Preparation method and drug detection application of ZIF-8-Fe metal organic framework nano-enzyme

Abstract

The invention provides a preparation method and drug detection application of ZIF-8-Fe metal organic framework nano-enzyme, the ZIF-8-Fe metal organic framework nano-enzyme is prepared by adopting a heating reflux method, and peroxidase-like activity and drug detection application of the ZIF-8-Fe metal organic framework nano-enzyme are researched. In the presence of H2O2, the material can catalytically oxidize TMB to generate a blue product and shows good peroxidase activity, and through optimization experiments, proper reaction temperature and pH buffer system and optimal concentrations of ZIF-8-Fe, TMB and H2O2 are determined. Kinetic analysis shows that the affinity of TMB is superior to that of natural HRP, and a colorimetric detection method is established based on the inhibition effect of TC on the catalytic reaction. The method disclosed by the invention is reasonable in linear range, relatively low in detection limit and good in sample recovery rate and relative standard deviation performance, can be used for detecting tetracycline tablets, and shows a potential application value of the ZIF-8-Fe nano-enzyme in the field of drug detection.

Description

Technical Field

[0001] This invention relates to the field of nanomaterials technology, and in particular to a method for preparing ZIF-8-Fe metal-organic framework nanozymes and their application in drug detection. Background Technology

[0002] Natural enzymes are large protein molecules with high catalytic activity that play a crucial role in the life processes of organisms. However, the high difficulty in purification, high production cost, poor stability, and difficulty in recycling of natural enzymes hinder their widespread application in industrial production, agriculture, and other fields. To overcome the shortcomings of natural enzymes, the development of artificial enzymes with high catalytic activity, strong stability, and diverse structures is of great significance. Nanozymes, as a type of nanomaterial with enzyme-like activity, have attracted widespread attention due to their high stability, high catalytic efficiency, low cost, and easy storage. Metal-organic framework nanozymes (MOFs), as an important branch of nanozymes, are organic-inorganic hybrid materials with intramolecular pores formed by the self-assembly of organic ligands and metal ions or clusters through coordination bonds. Their metal nodes and organic ligands can endow MOFs with intrinsic enzyme-like activity by mimicking the active sites of certain natural enzymes. MOFs possess many excellent characteristics, such as high specific surface area, high porosity, tunable porosity, and a uniform spatial structure of cavities, making them ideal materials for simulating biological enzyme systems. Their high stability allows for repeated use in enzyme encapsulation or simulation, further enhancing their application value. Furthermore, their ultra-high specific surface area enables MOFs to bind substrates and modify nanoparticles, providing ample convenience for improving the activity of the mimic enzyme. This advantage is particularly important in nanozyme systems, opening up more possibilities for their application in various fields. In summary, MOFs, as ideal materials for mimicking biological enzymes, are expected to play a significant role in the future.

[0003] Tetracycline antibiotics were discovered in the late 1940s and widely used in the 1960s and 70s. Tetracycline (TC), a broad-spectrum antibiotic, is inexpensive and widely used. However, its properties make it difficult to degrade naturally in the environment. If not used properly, it may remain in food and the environment, potentially spreading to humans through the food chain and posing a threat to human health. Therefore, developing detection methods for tetracycline antibiotics is of great significance in protecting human health. Currently, the detection of these drugs in my country mainly uses liquid chromatography-mass spectrometry / mass spectrometry, high-performance liquid chromatography, ROSA, and radioreceptor analysis. While existing methods offer high sensitivity and selectivity, they suffer from drawbacks such as complex operation and reliance on expensive equipment.

