Preparation method and application of nitrogen-doped carbon nanotube loaded Fe / Mg diatomic nanoscale enzyme

Abstract

The application discloses a preparation method and application of nitrogen-doped carbon nanotube loaded Fe / Mg diatomic nanoscale enzyme, and relates to the technical field of medical materials. The Fe / Mg-NC nanoscale enzyme has a hollow tubular structure, Fe and Mg are distributed on the carbon nanotube, the nanoscale enzyme has glucose oxidase (GOD) activity, catalase (CAT) activity and peroxidase (POD) activity, can decompose H2O2 to generate O2, hydroxyl radicals (OH ‑ ) and has excellent photothermal performance under near-infrared 808 nm light; the nanoscale enzyme is almost non-toxic to cells and has good biocompatibility in a concentration range of 0-20 mu g / mL; under the photothermal synergistic condition, the oxidation stress level in bacteria can be significantly enhanced, and the antibacterial effect is remarkable. The nanoscale enzyme has good multi-enzyme activity and photothermal performance, has a wide application prospect in the fields of antibacterial and wound healing, and can be used as a potential therapy for diabetic wound infection.

Description

Technical Field

[0001] This invention relates to the field of medical materials technology, specifically to a method for preparing and applying a nitrogen-doped carbon nanotube-supported Fe / Mg diatomic nanozyme. Background Technology

[0002] Nanozymes are a class of nanomaterials with enzyme-like catalytic activity. Compared to natural enzymes, they offer advantages such as low cost, high stability, and ease of large-scale preparation, showing broad application prospects in fields such as biosensing, antibacterial therapy, and inflammation regulation. In particular, single-atom nanozymes (SANs), by dispersing metal atoms in single-atom form on a carbon-based support, can maximize atom utilization efficiency and mimic the coordination structure of natural enzymes, becoming a research hotspot in the field of artificial enzymes. In antibacterial applications, nanozymes with multi-enzyme activities such as POD-like, OXD-like, and glutathione oxidase (GPx)-like activities can catalyze the generation of reactive oxygen species (ROS) or consume bacterial endogenous glutathione (GSH), thereby synergistically enhancing antibacterial effects. Furthermore, combining nanozymes with photothermal therapy (PTT) can further improve antibacterial efficiency and reduce dependence on high-concentration nanozymes.

[0003] Currently, relevant patent applications have disclosed different types of nanozymes and their preparation methods. For example, Chinese invention patent application CN119140839A (publication date: December 17, 2024) discloses a Fe / Mn-SNC double single-atom nanomaterial with multi-enzyme activity, its preparation method, and its applications. This invention designs and develops Fe / Mn... SNC dual single-atom nanozymes employ a localized fine-tuning strategy to precisely regulate the relationship between the host surface and spatial structure to support the dual active sites of the metal. Through a one-step pyrolysis method, a ligand etching-pyrolysis strategy is used to synthesize Yolk–Shell structured dual single-atom nanozymes. These nanomaterials exhibit stable structural properties, abundant active sites, and maximized enzyme-like activity. This nanomaterial possesses multi-enzyme activity, can initiate its own cascade reactions to generate abundant ROS, resulting in antibacterial effects without drug resistance and with strong versatility, thus possessing significant scientific importance and substantial commercial value. However, the nanozymes disclosed in this application primarily rely on endogenous oxygen and hydrogen peroxide for catalytic reactions, without addressing strategies for synergistic enhancement of antibacterial activity through exogenous photothermal stimulation. Furthermore, the preparation process of its yolk-shell structure is relatively complex, requiring precise control of pyrolysis conditions.

