A malleable enzyme-metal organic framework gel and a preparation method and application thereof

Abstract

The application belongs to the technical field of biological materials, and particularly relates to a plastic enzyme-metal organic framework gel as well as a preparation method and application thereof. 2+ The composite gel with controllable morphology is prepared by double cross-linking polymerization of ions and sodium alginate-polyacrylic acid. The enzyme conformation is tightly bound by the metal organic framework exoskeleton, which can significantly improve the stability of the enzyme. At the same time, the highly hydrophilic hydrogel microenvironment can enrich the enzyme reaction products, and show higher catalytic "signal". In addition, the composite gel can effectively solve the technical bottlenecks of poor processability and poor plasticity of the enzyme-metal organic framework microcrystalline material, and is further designed into a portable in-situ sensor.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of biological materials. More particularly, it relates to a plastic enzyme metal organic framework gel and a preparation method and application thereof. BACKGROUND

[0002] As a natural biological catalyst, enzymes have the characteristics of high catalytic activity and high selectivity, but they are also sensitive to environmental changes, such as high temperature, strong acidity or alkalinity, which can easily cause enzyme denaturation and inactivation. In order to solve the stability problem of enzymes, the existing technology often uses metal organic frameworks (MOFs) as ideal carriers for enzyme structure immobilization, and the obtained enzyme@MOF composite material can effectively improve the tolerance of enzymes to temperature, pH, solvent, etc. For example, a method for modifying acid-resistant organic metal framework immobilized enzyme is provided in a Chinese patent application. The method modifies 2-methyl imidazole with citric acid or sodium citrate, then dopes nano-silicon dioxide, zinc ion aqueous solution and protease, centrifuges, and the obtained precipitate is the immobilized enzyme; an acid-resistant modified organic metal framework is prepared by a water phase solution mixing method, and nano-silicon dioxide is doped as a carrier, which significantly improves the catalytic activity, pH tolerance and reuse rate of the immobilized lipase, but the enzyme@MOF material obtained by this method is in a microcrystalline state, which is difficult to process and plasticize, greatly limiting the application of enzyme@MOF materials in large-scale industrialization, and the stability still needs to be improved. SUMMARY

[0003] The technical problem to be solved by the present application is to overcome the defects and deficiencies of the existing enzyme@MOF composite material, which is in a microcrystalline state and difficult to process and plasticize, and has stability to be improved, and to provide a plastic enzyme metal organic framework gel with good stability.

[0004] The purpose of the present application is to provide a preparation method of the plastic enzyme metal organic framework gel.

[0005] Another purpose of the present application is to provide an application of the plastic enzyme metal organic framework gel.

[0006] The above purposes of the present application are achieved by the following technical solutions.

[0007] A preparation method of a plastic enzyme metal organic framework gel, specifically comprising the following steps:

[0008] S1, adding an enzyme into a 2-methyl imidazole solution, then adding a zinc salt solution, mixing uniformly, standing, taking the precipitate, post-treatment, and obtaining an enzyme metal organic framework;

[0009] S2, the enzyme-metal organic framework obtained in step S1 is placed in a 2,2'-azobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) solution, and is uniformly dispersed, sodium alginate is added while stirring, and is uniformly mixed to obtain a mixed solution;

[0010] S3, the mixed solution obtained in step S2 is molded into different shapes, is immersed in a mixed solution of a calcium salt and polyacrylic acid, and is polymerized to obtain the product.

[0011] In the present application, the enzyme is first encapsulated on a metal organic framework (ZIF-8) assembled by coordination of zinc ions and 2-methyl imidazole, and then the obtained enzyme-metal organic framework microcrystalline material is uniformly mixed with a sodium alginate solution by a simple mixing method, and the mixed solution is injected into a solution of a calcium ion-containing polyacrylic acid crosslinking agent to rapidly polymerize and mold to obtain a moldable enzyme-metal organic framework gel. 2+ The enzyme is tightly bound in the conformation of the metal organic framework exoskeleton, which can significantly improve the stability of the enzyme; at the same time, the highly hydrophilic hydrogel microenvironment can enrich the enzyme reaction products, and exhibits higher catalytic "signals". In addition, the composite hydrogel can effectively solve the technical bottlenecks of poor processability and moldability of the enzyme-metal organic framework microcrystalline material, and can be further designed into a portable in-situ sensor.

