polyvinyl alcohol are connected by ion-dipole interaction.

[0010] Another aspect of the present invention provides a method for preparing a non-bactericidal antifungal and antimicrobial material that dynamically responds to bacterial proliferation, comprising the following steps:

[0011] S1, Weigh out polyvinyl alcohol, carboxymethyl cellulose or their salts and dissolve them in pure water, then stir and heat to form a homogeneous mixed base liquid;

[0012] S2, Under stirring, add metal ion salt to the mixed base liquid, mix evenly, and let stand for at least 10 minutes to obtain a non-bactericidal antifungal and antimicrobial material with dynamic response to bacterial proliferation in solution form;

[0013] The metal ions include: Li + .

[0014] Optionally, the mass ratio of carboxymethyl cellulose or its salt to polyvinyl alcohol is 1:0.3-1:5; the mass ratio of metal ion salt to carboxymethyl cellulose or its salt is 1:0.05-1:10.

[0015] Optionally, in the solution-form, dynamically responsive, non-sterilizing antifungal and antimicrobial material for bacterial proliferation, the mass percentage concentration of metal ions is 0.5%-15%.

[0016] Optionally, the specific operation steps of step S1 are as follows:

[0017] S1.1 Weigh polyvinyl alcohol and add it to pure water. While stirring at 100 rpm to 3000 rpm, heat the solution to 50℃ to 95℃ using gradient heating, and continue stirring until a homogeneous polyvinyl alcohol aqueous solution is obtained.

[0018] S1.2, Weigh carboxymethyl cellulose or its salt and add it to the polyvinyl alcohol solution under stirring. Stir at 50℃-95℃ for 1 h-4 h to form the homogeneous mixed base liquid.

[0019] Optionally, the following processing may be included after step S2:

[0020] The non-sterilizing antifungal and antimicrobial material in solution form, which is dynamically responsive to bacterial proliferation, is prepared into a gel form through repeated freeze-thaw operations.

[0021] Optionally, the following processing may be included after step S2:

[0022] a. In the non-bactericidal antifungal and antibacterial material that dynamically responds to bacterial proliferation in solution form, a crosslinking agent with a mass ratio not exceeding 10% is added, and after mixing evenly, the reaction solution is allowed to stand and degas to obtain a film-forming solution.

[0023] b. Spraying the film-forming solution onto the surface of a substrate to form a continuous liquid film, wherein the liquid film is dried to form a non-sterilizing antifungal and antimicrobial material in the form of a film that dynamically responds to bacterial proliferation; wherein the crosslinking agent includes at least one of genipin or citrate.

[0024] In another aspect, the present invention also provides the application of the aforementioned anti-mildew and antibacterial materials, or the anti-mildew and antibacterial materials prepared by the aforementioned preparation method, in the anti-mildew and antibacterial application in the environment or on objects.

[0025] Compared with the prior art, the beneficial effects of the present invention include at least the following:

[0026] 1. This invention provides a supramolecular polymer material Li@CMC-PVA, wherein Li + As an "ion bridge," the CMC and PVA do not simply mix physically, but form a more compact structure whose density can vary with Li. + The precisely controlled supramolecular network structure, in turn, also provides Li + It provides a stable coordination environment and alters Li +The mechanism of interaction with target microorganisms (molds, bacteria) has changed from relying on concentration gradients for static, passive, and indiscriminate diffusion into a mechanism that only affects the excretion of Na during microbial metabolism. + Li will only be released as needed. + The dynamic, active, and targeted triggering release process solves the problem of Li in existing technologies. + It has the problems of being easily lost in the environment and having no obvious antibacterial effect even at high concentrations.

[0027] 2. The mechanism of action of the material of this invention is as follows: Na released by bacterial proliferation in the microenvironment involved. + As a signal medium, Li is released on demand through a coordination-dissociation process. + Furthermore, by utilizing the metabolic requirements of sodium excretion and potassium uptake during bacterial cell proliferation, Li + With K + Similar hydration radii, through "metabolic deception" by occupying potassium ion channels (such as the Trk and Kdp systems), induce bacterial cells to actively take up Li. + On the one hand, this leads to a lack of the essential nutrient K for bacterial cell replication. + Unable to complete the necessary preparation of substances for bacterial proliferation, replication is interrupted, and eventually the bacteria gradually die. On the other hand, by capturing water molecules from intracellular proteins, the protein's spatial conformation is altered, leading to inactivation. These two aspects work synergistically to achieve Li + It can effectively prevent mold and bacteria even at low concentrations, and its effect is far longer than that of traditional ionic antibacterial agents.

[0028] The aforementioned "metabolic deception" mechanism exhibited a significant broad-spectrum inhibitory effect on the molds and bacteria it encountered. The target microorganisms (such as molds and bacteria) relied on their low-selectivity potassium ion uptake systems (such as the Trk and Kdp systems) on their cell membranes to actively accumulate the potassium necessary for growth from the external environment. + Li + With K + Similar hydration radii can lead to misidentification and competitive uptake by this system, thereby blocking its basal nutrient metabolism. Conversely, potassium homeostasis in higher organisms' cells primarily depends on Na+. + / K + - The ATP pump is maintained, and its fine potassium ion channels are primarily used for electrical signal transduction and for Li + It has extremely high recognition capabilities. Therefore, this "metabolic deception" mechanism can precisely target the basic nutritional pathways unique to microorganisms, while having minimal impact on the basic physiological functions of human cells, resulting in high safety.

[0029] 3. Compared with the "direct poisoning" mechanism of traditional materials that destroy cell structure, the material of this invention has a mild effect and is less likely to trigger the stress death resistance response of bacteria, thus fundamentally reducing the risk of inducing microorganisms to develop drug resistance.

[0030] 4. The material of this invention can maintain stable and long-lasting anti-mildew and antibacterial properties even under harsh conditions of relative humidity ≥95% and darkness, solving the problem that traditional antibacterial materials are difficult to play an effective role in high humidity environments. Attached Figure Description

[0031] Figure 1A This is a schematic diagram of the molecular structure of Li@CMC-PVA, the antifungal and antibacterial material of this invention.

[0032] Figure 1B This is a schematic diagram illustrating the anti-mold and antibacterial mechanism of the anti-mold and antibacterial material Li@CMC-PVA of the present invention.

[0033] Figure 2 The images show the appearance of different forms of Li@CMC-PVA anti-mildew and antibacterial materials according to the present invention; wherein:

[0034] A indicates the liquid state;

[0035] B indicates gel form;

[0036] C indicates the thin film morphology;

[0037] D indicates powder form.

[0038] Figure 3A The 1H NMR spectrum of the 0.5% Li@CMC-PVA antifungal and antibacterial material sample prepared in Example 1 of this invention (… 1 (H NMR) image.

[0039] Figure 3B The 1H NMR spectrum of the 3% Li@CMC-PVA antifungal and antibacterial material sample prepared in Example 1 of this invention (…). 1 (H NMR) image.

[0040] Figure 3C The 1H NMR spectrum of the 5% Li@CMC-PVA antifungal and antibacterial material sample prepared in Example 1 of this invention (…). 1 (H NMR) image.

[0041] Figure 4 The image shows the dynamic light scattering (DLS) particle size distribution of Li@CMC-PVA antifungal and antibacterial material samples with different concentrations (0.5%, 3%, 5%) prepared in Example 1 of this invention.

[0042] Figure 5 In Example 1 of this invention, 5% Li alone + 1. Inhibition zone effect of CMC-PVA system alone and 5.0%Li@CMC-PVA solution sample against Aspergillus niger (drug susceptibility test paper disc method).

[0043] Figure 6A The graphs show the growth inhibition of the Li@CMC-PVA antifungal and antibacterial material in Example 1 of this invention after contact with bacteria (Staphylococcus aureus) for 8 hours and 24 hours.

[0044] Figure 6B The graphs show the growth inhibition of the Li@CMC-PVA antifungal and antibacterial material in Example 1 of this invention after contact with mold (Candida albicans) for 8 hours and 24 hours.

[0045] Figure 7A The results of the contact time and surface viable bacteria concentration of the Li@CMC-PVA antifungal and antibacterial material sample in Example 1 of this invention are shown.

[0046] Figure 7B The results of time-inhibition rate of Li@CMC-PVA antifungal and antibacterial material samples in Example 1 of this invention after contact with different bacteria.

