Praseodymium oxide particles, preparation method, application and antibacterial agent thereof

Abstract

The present invention discloses a praseodymium oxide particle, a preparation method, an application and an antibacterial agent thereof, and belongs to the field of antibacterial technology. The praseodymium oxide particle is a rod-shaped structure; the praseodymium in the praseodymium oxide is composed of Pr 3+ and Pr 4+ Composition, Pr 3+ The proportion of praseodymium oxide particles is 36%-40%; the specific surface area of ​​praseodymium oxide particles is 50-60m 2 / g. The present invention is applied to antibacterial properties, and solves the problem that the antibacterial properties of existing nano rare earth element oxides are far from the level of antibiotics and cannot be used on human bodies to achieve antibacterial effects. The present invention has excellent oxidase-like activity and peroxidase-like activity, excellent antibacterial properties, and is not easy for human bodies to develop drug resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of antibacterial, and in particular relates to praseodymium oxide particles, a preparation method and application thereof, and an antibacterial agent. Background Art

[0002] Bacterial infection is one of the biggest health problems in the world. To solve the problem of bacterial infection, the most commonly used antibacterial method is to use antibiotics to inhibit bacterial growth. However, in the past two decades, the abuse of antibiotics by humans has greatly enhanced bacterial resistance, and even super bacteria that cannot be killed by antibiotics have emerged. As a new non-biological tool, the development of nanomaterials has attracted the interest of researchers, and because nanomaterials are non-specific, pathogenic strains are unlikely to develop resistance to nanomaterials. Therefore, it is of great significance to find new nanomaterials for antibacterial purposes.

[0003] Chinese patent CN114958059A discloses an antibacterial non-stick coating for cookware, a manufacturing method thereof and the cookware, and specifically discloses that the weight ratio of the nano antibacterial material to the porous material is between 1:1 and 4:1, and the nano antibacterial material includes a nano rare earth element oxide and an antibacterial nano metal in a weight ratio between 1:9 and 9:1. The nano rare earth element oxide includes at least one of nano lanthanum oxide, nano cerium oxide, nano praseodymium oxide, nano neodymium oxide, nano promethium oxide, nano samarium oxide, nano europium oxide, nano gadolinium oxide, nano terbium oxide, nano dysprosium oxide, nano holmium oxide, nano erbium oxide, nano thulium oxide, nano ytterbium oxide, nano lutetium oxide, nano yttrium oxide and nano scandium oxide; the antibacterial nano metal includes at least one of nano silver, nano copper and nano zinc.

[0004] The above patent utilizes nano rare earth element oxides and antibacterial nano metals to achieve the antibacterial property of the cookware. However, the antibacterial property of nano rare earth element oxides is far from the level of antibiotics. At the same time, the above nano rare earth element oxides cannot be used on the human body and achieve antibacterial effects. Summary of the invention

[0005] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is that the antibacterial activity of the existing nano rare earth element oxides is far from the level of antibiotics and cannot be used on the human body to achieve an antibacterial effect. A praseodymium oxide particle with excellent oxidase-like activity and peroxidase-like activity, excellent antibacterial performance, and a resistance to which the human body is not likely to develop drug resistance, as well as a preparation method, application and antibacterial agent are proposed.

[0006] In order to solve the technical problem, the technical solution adopted by the present invention is:

[0007] In one aspect, the present invention provides a praseodymium oxide particle, wherein the praseodymium oxide particle is a rod-shaped structure; the praseodymium in the praseodymium oxide is composed of Pr3+ and Pr 4+ Composition, Pr 3+ The proportion is 36%-40%; the specific surface area of ​​the praseodymium oxide particles is 50-60m 2 / g.

[0008] Preferably, the praseodymium oxide particles have a particle size of 65-75 nm in length and 10-15 nm in width.

[0009] Preferably, the Km value of the oxidase-like activity of the praseodymium oxide particles is 0.018-0.042 mM, and the Km value of the peroxidase-like activity is 0.122-0.309 mM.

[0010] Another aspect of the present invention provides a method for preparing praseodymium oxide particles according to any of the above technical solutions, comprising the following steps:

[0011] Pr(NO3)3·6H2O is fully dissolved, and ammonia water is added to adjust the pH of the solution to produce a precipitate. The precipitate is taken out after centrifugation, and the precipitate is washed, dried, and calcined to obtain the praseodymium oxide particles; the pH of the solution after adding ammonia water to adjust the pH of the solution is 8.5-9.5.