[0012] Further, in step S1, the enzyme is selected from one or more of glucose oxidase, horseradish peroxidase, cholesterol oxidase, sarcosine oxidase, xanthine oxidase, beta-galactosidase, urease, urokinase, laccase, lipase, ethanol dehydrogenase, acetylcholine esterase, catalase, lactic acid oxidase, beta-glucuronidase, cytochrome C, uricase, and superoxide dismutase.

[0013] Preferably, in step S1, the enzyme is one of glucose oxidase-horseradish peroxidase, cholesterol oxidase-horseradish peroxidase, sarcosine oxidase-horseradish peroxidase, xanthine oxidase-horseradish peroxidase, and beta-galactosidase-glucose oxidase-horseradish peroxidase.

[0014] More preferably, in step S1, when the enzyme is a combination of two enzymes, the mass ratio of the two enzymes is 1:1, and there is a cascade reaction between the two enzymes. For example, glucose oxidase and horseradish peroxidase are selected to prepare the moldable enzyme-metal organic framework gel, when glucose is present, a cascade reaction of the enzymes is triggered, and a visual color signal is generated; the color signal can be quickly identified and data processed by an intelligent mobile phone APP that can identify colors through an RGB mode, so that in-situ monitoring of glucose can be achieved; further combined with a control, the content of glucose can be determined, and the specificity is strong and is not affected by other impurities.

[0015] Further, in step S1, the zinc salt is zinc acetate or zinc nitrate.

[0016] Further, in step S1, the enzyme is added in an amount of 0.1-2 mg / mL.

[0017] Further, in step S1, the molar ratio of 2-methylimidazole to zinc acetate is 4:1-12:1.

[0018] Further, in step S1, the standing time is 30 min-12 h.

[0019] Further, in step S1, the post-treatment is washing the precipitate with water for 2-4 times, washing with ethanol for 1-2 times, and drying.

[0020] Further, in step S2, the concentration of the ABTS solution is 1-20 mM.

[0021] Further, in step S2, the enzyme@metal-organic framework is added in an amount of 0.5-100 mg / mL.

[0022] Further, in step S2, the sodium alginate is added in an amount of 5-80 mg / mL.

[0023] Further, in step S3, the calcium salt is calcium chloride, calcium nitrate, calcium chlorate, calcium perchlorate, calcium bicarbonate or calcium dihydrogen phosphate.

[0024] Further, in step S3, in the mixed solution of the calcium salt and polyacrylic acid, the concentration of the calcium salt is 20-120 mol / L, and the concentration of the polyacrylic acid is 0.01-2 mol / L.

[0025] In addition, the application also provides a plastic enzyme@metal-organic framework gel prepared by the preparation method.

[0026] In addition, the application also claims the use of the plastic enzyme@metal-organic framework gel in sensing, biological catalysis, drug synthesis, food processing, enzyme-containing detergents, and biofuels.

[0027] The application has the following beneficial effects:

[0028] The application prepares a plastic enzyme@metal-organic framework gel. In the preparation process of the gel, the enzyme is first encapsulated in a porous metal-organic framework in situ, and then the Ca 2+The ion and sodium alginate-polyacrylic acid double crosslinking polymerization prepares the composite gel with controllable morphology. The metal organic framework outer skeleton tightly binds the conformation of the enzyme, which can significantly improve the stability of the enzyme; meanwhile, the highly hydrophilic hydrogel microenvironment can enrich the enzyme reaction products, and exhibits higher catalytic "signal". In addition, the composite hydrogel can effectively solve the technical bottlenecks of poor processability and poor plasticity of the enzyme-metal organic framework microcrystalline material, and can be further designed into a portable in-situ sensor. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The flowchart is for the embodiment 1 and 2 of the application.

[0030] Figure 2 The scanning electron microscope images of GH@ZIF-8 and GH@ZIF-8-ACP materials obtained in the embodiment 1 of the application and calcium alginate gel (ACP) are shown in the figure, wherein, Figure 2 (a) is GH@ZIF-8, Figure 2 (b) is calcium alginate gel, Figure 2 (c) is GH@ZIF-8-ACP.

[0031] Figure 3 The X-ray diffraction patterns of GH@ZIF-8 and GH@ZIF-8-ACP obtained in the embodiment 1 of the application are shown in the figure, wherein, Figure 3 (a) is the comparison of GH@ZIF-8-ACP, GH@ZIF-8 and ZIF-8, Figure 3 (b) is the comparison of GH@ZIF-8-ACP and ACP.

[0032] Figure 4 The Fourier transform infrared spectrograms of free enzyme (GOx: HRP = 1:1, enzyme), ZIF-8, GH@ZIF-8, GH@ZIF-8-ACP and ACP in the experimental example 1 of the application are shown in the figure.

