Fe3O4-V2O5 ultramicro composite foam nano-enzyme for serum creatinine detection and preparation method and application of Fe3O4-V2O5 ultramicro composite foam nano-enzyme

Abstract

The invention discloses Fe3O4-V2O5 ultramicro composite foam nano-enzyme for serum creatinine detection as well as a preparation method and application of the Fe3O4-V2O5 ultramicro composite foam nano-enzyme, and belongs to the technical field of serum creatinine detection and nano-enzyme preparation. Comprising the following steps: (1) dissolving vanadium dichloride, ferric trichloride hexahydrate and cane sugar in an ethanol solution, then adding a phytic acid aqueous solution, and drying to obtain a first solid; and (2) placing the first solid in a Joule thermal device graphite sample table, and carrying out rapid Joule thermal shock in an air atmosphere to obtain the Fe3O4-V2O5 ultramicro composite foam nano-enzyme. The sucrose is used as a template agent, so that the formation of an ultramicro composite foam structure is promoted, the specific surface area of the material is remarkably increased, and more active sites are provided. The synergistic effect between Fe3O4 and V2O5 improves the catalytic activity of the active site. The porous structure effectively prevents agglomeration of nano-enzyme, and provides more channels for rapid recognition and reaction of serum creatinine.

Description

Technical Field

[0001] The present invention relates to the technical field of serum creatinine detection and nanozyme preparation, and in particular to a Fe3O4-V2O5 ultrafine composite foam nanozyme for serum creatinine detection, and a preparation method and application thereof. Background Art

[0002] Serum creatinine is a product of human muscle metabolism and is often used as an important biomarker for assessing renal function. As renal function is impaired, serum creatinine levels will increase significantly, so accurate detection of serum creatinine is crucial for clinical diagnosis of kidney disease, assessment of patient condition and formulation of treatment plans. Traditional serum creatinine detection methods mainly rely on the picric acid method, which is susceptible to interference from non-creatinine substances in serum (such as glucose, uric acid, ketone bodies, etc.), resulting in false positive or false negative results, thus affecting the accuracy of the test. Compared with the picric acid method, the enzyme colorimetric method can utilize the high specificity of creatinase and react only with creatinine through enzyme-catalyzed reactions, greatly reducing nonspecific interference in the detection process and significantly improving the specificity and accuracy of the test. At the same time, the enzyme colorimetric method has a lower detection limit and can more accurately detect low concentrations of serum creatinine. This is especially important for assessing early renal function damage and can help detect mild renal function decline, thereby improving the sensitivity of early screening and diagnosis. However, the enzyme colorimetric method is often limited by problems such as enzyme stability and high cost.

[0003] In recent years, the emergence of nanozymes has provided new possibilities for serum creatinine detection. Nanozymes are nanomaterials with enzymatic catalytic activity. They have gradually attracted widespread attention due to their high stability and controllable catalytic performance. The application of nanozymes in serum creatinine detection can provide higher sensitivity, better stability and lower cost, and has become a research hotspot. However, the design and preparation methods of nanozymes for serum creatinine detection are still immature. At present, the preparation process of most nanozymes is relatively complicated and costly, and they are prone to size inhomogeneity and agglomeration during the preparation process, which in turn affects their catalytic performance and stability. This limits their application in clinical diagnosis. Therefore, it is of great scientific significance and application value to study and develop an efficient and stable nanozyme for serum creatinine detection. Summary of the invention

[0004] The purpose of the present invention is to provide a Fe3O4-V2O5 ultrafine composite foam nanozyme for serum creatinine detection and a preparation method and application thereof, so as to solve the problems of the above-mentioned prior art, such as complex preparation process, high cost, easy agglomeration, low catalytic efficiency, etc.

[0005] To achieve the above object, the present invention provides the following solutions: One of the technical solutions of the present invention is a method for preparing a Fe3O4-V2O5 ultrafine composite foam nanozyme for serum creatinine detection, comprising the following steps: (1) dissolving vanadium dichloride, ferric chloride hexahydrate and sucrose in an ethanol solution, then adding a phytic acid aqueous solution, and drying to obtain a first solid; (2) Placing the first solid object in a graphite sample stage of a Joule heat device and subjecting it to rapid Joule heat shock in an air atmosphere to obtain the Fe3O4-V2O5 ultrafine composite foam nanozyme.