[0012] Preferably, Pr(NO3)3·6H2O is fully dissolved to form a solution, stirred at 80°C for 3 hours, mixed with aqueous ammonia, cooled to room temperature for 48 hours, the mixed solution is centrifuged at 10000 rpm for 30 minutes, the precipitate is collected, and then the precipitate is washed three times with anhydrous ethanol and deionized water, dried at 100°C for 10 hours, and finally calcined at 500°C for 3 hours to obtain the praseodymium oxide particles.

[0013] Preferably, Pr(NO3)3·6H2O is fully dissolved in 50 mL of ultrapure water to form a solution.

[0014] The present invention also provides the use of the praseodymium oxide particles described in any of the above technical solutions in antibacterial aspects.

[0015] The present invention also provides an antibacterial agent comprising the praseodymium oxide particles described in any one of the above technical solutions.

[0016] Preferably, the antibacterial agent is used for preventing and treating diseases caused by Escherichia coli and Staphylococcus aureus.

[0017] Preferably, the praseodymium oxide particles combine with hydrogen peroxide to generate active oxygen to inhibit bacterial growth.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] In one aspect, the present invention provides a praseodymium oxide particle, the surface of which is 3+The higher ratio of praseodymium oxide can lead to the formation and migration of more oxygen vacancies, and the higher oxygen adsorption on the surface. These oxygen vacancies or oxygen defects can further lead to higher activity of reactive oxygen free radicals. In addition, the praseodymium oxide particles have a smaller particle size structure, which leads to a larger specific surface area. Therefore, compared with traditional commercial praseodymium oxide particles, they have excellent enzyme-like activity, especially oxidase-like and peroxidase-like activity.

[0020] Another aspect of the present invention provides a method for preparing praseodymium oxide particles. By optimizing the preparation method, especially by controlling the pH value, a chemical synthesis method is adopted to ensure that the synthesized praseodymium oxide particles present a rod-like structure, have a smaller particle size structure and a larger specific surface area, and the preparation method is simple.

[0021] The present invention also provides an antibacterial agent comprising praseodymium oxide particles, which has a good inhibitory effect on Escherichia coli and Staphylococcus aureus, and is helpful for solving the bacterial resistance caused by the abuse of antibiotics. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The praseodymium oxide (Pr6O 11 NR) TEM image of nanoparticles;

[0023] Figure 2 For commercial praseodymium oxide (Pr6O 11 C) TEM image;

[0024] Figure 3 The praseodymium oxide (Pr6O 11 NR) nanoparticles and commercial praseodymium oxide (Pr6O 11 C) XRD pattern;

[0025] Figure 4 The praseodymium oxide (Pr6O 11 NR) nanoparticles and commercial praseodymium oxide (Pr6O 11 C) BET diagram;

[0026] Figure 5 The praseodymium oxide (Pr6O 11 NR) Reaction kinetics fitting diagram of nanoparticles as oxidase (TMB as substrate);

[0027] Figure 6 For commercial praseodymium oxide (Pr6O 11 C) Reaction kinetics fitting diagram as an oxidase (TMB as substrate);

[0028] Figure 7 The praseodymium oxide (Pr6O11 NR) Reaction kinetics fitting diagram of nanoparticles as oxidase (H2O2 as substrate);

[0029] Figure 8 For commercial praseodymium oxide (Pr6O 11 C) Reaction kinetics fitting diagram as an oxidase (H2O2 as substrate);

[0030] Fig. 9 Escherichia coli (left) and Staphylococcus aureus (right) with 0.1 mg / mL Pr6O 11 , 0.05 mM H2O2, or both after incubation;

[0031] Fig.10 E. coli plates were soaked with physiological saline (control), H2O2 (0.05 mM), Pr6O 11

[0032] (0.1 mg / mL) and Pr6O 11 +H2O2 disc paper after the state diagram;

[0033] Fig.11 The cells were pre-coated with saline (control), H2O2 (0.05 mM), Pr6O 11 (0.1 mg / mL) and Pr6O 11 Diagram of the diameter of the bacterial migration circle on the agar plate with +H2O2;

[0034] Fig.12 For pre-coated with H2O2 (0.05mM), Pr6O 11 (0.1 mg / mL) and Pr6O 11 The ratio of the diameter D of the bacterial migration circle on the agar plate with +H2O2 to the diameter D0 of the bacterial migration circle in the control group. DETAILED DESCRIPTION

[0035] The technical scheme in the specific embodiment of the present invention will be described in detail and completely in conjunction with the accompanying drawings. Obviously, the described embodiments are only some specific implementation methods of the overall technical scheme of the present invention, rather than all implementation methods. Based on the overall concept of the present invention, all other embodiments obtained by ordinary technicians in this field fall within the scope of protection of the present invention.