[0004] For example, Chinese invention patent application CN117860780A (publication date: April 12, 2024) discloses a method for preparing FeZn-NC single-atom nanozymes and a method for preparing composite enzymes derived therefrom. This method involves in-situ loading of Fe metal during the preparation of a metal-organic framework (ZIF-8), followed by high-temperature calcination to construct a FeZn-NC single-atom nanozyme with POD-like activity. Then, GOD is loaded onto the surface of FeZn-N-CSAN via physical adsorption to synthesize a self-supplying H2O2 GOD@FeZn-NC composite nanozyme for treating diabetic wounds. The loaded GOD can oxidize glucose at the wound site to generate gluconic acid and H2O2. The generated H2O2 can be efficiently catalyzed and decomposed by FeZn-NC SAN under low pH conditions to produce OH-. - This allows the nanozymes to kill bacteria and promote wound healing. However, the nanozymes disclosed in this application have a solid polyhedral structure, and their specific surface area and the degree of exposure of active sites need to be further improved. At the same time, the preparation of its composite nanozymes involves the physical adsorption of enzymes, which poses a risk of GOD detachment. In addition, this application also does not involve the synergistic antibacterial application of photothermal properties and multi-enzyme activity.

[0005] In summary, existing technologies still have room for improvement in terms of structural design, enzyme activity types, and synergistic antibacterial strategies. How to organically combine excellent multi-enzyme activities (including GOD-like, CAT-like, and POD-like activities) with photothermal properties to construct a nanozyme with a hollow tubular structure, large specific surface area, fully exposed active sites, and both self-supplied H2O2 capacity and photothermal synergistic enhancement of antibacterial effects is a pressing technical problem to be solved in this field. Summary of the Invention

[0006] To address the problems existing in current nanozymes, this invention provides a nitrogen-doped carbon nanotube-supported Fe / Mg diatomic nanozyme (abbreviated as Fe / Mg-NC nanozyme) with multi-enzyme mimicry activity. The nitrogen-doped carbon nanotube-supported Fe / Mg diatomic nanozyme is a nitrogen-carbon material co-doped with iron and magnesium, and has a hollow tubular structure.

[0007] Furthermore, the nitrogen-doped carbon nanotube-supported Fe / Mg diatomic nanozyme includes a nitrogen-doped carbon nanotube carrier and Fe and Mg diatomic active sites loaded thereon.

[0008] Furthermore, the Fe:Mg atomic ratio in the nitrogen-doped carbon nanotube-supported Fe / Mg diatomic nanozyme is 0.4-0.48:1.

[0009] Furthermore, the nitrogen-doped carbon nanotube-supported Fe / Mg diatomic nanozyme possesses at least one or more of the following: GOD-like activity, CAT-like activity, and POD-like activity.

[0010] Furthermore, the nitrogen-doped carbon nanotube-supported Fe / Mg diatomic nanozyme exhibits photothermal properties under near-infrared 808 nm light irradiation.

[0011] Furthermore, the nitrogen-doped carbon nanotube-loaded Fe / Mg diatomic nanozyme exhibits biocompatibility, with a survival rate of nearly 90% for human umbilical vein endothelial cells (HUVECs) within a concentration range of 0-20 μg / mL.

[0012] This application also provides a method for preparing the above-mentioned nitrogen-doped carbon nanotube-supported Fe / Mg diatomic nanozyme, comprising the following steps: Step S1: Dissolve polyacrylonitrile, iron acetylacetonate and magnesium acetylacetonate dihydrate in N,N-dimethylformamide and stir to obtain an electrospinning precursor solution. Step S2: Electrospin the electrospinning precursor solution and collect the precursor fiber membrane. Step S3: Immerse the precursor fiber membrane in a mixed solution containing tetraethyl orthosilicate, ethanol, water and hydrochloric acid, and stir to grow a silicon dioxide layer on the membrane. Step S4: Pyrolyze the SiO2 coating film under an inert atmosphere to obtain pyrolysis products; Step S5: Wash the pyrolysis product with hydrofluoric acid solution for 12-24 hours to remove the silica shell and obtain the Fe / Mg-NC catalyst. Step S6: Grind and collect the Fe / Mg-NC catalyst to obtain the Fe / Mg-NC nanozyme.

[0013] Furthermore, in step S1, the amount of polyacrylonitrile is 1.0-2.0 g, the amount of ferric acetylacetone is 200-400 mg, the amount of magnesium acetylacetone dihydrate is 200-400 mg, the amount of N,N-dimethylformamide is 10-20 mL, the stirring time is 12-24 hours, and the stirring is carried out at room temperature.