[0047] Figure 8 The graph shows the results of the determination of the minimum inhibitory concentration (MIC) of the Li@CMC-PVA antifungal and antibacterial material against Aspergillus niger in Example 1 of this invention.

[0048] Figure 9 The graph shows the results of the determination of the minimum bactericidal concentration (MBC) of Li@CMC-PVA antifungal and antibacterial material against Aspergillus niger in Example 1 of this invention.

[0049] Figure 10 This is a photographic illustration of mold colony growth on the surface of a substrate that has been treated with or has not been treated with the Li@CMC-PVA anti-mold and antibacterial material in Example 1 of this invention.

[0050] Figure 11 These are on-site comparison photos of the anti-mold effect of Li@CMC-PVA anti-mold and antibacterial material on the wall surface in Embodiment 1 of the present invention.

[0051] Figure 12 These are field comparison photos of the anti-mold and antibacterial effects of Li@CMC-PVA anti-mold material in different application scenarios in Example 1 of this invention, wherein:

[0052] AB represents a comparison of the anti-mold effects of silage with and without the material of this invention;

[0053] CD represents a comparison of the anti-mildew effect of cardboard packaging with or without the material of this invention.

[0054] Figure 13 This is a white light photograph of the Li@CMC-PVA antifungal and antibacterial material in Example 1 of this invention, showing its toxicity to L929 fibroblasts (MTT).

[0055] A represents control cells that were not treated with 5.0% Li@CMC-PVA solution;

[0056] B represents the cells in the experimental group treated with 5.0% Li@CMC-PVA solution.

[0057] Figure 14 This is a SEM image showing the structural changes of Aspergillus niger treated with the Li@CMC-PVA antifungal and antibacterial material in Example 1 of this invention.

[0058] Figure 15 This is a transmission electron microscope (TEM) image of Aspergillus niger treated with the Li@CMC-PVA antifungal and antibacterial solution material in Example 1 of the present invention.

[0059] Figure 16 This is a rheological analysis data graph of the Li@CMC-PVA antifungal and antibacterial material in Example 2 of the present invention.

[0060] Figure 17A This is an atomic force microscope (AFM) height sensor image of the Li@CMC-PVA antifungal and antibacterial material sample in Example 3 of the present invention.

[0061] Figure 17B This is an atomic force microscope (AFM) phase image of the Li@CMC-PVA antifungal and antibacterial material sample in Example 3 of the present invention.

[0062] Figure 18 This is a schematic diagram of the cross-sectional SEM cross-linking degree of the 0% and 3% Li@CMC-PVA samples in Example 3 of the present invention.

[0063] Figure 19A The thermogravimetric curve (TG) of the Li@CMC-PVA antifungal and antibacterial material sample in Example 3 of this invention.

[0064] Figure 19B The thermogravimetric differential curve (DTG) of the Li@CMC-PVA antifungal and antibacterial material sample in Example 3 of this invention.

[0065] Figure 20A The electrochemical impedance spectroscopy (EIS) spectra of the CMC-PVA membrane under different conditions in Example 3 of this invention are shown.

[0066] Figure 20B The electrochemical impedance spectroscopy (EIS) spectra of the 3.0% Li@CMC-PVA composite film in Example 3 of this invention under different conditions are shown.

[0067] Figure 21The graph shows the antifungal and antibacterial performance test results of the Li@CMC-PVA antifungal and antibacterial material in Example 3 of this invention, wherein:

[0068] A represents a culture dish containing a 3.0% Li@CMC-PVA composite membrane;

[0069] B indicates a culture dish without a composite membrane. Detailed Implementation

[0070] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0071] Existing anti-mildew and antibacterial materials mainly include strong oxidizing agents (such as hypochlorite and hydrogen peroxide) and metal ion agents (such as Ag). + (1) The consumption mode of the effective antibacterial component is static and passive, that is, the effective antibacterial component begins to decay irreversibly after contact with the environment, which cannot adapt to the dynamic characteristics of mold latency, dormancy and re-proliferation, resulting in the premature consumption of the effective component in the early stage of protection, ultimately causing the anti-mold effect to be difficult to last and the effective protection period to be much shorter than the actual needs; (2) The mechanism of action is mostly a non-selective attack mode that destroys cell structure. Under this mechanism of action, in order to effectively kill resistant mold, high concentration or high activity preparations are often required, which greatly reduces the safety of use, poses potential hazards, and limits the application scenarios.

[0072] Therefore, there is an urgent need in this field to develop a new type of anti-mold and antibacterial material that can maintain stable and long-lasting anti-mold and antibacterial activity in complex environments (especially dark and humid environments) and has a safer and smarter mode of action to solve the problem of repeated mold contamination.

[0073] Lithium ion (Li + Lithium was once thought to have the potential to inhibit microbial growth due to its extremely small hydrated ionic radius and strong hydrophilicity, theoretically capable of inactivating proteins by depriving them of intracellular water molecules and altering their quaternary spatial structure. However, further research revealed that it is precisely this characteristic that makes Lithium... + It is highly susceptible to leaching in the environment, exhibits poor stability, and cannot achieve long-lasting antibacterial effects. Even with extremely high lithium salt concentrations (e.g., 40%), its killing or inhibitory effect on molds and bacteria with some resistance, such as Aspergillus niger and Staphylococcus aureus, immersed in it is still unsatisfactory. The reason for this is that in a high-salt, high-osmotic-pressure environment, bacteria easily activate their self-protection mechanisms and enter dormancy, ceasing to absorb external substances and therefore also ceasing to absorb Li. + This leads to high concentrations of Li + It is difficult for it to enter bacterial cells to exert its effects, resulting in a serious lack of antibacterial efficacy. Ultimately, it was not considered an effective antibacterial material, and its application has long been limited to non-antibacterial fields such as air conditioning desiccants.

[0074] Through extensive experimental research and analysis, this invention ultimately provides a non-bactericidal antifungal and antimicrobial material that dynamically responds to bacterial proliferation. The material comprises: polyvinyl alcohol, carboxymethyl cellulose or its salts, and metal ions, including: Li... + .

[0075] The polyvinyl alcohol, carboxymethyl cellulose, or their salts are bridged by the metal ion; specifically, the metal ion is connected to the carboxylate group (-COO) of carboxymethyl cellulose or its salts. - The metal ions are connected by electrostatic interaction, and the hydroxyl groups (-OH) of polyvinyl alcohol are connected by ion-dipole interaction.

[0076] Another aspect of the present invention provides a method for preparing a non-bactericidal antifungal and antimicrobial material that dynamically responds to bacterial proliferation, comprising the following steps:

[0077] S1, Weigh out polyvinyl alcohol, carboxymethyl cellulose or their salts and dissolve them in pure water, then stir and heat to form a homogeneous mixed base liquid;

[0078] S2, Under stirring, add metal ion salts to the mixed base solution, mix thoroughly, and let stand for at least 10 minutes to obtain a non-bacterial, antifungal, and antimicrobial material in solution form that dynamically responds to bacterial proliferation; wherein, the metal ions include: Li + .

[0079] The purpose of this application in dissolving polyvinyl alcohol, carboxymethyl cellulose, or their salts to form a base mixture before adding metal ion salts is to first allow the molecular chains of polyvinyl alcohol, carboxymethyl cellulose, or their salts to form a three-dimensional network structure through random, simple physical entanglement and weak hydrogen bonds. The subsequently added metal ions will then insert into the various gaps within this three-dimensional network. This not only facilitates the uniform distribution of metal ions but also ensures the smooth release of ions from the three-dimensional network structure. If metal ions are added after dissolving polyvinyl alcohol (or carboxymethyl cellulose or their salts), followed by the addition of carboxymethyl cellulose or their salts (or polyvinyl alcohol), the metal ions easily form highly internal connections and tight aggregations with the molecular chains of the individual substances, making subsequent ion dissociation difficult and hindering the material from releasing metal ions as needed to exert its antibacterial effect.

[0080] In some embodiments, the mass ratio of carboxymethyl cellulose or its salt to polyvinyl alcohol is 1:0.3-1:5; the mass ratio of metal ion salt to carboxymethyl cellulose or its salt is 1:0.05-1:10.

[0081] In some embodiments, the mass percentage concentration of metal ions in the solution-form, dynamically responsive, non-sterilizing antifungal and antimicrobial material for bacterial proliferation is 0.5%-15%.