[0033] Figure 5 The thermogravimetric analysis diagrams of ZIF-8, GH@ZIF-8, ACP and GH@ZIF-8-ACP in the experimental example 1 of the application are shown in the figure.

[0034] Figure 6 The N2 adsorption-desorption isotherms of ZIF-8, GH@ZIF-8, ACP and GH@ZIF-8-ACP in the experimental example 1 of the application are shown in the figure, wherein, Figure 6 (a) is ZIF-8, Figure 6 (b) is GH@ZIF-8, Figure 6 (c) is ACP, Figure 6 (d) is GH@ZIF-8-ACP.

[0035] Figure 7 Color R value change curve of the GH@ZIF-8-ACP in the spherical shape (a-1), linear shape (b-1) and flaky shape (c-1) in Experimental Example 2 of the present application with time and color development of the GH@ZIF-8-ACP in the spherical shape (a-2), linear shape (b-2) and flaky shape (c-2) with time.

[0036] Figure 8 Color development effect diagram of the GH@ZIF-8-ACP in the spherical shape, linear shape and flaky shape in Experimental Example 2 of the present application under the premise of ensuring the same enzyme content at different times.

[0037] Figure 9 Standard curve of R value change of the GH@ZIF-8-ACP in the flaky shape in Experimental Example 3 of the present application after color development for 15 minutes under different glucose concentrations.

[0038] Figure 10 Comparison diagram of the anti-interference experiment of the GH@ZIF-8-ACP color development in Experimental Example 4 of the present application.

[0039] Figure 11 Comparison diagram of the cross-reaction experiment of the GH@ZIF-8-ACP color development in Experimental Example 5 of the present application.

[0040] Figure 12 Statistical diagram of the storage stability exploration results of the GH@ZIF-8-ACP in Experimental Example 6 of the present application. DETAILED DESCRIPTION

[0041] The present application will be further described below in conjunction with the drawings and specific examples of the present application, but the examples do not limit the present application in any form. Unless otherwise specified, the reagents, methods and devices used in the present application are conventional reagents, methods and devices in the technical field.

[0042] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0043] Example 1 A moldable enzyme@metal organic framework gel

[0044] The preparation method of the moldable enzyme@metal organic framework gel comprises the following steps:

[0045] S1, respectively prepare 40mM zinc acetate solution and 160mM 2-methylimidazole solution, weigh 20mg glucose oxidase (GOx) and 20mg horseradish peroxidase (HPR), dissolve them in 20mL 160mM 2-methylimidazole solution, then add 20mL 40mM zinc acetate solution, and stand for 4 hours; centrifuge, discard the supernatant, wash with water for 3 times, wash with ethanol for 1 time, vacuum dry, grind, and obtain GH@ZIF-8;

[0046] S2, 40 mg of GH@ZIF-8 obtained in step S1 was weighed, 1 mL of 5 mM ABTS solution was added, and GH@ZIF-8 was uniformly dispersed in the ABTS solution by ultrasonic dispersion; after dispersion, the suspension was subjected to magnetic stirring, 20 mg of sodium alginate was added in the stirring process, and a mixed solution was obtained after uniform mixing;

[0047] S3, the mixed solution obtained in step S2 was loaded into a syringe, and was carefully dropped or directly injected into a solution containing 60 mol / L CaCl2 and 0.05 mol / L polyacrylic acid, and a spherical or linear composite gel GH@ZIF-8-ACP was formed after 10 min of polymerization.

[0048] Example 2 A moldable enzyme@metal organic framework gel

[0049] The preparation method of the moldable enzyme@metal organic framework gel comprises the following steps:

[0050] S1, 40 mM zinc acetate solution and 160 mM 2-methylimidazole solution were prepared respectively, 20 mg of glucose oxidase (GOx) and 20 mg of horseradish peroxidase (HPR) were weighed and dissolved in 20 mL of 160 mM 2-methylimidazole solution, and then 20 mL of 40 mM zinc acetate solution was added, and the mixture was allowed to stand for 4 hours; centrifugation, discarding the supernatant, washing with water for 3 times, washing with ethanol for 1 time, vacuum drying, grinding, and obtaining GH@ZIF-8;

[0051] S2, 40 mg of GH@ZIF-8 obtained in step S1 was weighed, 1 mL of 5 mM ABTS solution was added, and GH@ZIF-8 was uniformly dispersed in the ABTS solution by ultrasonic dispersion; after dispersion, the suspension was subjected to magnetic stirring, 20 mg of sodium alginate was added in the stirring process, and a mixed solution was obtained after uniform mixing;

[0052] S3, a glass plate was used as a substrate, and the mixed solution obtained in step S2 was uniformly coated on the glass plate on a film coating machine, and the thickness was set to 40 μm; the glass plate coated with the mixed solution was immersed in a solution containing 60 mol / L CaCl2 and 0.05 mol / L polyacrylic acid, and a sheet-shaped composite gel GH@ZIF-8-ACP was formed after 10 min of polymerization.