[0036] In one aspect, the present invention provides a praseodymium oxide particle, wherein the praseodymium oxide particle is a rod-shaped structure; the praseodymium in the praseodymium oxide is composed of Pr 3+ and Pr 4+ Composition, Pr 3+ The proportion is 36%-40%; the specific surface area of ​​the praseodymium oxide particles is 50-60m 2 / g. The surface Pr of the praseodymium oxide particles 3+ The ratio of praseodymium oxide to praseodymium oxide is higher, which can lead to the formation and migration of more oxygen vacancies, and the oxygen adsorption on the surface is also higher. These oxygen vacancies or oxygen defects can further lead to higher activity of reactive oxygen free radicals. In addition, the praseodymium oxide particles have a smaller particle size structure, which leads to a larger specific surface area. Therefore, compared with traditional commercial praseodymium oxide particles, it has excellent enzyme-like activity, especially oxidase-like and peroxidase-like activity. The praseodymium oxide (Pr6O 11 NR) nanoparticles and conventional commercial praseodymium oxide (Pr6O 11 C) was analyzed and the data fitting revealed that Pr6O 11 NR's Pr 3+ / Pr 4+ The ratio is 39%:61%, while Pr6O 11 C's Pr 3+ / Pr 4+ The ratio is 35%:65%, so Pr6O 11 NR surface Pr 3+ A higher ratio of praseodymium oxide leads to the formation and migration of more oxygen vacancies and higher surface oxygen adsorption. These oxygen vacancies or oxygen defects further lead to higher activity in the generation of reactive oxygen free radicals. It is understandable that the specific surface area of ​​praseodymium oxide particles can also be 51m 2 / g, 52m 2 / g, 53m 2 / g, 54m 2 / g, 55m 2 / g, 56m 2 / g, 57m 2 / g, 58m 2 / g, 59m 2 / g and any point value within its range.

[0037] In a preferred embodiment, the particle size of the praseodymium oxide particles is 65-75 nm in length and 10-15 nm in width. It is understandable that the particle size of the praseodymium oxide particles can also be 66 nm, 67 nm, 68 nm, 69 nm, 70 nm, 71 nm, 72 nm, 73 nm, 74 nm and any value within the range, and the width can also be 11 nm, 12 nm, 13 nm, 14 nm and any value within the range. 11 NR) nanoparticles have a smaller particle size structure, resulting in a larger specific surface area, so compared with traditional commercial praseodymium oxide (Pr6O 11 C) has excellent enzyme-like activities, especially oxidase-like and peroxidase-like activities.

[0038] In a preferred embodiment, the Km value of the oxidase activity of the praseodymium oxide particles is 0.018-0.042 mM, and the Km value of the peroxidase activity is 0.122-0.309 mM. 11 NR) nanoparticles and conventional commercial praseodymium oxide (Pr6O 11 C) enzyme activity was analyzed by enzyme reaction kinetics and it was found that Pr6O 11 NR vs Pr6O 11 C has a lower Km value, so after combining with hydrogen peroxide, it will produce more reactive oxygen species (ROS) to inhibit the growth of bacteria, so a smaller concentration can be used to inhibit more bacterial growth.

[0039] Another aspect of the present invention provides a method for preparing praseodymium oxide particles according to any of the above technical solutions, comprising the following steps:

[0040] Pr(NO3)3·6H2O is fully dissolved, and ammonia water is added to adjust the pH of the solution to produce a precipitate. The precipitate is taken out after centrifugation, and the precipitate is washed, dried, and calcined to obtain the praseodymium oxide particles; the pH of the solution after adding ammonia water to adjust the pH of the solution is 8.5-9.5. It is understandable that the pH can also be 9. By optimizing the preparation method, especially by controlling the pH value, a chemical synthesis method is used to ensure that the synthesized praseodymium oxide particles have a rod-like structure, a smaller particle size structure and a larger specific surface area. The preparation method is simple.