[0082] In some embodiments, the specific operation steps of step S1 are as follows:

[0083] S1.1 Weigh polyvinyl alcohol and add it to pure water. While stirring at 100 rpm to 3000 rpm, heat the solution to 50℃ to 95℃ using gradient heating, and continue stirring until a homogeneous polyvinyl alcohol aqueous solution is obtained.

[0084] S1.2, Weigh carboxymethyl cellulose or its salt and add it to the polyvinyl alcohol solution under stirring. Stir at 50℃-95℃ for 1 h-4 h to form the homogeneous mixed base liquid.

[0085] In some embodiments, the following process is included after step S2: the non-bactericidal antifungal and antimicrobial material in solution form that dynamically responds to bacterial proliferation is subjected to repeated freeze-thaw operations to prepare a non-bactericidal antifungal and antimicrobial material in gel form that dynamically responds to bacterial proliferation.

[0086] In some embodiments, the following processing is further included after step S2: a. Adding a crosslinking agent with a mass ratio not exceeding 10% to the solution-form dynamic response bacterial proliferation non-sterilizing antifungal and antimicrobial material, mixing evenly, and then allowing the reaction solution to stand and degas to obtain a film-forming solution; b. Spraying the film-forming solution onto the surface of a substrate to form a continuous liquid film, and drying the liquid film to form a thin film-form dynamic response bacterial proliferation non-sterilizing antifungal and antimicrobial material; wherein the crosslinking agent includes at least one of genipin or citrate.

[0087] As a specific example, the antifungal and antibacterial material is composed of polyvinyl alcohol (PVA), sodium carboxymethyl cellulose (CMC-Na), and Li. + Prepared from LiCl, hereinafter referred to as Li@CMC-PVA, the reaction process is as follows:

[0088]

[0089] In the formula, m is the degree of polymerization of CMC-Na, ranging from 500 to 1200; n is the degree of polymerization of PVA, ranging from 7000 to 9000.

[0090] The Li@CMC-PVA material system combines a three-dimensional network and multi-point potential constructed from sodium carboxymethyl cellulose (CMC-Na) and polyvinyl alcohol (PVA), through the application of Li + Potential trapping and ionic substitution grafting processes lead to the formation of stable ionicly grafted supramolecular polymers, whose basic building blocks are as follows: Figure 1AAs shown. In this unit structure, the carboxylate ion (-COO) generated by the dissociation of CMC-Na. - ) and Li + Strong electrostatic interactions occur, forming the primary ionic cross-linking sites; simultaneously, the hydroxyl groups (-OH) on the PVA chain interact with Li through ion-dipole interactions. + Coordination provides additional dynamic binding sites. These are Li + The core, dynamic, multi-coordination mechanism forms a supramolecular network structure at the molecular scale that combines mechanical stability and ion migration channels.

[0091] Furthermore, through research and experimentation, it has been discovered that the above-mentioned unit structure is not only Li + It provides a stable coordination environment and solves the problem of Li + The problem of easy loss in the environment is addressed; furthermore, through a dynamic coordination-dissociation process, Li is achieved... + It effectively translocates during bacterial cell proliferation and metabolism, thereby achieving a long-term stable antibacterial effect through a dual mechanism (mechanism I-II). See appendix. Figure 1B The antibacterial mechanism of the Li@CMC-PVA material is as follows:

[0092] (1) Li + Responding to bacterial cell proliferation to achieve "on-demand release": The supramolecular polymer material Li@CMC-PVA provided by this invention possesses a unique "sodium ion (Na+) release" capability. + Triggered by lithium ions (Li) + The "release" response characteristic. Specifically, during microbial proliferation, the Na+ released by the bacterial cells... + Li can be combined with polymer networks + Coordination site competition and ion exchange occur, resulting in the precise and orderly release of Li only when the bacteria are active. + It achieves an "on-demand release" mechanism in response to the dynamic proliferation characteristics of bacteria, solving the problem that the effective components of traditional antifungal and antibacterial materials are consumed prematurely in the early stage of protection due to passive loss, making it difficult to achieve long-lasting protection;

[0093] (2) "Metabolic deception" induces cells to actively take up Li + During the metabolic proliferation process of bacteria, which involves sodium excretion and potassium uptake, the released Li + Due to K + With similar hydrated ionic radii (approximately 3.82 Å and 3.31 Å, respectively), potassium ion channels on the cell membrane cannot effectively distinguish between the two, thus allowing Li... + "Impersonating" K + Once inside the cell, it is mistakenly identified as an essential nutrient by the bacteria and actively and efficiently absorbed into their own cells by occupying potassium ion channels, without any resistance process.

[0094] (3) Li entering the cell + It exerts its antibacterial effect through a dual-mechanism pathway:

[0095] Mechanism I: Once inside the cell, Li + Cannot fulfill K + This disrupts all physiological functions, leading to a dual predicament for bacterial reproduction: ① Energy and resource waste: the bacteria consume large amounts of energy and transport proteins to ingest and regulate these "pseudo-nutrients," yet cannot obtain the nutritional basis required for metabolism, similar to the "sweetener effect" in sugar-free beverages; ② Real nutrient deficiency: key potassium ion channels are blocked by Li + Excessive occupation severely hinders the absorption of potassium ions necessary for bacterial life activities.

[0096] In other words, the Li@CMC-PVA material incorporates Li + After being delivered into bacterial cells, it utilizes the bacteria's own metabolic logic to achieve a kind of "starvation therapy," causing the bacteria to appear "full" (having ingested a large amount of Li₂). + In this state, it is actually because the key K cannot be obtained. + When bacteria fall into "functional malnutrition," their proliferation and metabolic activities are inhibited, eventually leading to their death.

[0097] Mechanism II: With Li + It has an extremely strong hydration capacity, which can deprive intracellular proteins of water molecules, leading to changes in protein spatial conformation and inactivation.

[0098] In summary, the Li@CMC-PVA supramolecular composite material provided by this invention first releases the effective antibacterial component Li on demand through dynamic response to bacterial proliferation. + Li, who was released + Further utilize "metabolic deception" to induce bacterial cells to actively take up large amounts of Li + On the one hand, this leads to a lack of the essential nutrient K in the bacteria. + On the one hand, it gradually declines and dies; on the other hand, it inactivates the protein by depriving it of water molecules from the intracellular protein, causing a change in the protein's spatial conformation. These two aspects work synergistically to achieve Li + It provides long-lasting anti-mold and antibacterial effects even at low concentrations, and is highly safe to use with no obvious toxic side effects on the human body.

[0099] In another aspect, this invention also provides the application of the aforementioned anti-mildew and antibacterial materials, or the anti-mildew and antibacterial materials prepared by the aforementioned methods, in the prevention and control of mold and bacteria in the environment or on objects. These materials can be widely used in residential environments, air conditioning filters, air purifiers, packaging materials, agricultural product storage, cultural relic storage, leather products, and medical and health fields. By adding the materials of this invention to related products, walls, packaging, filters, textiles, etc., with long-lasting anti-mildew and antibacterial functions can be obtained. They are particularly suitable for public places such as grain warehouses, hotels, and cold chain transportation, effectively preventing mold growth on materials, reducing food loss, and providing a new path for high-tech upgrading and added value enhancement for traditional industries.

[0100] The following detailed description and verification of the research process of the present invention and the antifungal and antibacterial effects of the materials are provided through specific embodiments and accompanying drawings.

[0101] Unless otherwise stated, the experimental methods, detection methods, and preparation methods disclosed in this invention all employ conventional techniques in the fields of biochemistry, analytical chemistry, and related areas. Unless otherwise specified, all materials and reagents used in this invention are commercially available.

[0102] Example 1: Preparation, characterization, and antifungal and antibacterial performance testing of solution-form Li@CMC-PVA antifungal and antibacterial material.

[0103] (I) Preparation process

[0104] 1. Add 1000 mL of deionized water to a round-bottom flask. While stirring at 100 rpm-3000 rpm, add 5 g of polyvinyl alcohol (PVA, CAS: 9002-89-5, degree of hydrolysis 98±1.5%). Maintain stirring and heat the mixture to 50℃-95℃ using a gradient heating method. The gradient heating conditions are: increase the temperature every 30 to 120 minutes at a rate of 10℃ / h. After the solution has been heated and stabilized at 50℃-95℃, continue stirring for 30 to 120 minutes and observe the solution state. When the solution becomes transparent and there are no visible polyvinyl alcohol particles or flocculent matter, it indicates that it has been completely dissolved and a homogeneous polyvinyl alcohol aqueous solution has been obtained.