[0053] The flowchart of Example 1 and Example 2 is shown in Figure 1 .

[0054] Example 3 A moldable enzyme@metal organic framework gel

[0055] The difference between Example 3 and Example 1 is that the enzyme in Example 3 is replaced by cholesterol oxidase and horseradish peroxidase, and the rest of the parameters and operations refer to Example 1.

[0056] Example 4 A moldable enzyme@metal organic framework gel

[0057] The difference between Example 4 and Example 1 is that the enzyme is replaced by sarcosine oxidase and horseradish peroxidase, and the rest of the parameters and operations refer to Example 1.

[0058] Example 5 A moldable enzyme@metal organic framework gel

[0059] The difference between Example 5 and Example 1 is that the enzyme is replaced by xanthine oxidase and horseradish peroxidase, and the rest of the parameters and operations refer to Example 1.

[0060] Example 6 A moldable enzyme@metal organic framework gel

[0061] The difference between Example 6 and Example 1 is that the enzyme is replaced by β-galactosidase-glucose oxidase-horseradish peroxidase, wherein the mass ratio of β-galactosidase, glucose oxidase and horseradish peroxidase is 2:1:1, and the rest of the parameters and operations refer to Example 1.

[0062] The following takes the moldable enzyme@metal organic framework gel obtained in Examples 1 and 2 as an example to determine its structural characterization and performance parameters, and the effects of the rest of the examples are similar.

[0063] Experimental Example 1 Structural characterization of a moldable enzyme@metal organic framework gel

[0064] 1. Scanning electron microscopy was performed on the GH@ZIF-8 and GH@ZIF-8-ACP materials obtained in Example 1 and calcium alginate gel (ACP), and the results are shown in Figure 2 It can be seen from the figure that the GH@ZIF-8 in the GH@ZIF-8-ACP material prepared in the present application and Example 1 is uniformly dispersed in the ACP.

[0065] 2. X-ray diffraction testing was performed on the GH@ZIF-8 and GH@ZIF-8-ACP materials obtained in Example 1, and the results are shown in Figure 3 It can be seen from the figure that the GH@ZIF-8 and GH@ZIF-8-ACP are consistent with the PXRD pattern of standard ZIF-8, proving that the prepared composite material has a highly crystalline ZIF-8 structure; at the same time, this result also confirms that the GH@ZIF-8 is coated in the ACP.

[0066] 3. Fourier transform infrared spectroscopy was used to characterize the structures of the mixed free enzyme (GOx: HRP = 1:1, enzyme), ZIF-8, GH@ZIF-8, GH@ZIF-8-ACP and ACP, and the determination results are shown in Figure 4 It can be seen from the figure that the ZIF-8 has a characteristic absorption peak at 1580 cm-1 (C=N) and 1350-1500 cm -1 -1 and 1500-1600 cm -1 characteristic absorption bands of amide II and I bands of protein backbone, respectively; in addition, GH@ZIF-8 appeared both the infrared characteristic absorption bands of the enzyme and the characteristic absorption bands of ZIF-8, indicating that the enzyme was successfully encapsulated into ZIF-8.

[0067] 4. Thermogravimetric analysis was used to characterize ZIF-8, GH@ZIF-8, ACP, and GH@ZIF-8-ACP, and the results are shown in Figure 5 Fig. 4. As can be seen from the figure, at 220-500℃, the weight loss of GH@ZIF-8 is faster than that of ZIF-8, which can be attributed to the decomposition of the enzyme coated in GH@ZIF-8 at high temperature; comparing GH@ZIF-8 with GH@ZIF-8-ACP, it can be found that the weight loss trends of the two are similar, but GH@ZIF-8-ACP loses more weight, which is related to the decomposition of ACP; comparing ACP with GH@ZIF-8-ACP, it can be found that GH@ZIF-8-ACP loses less weight, which is related to the inclusion of ZIF-8-ACP in GH@ZIF-8-ACP.

