A high-efficiency low-temperature low-noble-metal multi-element bacteriostatic material for static cold preservation of organs and a preparation method and application thereof

Abstract

The application discloses a kind of high-efficiency low temperature, low noble metal load multi-element bacteriostatic material for organ static cold preservation and its preparation method and application, belong to biomedical materials and organ transplantation technical field.The bacteriostatic material is loaded on TiO2-MO x Low noble metal multi-element bacteriostatic system on composite carrier, general formula is Ag-N / TiO2-MO x Wherein N is one of Cu, Co, Mn, MO x It is one of CeO2, WO3, MoO3.The bacteriostatic efficiency of the material in the present application is greater than 90% in the low temperature interval of 0-40 DEG C to gram-positive bacteria and gram-negative bacteria, effectively overcome the problems of high cost of existing Ag bacteriostatic material and insufficient activity and stability of non-noble metal material, with high bacteriostatic activity, excellent anti-poisoning capacity and low cost advantage, especially suitable for static cold preservation of organ in vitro in organ transplantation, can significantly inhibit bacterial growth, prolong the organ survival time.

Description

Technical Field

[0001] This invention belongs to the field of biomedical materials and organ transplantation technology, and specifically relates to a highly efficient, low-temperature, low-precious-metal-loaded multi-element antibacterial material for static cryopreservation of organs, its preparation method and application. Background Technology

[0002] Organ transplantation, as the most effective treatment for end-stage organ failure, has made significant progress globally in recent years. However, its development faces two major bottlenecks: first, a severe shortage of donor organs, with the number of patients waiting for transplants worldwide far exceeding the number of available organs; and second, the mismatch between donors and recipients in time and space, making the preservation quality and duration of ex vivo organs key factors affecting transplant success rates.

[0003] Currently, static cold storage (SCS) is the most widely used standard preservation technique in clinical organ transplantation. In this system, the excised organ is placed in a specialized preservation device and maintained at a low temperature of 0-4 °C. While low temperature can significantly slow down cell metabolism and prolong organ survival time, it cannot completely avoid the following key issues:

[0004] First, ischemia-reperfusion injury remains a major obstacle to the recovery of organ function after transplantation. During cryopreservation, the organ is in a state of ischemia, cellular energy metabolism is hindered, ion pump function is disrupted, leading to cell edema and accumulation of metabolic products. When blood flow is restored to the organ after transplantation, a large number of oxygen free radicals are generated, triggering oxidative stress and exacerbating tissue damage.

[0005] Secondly, the risk of microbial contamination cannot be ignored. Despite strict aseptic techniques throughout the organ acquisition, transportation, and preservation process, it is still difficult to completely avoid the introduction of microorganisms. Traditional antimicrobial methods mainly rely on adding antibiotics to the preservation solution, but this method has significant limitations: first, antibiotic resistance is becoming increasingly serious, with some strains already resistant to commonly used antibiotics; second, antibiotics may have direct toxicity to organ cells, affecting organ viability; and third, antibiotics have a limited antimicrobial spectrum, failing to cover all possible contaminating microorganisms.

[0006] More importantly, existing antibacterial strategies often overlook the crucial aspect of preserving the inner wall of the device. During long-term storage, the inner wall can become a breeding ground for bacteria, and currently, there is a lack of effective antibacterial solutions targeting this area. Coating the inner wall with antibacterial materials, through contact inhibition, can prevent bacteria from colonizing and multiplying on the device surface at the source, providing a more direct and effective antibacterial approach.

[0007] Silver (Ag)-based antibacterial materials have attracted widespread attention due to their broad-spectrum and highly effective antibacterial properties. However, in practical applications, traditional Ag-based materials have been found to have the following prominent problems: First, the material cost is high, especially for high-loading Ag-based materials, which severely limits their large-scale clinical application; second, Ag... + The release rate of Ag is difficult to control, often resulting in an initial release that is too rapid and a later release that is insufficient, leading to an unsustainable antibacterial effect; thirdly, in complex usage environments, Ag... + It readily reacts with gaseous pollutants such as hydrogen sulfide and sulfur dioxide in the air, or with sulfur-containing metabolites released by organs, forming Ag2S and becoming inactive. This phenomenon is medically known as "sulfur poisoning." Similarly, its reaction with chloride ions to form AgCl also significantly reduces the antibacterial activity of the material.