[0105] 2. Weigh 10 g of sodium carboxymethyl cellulose (CMC-Na, CAS: 9004-32-4, degree of substitution DS: 0.85±0.1), add it to the polyvinyl alcohol aqueous solution along the edge of the vortex formed by stirring, and stir for 1 h to 4 h at 50℃-95℃ and 300 rpm-3000 rpm to form a homogeneous mixed base solution; in other embodiments, sodium carboxymethyl cellulose can also be replaced with carboxymethyl cellulose, calcium carboxymethyl cellulose, potassium carboxymethyl cellulose, etc.

[0106] 3. Prepare a 1M LiCl (CAS: 7447-41-8) solution. While stirring, add different volumes of the aforementioned LiCl solution to the mixed base solution that has cooled to room temperature. After mixing thoroughly, allow it to stand and age for 1-4 hours at room temperature or under refrigeration to obtain different LiCl solutions. + Li@CMC-PVA solutions at concentrations of 0.5%, 3.0%, and 5.0% are non-bacterial, antifungal, and antimicrobial materials that dynamically respond to bacterial proliferation in solution form. See product appearance below. Figure 2 A.

[0107] (II) Structural and performance characterization

[0108] Using a Bruker AVANCE III 400 MHz nuclear magnetic resonance spectrometer with deuterated water (D₂O) as solvent, the above-prepared Li₂S samples with different loadings were analyzed at 298 K. + Li@CMC-PVA material solutions with concentrations (0.5%, 3%, 5%) were subjected to... 1 1H NMR analysis (requires freeze-drying and then dissolution in deuterated water (D2O) solvent) and dynamic light scattering analysis (DLS).

[0109] like Figures 3A-3C As shown, 1 ¹H NMR analysis results show that it belongs to CMC carboxymethyl methylene (-CH₂COO₃) - The proton signal of Li, whose chemical shift varies with Li + The increase in concentration systematically shifted from δ 3.60 ppm to δ 3.72 ppm, while the peak width sharpened from 0.10 ppm to 0.06 ppm, indicating that Li + With -COO - The group underwent concentration-dependent ion coordination, significantly improving the homogeneity of the surrounding chemical environment. Furthermore, the broad proton signal attributed to the PVA hydroxyl group (-OH) increased with Li... + With increasing concentration, the distribution range merged and shifted from δ 1.45-1.85 ppm to δ 1.50-2.00 ppm, and the full width at half maximum (FWHM) decreased from 0.25 ppm to 0.16 ppm, indicating that Li + The introduction of [a specific substance] competitively weakens the complex hydrogen bond network of PVA itself, and through Li [a specific mechanism]... + -OH coordination forms new, more ordered supramolecular interactions.

[0110] The aforementioned gradient trends of chemical shift and peak width (shift positively correlated with concentration, peak width negatively correlated with concentration), along with the experimental results showing no new impurity peaks, confirm for the first time at the molecular level that the Li introduced in this invention... +Li achieved precise and reversible regulation of the strength and uniformity of the supramolecular interaction between CMC and PVA. + As an "ion bridge," the CMC and PVA are no longer simply physically mixed, but form a more compact structure whose density can vary with Li. + Supramolecular complexes with precisely controlled concentrations; the structure of the supramolecular complexes is as follows: Figure 2 As shown.

[0111] like Figure 4 As shown, dynamic light scattering (DLS) results indicate that when Li + At a concentration of 0.5%, only a weak signal with a hydrodynamic diameter less than 30 nm was detected in the system, indicating that the assembly of the supramolecular complex had not yet formed; when Li + When the concentration increased to 3%, a significant scattering peak with uniform size and an average diameter of approximately 35 nm appeared, indicating the beginning of the large-scale formation of stable supramolecular complexes. The distribution narrowed compared to the 0.5% concentration, corresponding to a stable assembly state. When Li + When the concentration increased to 5%, the size of the assembly further increased and stabilized at approximately 98 nm–120 nm, demonstrating a gradually strengthening and more robust assembly state with increasing concentration. Notably, the average hydrodynamic diameter of the complex at 5% concentration (71 nm–120 nm) was significantly higher than that at 0.5% concentration (~26 nm), indicating that with increasing concentration of the active ingredient, CMC and PVA molecules formed a larger and more stable ordered assembly through supramolecular interactions.

[0112] (III) Anti-mildew and antibacterial performance testing

[0113] 1. Antifungal performance testing

[0114] The antifungal (Aspergillus niger) performance of the 5.0% Li@CMC-PVA solution prepared in this embodiment was tested using the inhibition zone test method. 5.0% LiCl solution and CMC-PVA solution were also included as experimental controls.

[0115] The results are as follows Figure 5 As shown, the culture plates of the 5.0% Li@CMC-PVA group showed obvious inhibition zones and significant antibacterial effects, while the culture plates of the 5.0% LiCl group and the CMC-PVA group showed no obvious inhibition zones and no antibacterial effects.

[0116] 2. Antifungal and antibacterial performance testing

[0117] The specific steps of the test are as follows:

[0118] Step 1: Candida albicans, Staphylococcus aureus, and Escherichia coli were selected to evaluate the antibacterial activity of the 5.0% Li@CMC-PVA solution prepared in this example. The concentration of the three bacterial suspensions was diluted to ~10% with distilled water. 7 CFU / mL, refrigerated for later use; artificial "blood" was prepared using defatted fibrous sheep blood, horse serum, phosphate buffer, yeast extract, and tryptone soybean broth (TSB), and refrigerated for later use;

[0119] Step 2: Take 5 mL of 5.0% Li@CMC-PVA solution and spray it evenly onto the surface of an unbleached pure cotton fiber (as a simulated contamination substrate, experimental group) measuring 2cm*4cm. After air drying, place it and the unbleached pure cotton fiber (control group) that was not sprayed with 5.0% Li@CMC-PVA solution into sterile petri dishes for later use.

[0120] Step 3: Take 9.7 mL of artificial "blood" and mix it with 0.1 mL of each of the three bacterial suspensions to obtain contaminated "blood".

[0121] Step 4: Add 0.5 mL of contaminated "blood" to each pure cotton fiber in the experimental and control groups; incubate in a 37°C constant temperature incubator.

[0122] Step 5: Samples were taken at 0, 4, 8, and 24 hours and transferred to sterile centrifuge tubes measuring 2cm*1cm. 30 mL of phosphate buffer containing 0.01% Tween 80 was added for elution. After elution, 0.1 mL of the eluent was mixed with 15 mL of Sabouraud agar. Another 0.1 mL of the eluent was mixed with 15 mL of tryptic soy agar. After solidification, the mixture was placed in an incubator and inverted for 24 hours. The colony counts of fungi and bacteria were counted to evaluate the antibacterial properties.

[0123] The results are as follows Figures 6A-6B As shown in Figures 7A-7B, compared with the control group, the surface viable bacterial concentrations of Candida albicans, Staphylococcus aureus, and Escherichia coli were significantly reduced after treatment with 5.0% Li@CMC-PVA solution for 24 h, with inhibition rates of 99.2%, 100%, and 100%, respectively, demonstrating significant antibacterial effects.

[0124] 4. Determination of minimum inhibitory concentration (MIC)

[0125] According to the Clinical and Laboratory Standards Institute (CLSI) M38 guidelines, the minimum inhibitory concentration (MIC) of the 5.0% Li@CMC-PVA solution prepared in this example against Aspergillus niger was determined by microbroth dilution using RPMI 1640 liquid medium (containing 0.165M MOPS buffer, pH 7.0).

[0126] The results are as follows Figure 8 As shown, the MIC value of 5.0% Li@CMC-PVA solution against Aspergillus niger is approximately 15739 µg / mL, which is significantly higher than that of conventional Ag. + The concentration characteristics of the antibacterial agent (calculated as AgNO3) were observed (5~20 µg / mL). These results reveal that the Li@CMC-PVA material provided by this invention does not exert its effect by rapidly disrupting cell structure, but rather relies on a milder and more persistent ion exchange process to exert its antifungal and antibacterial effects. At this concentration, the material can continuously and stably interact with mold proliferation, undergo ion exchange, and subsequently intervene in the metabolic process of "sodium excretion and potassium uptake," occupying potassium ion channels and disrupting the necessary material preparation basis for mold proliferation, thereby effectively inhibiting its growth and metabolism rather than directly killing it. This characteristic of "high effective concentration and low cytotoxicity" indicates that the Li@CMC-PVA material provided by this invention will have higher biocompatibility and environmental safety in applications, is less likely to induce drug resistance in microorganisms, and is particularly suitable for antifungal scenarios requiring long-term, safe contact (such as packaging materials, home building materials, and cultural relic preservation).