[0004] Therefore, designing a simple and cost-effective method for TC detection remains a significant challenge. Among various detection techniques, colorimetry is the most intuitive and commonly used. This method is based on reactions such as chemiluminescence, enzyme-catalyzed colorimetry, or aggregation-based colorimetry, allowing for qualitative or semi-quantitative analysis by visually observing color changes. Simultaneously, rapid quantitative analysis can be performed using instruments or software. Most colorimetric methods offer advantages such as portability, speed, and ease of operation, making them suitable for rapid interpretation of analytical results in laboratories or for conducting bioanalytical work in resource-scarce areas. Based on these considerations, this invention experimentally establishes a novel colorimetric detection method for tetracycline antibiotics. This research will provide a new technology and method for antibiotic molecular analysis that is highly sensitive, selective, economical, and simple. Summary of the Invention

[0005] Therefore, this invention proposes a method for preparing ZIF-8-Fe metal-organic framework nanozymes and their application in drug detection, thereby solving the above-mentioned problems.

[0006] The technical solution of this invention is achieved as follows: a method for preparing ZIF-8-Fe metal-organic framework nanozymes, comprising the following steps: S1. Preparation of solution A: Dissolve the iron salt and zinc salt in an organic solvent and stir until completely dissolved; S2. Preparation of solution B: Dissolve 2-methylimidazole in an organic solvent and stir until completely dissolved; S3. Add solution B to solution A and reflux with stirring; S4. Centrifuge the reaction product, wash the precipitate, dry it and grind it to obtain ZIF-8-Fe powder, which is ZIF-8-Fe metal-organic framework nanozyme.

[0007] Furthermore, the iron salt is ferric nitrate nonahydrate, and the zinc salt is zinc acetate dihydrate, with a mass ratio of 0.5:1-2.

[0008] Furthermore, the mass ratio of the 2-methylimidazole to the zinc salt is (2.5-3.5):1.

[0009] Furthermore, the organic solvent in steps S1 and S2 is methanol, the mass-to-volume ratio of the iron salt to methanol is 30-40 mg:1 mL, and the mass-to-volume ratio of the 2-methylimidazole to methanol is 150-200 mg:1 mL.

[0010] Furthermore, the reflux stirring temperature in step S3 is 50-70°C, and the time is 8-12 hours.

[0011] Furthermore, in step S4, the centrifugation speed is 5000-7000 rpm and the drying temperature is 50-70℃.

[0012] Furthermore, the prepared ZIF-8-Fe metal-organic framework nanozyme was applied in drug detection.

[0013] Furthermore, the drug detection includes mixing the ZIF-8-Fe metal-organic framework nanozyme with the drug sample to be tested and detecting changes in its peroxidase activity.

[0014] Furthermore, the drug sample to be tested is a tetracycline antibiotic.

[0015] Furthermore, the peroxidase activity was detected by a colorimetric reaction of 3,3',5,5'-tetramethylbenzidine and hydrogen peroxide.

[0016] Compared with the prior art, the beneficial effects of the present invention are: This invention synthesizes a metal-organic framework nanozyme, ZIF-8-Fe, via a reflux heating method. This nanomaterial exhibits excellent peroxidase-like activity. Enzyme-catalyzed reaction kinetics experiments show that ZIF-8-Fe has a superior affinity for the substrate H₂O₂ compared to natural HRP. The mechanism revealed that the ·OH generated in the system plays a crucial role in the formation of oxidized TMB. Based on the peroxidase-like activity of ZIF-8-Fe and the effective inhibition of TC on the catalytic oxidation of TMB, a highly sensitive and selective colorimetric method for TC detection was constructed, exhibiting good linearity and detection limit. The results demonstrate that this detection method has high accuracy and repeatability, is simple to operate, and provides important reference value for the sensitive, specific, and convenient detection of TC in real samples. Attached Figure Description

[0017] Figure 1 Absorption spectra and color diagrams of different systems; Figure 2 Absorption spectra of ZIF-8-Fe with different proportions; Figure 3 The effects of pH (a), temperature (b), ZIF-8-Fe concentration (c), TMB concentration (d), and H2O2 concentration (e) on the catalytic performance of nanozymes were investigated. Figure 4 The reaction rates of ZIF-8-Fe (0.229 mM) and TMB (0.229 mM) / H2O2 (0.057 mM) were determined at different H2O2 (a) and TMB (c) concentrations. v , and its corresponding double reciprocal diagrams (b) and (d); Figure 5 To optimize the standard curves of TC at different concentrations under the conditions (a), the standard curve of TC after selection (b) is shown. Figure 6The absorbance of ZIF-8-Fe at 652 nm for catalytic oxidation of TMB in the presence of potential interfering substances (a) and the competition experiment with TC coexisting substances (b). Detailed Implementation

[0018] To better understand the technical content of this invention, specific embodiments are provided below to further illustrate the invention.