[0041] In a preferred embodiment, Pr(NO3)3·6H2O (Sigma-Aldrich) is fully dissolved to form a solution, stirred at 80°C for 3 hours, mixed with ammonia water (China Xilong Chemical), cooled to room temperature for 48 hours, and the mixed solution is centrifuged at 10000 rpm for 30 minutes to collect the precipitate, which is then washed three times with anhydrous ethanol and deionized water, dried at 100°C for 10 hours, and finally calcined at 500°C for 3 hours to obtain the praseodymium oxide particles. In a preferred embodiment, Pr(NO3)3·6H2O is fully dissolved in 50 mL of ultrapure water (ddw) to form a solution.

[0042] The present invention also provides an application of the praseodymium oxide particles described in any of the above technical solutions in antibacterial aspects. When the praseodymium oxide particles are used in antibacterial aspects, since the praseodymium oxide particles can generate more active oxygen after combining with hydrogen peroxide, they can effectively inhibit the growth of bacteria.

[0043] The present invention also provides an antibacterial agent comprising the praseodymium oxide particles described in any of the above technical solutions. In a preferred embodiment, the antibacterial agent is used for the prevention and treatment of diseases caused by Escherichia coli and Staphylococcus aureus. In a preferred embodiment, the praseodymium oxide particles are combined with hydrogen peroxide to generate active oxygen to inhibit the growth of bacteria. The antibacterial agent has a good inhibitory effect on Escherichia coli and Staphylococcus aureus, which is conducive to solving the bacterial resistance caused by the abuse of antibiotics.

[0044] In order to more clearly and in detail introduce the praseodymium oxide particles, preparation methods, applications and antibacterial agents provided by the embodiments of the present invention, they will be described below in conjunction with specific embodiments.

[0045] Example 1

[0046] 0.1M Pr(NO3)3·6H2O was fully dissolved in 50mL ultrapure water to form a solution, stirred at 80°C for 3 hours, mixed with 25mL ammonia water (China Xilong Chemical), adjusted the pH value of the solution to 9, cooled to room temperature for 48 hours, centrifuged the mixed solution at 10000rpm for 30 minutes, collected the precipitate, and then washed three times with anhydrous ethanol and deionized water, dried at 100°C for 10 hours, and finally calcined at 500°C for 3 hours to obtain praseodymium oxide (Pr6O 11 NR) nanoparticles; all chemicals were purchased from Sigma-Aldrich. Commercial Pr6O 11 The samples were purchased from Alfa Aesar.

[0047] The prepared praseodymium oxide (Pr6O 11 NR) nanoparticles were characterized: their shape was a rod-like structure, Pr6O 11 Medium 3+ / Pr 4+ The ratio is 39%:61%, praseodymium oxide (Pr6O 11 The specific surface area of ​​NR nanoparticles is 56 m 2 / g, the particle size of praseodymium oxide particles is 70nm in length and 13nm in width, the Km value of oxidase-like activity is 0.018mM, and the Km value of peroxidase-like activity is 0.122mM.

[0048] Example 2

[0049] 0.95M Pr(NO3)3·6H2O was fully dissolved in 50mL ultrapure water to form a solution, stirred at 80°C for 3 hours, mixed with 25mL ammonia water (China Xilong Chemical), adjusted the pH value of the solution to 8.7, cooled to room temperature for 48 hours, centrifuged the mixed solution at 10000rpm for 30 minutes, collected the precipitate, and then washed three times with anhydrous ethanol and deionized water, dried at 100°C for 10 hours, and finally calcined at 500°C for 3 hours to obtain praseodymium oxide (Pr6O 11 NR) nanoparticles; all chemicals were purchased from Sigma-Aldrich. Commercial Pr6O 11 The samples were purchased from Alfa Aesar.

[0050] The prepared praseodymium oxide (Pr6O 11 NR) nanoparticles were characterized: their shape was a rod-like structure, Pr6O 11 Medium 3+ / Pr 4+ The ratio is 38%:62%, praseodymium oxide (Pr6O 11 The specific surface area of ​​NR nanoparticles is 53 m 2 / g, the particle size of praseodymium oxide particles is 73nm long and 15nm wide, the Km value of oxidase-like activity is 0.035mM, and the Km value of peroxidase-like activity is 0.261mM. The morphology and characterization are similar to those of Example 1, so they have similar enzyme-like activity and antibacterial properties.

[0051] Example 3

[0052] 1.1M Pr(NO3)3·6H2O was fully dissolved in 50mL water to form a solution, stirred at 80℃ for 3 hours, mixed with 25mL ammonia water (China Xilong Chemical), adjusted the pH value of the solution to 9.4, cooled to room temperature for 48 hours, centrifuged the mixed solution at 10000rpm for 30 minutes, collected the precipitate, and then washed three times with anhydrous ethanol and deionized water, dried at 100℃ for 10 hours, and finally calcined at 500℃ for 3 hours to obtain praseodymium oxide (Pr6O 11 NR) nanoparticles; all chemicals were purchased from Sigma-Aldrich. Commercial Pr6O 11 The samples were purchased from Alfa Aesar.