[0127] 5. Minimum bactericidal concentration (MBC) determination

[0128] After determining the minimum inhibitory concentration (MIC) according to the CLSI M38 guidelines, the minimum bactericidal concentration (MBC) was further determined through a subculture transfer experiment. Specifically, the liquid from each well at each concentration that showed sterile growth in the MIC test was transferred and spread onto fresh RPMI 1640 agar plates without the drug, and incubated for another 48 hours.

[0129] The results are as follows Figure 9 As shown, even at concentrations significantly higher than the MIC, colonies still appeared on fresh plates after treatment, with the number decreasing by less than 99.9% (i.e., 3 logarithmic levels) compared to the original inoculum. The minimum bactericidal concentration (MBC) of the material of this invention has not yet been determined according to standard definitions, but based on the measured results, its MBC is much higher than its minimum inhibitory concentration (MBC > 16 × MIC), indicating that it does not possess potent bactericidal activity at inhibitory concentrations, and its mechanism of action is primarily growth inhibition. This is entirely consistent with the "non-bacterial" mechanism of action of the material of this invention, which involves ion exchange and alteration of the microenvironment rather than destruction of cell structure. This characteristic ensures high safety of the material in application and greatly reduces the risk of inducing microbial resistance.

[0130] 6. Testing of anti-mildew and antibacterial performance in practical application scenarios

[0131] To illustrate the application effect of the solution-form Li@CMC-PVA anti-mildew and antibacterial material prepared in this embodiment in a high-humidity indoor environment, the anti-mildew effect of the liquid material in this embodiment was first verified using a residential gypsum wall as the substrate. The specific implementation process is as follows:

[0132] Step 1: Aspergillus niger was selected to evaluate the antifungal and antibacterial properties of the solution-form Li@CMC-PVA antifungal and antibacterial material prepared in this embodiment. After measuring the concentration of the bacterial suspension using a hemocytometer, the Aspergillus niger suspension was uniformly diluted to a concentration of 10 with distilled water. 7 CFU / mL;

[0133] Step 2: Select plasterboard (a typical interior wall material for residential spaces) as the test substrate. Cut the test substrate into 50 mm * 50 mm * 5 mm blocks. Set up experimental and control groups. Inoculate the plasterboard surfaces of both experimental and control groups with Aspergillus niger spores (400 µL per group, concentration 10). 7 (CFU / mL)

[0134] Step 3: The liquid material prepared in this embodiment is evenly sprayed onto the surface of the gypsum in the test group using a low-pressure spray method. The coating amount is about 50 mL per square meter. The gypsum surface of the control group is not sprayed.

[0135] Step 4: Place the two sets of plasterboards that have completed Step 3 into a constant temperature and humidity incubator with a temperature of 30±1℃ and a relative humidity of ≥95% without light source and incubate them. According to GB21551.2—2010 test method for anti-mildew performance, take pictures, count and analyze the colony-forming units every week. The test period is long-term and has exceeded 12 months (300+ days) as of the writing of this application document.

[0136] The results are as follows Figure 10 As shown, after 6 days of cultivation, the surface of the control group plaster (i.e., the ordinary surface in the figure) was covered with mold, while the surface of the plaster treated with the liquid material in this embodiment (i.e., the product effect in the figure) did not show any mold growth. More importantly, even after more than 300 days of cultivation, no obvious mold growth was observed. This indicates that the solution-form Li@CMC-PVA anti-mold and antibacterial material prepared in this embodiment has a long-term, efficient, and stable anti-mold effect, which can prevent repeated mold contamination.

[0137] In addition, the anti-mold effect was verified in different real-world scenarios, including gypsum walls, silage, and cardboard packaging. The results are as follows... Figure 11 and 12 As shown, after the moldy corner of a villa was treated with mold removal, it was sprayed with the liquid material described in this embodiment. After a full three-month rainy season, no mold was found on the wall. Figure 11When silage coated with the liquid material of this embodiment and silage without any coating were placed in the same high-humidity environment, the results showed that the untreated silage became moldy after only 7 days, while the silage treated with the liquid material of this invention did not show any mold growth after long-term storage (more than 60 days). Figure 12 (AB); Untreated paper packaging boxes became severely moldy after being stored in a warehouse for a month, while after being treated with the liquid material of this invention, no mold was observed in the paper packaging boxes after long-term storage. Figure 12 (CD).

[0138] The above experimental results show that the liquid form Li@CMC-PVA anti-mold and antibacterial material prepared in this embodiment has a significant anti-mold and antibacterial effect, and the effective anti-mold time is relatively long, reaching more than 300 days.

[0139] 7. Cytotoxicity (MTT) assay

[0140] L929 cells in the logarithmic growth phase were used for cell counting, and the cell concentration was adjusted to 6 × 10⁻⁶ cells / year. 3 Cells were seeded per well into 96-well plates and cultured overnight in a 5% CO2, 37°C incubator to allow cell adhesion. Cells were then treated with 5.0% Li@CMC-PVA solution in the experimental group, while the control group received no treatment with 5.0% Li@CMC-PVA solution. Both groups were cultured for 24 hours in a 5% CO2, 37°C incubator. The culture medium was removed, and each well was washed three times with PBS. 100 μL of medium containing 0.5 mg / mL LMT was added to each well, and the cells were cultured for 4 hours in a 5% CO2, 37°C incubator. The supernatant was discarded, and 100 μL of DMSO was added to each well. The cells were gently shaken for 10 min, and the absorbance at 570 nm was measured.

[0141] See Figure 13 Cytotoxicity (MTT) assessment showed that, compared to the control group, the metabolic activity of L929 cells co-cultured in 5.0% Li@CMC-PVA solution in this embodiment was significantly reduced. However, even under conditions of significantly inhibited metabolic activity, concurrent cell morphology observation (white light imaging) showed that the cells remained intact, maintaining normal adherence, with intact cell membranes and no obvious signs of acute toxic damage such as shrinkage or rupture. The morphology of L929 cells was not significantly different from that of the control group. This result further demonstrates that the mechanism of action of the material of this invention differs from traditional toxins that cause rapid cell disintegration. It may achieve antifungal and antibacterial effects by influencing cell metabolism and substance exchange, or by exerting certain effects on the extracellular matrix.

[0142] The above results demonstrate that the Li@CMC-PVA material prepared in this invention possesses excellent and long-lasting antifungal and antibacterial effects. Furthermore, unlike traditional antibacterial agents that directly destroy cell structures, the antibacterial mechanism of this invention is as follows: the material responds to bacterial proliferation by undergoing ion exchange, releasing metal ions (such as Li...). + It intervenes in the metabolic process of "sodium excretion and potassium uptake" and occupies potassium ion channels, ultimately inhibiting bacterial growth and achieving long-lasting anti-mold and antibacterial effects.

[0143] Based on the above research findings, to reveal the antibacterial mechanism of this invention at the microscopic level, electron microscopy (SEM) observations were performed on Aspergillus niger before and after treatment with 5.0% Li@CMC-PVA solution. The experimental design followed the norms of microbial morphology research, and a rigorous "transient fixation" sample preparation was performed to ensure that the observation results accurately reflected the physiological state of the spores at the end of treatment. The specific procedures for transient fixation and sample preparation are as follows: After co-culturing Aspergillus niger spores with 5.0% Li@CMC-PVA solution for 24 hours, the mixed suspension was immediately (within 1 minute) mixed with pre-cooled glutaraldehyde fixative to achieve a final glutaraldehyde concentration of 1.25%. This step aims to instantly terminate all biochemical reactions and fix the cell structure, effectively preventing morphological changes caused by subsequent operations or cell autolysis. The fixed samples were washed with buffer and finally stored in 2.5% glutaraldehyde at 4°C for testing.