[0019] Unless otherwise specified, the experimental methods used in the embodiments of this invention are all conventional methods.

[0020] Unless otherwise specified, all materials and reagents used in the embodiments of this invention are commercially available.

[0021] Example 1 - Preparation method of ZIF-8-Fe metal-organic framework nanozymes Prepare solution A: Dissolve 618.3 mg ferric nitrate nonahydrate and 1855 mg zinc acetate dihydrate in 20 mL of methanol and seal the film. Stir magnetically at room temperature for 60 min to ensure complete dissolution. Prepare solution B: Dissolve 5600 mg of 2-methylimidazole in 30 mL of methanol and seal the container. Stir magnetically at room temperature for 60 min to ensure complete dissolution.

[0022] After stirring, pour solution B into solution A, reflux and stir for 10 hours under water bath heating at 60°C.

[0023] The obtained product was centrifuged at 6000 rpm for 20 min to separate the precipitate from the supernatant. The precipitate was retained and washed with deionized water. After washing, it was centrifuged again at 6000 rpm for 15 min, the precipitate was retained and washed with deionized water. This process was repeated twice. The obtained precipitate was dried at 60℃ for 10 h and then ground to obtain ZIF-8-Fe powder.

[0024] Example 2 - Optimization of catalytic conditions for ZIF-8-Fe peroxidase Using TMB as the chromogenic substrate, under the condition of H2O2, the effects of different pH values ​​(3, 3.5, 4, 4.5, 5, 5.5, 6), different temperatures (25℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃), and different ZIF-8-Fe concentrations (0.2 mg·mL⁻¹, 50 μL, 100 μL, 150 μL, 200 μL, 250 μL, 300 μL, 400 μL, 500 μL, 600 μL, 7 μL) on the chromogenic substrate were investigated. The absorbance of the system at 652 nm after shaking in a constant temperature mixer for 15 min under different TMB concentrations (10 mM, 20 μL, 40 μL, 60 μL, 80 μL, 100 μL, 120 μL, 160 μL, 200 μL) and different H2O2 concentrations (10 mM, 5 μL, 10 μL, 15 μL, 20 μL, 25 μL, 30 μL) was recorded, and the relationship between the absorbance of the system and the variables was also recorded.

[0025] Example 3 - Kinetic Analysis of ZIF-8-Fe Peroxidase By controlling for single variables, the concentrations of TMB and H2O2 were varied to evaluate the peroxidase-like activity of ZIF-8-Fe exhibiting the best catalytic effect. Details are as follows: The sample was contained in a 3.5 mL acetate buffer system (pH=3.5) at a concentration of 0.2 mg / mL. -1 200 μL of ZIF-8-Fe was added, and 20 μL of 10 mM H₂O₂ was added. Different concentrations of TMB were then added, and the mixed solutions were placed in quartz cuvettes. The absorbance of the system was monitored every 20 s over 5 min using a UV-Vis spectrometer. Next, 80 μL of 10 mM TMB was added, and different concentrations of H₂O₂ were added. The mixed solutions were placed in quartz cuvettes, and the absorbance was monitored every 20 s over 5 min using a UV-Vis spectrometer. The Michaelis-Menten equation can be used to fit the data to further evaluate its catalytic performance. However, since the Michaelis-Menten equation has difficulties in solving for the Michaelis constant Km and the maximum initial rate Vmax, a Lineweaver-Burk plot (i.e., the double reciprocal plot method) was used to calculate the steady-state kinetic parameters. The Michaelis constant Km represents the enzyme's affinity for the substrate, and Vmax represents the maximum initial rate of the enzymatic reaction.