[0008] In addition, although some non-precious metal antibacterial materials (such as Cu and Zn oxides) are low in cost, they generally suffer from insufficient antibacterial activity, poor stability, and weak antitoxicity, making it difficult to meet the stringent requirements for antibacterial materials in organ preservation.

[0009] The unique characteristics of the current organ preservation environment place higher demands on antibacterial materials: on the one hand, they need to maintain high antibacterial activity under low temperature conditions (0-4 ℃); on the other hand, they need to have good biocompatibility and not produce toxic effects on organ cells; at the same time, they also need to have stable chemical properties and be able to resist various factors in the environment that may cause the material to become inactive.

[0010] Therefore, developing a novel antibacterial material that can maintain high efficiency, stability, and broad-spectrum antibacterial activity at low temperatures, while possessing excellent anti-toxicity capabilities and good biocompatibility, is of great clinical significance and application value for improving organ preservation quality, extending preservation time, and promoting the development of organ transplantation technology. Summary of the Invention

[0011] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a highly efficient, low-temperature, low-precious-metal-loaded multi-element antibacterial material for static cryopreservation of organs, along with its preparation method and applications. Through ingenious structural design, this material achieves highly efficient, stable, and broad-spectrum antibacterial activity within the 0-40 °C low-temperature range while significantly reducing the amount of precious metals used.

[0012] To achieve the above objectives, the present invention adopts the following technical solution:

[0013] A highly efficient, low-temperature, low-precious-metal-loaded multi-element antibacterial material for static cryopreservation of organs, wherein the antibacterial material is supported on TiO2-MO. x Low-noble-metal multi-element antibacterial system on a composite carrier, with the general formula Ag-N / TiO2-MO xN is one of Cu, Co, and Mn, and MO x It is one of CeO2, WO3, and MoO3.

[0014] Furthermore, the antibacterial material exhibits an antibacterial efficiency greater than 90% against Gram-positive bacteria (such as Staphylococcus aureus) and Gram-negative bacteria (such as Escherichia coli) in the temperature range of 0-40 °C.

[0015] Furthermore, the antibacterial material comprises at least one of the following structures: single-atom dispersion sites of the noble metal Ag, a core-shell structure Ag@TiO2, and an Ag-N bimetallic interface synergistic structure. These structures help maximize the utilization of the noble metal, enhance the interfacial synergistic effect, and improve the structural stability and anti-poisoning ability of the material.

[0016] Furthermore, based on the total mass of the antibacterial material, the mass fraction of precious metal Ag is 0.05%-2.0%, and the mass fraction of transition metal N is 0.5%-5.0%. This ratio of low precious metal and high transition metal effectively controls costs while ensuring high performance.

[0017] Furthermore, the specific surface area of ​​the antibacterial material is 50-200 m². 2 / g, with an average pore size of 5-30 nm. This facilitates the exposure of active sites and the release and contact of antibacterial components.

[0018] A method for preparing a highly efficient, low-temperature, low-precious-metal-loaded multi-component antibacterial material for static cryopreservation of organs includes the following steps:

[0019] (S1) TiO2-MO was prepared by co-precipitation or sol-gel method. x Composite carrier;

[0020] (S2) Load Ag precursor and N precursor onto TiO2-MO obtained in step (S1) by impregnation or photodeposition. x On the composite carrier;

[0021] (S3) The product obtained in step (S2) is dried (80-120 ℃) ​​and calcined. The calcination temperature is 300-500 ℃, the calcination time is 2-6 hours, and the atmosphere is air or inert gas to obtain the final antibacterial material.