[0014] Furthermore, in step S2, the electrospinning flow rate is 0.02-0.04 mL / min, the applied voltage is 10-14 kV, and the distance from the needle to the aluminum foil is 10-20 cm.

[0015] Furthermore, in step S3, the amount of the precursor fiber membrane used is 200-400 mg; the mixed solution consists of 4-8 mL tetraethyl orthosilicate, 15-30 mL ethanol, 5-10 mL water and 1.5-3.0 mL hydrochloric acid with a mass fraction of 37.5%; the stirring time is 3-6 hours.

[0016] Furthermore, in step S4, the inert atmosphere is argon, the pyrolysis temperature is 800-900℃, and the pyrolysis time is 2-4 hours.

[0017] This application also provides the application of the Fe / Mg-NC nanozyme prepared according to the above method in the preparation of drugs for diabetic wound infection.

[0018] Furthermore, the drug enhances the level of ROS within bacteria through photothermal synergy to kill bacteria.

[0019] Compared with existing technologies, the advantages and effects of this application are as follows: 1. Compared with the polyhedral structure in the prior art, this application adopts an electrospinning combined with silica template pyrolysis strategy to prepare Fe / Mg-NC nanozymes with hollow tubular structure. The hollow structure is conducive to the mass transfer of substrate and diffusion of products in catalytic reaction, while fully exposing Fe and Mg active sites on the surface, which significantly improves atom utilization efficiency and catalytic activity.

[0020] 2. Most nanozymes prepared by existing technologies only exhibit POD-like activity and require physical adsorption to load exogenous GOD to achieve self-supply of H2O2. The Fe / Mg-NC nanozyme of this application possesses GOD-like, CAT-like, and POD-like enzyme activities simultaneously. Specifically, the GOD-like activity catalyzes the oxidation of glucose to gluconic acid and H2O2 without requiring exogenous enzyme loading; the POD-like activity catalyzes the decomposition of H2O2 to produce OH-. - It effectively kills bacteria; its CAT-like activity can catalyze the decomposition of H2O2 to produce O2, alleviating the hypoxic microenvironment at the site of infection.

[0021] 3. This application confirms, through near-infrared 808 nm light irradiation testing, that the Fe / Mg-NC nanozyme exhibits excellent photothermal effects under 1.6 W NIR radiation. The antibacterial effect is also strongest under synergistic photothermal conditions, significantly superior to using nanozymes alone or photothermal therapy alone. The synergistic photothermal strategy achieves highly efficient antibacterial activity at lower nanozyme concentrations, further reducing the potential toxicity risk to normal cells.

[0022] 4. The Fe / Mg-NC nanozyme prepared in this application can achieve efficient antibacterial activity through photothermal synergy at a low concentration, further improving biosafety.

[0023] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the preferred embodiments of this application are described in detail below with reference to the accompanying drawings.