[0068] 5. N2adsorption-desorption isotherms of ZIF-8, GH@ZIF-8, ACP, and GH@ZIF-8-ACP were measured, and the results are shown in Figure 6 Fig. 5. As can be seen from the figure, the specific surface areas of ZIF-8, GH@ZIF-8, ACP, and GH@ZIF-8-ACP are 1289.6725 m 2 / g, 4.0912 m 2 / g, 1.6866 m2 / g, and 16.8725 m 2 / g, respectively; among them, the specific surface area of GH@ZIF-8 is greatly reduced compared with ZIF-8, which proves that the voids of ZIF-8 are occupied by the enzyme, and also proves that the enzyme is embedded in the material.

[0069] Experimental Example 2 Comparison of glucose recognition ability of GH@ZIF-8-ACP and GH@ZIF-8

[0070] Under the premise of ensuring the same enzyme content, the glucose (1 mM) recognition ability of pure GH@ZIF-8 and spherical and flaky GH@ZIF-8-ACP (Note: In order to facilitate performance comparison, the GH@ZIF-8-ACP here does not pre-encapsulate ABTS) was compared, as follows: ​

[0071] A certain mass of spherical, linear and flaky GH@ZIF-8-ACP was added to a 96-well plate, respectively, and GH@ZIF-8 of the corresponding mass was used as a control; 5 mM ABTS and 1 mM glucose were added to each test group, and the camera of a mobile phone was used to take pictures of each test group every 1 min, and the color was identified by the RGB mode of the color picker APP, and the curve of the change of the color R value with time was drawn, and the results are shown in Figure 7 and Figure 8 .

[0072] As can be seen from the figure, the GH@ZIF-8-ACP of spherical, linear and flaky shapes all have higher ΔR values than the pure GH@ZIF-8; the color developing ability of the GH@ZIF-8-ACP made into a gel material is stronger than that of the GH@ZIF-8 free in the solution, which indicates that the GH@ZIF-8-ACP helps to improve the recognition sensitivity to glucose.

[0073] Experimental Example 3 Quantitative analysis of GH@ZIF-8-ACP on glucose

[0074] The flaky GH@ZIF-8-ACP was cut into square pieces with a size of 0.5 cm x 0.5 cm, 27 pieces were taken and placed on a glass plate separately, photographed by a mobile phone camera, and the R value of the color RGB value extracted by the color picker APP was used as the background value; 1 μL of glucose solution with a concentration of 0 mM, 0.05 mM, 0.1 mM, 0.25 mM, 0.5 mM, 1 mM, 2 mM, 3 mM and 4 mM was added to different GH@ZIF-8-ACP pieces, respectively, each group was tested in triplicate, and the color R value was extracted after 15 min of photography and the curve of the glucose concentration versus ΔR value was drawn, and the results are shown in Figure 9 .

[0075] As can be seen from the figure, the GH@ZIF-8-ACP has a segmented linear response range to glucose, the first segment is 0-0.25 mM, and the second segment is 0.25-4 mM, and both segments have good linear relationships within the corresponding concentration ranges; the above test results prove that the GH@ZIF-8-ACP can realize the accurate quantification of glucose by being combined with the color recognition software of a smart phone, and the method has the advantages of simplicity and portability, and can be applied to the in-situ monitoring of glucose.

[0076] Experimental Example 4 Anti-interference experiment of GH@ZIF-8-ACP-based glucose detection

[0077] The sheet-shaped GH@ZIF-8-ACP is cut into square pieces with a size of 0.5 cm x 0.5 cm, 36 pieces are taken and placed separately on a glass plate, photographed by a mobile phone camera, and the R value of the color RGB value is extracted as the background value by a color picking APP; 1 μL of fructose, xylose, rhamnose, sucrose, lactose, galactose, maltose, glycine, BSA, urea, histidine, arginine, glutamic acid and alanine solution (all with a concentration of 10 mM) is added dropwise on the GH@ZIF-8-ACP piece, in addition, 1 μL of glucose solution with a concentration of 1 mM and 1 μL of deionized water are added dropwise as a comparison, each group is tested in triplicate, photographed after 15 min, and the color R value is extracted, and the results are shown in Figure 10 .

[0078] As can be seen from the figure, when the concentrations of fructose, xylose, rhamnose, sucrose, lactose, galactose, maltose, glycine, BSA and urea solution are all 10 times higher than that of glucose, only the R value of the GH@ZIF-8-ACP piece added with glucose changes obviously, which indicates that the GH@ZIF-8-ACP prepared in the application has specificity for glucose.