[0022] Furthermore, in step (S1), the TiO2 and MO xThe molar ratio is 10:1 to 1:1; in step (S2), the Ag precursor is one of silver nitrate, silver oxalate, silver ammonia solution, silver sulfate, and silver chloride, and the N precursor is the corresponding nitrate, chloride, or acetate; in step (S1), at least one of ammonium metatungstate, ammonium metamolybdate, and cerium nitrate hexahydrate is used with titanium dioxide as the carrier precursor, and the mass ratio of the carrier precursor to the Ag precursor and N precursor in step (S2) is (95-105):(0.2-1.5):(3-12). x The introduction of (CeO2, WO3, MoO3) can modulate the redox properties of the support, increase the surface oxygen vacancy concentration, and thus enhance the anchoring ability and synergistic effect of Ag and N. By controlling parameters such as precursor concentration, pH value, and loading sequence, specific structures such as single-atom, core-shell, or bimetallic interfaces can be formed.

[0023] Application of the antibacterial material described above in a cryogenic long-term preservation device for transplanted organs. The antibacterial material is coated on the inner surface of the preservation device to inhibit bacterial growth inside the device.

[0024] The beneficial effects of this invention are:

[0025] 1. Highly efficient low-temperature antibacterial effect: Through the construction of Ag-N / TiO2-MO x The multi-component synergistic system exhibits an antibacterial efficiency of over 90% against representative Gram-positive and Gram-negative bacteria in a low-temperature environment of 0-40 ℃, effectively meeting the antibacterial requirements for organ cryopreservation.

[0026] 2. Low cost and high activity / stability: By employing strategies such as single-atom dispersion of precious metals, core-shell structure and bimetallic interface synergy, high antibacterial activity and long-term stability are achieved while significantly reducing the amount of precious metal Ag (as low as 0.05-2.0 wt%), thus resolving the contradiction between the high cost of traditional Ag materials and the insufficient performance of non-precious metal materials.

[0027] 3. Excellent resistance to poisoning: TiO2-MO x The composite carrier and the synergistic effect of the Ag-N interface significantly enhance the material's tolerance to sulfur-containing gases such as hydrogen sulfide and sulfur dioxide in the environment, as well as sulfur-containing metabolites released by organs, effectively preventing performance degradation caused by sulfur poisoning.

[0028] 4. Innovative application method: This antibacterial material is specially designed to be coated on the inner wall of a long-term preservation device for isolated organs. It directly inhibits the growth of bacteria inside the device through a contact antibacterial mechanism, avoiding the drug resistance and toxicity problems of traditional antibiotic immersion methods, and controlling the risk of contamination from the source.

[0029] 5. Good biocompatibility: By precisely controlling the release rate of Ag and selecting the carrier material, it is ensured that the material has no toxic side effects on organ cells while inhibiting bacteria, thus meeting the biosafety requirements of medical devices. Attached Figure Description

[0030] Figure 1 SEM comparison images of G5 and the antibacterial material synthesized in Example 1;

[0031] Figure 2 XRD comparison diagrams of G5 (TiO2), the antibacterial material synthesized in Example 1 (Ag0.05), and the material synthesized in Comparative Example 2 (Ag0.1);

[0032] Figure 3 Colony diagrams of Staphylococcus aureus and Escherichia coli in different samples after incubation at 37 ℃ for 24 h. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] This invention relates to a highly efficient, low-temperature, low-precious-metal-loaded multi-component antibacterial material for static cryopreservation of organs, with the general formula Ag-N / TiO2-MO. x N is one of Cu, Co, and Mn, and MO x It is one of CeO2, WO3, and MoO3. This material achieves an antibacterial efficiency greater than 90% against Gram-positive bacteria (such as Staphylococcus aureus) and Gram-negative bacteria (such as Escherichia coli) in the low-temperature range of 0-40 °C by constructing at least one of the following structures: noble metal single-atom dispersion sites, core-shell structure (Ag@TiO2), and Ag-N bimetallic interface synergistic structure. The specific surface area of ​​the antibacterial material of this invention is 50-200 m². 2 / g, with an average pore size of 5-30 nm. Based on the total mass of the antibacterial material, the mass fraction of noble metal Ag is 0.05%-2.0%, and the mass fraction of transition metal N is 0.5%-5.0%.