[0024] The above and other objects, advantages and features of this application will become more apparent to those skilled in the art from the following detailed description of specific embodiments in conjunction with the accompanying drawings. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0026] in: Figure 1 This is a flowchart of the preparation process of Fe / Mg-NC nanozymes; Figure 2 The diagram shows the transmission electron microscopy (TEM) and EDS mapping results of Fe / Mg-NC nanozymes, with Bar = 100 nm. In the diagram, a is a schematic diagram of the structure of Fe / Mg-NC nanozymes, b is a schematic diagram of the distribution of N atoms, c is a schematic diagram of the distribution of C atoms, d is a schematic diagram of the distribution of Fe atoms, and e is a schematic diagram of the distribution of Mg atoms. Figure 3 The graph shows the GOD-like activity detection results of Fe / Mg-NC nanozymes. Figure 4 The graph shows the CAT-like activity detection results of Fe / Mg-NC nanozymes. Figure 5 The graph shows the POD-like activity detection results of Fe / Mg-NC nanozymes. Figure 6 This is a diagram showing the biocompatibility analysis of Fe / Mg-NC nanozymes. Figure 7 A schematic diagram showing the photothermal performance test results of Fe / Mg-NC nanozymes; Figure 8 This is a schematic diagram showing the results of the ROS production capacity of Fe / Mg-NC nanozymes in bacteria, Bar=100 μm. Among them, a is the control group, b is the NIR group, c is the Fe / Mg-NC nanozyme group, and d is the Fe / Mg-NC nanozyme + NIR group. Figure 9 Statistical analysis of the results of detecting the ROS production capacity of Fe / Mg-NC nanozymes in bacteria; Figure 10The diagram shows the results of the antibacterial effect test of Fe / Mg-NC nanozyme, where a is the control group, b is the NIR group, c is the Fe / Mg-NC nanozyme group, and d is the Fe / Mg-NC nanozyme + NIR group. Figure 11 This is a statistical analysis chart showing the antibacterial effect of Fe / Mg-NC nanozymes. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. In the following description, specific details such as specific configurations and components are provided merely to help fully understand the embodiments of this application. Therefore, those skilled in the art should understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. In addition, for clarity and brevity, descriptions of known functions and structures are omitted in the embodiments.

[0028] It should be understood that the phrase "an embodiment" or "this embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "an embodiment" or "this embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0029] Furthermore, reference numerals and / or letters may be repeated in different examples within this application. Such repetition is for the purpose of simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or settings discussed.

[0030] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist simultaneously. The term " / and" describes another type of relationship between related objects, indicating that two relationships can exist. For example, A / and B can mean: A exists alone, and A and B exist alone. In addition, the character " / " in this article generally indicates that the related objects before and after it have an "or" relationship.

[0031] In this article, the term "at least one" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, "at least one of A and B" can mean: A exists alone, A and B exist simultaneously, or B exists alone.

[0032] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion.

[0033] Example 1 This embodiment describes a method for preparing Fe / Mg diatomic nanozymes supported on nitrogen-doped carbon nanotubes and the Fe / Mg-NC nanozymes obtained therefrom. Please refer to the appendix. Figure 1 , Figure 1 This is a flowchart of the preparation process of Fe / Mg-NC nanozymes; Includes the following steps: Step S1: Dissolve polyacrylonitrile, iron acetylacetonate and magnesium acetylacetonate dihydrate in N,N-dimethylformamide and stir to obtain an electrospinning precursor solution. Step S2: Electrospin the electrospinning precursor solution and collect the precursor fiber membrane. Step S3: Immerse the precursor fiber membrane in a mixed solution containing tetraethyl orthosilicate, ethanol, water and hydrochloric acid, and stir to grow a silicon dioxide layer on the membrane. Step S4: Pyrolyze the SiO2 coating film under an inert atmosphere to obtain pyrolysis products; Step S5: Wash the pyrolysis product with hydrofluoric acid solution for 12-24 hours to remove the silica shell and obtain the Fe / Mg-NC catalyst. Step S6: Grind and collect the Fe / Mg-NC catalyst to obtain the Fe / Mg-NC nanozyme.

[0034] Furthermore, in step S1, the amount of polyacrylonitrile is 1.0-2.0 g, the amount of ferric acetylacetone is 200-400 mg, the amount of magnesium acetylacetone dihydrate is 200-400 mg, the amount of N,N-dimethylformamide is 10-20 mL, the stirring time is 12-24 hours, and the stirring is carried out at room temperature.

[0035] Furthermore, in step S2, the electrospinning flow rate is 0.02-0.04 mL / min, the applied voltage is 10-14 kV, and the distance from the needle to the aluminum foil is 10-20 cm.

[0036] Furthermore, in step S3, the amount of the precursor fiber membrane used is 200-400 mg; the mixed solution consists of 4-8 mL tetraethyl orthosilicate, 15-30 mL ethanol, 5-10 mL water and 1.5-3.0 mL hydrochloric acid with a mass fraction of 37.5%; the stirring time is 3-6 hours.