[0144] The results are as follows Figure 14 As shown, the Aspergillus niger spores treated with the material of this invention did not show statistically significant differences in cell morphology, size, surface wrinkling, and cell wall integrity compared to the untreated control group spores. No lethal damage morphologies typical of traditional fungicides, such as cell collapse, plasmolysis, and surface lysis, were observed. This result indicates that the antifungal and antibacterial effect of the material of this invention does not target the structural integrity of the cell wall or cell membrane. The complete preservation of spore morphology suggests that the material of this invention does not exert its effect through conventional fungicidal pathways such as physical destruction, membrane dissolution, or strong oxidative stress. It should be noted that under scanning electron microscopy, both the control and treated groups of Aspergillus niger spores exhibited their inherent wrinkled texture and some minor structural undulations on the surface. These features are common natural morphologies of Aspergillus niger conidia and may be moderately highlighted during sample preparation (such as critical point drying), representing background phenomena.

[0145] Furthermore, using a Hitachi-7800 transmission electron microscope (TEM), after fixation with 2.5% glutaraldehyde, dehydration, embedding, and polymerization, the spores of Aspergillus niger were observed after ultrathin sectioning and staining. The results were obtained before and after treatment with the 5.0% Li@CMC-PVA solution of this invention.

[0146] The results are as follows Figure 15As shown, the control group of Aspergillus niger spores had an intact structure, continuous and dense cell walls, uniformly distributed cytoplasm, clearly distinguishable organelles (such as mitochondria and endoplasmic reticulum), and moderate electron density, exhibiting a typical undisturbed physiological state. However, the Aspergillus niger spores treated with 5.0% Li@CMC-PVA solution showed significant physiological abnormalities: cytoplasmic condensation, blurred or even absent organelles (such as mitochondria and endoplasmic reticulum) (unclear mitochondrial cristae structure), and numerous vacuoles within the cells. However, the cell wall structure remained intact, without rupture or dissolution.

[0147] The above TEM results confirm at the subcellular level that the material of this invention has the following innovative mechanism of action and advantages:

[0148] (1) Mechanism innovation: Through the physical-chemical synergistic effect of ion exchange, the natural metabolic process of potassium uptake and sodium excretion of Aspergillus niger spores is interfered with, leading to intracellular ion imbalance, which in turn causes cytoplasmic condensation, organelle dysfunction and vacuolization. This "metabolic induction" rather than "direct destruction" mechanism is the core innovation of this invention that distinguishes it from traditional bactericides (such as cell wall destruction and nucleic acid synthesis inhibition);

[0149] (2) Durability of effect: Since the cell wall or cell membrane is not damaged, the material of the present invention will not trigger the stress response of mold (such as the production of resistance proteins), so that the anti-mold effect has long-term stability;

[0150] (3) Application compatibility: The non-sterilizing mechanism of action makes the material of this invention suitable for fields with high safety requirements such as packaging, building materials, and textiles, solving the problem that traditional bactericides "may contaminate food or damage material properties".

[0151] The above SEM and TEM results corroborate each other, showing that the material of this invention achieves antifungal and antibacterial effects through metabolic induction rather than direct sterilization. Its innovative mechanism of action (ion exchange-metabolic interference), long-lasting effect (no drug resistance), and application compatibility (green and mild) are significantly different from existing technologies.

[0152] 8. Acute inhalation toxicity test

[0153] The applicant commissioned SGS (Shanghai) Testing Center to conduct an acute inhalation toxicity test in accordance with the "Disinfection Technical Specification" (2002 edition) SPGG20201207003-2020 to test the safety of the anti-mildew and antibacterial material of the present invention.

[0154] Twenty SPF-grade ICR mice (half male and half female) were selected and placed in a static exposure chamber (0.12 m³). 3 ), add 1.2 g of the 5.0% Li@CMC-PVA solution and allow it to evaporate, resulting in a concentration of 10000 mg / m³.3 Animals were exposed to the air for 2 hours by inhalation, and mortality was observed within 14 days after exposure.

[0155] The results showed that no obvious signs of poisoning were observed in any of the experimental animals during the entire observation period. No animals died during the observation period, and autopsies revealed no abnormalities. No obvious poisoning symptoms related to the test substance were observed. The acute inhalation median lethal concentration (LC50) of the 5.0% Li@CMC-PVA solution material was calculated. 50 Greater than 10000 mg / m 3 According to the "Disinfection Technical Specifications" (2002 edition), this material is classified as practically non-toxic in inhalation tests.

[0156] The above results indicate that the Li@CMC-PVA material provided by this invention has extremely low acute inhalation toxicity and high safety in use.

[0157] Example 2: Preparation and characterization of gel-like Li@CMC-PVA antifungal and antibacterial material

[0158] (I) Preparation process

[0159] 1. Following the method in Example 1, prepare 100 mL to 1000 mL of 5.0% Li + A concentrated Li@CMC-PVA solution was sealed in an Erlenmeyer flask and allowed to stand for 1–4 hours.

[0160] 2. Place the sealed solution in the freezer compartment of the refrigerator, set the temperature to -80~-20℃, and freeze for 24 hours;

[0161] 3. After 24 hours, remove the sample and place it in a room temperature environment, where it will stand for 24 hours.

[0162] 4. Repeat the above freeze-thaw process, i.e., freeze for 24 hours and let stand at room temperature for 24 hours, cycle 2 to 10 times until gel is formed; it should be noted that the number of cycles depends on the gel formation requirements of different concentrations of Li@CMC-PVA solution, and the number of cycles can be increased or decreased according to the actual situation. This invention does not impose specific limitations on this.

[0163] 5. After the freeze-thaw cycle is completed, the sample is removed, and the gel-like Li@CMC-PVA antifungal and antibacterial material is obtained. See the product appearance section below. Figure 2 B.

[0164] (II) Structural and performance characterization

[0165] The gel material prepared above was characterized using dynamic oscillatory rheology. The results are as follows: Figure 16As shown, within a wide frequency scanning range of 0.1 Hz to 100 Hz, the storage modulus (G') of the material is always higher than the loss modulus (G''), and both are stable at 10 Hz. 5 ~10 6 Pa and 10 4 ~10 5 In the high modulus range of Pa, the G' value is generally an order of magnitude higher than G'', indicating that the material exhibits an elastic-dominated solid-like gel behavior throughout the testing conditions. Furthermore, the phase angle (γ) of the material is strictly limited to a narrow range of 10.41° to 24.19°, a value clearly within the range of typical strong gels, indicating that the material possesses both excellent elastic recovery and moderate flexibility, resulting in balanced mechanical properties. More importantly, G', G'', and δ change smoothly across the entire frequency range without abrupt changes or modulus crossovers. This reveals that the three-dimensional network constructed by supramolecular interactions within the material possesses extremely high structural integrity, uniformity, and dynamic stability, and its mechanical properties are independent of the frequency of external interactions.

[0166] The above results demonstrate that this embodiment successfully prepared a supramolecular gel material with high mechanical strength, stable structure, and balanced elasticity and toughness, which lays a key physical property foundation for its application in scenarios requiring mechanical stress, such as anti-mildew coatings and medical dressings.

[0167] Example 3: Preparation and characterization of thin-film Li@CMC-PVA antifungal and antibacterial material

[0168] (I) Preparation process

[0169] 1. Following the method in Example 1, prepare 500 mL of 3.0% Li@CMC-PVA solution and place it in an Erlenmeyer flask. After the solution is cooled to room temperature, slowly add genipin or citrate, or other crosslinking agents with a mass ratio not exceeding 10%, and stir continuously with a glass rod until completely dissolved to form a homogeneous mixture. Let the mixture stand at room temperature for 1-4 hours to remove bubbles and obtain the film-forming solution. During the standing process, seal the bottle opening with plastic wrap to prevent contamination and solvent evaporation.

[0170] 2. Transfer the film-forming solution to the sprayer's reservoir. Spray the solution onto the substrate surface using a spray gun with a nozzle diameter of 1.0 mm - 2.0 mm and a distance of 10 cm - 30 cm from the substrate surface. Maintain a uniform spraying speed to ensure the solution completely covers the mold surface, forming a continuous liquid film without drips or omissions (film coverage is 10~1000 mL / m). 2 );

[0171] 3. Place the substrate with the liquid film formed on its surface in a pre-set oven at 35℃~80℃ and dry for 12 h~48 h. After drying, remove the substrate and demold it to obtain a uniform and continuous white film, which is the solid film form of Li@CMC-PVA anti-mildew and antibacterial material (hereinafter referred to as Li@CMC-PVA composite film). See the product appearance section below. Figure 2 C.