[0026] Example 4 - Detection of TC in Tetracycline Tablets Under optimized conditions, different concentrations of TC solution were added, and a standard curve was plotted based on the experimental data. Quantitative testing was performed on TC antibiotics (tetracycline tablets) purchased from a local pharmacy. The tablets were ground into powder, and 100.0 mg was dissolved in 100 mL of hydrochloric acid solution, brought to a final volume of 200 mL, and then diluted four times. A certain amount of standard substance was added within the reasonable detection limit. The amount added needs to be determined based on the sample concentration. Literature review indicates that the optimal spiking concentration is 1-5 times the expected detection limit, and the spiking concentration must not be less than the standard deviation. The absorbance at 652 nm was recorded after shaking in a 37℃ constant-temperature mixer for 15 min, and the recovery rate was calculated.

[0027] result: 1. Preliminary investigation into the properties of ZIF-8-Fe peroxidases By mimicking a mechanism similar to horseradish peroxidase found in nature, it is hypothesized that MOF nanozymes should possess the ability to catalyze the decomposition of hydrogen peroxide to generate hydroxyl radicals (·OH). TMB is a novel chromogenic substrate that can act as a hydrogen donor. The TMB colorimetric reaction is based on benzidine in its molecular structure, which contains two easily oxidized amino groups. It can be oxidized to colored products via single-electron and two-electron pathways. Due to the relatively small steric hindrance at the ortho positions of amines, substitution at the 3-, 3′-, 5-, and 5′ positions of benzidine is more suitable. Under the catalysis of the enzyme, TMB can be oxidized to 3,3′,5,5′-tetramethylbenzidinediimine, turning the solution blue. This color change can be read at a wavelength of 652 nm on a spectrophotometer. This demonstrates that hydroxyl radicals can convert colorless substrate (TMB) into blue (oxTMB), producing a characteristic absorption peak at 652 nm. ZIF-8-Fe exhibits peroxidase-like activity, promoting the degradation of H2O2 and generating highly active hydroxyl radicals, thus giving the system a blue color. This allows for comparison of the peroxidase-like activity of ZIF-8-Fe under different conditions. The reaction time was controlled at 37℃ for 15 min, and the changes in absorbance at 652 nm were compared between different systems. When ZIF-8 was present in the system (the concentration of each component in a total volume of 3.5 mL was 0.2 mg / mL ZIF-8), the results were compared. -1 The solution system containing ZIF-8-Fe (200 μL, 10 mM TMB, 80 μL, 10 mM H₂O₂, 20 μL) changed from colorless to a visible blue, and the absorption spectrum showed a characteristic absorption peak of oxTMB at 652 nm. When ZIF-8-Fe (concentrations of each component in a total volume of 3.5 mL are: ZIF-8-Fe (Zn:Fe = 1.5:0.5) 0.2 mg·mL⁻¹) was present in the system... -1200 μL of TMB (10 mM), 80 μL of TMB, and 20 μL of H₂O₂ (10 mM) all resulted in a color change from colorless to a visible blue color. The absorption spectrum at 652 nm exhibited characteristics of oxTMB. Furthermore, the absorbance at 652 nm was significantly higher in the ZIF-8-Fe (Zn:Fe = 1.5:0.5) system compared to the ZIF-8 system under the same conditions. Figure 1 This demonstrates that ZIF-8-Fe (Zn:Fe=1.5:0.5) possesses peroxidase-like activity, and its catalytic activity is superior to that of single-metal ZIF-8, making it a promising peroxidase-like nanozyme.