[0035] The antibacterial material of this invention is prepared through the following steps:

[0036] (S1) TiO2-MO was prepared by co-precipitation method or sol-gel method. x Composite support, TiO2 and MO x The molar ratio is 10:1 to 1:1.

[0037] TiO2-MO was prepared by coprecipitation method. x The steps for preparing the composite carrier are as follows: The carrier precursor and the precipitant, deionized water, are mixed to obtain a suspension; the suspension is allowed to stand and age, then centrifuged, washed with water (to achieve a neutral pH of approximately 7), dried (at 80 °C for 4–8 h), and calcined (at 500–600 °C for 4.0–6.0 h) to obtain TiO2-MO. x Composite carrier. The carrier precursor is one or more of ammonium metatungstate, ammonium metamolybdate, and cerium nitrate hexahydrate combined with titanium dioxide; the precipitant is selected from ammonia water, NaOH solution, and ammonium chloride solution, and the pH of the suspension is adjusted to 9-10 using the precipitant.

[0038] The sol-gel method was used to prepare TiO2-MO. x The steps for constructing the composite support are as follows: dissolve the titanium source in an organic solvent, stir, and form a homogeneous solution A. Separately, add MO... x The precursor is dissolved in the same organic solvent or deionized water to form solution B. Solution B is slowly added dropwise to solution A under continuous stirring to form a mixed sol. A suitable amount of deionized water or an acidic / basic catalyst is slowly added to promote the hydrolysis-condensation reaction. Stirring continues until a transparent or translucent sol is formed. The mixed sol is allowed to stand to gradually gel. The gel is aged at room temperature for 12-48 hours to enhance the stability of the network structure. The aged gel is dried at 60-120 °C to remove solvent and moisture, obtaining a dry gel. The dry gel is ground into a uniform powder. The powder is calcined at a predetermined temperature (usually 400-600 °C) for 2-6 hours to obtain TiO2-MO. x Composite carrier.

[0039] The titanium source is one or more of tetrabutyl titanate, tetraisopropyl titanate, and titanium tetrachloride, and the organic solvent is one or more of anhydrous ethanol, isopropanol, and ethylene glycol; MO x The precursor is one or more of ammonium metatungstate, ammonium metamolybdate, and cerium nitrate hexahydrate; the alkaline catalyst is one or more of ammonia, urea, and sodium hydroxide solution; and the acidic catalyst is one or more of nitric acid, hydrochloric acid, and acetic acid.

[0040] (S2) Load Ag precursors and N precursors onto TiO2-MO by impregnation or photodeposition. xThe antibacterial material is obtained by drying and calcining on a composite carrier. The mass ratio of the carrier precursor to the Ag precursor and N precursor in step (S2) is (95-105):(0.2-1.5):(3-12). The Ag precursor is one of silver nitrate, silver oxalate, silver ammonia solution, silver sulfate, and silver chloride, and the N precursor is the corresponding nitrate, chloride, or acetate. The calcination temperature is 300-500 ℃, the calcination time is 2-6 hours, and the atmosphere is air or an inert gas.

[0041] TiO2-MO was prepared using an impregnation method. x The specific steps for loading Ag-N bimetallic components onto a composite support are as follows: Ag and N precursors are dissolved in a certain amount of deionized water and stirred to obtain solution A; a certain amount of TiO2-MO is then added... x The composite carrier was added to solution A and stirred for 0.5 h; the resulting mixed solution was placed in a rotary evaporator to dry it into a solid powder, and finally placed in a muffle furnace for calcination at a temperature of 400-600 ℃ for 3-5 hours in an air atmosphere.

[0042] TiO2-MO was produced using a photo-induced in-situ metal anchoring and reduction method (i.e., photodeposition). x The specific steps for loading Ag-N bimetallic components onto a composite support are as follows: A TiO2-CeO2 composite support, Ag precursor, N precursor, and deionized water are mixed to prepare suspension A. Suspension A is added to a photochemical reactor, dissolved oxygen is removed with nitrogen, and suspension A is irradiated with a 300 W xenon lamp (equipped with an ultraviolet cutoff filter, primarily outputting visible light) for 2-3 hours. The resulting mixed solution is then dried by rotary evaporation to obtain a solid powder, which is finally calcined in a muffle furnace at 400-600 ℃ for 3-5 hours in an air atmosphere.