[0172] Following the above method, a 5.0% Li@CMC-PVA composite membrane was also prepared.

[0173] (II) Structural and performance characterization

[0174] 1. AFM and SEM detection

[0175] The surface morphology and structure of the 3.0% Li@CMC-PVA composite film prepared above were characterized using atomic force microscopy (AFM). The results are as follows: Figure 17A As shown, the height map of the thin film reveals that within a 500 nm × 500 nm scanning region, the surface of the thin film material is extremely flat, with very low root-mean-square roughness. This indicates that the film is continuous, dense, and free of macroscopic defects, possessing excellent film quality. More importantly, as... Figure 17B As shown in the phase diagram, the phase angle signal is distributed within a narrow range (approximately 13.5° to 15.5°) across the entire observation range, exhibiting only a slight contrast variation. This directly proves the highly uniform mechanical properties of the film surface at the nanoscale. The CMC-Na and PVA components did not undergo phase separation but instead formed a uniform, single new phase—a supramolecular composite phase—through supramolecular interactions. These results demonstrate that this embodiment successfully prepared a supramolecular composite film with a smooth surface morphology and uniform nanostructure size. This coherent porous network structure provides an effective transport channel for ion exchange, ensuring the transport of functional components (such as Li)... + The uniform distribution of the microorganisms on the surface of the material provides a foundation and guarantee for achieving uniform and long-lasting anti-mildew function.

[0176] Furthermore, scanning electron microscopy (SEM) was used to examine the CMC-PVA film (i.e., Li...). + Multi-scale characterization was performed on the cross-sections of the 0% Li@CMC-PVA composite film and the 3.0% Li@CMC-PVA composite film prepared in this example to reveal the microstructure of Li. + A precise control mechanism for supramolecular network structure. Results are as follows: Figure 18The left-middle figure shows that the cross-section of the CMC-PVA film exhibits a loose, random layered structure at the 10 μm scale. Magnified to the 2 μm scale, poor dispersion of the internal framework and obvious local aggregation are visible. Further magnification at 300 nm reveals only amorphous molecular chain aggregates, lacking a continuous micro-network structure. This is because the CMC and PVA molecular chains in the CMC-PVA film are only linked by random physical entanglement and weak hydrogen bonds, lacking the driving force for directional assembly. Therefore, the structure is loose and disordered, making it difficult to form a stable supramolecular network structure. In stark contrast, the 3.0% Li@CMC-PVA composite film prepared in this invention achieves fundamental optimization of its cross-sectional morphology, specifically as follows: Figure 18 The right-middle figure shows that at the 10 μm scale, the cross-section of the 3.0% Li@CMC-PVA composite membrane exhibits a highly uniform three-dimensional porous sponge structure. The uniformity of pore size distribution is far superior to that of the CMC-PVA membrane, with no local aggregation or pore collapse. This is due to the Li + The role of the "structural guidance center": Li + The Li@CMC-PVA composite film simultaneously binds the carboxyl groups of CMC and the hydroxyl groups of PVA through ion-coordination, inhibiting the random aggregation of molecular chains. Scaled up to 2 μm, the network framework of the Li@CMC-PVA composite film is composed of interconnected continuous units, exhibiting a significantly improved structural density. This is attributed to the Li... + The "bridging effect": a single Li + It can simultaneously bind to the polar groups of multiple CMC-Na / PVA molecular chains, forming multi-point cross-linked framework units, replacing the weakly interacting dispersed aggregates in the CMC-PVA film; further magnified to 300 nm high-magnification imaging, fibrous / sheet-like structures with diameters of approximately tens of nanometers can be clearly observed to interweave and tightly intertwine, forming a continuous, through-type nanoscale interpenetrating network structure. This is Li + The direct manifestation of the role of "directional assembly": Li + The ion-coordination provides anchoring points for the ordered arrangement of molecular chains, driving the CMC-Na and PVA molecular chains to extend and intertwine along the ion crosslinking points, ultimately forming a long-range continuous nanonetwork.

[0177] The above SEM results indicate that Li + The introduction of this technology utilizes a three-level structure-guided mechanism of "ion crosslinking points - bridging - directional assembly" to transform the physical blending system of CMC-Na and PVA into a long-range ordered, three-dimensionally penetrating nanoscale supramolecular crosslinking network. This unique microstructure is the core structural basis for the antifungal and antibacterial material of this invention to achieve excellent mechanical strength, efficient ion transport capability, enhanced thermal stability, and long-lasting antifungal performance.

[0178] 2. Precise elemental analysis using inductively coupled plasma optical emission spectroscopy (ICP-OES)

[0179] To quantitatively verify Li + Successful loading and its impact on material composition, for CMC-PVA film (i.e., Li) + Precise elemental analysis was performed on 0% and 3.0% Li@CMC-PVA composite membranes using inductively coupled plasma atomic emission spectrometry (ICP-OES). Samples were completely dissolved and digested using a super-microwave apparatus before analysis using an Agilent 5110 ICP-OES spectrometer.

[0180] Table 1 Li + Elemental composition analysis of supramolecular composites before and after loading (ICP-OES)

[0181]

[0182] The results are shown in Table 1. In the control CMC-PVA film, the lithium content was detected at a background level of only 0.016 wt%, while in the 3.0% Li@CMC-PVA composite film prepared in this embodiment, the lithium content increased to 0.46 wt%, an increase of nearly 30 times, indicating that Li + It is efficiently and extensively introduced and embedded into the material structure, rather than through surface physical adsorption. Meanwhile, calcium (Ca) in the material... 2+ The content of ) changed from 0.048 wt% before loading to 0.37 wt% after loading, indicating that the supramolecular network structure material constructed in this embodiment exhibits excellent multi-cation synergistic coordination and loading characteristics. Specifically, Li + The successful introduction of Ca did not hinder 2+ With the simultaneous binding of other cations to the carboxyl sites of the supramolecular network, the supramolecular network structure material of this invention possesses abundant and accessible anionic binding sites, enabling flexible control over the composition of various cations. It should be noted that in this embodiment, Ca... 2+ Because of the raw materials used, such as LiCl, the purity of commercially available LiCl is usually 99%, and it inevitably contains other impurities such as Ca. 2+ .

[0183] The above results demonstrate that the Li@CMC-PVA material provided by this invention is essentially a dynamic ion exchange platform, allowing for the design and control of cation types and content composition according to different objectives. In this embodiment, the Li content is controlled to be much higher than the Ca content, so that when the Na in the environment... + As the concentration increases, the material can preferentially and selectively release Li. + Instead of other coexisting ions, ensure the release of ions (Li) +In terms of size and charge, it can be detected by microbial potassium ion channels (K). + The channel specifically recognizes and actively ingests the substance, thereby precisely triggering the subsequent "metabolic deception" process, achieving a closed-loop intelligent antibacterial mechanism from chemical triggering to biological response. It can be understood that, while ensuring Li... + When used as the main metal ion component, other metal ions that help regulate the cross-linking network and enhance mechanical properties can also be introduced to enhance the material's sustained-release performance.

[0184] 3. TGA Testing

[0185] To quantitatively evaluate Li from a thermodynamic perspective + The stabilizing effect of supramolecular composite material structure was assessed using a thermogravimetric analyzer (HITACHI STA200) on the 3.0% Li@CMC-PVA composite film of this invention, and a CMC-PVA film (i.e., Li) prepared by the same mass ratio and process. + A comparative TGA test was conducted using a 0% concentration of nitrogen under a strictly controlled high-purity nitrogen atmosphere to completely eliminate interference from oxidation and decomposition, with the heating rate precisely controlled at 10℃ / min. The results are as follows: Figure 19A and Figure 19B As shown, Li + The introduction of this technology fundamentally improves the thermal stability of the Li@CMC-PVA composite film of this invention, significantly increasing both its initial thermal decomposition temperature and its most severe decomposition temperature. This improvement is specifically reflected in the following three core dimensions:

[0186] (1) A qualitative change occurs in thermal stability: the decomposition temperature shifts significantly later.

[0187] Thermogravimetric analysis (TG) curves show that the main decomposition peak temperature of the CMC-PVA film under an inert nitrogen atmosphere is 272°C, while the main decomposition peak temperature of the Li@CMC-PVA composite film is significantly increased to 390°C, shifting to the high-temperature region by approximately 118°C. It can be reasonably inferred that the material of this invention can maintain the integrity of its supramolecular network structure even at temperatures as high as approximately 390°C, exhibiting excellent thermal reliability.