[0006] The second technical solution of the present invention is the Fe3O4-V2O5 ultrafine composite foam nanozyme prepared by the preparation method.

[0007] The third technical solution of the present invention is the use of the Fe3O4-V2O5 ultrafine composite foam nanozyme in the preparation of products for detecting serum creatinine.

[0008] The fourth technical solution of the present invention is a product for detecting serum creatinine, comprising the Fe3O4-V2O5 ultrafine composite foam nanozyme.

[0009] The sucrose-assisted Joule heat calcination method proposed in the present invention can quickly and efficiently prepare Fe3O4-V2O5 ultrafine composite foam nanozymes. This Fe3O4-V2O5 ultrafine composite foam structure has a large specific surface area, can provide more active sites, and the synergistic effect between the internal multiple components improves the catalytic activity of the single point, thereby significantly improving the catalytic efficiency of the nanozyme. Secondly, this porous structure can effectively prevent the agglomeration of the nanozyme and maintain its good dispersibility and stability. In addition, the porous characteristics of the ultrafine composite foam structure can provide more channels for the rapid identification and reaction of serum creatinine, effectively shortening the detection time. The colorimetric sensor for serum creatinine detection based on this ultrafine composite foam nanozyme has a low detection limit (LOD) as low as 0.179µM and high stability, providing new ideas and methods for the efficient and accurate detection of serum creatinine.

[0010] Based on the above technical solution, the present invention has the following technical effects: 1. The present invention proposes a sucrose-assisted Joule heat calcination method, which can quickly and efficiently prepare Fe3O4-V2O5 ultrafine composite foam nanozymes. Sucrose, as a template, promotes the formation of ultrafine composite foam structure, significantly increases the specific surface area of ​​the material, and provides more active sites. The synergistic effect between Fe3O4 and V2O5 enhances the catalytic activity of the active sites. In addition, this porous structure effectively prevents the aggregation of nanozymes, maintains good dispersibility and stability, and provides more channels for the rapid recognition and reaction of serum creatinine, shortening the detection time.

[0011] 2. The Joule heat calcination method utilizes the Joule heat generated by electric current passing through the material. It is fast, efficient, and energy-saving. It can achieve high-temperature treatment in a short time and promote the formation of nanozymes.

[0012] 3. The ultrafine composite foam nanozyme prepared based on this method was used to construct a serum creatinine colorimetric sensor, which showed a low limit of detection (LOD) and high stability, providing a new idea and method for the efficient and accurate detection of serum creatinine. This method is simple, fast, low-cost, and has good application and promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0014] Figure 1 This is the X-ray powder diffraction pattern of Example 1.

[0015] Figure 2 The scanning electron microscope image and element distribution diagram of Example 1 are shown.

[0016] Figure 3 This is the scanning electron microscope image of Comparative Example 1.

[0017] Figure 4 This is the scanning electron microscope image of Comparative Example 2.

[0018] Figure 5 This is the nitrogen adsorption-desorption isotherm curve of Example 1.

[0019] Figure 6 1 and 2 are X-ray photoelectron spectroscopy (XPS) graphs of Example 1, Comparative Example 3 and Comparative Example 4. Wherein, a is the V 2p XPS graph of Example 1 and Comparative Example 3, and b is the Fe 2p XPS graph of Example 1 and Comparative Example 4.

[0020] Figure 7 The figure is a comparison chart of the peroxidase-like activity of the samples of Example 1 and Comparative Examples 1-4.

[0021] Figure 8 The UV absorption spectra of the CR / TMB / H2O2 / Fe3O4-V2O5-1 nanozyme system with different creatinine (CR) concentrations.

[0022] Fig. 9 This is the relationship between UV absorption value and creatinine concentration.

[0023] Fig.10This is a graph of the active peroxidase activity after 9 cycles of detecting creatinine in Example 1.