[0043] The preferred embodiments are as follows:

[0044] Example 1:

[0045] (S1) Preparation of TiO2-CeO2 composite support

[0046] TiO2-CeO2 composite support was prepared by co-precipitation. The specific steps are as follows: 12.6109 g of cerium nitrate hexahydrate was dissolved in deionized water and stirred to form a homogeneous solution. Ammonia was slowly added dropwise (to adjust the pH to 9.5), followed by the addition of 5.7471 g of G5 (i.e., ultrafine titanium dioxide purchased from Cristalactiv, model G5, with a TiO2 content of 87%). The mixture was stirred continuously at room temperature for 1.5 h (pH was measured every half hour to ensure it remained between 9 and 10), forming a suspension. After aging for 12 h, the precipitate was collected by centrifugation, washed with deionized water until neutral (pH≈7), dried in an oven at 80 ℃ for 8 h, and then calcined in a muffle furnace at 500 ℃ for 4 h to obtain the TiO2-CeO2 composite support. The specific surface area of ​​this support was determined to be 80 m². 2 / g, with an average pore size of 15 nm.

[0047] (S2) Loading of Ag and Cu

[0048] The reduction of metallic Ag was achieved using a photo-induced in-situ anchoring and reduction method (i.e., photodeposition). + Plasma generates oxygen vacancies or Ti atoms that preferentially anchor on the support surface. 3+ Zero-valent or low-valent metals at defect sites. The specific steps are as follows: Disperse the above TiO2-CeO2 composite support (10.0 g) in deionized water, and add a solution containing 0.0155 g of silver oxalate (containing 0.1 wt% Ag) and a solution containing 0.5903 g of copper nitrate (containing 2.0 wt% Cu) in sequence to obtain suspension A; add the above suspension A to the photochemical reactor, turn on magnetic stirring, and introduce nitrogen gas for 15 minutes to remove dissolved oxygen and avoid its interference with the reaction process. Irradiate suspension A with a 300 W xenon lamp (equipped with an ultraviolet cutoff filter, mainly outputting visible light) and continue the reaction for 2 hours.

[0049] (S3) Drying and calcination

[0050] The reaction product was placed in a rotary evaporator and evaporated at 80 °C until a dry powder was obtained. Then, it was calcined in an air atmosphere at 500 °C for 4 hours to obtain the Ag-Cu / TiO2-CeO2 antibacterial material. Characterization showed that the material contained 0.1% Ag by mass, 2.0% Cu by mass, and an average pore size of 20 nm. The obtained product was named Sample 1.

[0051] Comparative Example 1:

[0052] Prepared according to the method of Example 1, but step (S1) was changed as follows: 12.6109 g of cerium nitrate hexahydrate was dissolved in deionized water and stirred to form a homogeneous solution. 5.7471 g of G5 was added and stirred continuously at room temperature for 1.5 h to form a suspension. The water was initially removed using a rotary evaporator at 80 °C, and then calcined in a muffle furnace at 500 °C for 4 h to obtain the TiO2-CeO2 composite support. The obtained product was named Sample 2.

[0053] Comparative Example 2:

[0054] Prepared according to the method of Example 1, but step (S2) is changed to loading Ag metal by impregnation. + The plasma method involved dispersing the above-mentioned TiO2-CeO2 composite support (10.0 g) in deionized water, followed by the sequential addition of a solution containing 0.0155 g of silver oxalate (containing 0.1 wt% Ag) and a solution containing 0.5903 g of copper nitrate (containing 2.0 wt% Cu) to obtain a suspension. The resulting product was named Sample 3.