[0188] (2) Decomposition kinetics tend to be moderate: the decomposition rate decreases significantly.

[0189] At the point of maximum decomposition rate, the decomposition rate of the Li@CMC-PVA composite film (-0.155% / ℃) was reduced by approximately 40% compared to the CMC-PVA film (-0.26% / ℃), and its differential thermogravimetric (DTG) curve showed a wider and flatter peak. This indicates that in a uniform thermal field under nitrogen protection, the material decomposition process changed from relatively "violent" to "gradual," with significantly enhanced kinetic stability.

[0190] (3) Changes in intrinsic properties of materials: increased residual rate and decreased hydrophilicity

[0191] At high temperatures, the residual rate of the Li@CMC-PVA composite film (44.44%) was significantly higher than that of the CMC-PVA film (37.3%), which is directly attributable to the formation of stable inorganic lithium compounds. Furthermore, the weight loss of the Li@CMC-PVA composite film in the low-temperature region (30°C - 200°C) was much lower than that of CMC-PVA, indicating that Li... + The coordination effect effectively regulates the hydrophilicity of the material.

[0192] The above results indicate that Li + The introduction of this material transforms the physical blending system of PVA and CMC-Na into an "ion-crosslinked supramolecular composite material" with strong chemical bonding characteristics, resulting in a leap in thermal stability (decomposition temperature increased by >35°C). This characteristic directly translates into two key application advantages, ensuring the practicality of the material in the following aspects: (1) Processing reliability: A higher thermal decomposition temperature means that the material has a wider process window and better thermal dimensional stability during processing and molding (such as hot pressing, coating and curing); (2) Durability: Excellent thermal stability is the fundamental guarantee for the material to resist thermal aging and maintain its antifungal and antibacterial functions for a long time when used in complex temperature environments. In summary, in scenarios involving medium-temperature processing or use (e.g., heat treatment steps in material processing, or long-term application in heated environments), the composite material of this invention can better maintain its structural integrity and functionality, thus providing a wider safe operating window and a longer service life for antifungal and antibacterial products based on this material. This characteristic provides a key guarantee for the material of this invention to be used for a long time in environments that require heat treatment processes (such as hot pressing film formation, high-temperature curing) or heated environments, significantly expanding its application boundaries.

[0193] 4. Electrochemical Impedance Spectroscopy (EIS)

[0194] To investigate the structural basis of the ion exchange capacity of the Li@CMC-PVA composite membrane of this invention, electrochemical impedance spectroscopy (EIS) analysis was performed on the composite membrane in a symmetrical stainless steel blocking electrode (SS / SPE / SS) structure.

[0195] The obtained Nyquist diagram is as follows Figure 20A and Figure 20B As shown, it reveals a fundamental shift in the ion transport behavior of the material of the present invention: the spectrum of the CMC-PVA film exhibits simple diffusion-controlled characteristics ( Figure 20A Its bulk resistance is relatively low; however, the spectrum of the 3.0%Li@CMC-PVA composite film of this invention exhibits complex three-stage characteristics, and its overall impedance is significantly increased compared to the pure film. Figure 20BThis phenomenon is highly consistent with the results of the aforementioned structural characterization (SEM, TGA): Li + The introduction of [a specific substance] forms a robust ionic crosslink with the polymer network, leading to a denser and more rigid network structure, thereby increasing the overall resistance to ion migration. More importantly, the finite-space diffusion characteristics observed in the spectrum confirm that ion transport in the bulk phase of the material is controlled and achievable.

[0196] The above results indicate that the core innovation of this invention lies in constructing a dense Li-based... + This supramolecular network, consisting of crosslinking / exchange sites, enhances the material's thermodynamic stability (TGA) and also provides Li... + With environmental ions (such as Na+) + This provides a structural basis for specific and controlled ion exchange. This design, which trades overall conductivity for specific ion exchange function and material stability, provides a unique electrochemical kinetic explanation for the long-lasting, non-bactericidal antifungal function of the material of this invention.

[0197] (III) Anti-mildew and antibacterial performance testing

[0198] The antifungal (Aspergillus niger) performance of the 3.0% Li@CMC-PVA composite membrane prepared in this embodiment was tested. Specifically, the 3.0% Li@CMC-PVA composite membrane was placed in a petri dish as the experimental group, and a petri dish without the composite membrane was included as the control group. The same volume of Aspergillus niger solution (concentration 10) was sprayed into both groups of petri dishes. 7 After contamination (CFU / mL), the samples were placed in a 99%~100% constant temperature and high humidity incubator at 28℃ for one month.

[0199] The results are as follows Figure 21 As shown, after one month of cultivation, the control group's petri dishes were covered with mold. Figure 21 (B), while no mold growth was observed in the culture dishes of the experimental group ( Figure 21 The A) indicates that the Li@CMC-PVA composite film provided by the present invention has a significant anti-mildew effect.

[0200] In some embodiments, the present invention also prepares powdered Li@CMC-PVA antifungal and antibacterial material from solution-state Li@CMC-PVA using vacuum freeze-drying and grinding technology. (See attached image for product appearance.) Figure 2 D.

[0201] In summary, this invention discloses a non-sterilizing antifungal and antimicrobial material, Li@CMC-PVA, which dynamically responds to bacterial proliferation. This material can achieve highly efficient antifungal and antimicrobial effects at low concentrations, and its duration of action far exceeds that of traditional ionic antimicrobial agents. In addition, this material has a mild effect and no obvious toxic side effects on the human body, and has excellent market application prospects.

[0202] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A method for preparing a non-bactericidal antifungal and antimicrobial material that dynamically responds to bacterial proliferation, characterized in that, Includes the following steps: S1, Weigh out polyvinyl alcohol, carboxymethyl cellulose or their salts and dissolve them in pure water, then stir and heat to form a homogeneous mixed base liquid; S2, Under stirring, add metal ion salt to the mixed base liquid, mix evenly, and let stand for at least 10 minutes to obtain a non-bactericidal antifungal and antimicrobial material with dynamic response to bacterial proliferation in solution form; Wherein, the metal ion is Li + In the non-bactericidal antifungal and antimicrobial material in solution form that dynamically responds to bacterial proliferation, the mass percentage concentration of metal ions is 0.5%-15%.

2. The preparation method according to claim 1, characterized in that, The mass ratio of carboxymethyl cellulose or its salt to polyvinyl alcohol is 1:0.3-1:5; the mass ratio of metal ion salt to carboxymethyl cellulose or its salt is 1:0.05-1:

10.

3. The preparation method according to claim 1, characterized in that, The specific operation steps of step S1 are as follows: S1.1 Weigh polyvinyl alcohol and add it to pure water. While stirring at 100 rpm to 3000 rpm, heat the solution to 50℃ to 95℃ using gradient heating, and continue stirring until a homogeneous polyvinyl alcohol aqueous solution is obtained. S1.2, Weigh carboxymethyl cellulose or its salt and add it to the polyvinyl alcohol solution under stirring. Stir at 50℃-95℃ for 1 h-4 h to form the homogeneous mixed base liquid.

4. The preparation method according to claim 1, characterized in that, The following processing is included after step S2: The non-sterilizing antifungal and antimicrobial material in solution form, which is dynamically responsive to bacterial proliferation, is prepared into a gel form through repeated freeze-thaw operations.

5. The preparation method according to claim 1, characterized in that, The following processing is included after step S2: a. In the non-bactericidal antifungal and antibacterial material that dynamically responds to bacterial proliferation in solution form, a crosslinking agent with a mass ratio not exceeding 10% is added, and after mixing evenly, the reaction solution is allowed to stand and degas to obtain a film-forming solution. b. Spray the film-forming solution onto the surface of a substrate to form a continuous liquid film. After drying, the liquid film forms a non-sterilizing, mildew-resistant, and antibacterial material with a thin film morphology that dynamically responds to bacterial proliferation. The crosslinking agent includes at least one of genipin or citrate.

6. A non-bactericidal antifungal and antimicrobial material that dynamically responds to bacterial proliferation, characterized in that, The antifungal and antibacterial material is prepared by the preparation method described in any one of claims 1-5.

7. The application of the anti-mildew and antibacterial material according to claim 6 in the prevention and control of mildew and bacteria in the environment or on articles.

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