[0079] Experimental Example 5: Cross-reaction experiment of GH@ZIF-8-ACP coloration

[0080] The sheet-shaped GH@ZIF-8-ACP is cut into square pieces with a size of 0.5 cm x 0.5 cm, 36 pieces are taken and placed separately on a glass plate, photographed by a mobile phone camera, and the R value of the color RGB value is extracted as the background value by a color picking APP; 1 μL of fructose, xylose, rhamnose, sucrose, lactose, galactose, maltose, glycine, BSA, urea, histidine, arginine, glutamic acid and alanine solution (all with a concentration of 10 mM) is added dropwise on the GH@ZIF-8-ACP piece, in addition, 1 μL of glucose solution with a concentration of 1 mM and 1 μL of deionized water are added dropwise as a comparison, each group is tested in triplicate, photographed after 15 min, and the color R value is extracted, and the results are shown in Figure 11 .

[0081] As can be seen from the figure, the R value change of the mixed solution is similar to that of the pure glucose solution, which indicates that in the presence of high-concentration interfering substances, GH@ZIF-8-ACP still has accurate recognition ability for glucose.

[0082] Experimental Example 6: Storage stability of GH@ZIF-8-ACP

[0083] The GH@ZIF-8-ACP in sheet form is cut into square pieces with a size of 0.5 cm x 0.5 cm, placed on a glass plate, photographed by a mobile phone camera, and the R value of the color RGB value is extracted as the background value by a color picking APP; the GH@ZIF-8-ACP square pieces are placed at room temperature, 5 μL of 1 mM glucose is added to the center of each square piece every time interval, photographed after 15 min, and the color R value is extracted, the average value of the color R value change of the GH@ZIF-8-ACP square pieces for glucose recognition after different storage times is calculated to evaluate the storage stability, and the results are shown in Figure 12 .

[0084] As shown in the figure, the ΔR value of the GH@ZIF-8-ACP prepared by the application is 85.88% ± 10.30% of the original data after 30 days of storage at room temperature, indicating that the GH@ZIF-8-ACP has excellent storage stability.

[0085] The above examples are preferred embodiments of the application, but the embodiments of the application are not limited by the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the application shall be equivalent replacement methods, and all shall be included in the protection scope of the application.

Claims

1. A method for preparing a plastic enzyme@metal-organic framework gel, characterized in that, Specifically comprising the following steps: S1, adding enzyme into 2-methylimidazole solution, then adding zinc salt solution, mixing uniformly, standing, taking precipitate, post-treatment, obtaining enzyme-metal organic framework; S2, taking enzyme-metal organic framework obtained in step S1, dispersing uniformly in ABTS solution, adding sodium alginate while stirring, mixing uniformly, obtaining mixed solution; S3, shaping the mixed solution obtained in step S2 into linear shape, immersing in mixed solution of calcium salt and polyacrylic acid, polymerizing completely, obtaining the same; In step S1, the enzyme is one of glucose oxidase-horseradish peroxidase, cholesterol oxidase-horseradish peroxidase, sarcosine oxidase-horseradish peroxidase, xanthine oxidase-horseradish peroxidase, and β-galactosidase-glucose oxidase-horseradish peroxidase.

2. The method of claim 1, wherein, In step S1, the zinc salt is zinc acetate or zinc nitrate.

3. The preparation method according to claim 1, characterized in that, In step S1, the adding amount of enzyme is 0.1-2 mg / mL.

4. The preparation method according to claim 1, characterized in that, In step S2, the adding amount of enzyme-metal organic framework is 0.5-100 mg / mL.

5. The method of claim 1, wherein the step of forming the first and second layers is performed by a process selected from the group consisting of: sputtering, evaporation, and chemical vapor deposition. In step S2, the adding amount of sodium alginate is 5-80 mg / mL.

6. The method of claim 1, wherein the step of forming the first and second layers is performed by a process selected from the group consisting of: sputtering, evaporation, and chemical vapor deposition. In step S3, the calcium salt is calcium chloride, calcium bromide, calcium nitrate, calcium chlorate, calcium perchlorate, calcium bicarbonate, or calcium dihydrogen phosphate.

7. A malleable enzyme-metal organic framework gel, characterized in that, The moldable enzyme-metal organic framework gel is prepared by the preparation method of any one of claims 1-6.

8. The moldable enzyme-metal organic framework gel of claim 7 is used in sensing, drug synthesis, food processing, enzyme-containing detergent, and biofuel.

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