[0037] Furthermore, in step S4, the inert atmosphere is argon, the pyrolysis temperature is 800-900℃, and the pyrolysis time is 2-4 hours.

[0038] The nitrogen-doped carbon nanotube-loaded Fe / Mg diatomic nanozyme obtained by the above preparation method is a nitrogen-carbon material co-doped with iron and magnesium, and has a hollow tubular structure.

[0039] Furthermore, the nitrogen-doped carbon nanotube-supported Fe / Mg diatomic nanozyme includes a nitrogen-doped carbon nanotube carrier and Fe and Mg diatomic active sites loaded thereon.

[0040] Furthermore, the Fe:Mg atomic ratio in the nitrogen-doped carbon nanotube-supported Fe / Mg diatomic nanozyme is 0.4-0.48:1.

[0041] The effects achieved in this embodiment are as follows: This embodiment adopts a preparation strategy of electrospinning combined with silica coating, high-temperature pyrolysis, and hydrofluoric acid etching. The parameters of each step are clear and the operation is controllable. Moreover, it does not require the use of precious metal raw materials, resulting in lower costs and easy large-scale production.

[0042] Example 2 The Fe / Mg-NC nanozyme prepared in Example 1 was used to observe its microstructure using transmission electron microscopy (TEM), and its elemental distribution was analyzed using energy-dispersive X-ray spectroscopy (EDS Mapping). See results Figure 2 The nanomaterial exhibits a tubular, hollow structure, with Fe and Mg elements distributed on the carbon nanotubes, indicating the successful construction of a bimetallic-supported hollow carbon nanotube structure.

[0043] The results achieved in this embodiment are as follows: This embodiment demonstrates that the Fe / Mg-NC nanozyme has a hollow tubular structure and that the Fe and Mg active sites are uniformly dispersed.

[0044] Example 3 Based on Example 1, this example performs GOD-like activity testing on Fe / Mg-NC nanozymes; Reference Figure 3A 30 mmol / L glucose solution was prepared using glucose as a substrate. 20 μg / mL Fe / Mg-NC nanozyme (experimental group), an equal volume of Fe-NC (single-metal control group), an equal volume of PBS (negative control group), and an equal volume of NC (blank control group) were mixed with the glucose solution, and the pH change of the reaction system was measured at different time points (0-24 hours). A lower pH value indicates more gluconic acid produced and stronger GOD activity.

[0045] The results showed that the pH value of the Fe / Mg-NC nanozyme group decreased significantly over time, dropping to about 4 after 12 hours; the pH value of the Fe-NC group decreased relatively slowly, dropping to about 4.7 after 12 hours; the pH values ​​of the NC group and the PBS group remained basically unchanged, between 6.2 and 6.5.

[0046] The results showed that the Fe / Mg-NC nanozyme exhibited good GOD-like mimicry activity.

[0047] The effect achieved in this embodiment is as follows: This embodiment demonstrates that Fe / Mg-NC nanozymes have GOD-like activity.

[0048] Example 4 Based on Example 1, this example performs CAT-like activity testing on Fe / Mg-NC nanozymes; Reference Figure 4 Fe / Mg-NC nanozymes of different concentrations (0, 5, 10, 15, 20, 25 μg / mL) were added to H2O2 solution, and the changes in dissolved O2 concentration in the reaction system were detected using a dissolved oxygen meter.

[0049] The results showed that the concentration of O2 increased significantly with the increase of Fe / Mg-NC nanozyme concentration, and the increase was obvious in a concentration-dependent manner; when the concentration of Fe / Mg-NC nanozyme was 25 μg / mL, the concentration of O2 rose to about 22 mg / L within 5 minutes.

[0050] The results showed that the Fe / Mg-NC nanozyme had good CAT-like activity and could effectively decompose H2O2 to produce O2.

[0051] The effects achieved in this embodiment are as follows: This embodiment demonstrates that Fe / Mg-NC nanozymes can catalyze the decomposition of H2O2 to produce O2, exhibiting CAT-like activity that is concentration-dependent.