[0055] Comparative Example 3:

[0056] Prepared according to the method of Example 1, but step (S2) was changed as follows: the above TiO2-CeO2 composite support (10.0 g) was dispersed in deionized water, and a solution containing 0.0077 g of silver oxalate (containing 0.05 wt% Ag) and a solution containing 0.5903 g of copper nitrate (containing 2.0 wt% Cu) were added sequentially to obtain suspension A. The obtained product was named Sample 4.

[0057] Comparative Example 4:

[0058] The TiO2-CeO2 composite support was replaced with an equal mass of TiO2, and the product was prepared according to steps (S2) and (S3) of Example 1. The resulting product was named Sample 5.

[0059] Comparative Example 5:

[0060] The sample was prepared according to Example 1, but without adding copper nitrate solution in step (S2), and the resulting product was named Sample 6.

[0061] Comparative Example 6:

[0062] The sample was prepared according to Example 1, but silver oxalate solution was not added in step (S2), and the resulting product was named Sample 7.

[0063] The specific surface areas of different samples are shown in Table 1.

[0064] Table 1. Specific surface area data of different samples

[0065]

[0066] The antibacterial properties of the samples were tested according to GB / T21510-2024 "Test Methods and Evaluation of Antibacterial Properties of Nano-Inorganic Materials". Since the test material was in powder form, the shaking method was selected for the antibacterial performance test. The test strains for this antibacterial test were Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli). Staphylococcus aureus was purchased from Qingdao Rishui Biotechnology Co., Ltd., model: CMCC(B)26003; Escherichia coli was purchased from Shanghai Koraman Reagent Co., Ltd., model: Escherichia coli DH5α.

[0067] The antibacterial test results for different samples are shown in Table 2. The formula for calculating the antibacterial rate is: Antibacterial rate = (Number of colonies in the control group - Number of colonies in the experimental group) / Number of colonies in the control group × 100%

[0068] Table 2 Antibacterial rates of different samples

[0069]

[0070] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a highly efficient, low-temperature, low-precious-metal-loaded multi-element antibacterial material for static cryopreservation of organs, characterized in that, Includes the following steps: (S1) TiO2-CeO2 composite support was prepared by co-precipitation method; (S2) The Ag precursor and N precursor are loaded onto the TiO2-CeO2 composite support obtained in step (S1) by photodeposition; the N precursor is copper nitrate, copper chloride or copper acetate. (S3) The product obtained in step (S2) is dried and calcined to obtain the final antibacterial material; The antibacterial material exhibits an antibacterial efficiency greater than 90% against Gram-positive and Gram-negative bacteria within a temperature range of 0-40℃.

2. The method for preparing a highly efficient, low-temperature, low-precious-metal-loaded multi-element antibacterial material for static cryopreservation of organs according to claim 1, characterized in that, Based on the total mass of the antibacterial material, the mass fraction of precious metal Ag is 0.05%-2.0%, and the mass fraction of transition metal N is 0.5%-5.0%.

3. The method for preparing a high-efficiency, low-temperature, low-precious-metal-loaded multi-element antibacterial material for static cryopreservation of organs according to claim 1, characterized in that, The specific surface area of ​​the antibacterial material is 50-200 m². 2 / g, with an average pore size of 5-30nm.

4. The method for preparing a highly efficient, low-temperature, low-precious-metal-loaded multi-element antibacterial material for static cryopreservation of organs according to claim 1, characterized in that, In step (S1), the molar ratio of TiO2 to CeO2 is 10:1 to 1:1; in step (S2), the Ag precursor is one of silver nitrate, silver oxalate, silver ammonia solution, silver sulfate, and silver chloride; in step (S1), cerium nitrate hexahydrate and titanium dioxide are used as the carrier precursor, and the mass ratio of the carrier precursor to the Ag precursor and N precursor in step (S2) is (95-105):(0.2-1.5):(3-12).

5. The application of an antibacterial material prepared by the method of any one of claims 1-4 in a low-temperature long-term preservation device for transplanted organs.

6. The application of the antibacterial material according to claim 5 in a cryogenic long-term preservation device for transplanted organs, characterized in that, The antibacterial material is coated on the inner surface of the preservation device.

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