[0024] Fig.11 This is a scanning electron microscope image of Example 1 after 9 cycles of detecting creatinine. DETAILED DESCRIPTION

[0025] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0026] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0027] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0028] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present application description and examples are exemplary only.

[0029] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0030] The technical solutions described in the present invention, unless otherwise specified, are all conventional solutions in the art, and the reagents or raw materials used, unless otherwise specified, are purchased from commercial channels or have been disclosed.

[0031] The embodiment of the present invention provides a method for preparing Fe3O4-V2O5 ultrafine composite foam nanozyme for serum creatinine detection, comprising the following steps: (1) dissolving vanadium dichloride, ferric chloride hexahydrate and sucrose in an ethanol solution, then adding a phytic acid aqueous solution, and drying to obtain a first solid; (2) Placing the first solid object in a graphite sample stage of a Joule heat device and subjecting it to rapid Joule heat shock in an air atmosphere to obtain the Fe3O4-V2O5 ultrafine composite foam nanozyme.

[0032] In some specific embodiments, the mass ratio of vanadium dichloride, ferric chloride hexahydrate, sucrose and phytic acid is 1:(1-3):(10-20):(8-12).

[0033] In some specific embodiments, the mass concentration of the ethanol solution is 40%; the mass concentration of the phytic acid aqueous solution is 50%.

[0034] In some specific embodiments, the drying condition is: keeping warm at 90° C. for 24 hours.

[0035] In some specific embodiments, the temperature of the rapid Joule thermal shock is 550-900° C., the heating rate is 1000-2000° C. / s, and the number of times is 1-10 times.

[0036] In the present invention, the Joule thermal shock is heating from room temperature to the target temperature and then naturally cooling to room temperature, which is represented as one time.

[0037] The embodiment of the present invention also provides the Fe3O4-V2O5 ultrafine composite foam nanozyme prepared by the preparation method.

[0038] The embodiment of the present invention also provides the use of the Fe3O4-V2O5 ultrafine composite foam nanozyme in the preparation of a product for detecting serum creatinine.

[0039] An embodiment of the present invention also provides a product for detecting serum creatinine, comprising the Fe3O4-V2O5 ultrafine composite foam nanozyme.

[0040] The present invention provides a preparation method of Fe3O4-V2O5 ultrafine composite foam nanozyme for serum creatinine detection, which can solve the problems that the nanozyme prepared by the traditional method is relatively complicated, costly, easy to agglomerate, and has low catalytic efficiency. The sucrose-assisted Joule heat calcination method proposed in the present invention can promote the rapid nucleation and growth of crystals, inhibit the agglomeration of crystals, and sucrose as a pore-forming agent can promote the formation of a rich pore structure, thereby quickly and efficiently preparing Fe3O4-V2O5 ultrafine composite foam nanozyme. This Fe3O4-V2O5 ultrafine composite foam structure has a large specific surface area, can provide more active sites, and the synergistic effect between internal Fe3O4 and V2O5 improves the catalytic activity of the active sites, thereby significantly improving the catalytic efficiency of the nanozyme. Secondly, this porous structure can effectively prevent the agglomeration phenomenon of the nanozyme and maintain its good dispersibility and stability. In addition, the porous characteristics of the ultrafine composite foam structure can provide more channels for the rapid recognition and reaction of serum creatinine, effectively shortening the detection time. The colorimetric sensor for serum creatinine detection based on this ultrafine composite foam nanozyme has a low detection limit (LOD) as low as 0.179µM and high stability, and can be used in multiple cycles, which is of great significance for the trace determination of creatinine in actual samples.

[0041] Example 1 Step S1, dissolving 5 mg of vanadium dichloride, 10 mg of ferric chloride hexahydrate, and 70 mg of sucrose in 100 mL of 40% ethanol solution, then adding 50 mg of 50% phytic acid aqueous solution under stirring, and then placing in a forced air drying oven at 90° C. for 24 hours to obtain a first solid.