[0052] Example 5 Based on Example 1, this example performs a POD-like activity test on Fe / Mg-NC nanozymes; Reference Figure 5The POD-like activity of Fe / Mg-NC nanozymes was evaluated using 3,3',5,5'-tetramethylbenzidine (TMB) as a probe.

[0053] Fe / Mg-NC nanozymes at different concentrations (0, 5, 10, 15, 20, 25 μg / mL) were used, and the absorption peak at 652 nm was detected using a UV-Vis spectrophotometer. Higher absorbance indicates the generation of OH-. - The more.

[0054] The results showed that as the concentration of Fe / Mg-NC nanozyme increased, the intensity of the absorption peak at 652 nm gradually increased, and the absorbance of the 25 μg / mL group reached 1.8.

[0055] The results showed that the Fe / Mg-NC nanozyme exhibited good POD-like activity.

[0056] Example 6 Based on Example 1, this example conducts a biocompatibility test on Fe / Mg-NC nanozymes; Reference Figure 6 HUVECs were co-cultured with Fe / Mg-NC nanozymes at different concentrations (0, 5, 10, 20, 30, 40, 50 μg / mL) for 24 hours, and cell viability was assessed using the CCK-8 assay.

[0057] The results showed that the survival rate of HUVECs cells was close to 90% within the experimental concentration range of 0-20 μg / mL; when the concentration was increased to 50 μg / mL, the survival rate was still higher than 70%.

[0058] The results showed that Fe / Mg-NC nanozymes had almost no toxicity to normal cells within the effective antibacterial concentration range and exhibited good biocompatibility.

[0059] Example 7 Based on Example 1, this example tests the photothermal performance of Fe / Mg-NC nanozymes; Reference Figure 7 Fe / Mg-NC nanozyme (experimental group), H2O (negative control), NC (blank control group), and Fe-NC (single metal control group) were irradiated with an 808 nm near-infrared (NIR) laser at a power of 1.6 W for 0-480 seconds. The results showed that Fe / Mg-NC nanozyme had the best photothermal effect under NIR radiation at a power of 1.6 W, and the temperature rose to 52℃ within 360 seconds.

[0060] The results show that Fe / Mg-NC nanozymes have good photothermal properties.

[0061] Example 8 Based on Example 1, this example tests the ability of Fe / Mg-NC nanozymes to generate ROS in bacteria; Reference Figure 8-9 The ability of Fe / Mg-NC nanozymes to generate ROS in bacteria was determined using the DCFH-DA fluorescent probe method.

[0062] Set up the Control group, NIR group (1.6 W, 8 min), Fe / Mg-NC nanozyme group and Fe / Mg-NC nanozyme + NIR group (photothermal synergistic group). After treatment, add DCFH-DA probe, incubate, and observe the green fluorescence intensity with a fluorescence microscope.

[0063] The results showed that the Fe / Mg-NC nanozyme treatment group (i.e., Fe / Mg-NC nanozyme + NIR group) under photothermal synergy conditions produced the strongest green fluorescence, with a fluorescence intensity approximately 3.3 times that of the control group, which was significantly higher than that of the Fe / Mg-NC nanozyme group alone and the NIR group alone.

[0064] The results showed that photothermal synergy could enhance the ability of Fe / Mg-NC nanozymes to generate ROS in bacteria and increase the level of oxidative stress in bacteria.

[0065] Example 9 Based on Example 1, this example tests the antibacterial ability of Fe / Mg-NC nanozymes; Reference Figure 10-11 The killing ability of Fe / Mg-NC nanozyme against Staphylococcus aureus was determined by plate coating method.

[0066] The bacteria were divided into four groups: Control group, NIR group (1.6 W, 8 min), Fe / Mg-NC nanozyme group and Fe / Mg-NC nanozyme + NIR group (photothermal synergistic group). After treatment, each group was plated on LB agar plates and incubated at 37°C for 18-24 hours. Colony forming units were counted.

[0067] The results showed that the Fe / Mg-NC nanozyme + NIR group had the fewest colonies and a sterilization rate of >99.9%, which was significantly better than the other groups.