[0053] The prepared praseodymium oxide (Pr6O 11 NR) nanoparticles were characterized: their shape was a rod-like structure, Pr6O 11 Medium 3+ / Pr 4+ The ratio is 36:64%, praseodymium oxide (Pr6O 11The specific surface area of ​​NR nanoparticles is 52 m 2 / g, the particle size of praseodymium oxide particles is 75nm long and 14nm wide, the Km value of oxidase-like activity is 0.042mM, and the Km value of peroxidase-like activity is 0.309mM. The morphology and characterization are similar to those of Example 1, so they have similar enzyme-like activity and antibacterial properties.

[0054] Comparative Example 1

[0055] 0.1M Pr(NO3)3·6H2O was fully dissolved in 50mL water to form a solution, stirred at 80°C for 3 hours, mixed with 25mL ammonia water (China Xilong Chemical), adjusted the solution pH to 8, cooled to room temperature for 48 hours, centrifuged the mixed solution at 10000rpm for 30 minutes, collected the precipitate, and then washed the precipitate three times with anhydrous ethanol and deionized water, dried at 100°C for 10 hours, and finally calcined at 500°C for 3 hours to obtain praseodymium oxide particles; all chemicals were purchased from Sigma-Aldrich. Commercial Pr6O 11 The samples were purchased from Alfa Aesar.

[0056] The prepared praseodymium oxide particles were characterized: Since the pH was not in the range of 8.5-9.5, the shape of the synthesized particles was a non-rod-like (irregular) structure, so the morphology could not be controlled, the performance was poor, and no subsequent characterization was performed.

[0057] Comparative Example 2

[0058] 0.1MPr(NO3)3·6H2O was fully dissolved in 50mL water to form a solution, stirred at 80℃ for 3 hours, mixed with 25mL ammonia water (China Xilong Chemical), adjusted the pH value of the solution to 10, cooled to room temperature for 48 hours, centrifuged the mixed solution at 10000rpm for 30 minutes, collected the precipitate, and then washed the precipitate three times with anhydrous ethanol and deionized water, dried at 100℃ for 10 hours, and finally calcined at 500℃ for 3 hours to obtain praseodymium oxide particles; all chemicals were purchased from Sigma-Aldrich. Commercial Pr6O 11 The samples were purchased from Alfa Aesar.

[0059] The prepared praseodymium oxide particles were characterized: Since the pH was not in the range of 8.5-9.5, the shape of the synthesized particles was a non-rod-like (irregular) structure, so the morphology could not be controlled, the performance was poor, and no subsequent characterization was performed.

[0060] Performance Testing

[0061] The praseodymium oxide (Pr6O 11NR) nanoparticles and conventional commercial praseodymium oxide (Pr6O 11 C) (purchased from Alfa Aesar) was subjected to TEM, XRD and BET characterization. The results are as follows Figure 1-4 As shown, the results show that:

[0062] Synthetic praseodymium oxide (Pr6O 11 NR) nanoparticles are rod-shaped, about 70nm long and 13nm wide. 11 C) is irregular in shape and has a particle size of about 500 nm. XRD of both samples shows that Pr6O 11 (JCPDS 42-1121) has a uniform crystal structure, indicating that the sample does not contain impurities. According to the full width at half maximum of the XRD peak and the Scherrer equation, the synthesized Pr6O 11 NR and commercial Pr6O 11 The crystal sizes of Pr6O and C are 11 nm and 7.3 nm respectively. The contrast of their size and morphology directly affects their specific surface area. 11 NR's BET is 56.04m 2 / g, much higher than Pr6O 11 C: 4.07m 2 / g, relatively higher enzyme activity

[0063] The praseodymium oxide (Pr6O 11 NR) nanoparticles and conventional commercial praseodymium oxide (Pr6O 11 C) enzyme activity was analyzed for enzyme reaction kinetics, and the results were as follows Figure 5-8 The results show that, whether as an oxidase or a peroxidase, Pr6O 11 The activity of NR is much higher than that of Pr6O 11 C. For example, for the oxidation of TMB, Pr6O 11 The Km value of NR (0.018 mM) is higher than that of Pr6O 11 C (0.18 mM) is one order of magnitude lower. Similarly, when H2O2 is used as the substrate, Pr6O 11 NR and Pr6O 11 C showed unusually high simulated peroxidase kinetics, with Km values ​​of 0.122 and 4.17 mM, respectively. 11 Another parameter Vm of NR also has a similar trend. Whether it is an oxidase or a peroxidase, it is much higher than that of Pr6O 11 C is therefore Pr6O 11 NR has higher enzyme-like activity.