[0028] Using TMB as a chromogenic substrate for peroxidase, the catalytic performance of ZIF-8-Fe with different ratios (Zn:Fe = 1.5:0.1, 1.5:0.3, 1.5:0.5, 1.5:0.7, 1.5:1.5) was investigated. 200 μL of the same concentration (0.2 mg / mL) of TMB was added to an acetate buffer (pH = 3.5) system (TMB concentration 10 mM, 80 μL; H2O2 concentration 10 mM, 20 μL) at 37 °C. -1 Different proportions of ZIF-8-Fe were used, with a total system volume of 3.5 mL. The absorbance of different systems in the range of 300–800 nm was as follows: Figure 2 As shown. By Figure 2 It can be seen that the ZIF-8-Fe (Zn:Fe=1.5:0.5) system exhibits the highest absorbance at 652 nm. Therefore, ZIF-8-Fe (Zn:Fe=1.5:0.5) can be identified as the material with the best catalytic activity for subsequent experimental testing.

[0029] 2. Optimization of catalytic conditions for ZIF-8-Fe peroxidases The catalytic activity of MOFs is similar to that of natural enzymes, and is affected by pH, temperature, and enzyme concentration. To determine the optimal reaction conditions for ZIF-8-Fe (Zn:Fe = 1.5:0.5), different pH values ​​(3, 3.5, 4, 4.5, 5, 5.5, 6), different temperatures (20℃, 25℃, 30℃, 35℃, 40℃, 45℃), and different ZIF-8-Fe concentrations (0.2 mg·mL⁻¹) were investigated. -1 The absorption spectra of the system at different concentrations (50 μL, 100 μL, 150 μL, 200 μL, 250 μL, 300 μL, 400 μL, 500 μL, 600 μL, 700 μL, 800 μL, 900 μL), different TMB concentrations (10 mM, 20 μL, 40 μL, 60 μL, 80 μL, 100 μL, 120 μL, 160 μL, 200 μL), and different H2O2 concentrations (10 mM, 5 μL, 10 μL, 15 μL, 20 μL, 25 μL, 30 μL) are shown below. Figure 3 Figure 3(a) shows that the catalytic activity of ZIF-8-Fe peroxidases gradually decreases as the pH value increases from 3 to 6. This may be due to the diamine structure of TMB, which has poor solubility at higher pH values. It is noteworthy that when the pH of the system drops below 3, the solution turns blue-green, which is due to the solution being too acidic. At pH = 3.5, the absorbance of ZIF-8-Fe (Zn:Fe = 1.5:0.5) is high and the reaction system is blue. To avoid affecting subsequent colorimetric experiments, pH = 3.5 was chosen as the optimal pH for subsequent experiments. Figure 3 (b) shows that the absorbance of the system is highest when the temperature reaches 45℃, but the solution is blue-green when the temperature of the system is above 40℃. To avoid the influence of color, 35℃ is selected as the optimal temperature. Figure 3 (c) indicates that when the ZIF-8-Fe concentration in the system increases from 11.43 μg·mL... -1 Increased to 51.42 ug·mL -1 The increase in absorbance of the system gradually leveled off, indicating that its catalytic activity changed slowly with increasing ZIF-8-Fe concentration. Therefore, a ZIF-8-Fe concentration of 0.2 mg / mL was chosen. -1 The concentration of the substance in the system was 11.43 μg·mL (200 μL). -1 This will serve as the optimal concentration for subsequent experiments; Figure 3 Similarly, (d) and (e) the optimal concentrations for subsequent experiments were determined: TMB concentration (10 mM, 80 μL) was 0.2286 mM, and H2O2 concentration (10 mM, 20 μL) was 0.05710 mM. The final optimal concentration for ZIF-8-Fe (Zn:Fe = 1.5:0.5) was determined to be 11.43 μg·mL. -1 The optimized experimental conditions were set with TMB concentration of 0.2286 mM, H2O2 concentration of 0.05710 mM, and pH=3.5 acetate buffer system. Subsequent experiments were conducted at the normal human body temperature of 37°C.

[0030] 3. Kinetic analysis of ZIF-8-Fe peroxidases Steady-state parameters were studied based on enzyme kinetic theory. The catalytic characterization of nanozymes depends on their kinetic constants, which, according to the Michaelis-Menten equation, relate the reaction rate to the substrate concentration. This invention details the Michaelis-Menten kinetics of colorimetric reactions catalyzed by peroxidase nanozymes in the presence of different concentrations of colorimetric substrates, and determines the catalytic kinetic constants from the kinetic curves by fitting the reaction rate values ​​and initial substrate concentrations to the Michaelis-Menten equation.