[0068] The results showed that Fe / Mg-NC nanozyme synergistic photothermal therapy can effectively kill bacteria and has the strongest antibacterial effect, proving that Fe / Mg-NC nanozyme synergistic photothermal therapy can effectively kill bacteria.

[0069] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A nitrogen-doped carbon nanotube-supported Fe / Mg diatomic nanozyme, characterized in that, The nitrogen-doped carbon nanotube-supported Fe / Mg diatomic nanozyme is a nitrogen-carbon material co-doped with iron and magnesium, and has a hollow tubular structure.

2. The nitrogen-doped carbon nanotube-supported Fe / Mg diatomic nanozyme according to claim 1, characterized in that, The nitrogen-doped carbon nanotube-supported Fe / Mg diatomic nanozyme includes a nitrogen-doped carbon nanotube carrier and Fe and Mg diatomic active sites loaded thereon. The Fe:Mg atomic ratio in the nitrogen-doped carbon nanotube-supported Fe / Mg diatomic nanozyme is 0.4-0.48:

1.

3. The nitrogen-doped carbon nanotube-supported Fe / Mg diatomic nanozyme according to claim 1 or 2, characterized in that, The nitrogen-doped carbon nanotube-supported Fe / Mg diatomic nanozyme has at least one or more of the following: GOD-like activity, CAT-like activity, and POD-like activity.

4. The nitrogen-doped carbon nanotube-supported Fe / Mg diatomic nanozyme according to claim 1, characterized in that, The nitrogen-doped carbon nanotube-loaded Fe / Mg diatomic nanozyme exhibits photothermal properties under near-infrared 808 nm light irradiation.

5. A method for preparing the nitrogen-doped carbon nanotube-supported Fe / Mg diatomic nanozyme according to any one of claims 1-4, characterized in that, Includes the following steps: Step S1: Dissolve polyacrylonitrile, iron acetylacetonate and magnesium acetylacetonate dihydrate in N,N-dimethylformamide and stir to obtain an electrospinning precursor solution. Step S2: Electrospin the electrospinning precursor solution and collect the precursor fiber membrane. Step S3: Immerse the precursor fiber membrane in a mixed solution containing tetraethyl orthosilicate, ethanol, water and hydrochloric acid, and stir to grow a silicon dioxide layer on the membrane. Step S4: Pyrolyze the silicon dioxide coating film under an inert atmosphere to obtain pyrolysis products; Step S5: Wash the pyrolysis product with hydrofluoric acid solution for 12-24 hours to remove the silica shell and obtain the Fe / Mg-NC catalyst. Step S6: Grind and collect the Fe / Mg-NC catalyst to obtain the Fe / Mg-NC nanozyme.

6. The method according to claim 5, characterized in that, In step S1, the amount of polyacrylonitrile is 1.0-2.0g, the amount of ferric acetylacetone is 200-400 mg, the amount of magnesium acetylacetone dihydrate is 200-400 mg, the amount of N,N-dimethylformamide is 10-20 mL, the stirring time is 12-24 hours, and the stirring is carried out at room temperature.

7. The method according to claim 5, characterized in that, In step S2, the electrospinning flow rate is 0.02-0.04 mL / min, the applied voltage is 10-14 kV, and the distance from the needle to the aluminum foil is 10-20 cm.

8. The method according to claim 5, characterized in that, In step S3, the amount of the precursor fiber membrane used is 200-400 mg; the mixed solution consists of 4-8 mL tetraethyl orthosilicate, 15-30 mL ethanol, 5-10 mL water and 1.5-3.0 mL hydrochloric acid with a mass fraction of 37.5%; the stirring time is 3-6 hours.

9. The method according to claim 5, characterized in that, In step S4, the inert atmosphere is argon, the pyrolysis temperature is 800-900℃, and the pyrolysis time is 2-4 hours.

10. The application of the nitrogen-doped carbon nanotube-supported Fe / Mg diatomic nanozyme prepared by any one of claims 5-9 in the preparation of drugs for diabetic wound infection.

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