[0064] The praseodymium oxide (Pr6O 11 NR) nanoparticles and conventional commercial praseodymium oxide (Pr6O 11 C) was tested for its antibacterial properties, and the results were as follows Figure 9-12 As shown, the results show that: Pr6O 11 NR and Pr6O 11 C could inhibit the growth of E. coli, with survival rates of 24.95% and 49.02%, respectively. After adding H2O2, the survival rates continued to decrease, reaching 11.83% and 29.78%, respectively, indicating a significant inhibitory effect on the growth of E. coli. However, no such inhibitory effect was observed on Staphylococcus aureus, except for Pr6O 11 The survival rate was greater than 63.92% under all conditions except for NR+H2O2, which was slightly reduced. This may be related to the unique composition and structural changes of the cell walls of E. coli and S. aureus. Gram-negative bacteria such as E. coli have a thin layer of peptidoglycan of 7-8 nm, and its outer membrane is rich in lipopolysaccharides and phospholipids, while Gram-positive bacteria such as S. aureus have a thicker peptidoglycan layer (20-80 nm) but do not have any outer membrane. The inhibition zone method and group movement both proved that Pr6O 11 The effect is more effective than that without adding H2O2. From all the results, Pr6O 11 NR vs Pr6O 11 C is more active, which may be due to the fact that Pr6O 11 NR vs Pr6O 11 C has a higher specific surface area and produces h + and free radical-like enzyme activity.

Claims

1. A praseodymium oxide particle, characterized in that: The praseodymium oxide particles are rod-shaped; the praseodymium in the praseodymium oxide is composed of Pr 3+ and Pr 4+ Composition, Pr 3+ The proportion is 36%-40%; the specific surface area of ​​the praseodymium oxide particles is 50-60m 2 / g; The preparation method of the praseodymium oxide particles comprises the following steps: Pr(NO3)3·6H2O is fully dissolved to form a solution, stirred at 80°C for 3 hours, mixed with ammonia water, cooled to room temperature for 48 hours, centrifuged the mixed solution at 10000 rpm for 30 minutes, collected the precipitate, then washed the precipitate three times with anhydrous ethanol and deionized water, dried at 100°C for 10 hours, and finally calcined at 500°C for 3 hours to obtain the praseodymium oxide particles; The solution is mixed with ammonia water, and the pH of the solution after adding ammonia water to adjust the pH of the solution is 8.5-9.

5.

2. The praseodymium oxide particles according to claim 1, characterized in that The praseodymium oxide particles have a particle size of 65-75 nm in length and 10-15 nm in width.

3. The praseodymium oxide particles according to claim 1, characterized in that The Km value of the oxidase activity of the praseodymium oxide particles is 0.018-0.042 mM, and the Km value of the peroxidase activity is 0.122-0.309 mM.

4. The method for preparing praseodymium oxide particles according to any one of claims 1 to 3, characterized in that: The following steps are involved: Pr(NO3)3·6H2O is fully dissolved to form a solution, stirred at 80°C for 3 hours, mixed with ammonia water, cooled to room temperature for 48 hours, centrifuged the mixed solution at 10000 rpm for 30 minutes, collected the precipitate, then washed the precipitate three times with anhydrous ethanol and deionized water, dried at 100°C for 10 hours, and finally calcined at 500°C for 3 hours to obtain the praseodymium oxide particles; The solution is mixed with ammonia water, and the pH of the solution after adding ammonia water to adjust the pH of the solution is 8.5-9.

5.

5. The method for preparing praseodymium oxide particles according to claim 4, characterized in that: Fully dissolve Pr(NO3)3·6H2O in 50 mL of ultrapure water to form a solution.

6. An antibacterial agent comprising the praseodymium oxide particles according to any one of claims 1 to 3.

7. The antibacterial agent according to claim 6, characterized in that The antibacterial agent is used for preventing and treating diseases caused by Escherichia coli.

8. The antibacterial agent according to claim 7, characterized in that The praseodymium oxide particles combine with hydrogen peroxide to generate active oxygen to inhibit the growth of bacteria.

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