[0031] (3-1) In this experiment, TMB and H2O2 were used as enzyme reaction substrates. By changing the concentration of the enzyme reaction substrate [S], a series of initial reaction rates were obtained. Substituting these rates into formula (3-1), where the enzyme... v Represents the initial rate of a kinetic reaction, V max Represents the maximum initial rate of enzyme-catalyzed kinetics. K m Representing the Michaelis constant, we obtain the enzyme steady-state kinetics curve of the material with respect to the substrate TMB. Based on the steady-state kinetics, a Lineweaver-Burk plot can be plotted. Reversing both sides of Equation 3-1 yields Equation 3-2: (3-2) The horizontal axis represents the reciprocal of the substrate concentration (1 / [S]), and the vertical axis represents the reciprocal of the reaction rate (1 / [S]). v Linear fitting yields 1 / v The slope of the fitted line for the equation about 1 / [S] is... K m / V max The intersection of the y-axis and the y-axis is the intercept 1 / V max This makes it easier to calculate. K m and V max . K m and V max It is an important parameter reflecting the enzyme's activity on its substrate. V max Represents the rate of enzyme-catalyzed reaction. K m Reflects the enzyme's affinity for its substrate. K m The smaller the value, the stronger the affinity for the corresponding substrate, such as Figure 4 As shown.

[0032] Table 1 Kinetic parameters of ZIF-8-Fe peroxidases

[0033] In this invention, ZIF-8-Fe was compared with the natural peroxidase horseradish peroxidase (HRP). The enzyme steady-state kinetic parameters were obtained using the Michaelis-Menten equation and Lineweaver-Burk plotting. K m and V max The calculated Km Value and V max The values ​​are summarized in Table 1. The obtained values ​​are... V max The higher the value, the higher the catalytic activity of the material for TMB in the presence of H2O2. Current technology shows that HRP uses TMB and H2O2 as substrates. K m The concentrations were 0.434 mM and 3.70 mM, respectively; HRP used TMB and H2O2 as substrates. V max They are 10.0 × 10 -8 M·s -1 8.71×10 -8 M·s -1 This indicates that ZIF-8-Fe has a lower affinity for TMB than HRP, but a higher affinity for H2O2. Steady-state parameters suggest that ZIF-8-Fe exhibits good peroxidase-like activity, making it a potentially good alternative to natural enzymes.

[0034] 4. Colorimetric detection of TC ZIF-8-Fe can accelerate the catalytic oxidation of TMB by H₂O₂ to generate the blue oxidation product oxTMB, which has an absorption peak at 652 nm, and produces more blue product. However, when a certain amount of TC is added, the absorbance decreases, and the color of the blue product becomes lighter, indicating that the amount of oxTMB is significantly reduced, and TC significantly inhibits the catalytic activity of ZIF-8-Fe. With the increase of TC concentration, the absorption spectrum gradually decreases, and the solution color changes significantly from blue to light blue. Based on these characteristics, it can be used to detect TC in actual drugs, and a spiked recovery experiment can be performed to verify the feasibility of the method.

[0035] For the detection of tetracycline, under optimized conditions, the UV-Vis absorption spectra of the ZIF-8-Fe / TMB / H2O2 system with different TC concentrations were measured, and plotted. Figure 5 (a). By Figure 5 (a) Then, points with a relatively close linear relationship are selected to construct a linear relationship based on tetracycline concentration and absorbance value, such as... Figure 5 (b) The absorbance at 652 nm showed a linear relationship with the TC concentration in the range of 0.02857 mM to 0.1143 mM, yielding the linear regression equation ΔA = 7.02C - 0.1624, R0 2 =0.99401.

[0036] The limit of detection (LOD) for TC was calculated using the formula LOD = 3σ / S, where σ represents the standard deviation of the response value and S represents the slope of the standard curve. To calculate the LOD, the slope value obtained from the linear regression equation and the standard deviation value obtained from 10 blank experiments were substituted into the LOD equation to obtain a minimum detection limit of 0.01037 mM. When a certain amount (10 μL, 14 μL, 18 μL) of standard substance was added to a sample solution of known concentration (0.01 mM), the recovery rate of TC in this experiment was 94.10–107.3%, with an RSD < 5.000%. The results indicate that this method has high accuracy and repeatability and can successfully detect TC in tetracycline tablets. It provides great potential for the sensitive, specific, and convenient detection of TC in real samples.

[0037] To evaluate the high selectivity of this ZIF-8-Fe for TC, the cation (Ca) was tested under the same conditions. 2+ K + Mg 2+ Zn 2+ (100mM) anion (SO4) 2- (100mM)), antibiotic chloramphenicol ( Chloramphenicol The effect of CAP (100 mM) on ZIF-8-Fe peroxidase activity. Figure 6 (a) and (b) clearly show that the presence of TC (10 mM) significantly reduces the absorbance of the ZIF-8-Fe / TMB / H2O2 system. When other interfering substances are present, the absorbance of the ZIF-8-Fe / TMB / H2O2 system does not show a significant decrease. When TC is mixed with potential interfering substances, even at relatively high concentrations, the absorbance at 652 nm is close to that when TC is introduced. These results indicate that these inorganic ions and antibiotics do not interfere with the detection of TC, and the established colorimetric strategy has good anti-interference ability and high selectivity.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, 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 method for preparing a ZIF-8-Fe metal-organic framework nanoszyme, characterized in that, The method comprises the following steps: S1, preparing A liquid: dissolving iron salt and zinc salt in an organic solvent and stirring until completely dissolved; S2, preparing B liquid: dissolving 2-methylimidazole in an organic solvent and stirring until completely dissolved; S3, adding B liquid into A liquid and refluxing and stirring; S4, centrifuging the reaction product, washing the precipitate, drying and grinding to obtain ZIF-8-Fe powder, which is a ZIF-8-Fe metal organic framework nanoscale enzyme.

2. The method for preparing ZIF-8-Fe metal-organic framework nanozymes as described in claim 1, characterized in that, The iron salt is ferric nitrate nonahydrate and the zinc salt is zinc acetate dihydrate, and the mass ratio of the two is 0.5:1.

5.

3. The method of preparing ZIF-8-Fe metal organic framework nanoszyme as claimed in claim 1, wherein, The mass ratio of 2-methylimidazole to zinc salt is (2.5-3.5):

1.

4. The method for preparing ZIF-8-Fe metal-organic framework nanozymes as described in claim 1, characterized in that, The organic solvent in steps S1 and S2 is methanol, the mass-volume ratio of the iron salt to methanol is 30-40 mg:1 mL, and the mass-volume ratio of 2-methylimidazole to methanol is 150-200 mg:1 mL.

5. The method for preparing ZIF-8-Fe metal-organic framework nanozymes as described in claim 1, characterized in that, The temperature of refluxing and stirring in step S3 is 50-70℃, and the time is 8-12 hours.

6. The method for preparing ZIF-8-Fe metal-organic framework nanozymes as described in claim 1, characterized in that, The centrifugation speed in step S4 is 5000-7000 rpm, and the drying temperature is 50-70℃.

7. A ZIF-8-Fe metal organic framework nanoscale enzyme prepared by the method of any one of claims 1-6 for use in drug detection.

8. Use according to claim 7, wherein the compound is ###0002### The drug detection comprises mixing the ZIF-8-Fe metal organic framework nanoscale enzyme with a drug sample to be detected and detecting the change in peroxidase activity.

9. Use according to claim 8, wherein the compound is ###0002### The drug sample to be detected is a tetracycline antibiotic.

10. The use according to claim 8, wherein the compound is ###00003### or a pharmaceutically acceptable salt thereof. The peroxidase activity is detected by color development reaction of 3,3',5,5'-tetramethylbenzidine and hydrogen peroxide.

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