[0042] Step S2, placing 50 mg of the first solid in a graphite sample stage of a Joule heat device, and subjecting it to a rapid Joule heat shock in an air atmosphere, wherein the rapid Joule heat shock temperature is 650°C, the Joule heat shock heating rate is 1500°C / s, and the number of Joule heat shocks is 5 times. An ultrafine composite foam nanozyme is obtained, which is named Fe3O4-V2O5-1.

[0043] Step S3, add 10 μL 2 mg / mL Fe3O4-V2O5-1 ultrafine composite foam nanozyme suspension, 10 μL 10 mM H2O2 and 10 μL 1 mM TMB to 2970 μL 0.2 M sodium acetate-acetic acid (NaAc-HAc, pH = 4.5) buffer solution, incubate at room temperature for 20 min, and measure the absorbance of the reaction solution at 652 nm using a UV-visible spectrophotometer to detect the activity of the Fe3O4-V2O5 ultrafine composite foam nanozyme.

[0044] Step S4, 80 μL 0.015M phosphate buffer (PBS, pH = 7.5) was mixed with 10 μL 0.1mg / mL creatinase solution, 10 μL 0.2mg / mL creatinase solution, 10 μL 0.2mg / mL sarcosine oxidase solution, and 20 μL creatinine solution (0~82.5mM), and incubated at 37°C for 30min. Then, 2850 μL 0.2M NaAc-HAc buffer (pH = 4.5), 10 μL 2mg / mL Fe3O4-V2O5-1 ultrafine composite foam nanozyme suspension and 10 μL 1mM TMB were added to the above solution and incubated at room temperature for 5min. Finally, the absorbance of the reaction solution was measured at 652nm using a UV-visible spectrophotometer to detect the creatinine content in the solution, and then the detection sensitivity of the colorimetric sensing method based on the nanozyme for creatinine was evaluated.

[0045] Example 2 The only difference from Example 1 is that 70 mg of sucrose is replaced by 50 mg of sucrose in step S1. The rest of the method is exactly the same as that of Example 1, and is recorded as Fe3O4-V2O5-2.

[0046] Example 3 The only difference from Example 1 is that 70 mg of sucrose is replaced by 100 mg of sucrose in step S1. The rest of the method is exactly the same as that of Example 1, and is recorded as Fe3O4-V2O5-3.

[0047] Example 4 The only difference from Example 1 is that in step S1, 50 mg of 50% phytic acid aqueous solution is replaced by 40 mg of 50% phytic acid aqueous solution. The rest of the method is exactly the same as Example 1, and is recorded as Fe3O4-V2O5-4.

[0048] Example 5 The only difference from Example 1 is that in step S1, 50 mg of 50% phytic acid aqueous solution is replaced by 60 mg of 50% phytic acid aqueous solution. The rest of the method is exactly the same as Example 1, and is recorded as Fe3O4-V2O5-5.

[0049] Example 6 The only difference from Example 1 is that in step S2, the rapid Joule heat calcination conditions are changed to: Joule heat shock temperature is 550°C, Joule heat shock heating rate is 1000°C / s, and the number of Joule heat shocks is 10. The rest of the method is exactly the same as Example 1, recorded as Fe3O4-V2O5-6.

[0050] Example 7 The only difference from Example 1 is that in step S2, the rapid Joule heat calcination conditions are changed to: Joule heat shock temperature is 900°C, Joule heat shock heating rate is 2000°C / s, and the number of Joule heat shocks is 1. The rest of the method is exactly the same as Example 1, recorded as Fe3O4-V2O5-7.

[0051] Comparative Example 1 The only difference from Example 1 is that sucrose is not added in step S1. The rest of the method is exactly the same as Example 1, and is recorded as Fe3O4-V2O5-a.

[0052] Comparative Example 2 The only difference from Example 1 is that the Joule heat heating method is replaced by muffle furnace heating in step S1. The specific steps are as follows: 50 mg of the first solid material is placed in a muffle furnace. In an air atmosphere, the heating rate is 10°C / min, heated to 650°C, and kept warm for 0.5h. The rest of the method is exactly the same as Example 1, recorded as Fe3O4-V2O5-b.

[0053] Comparative Example 3 The only difference from Example 1 is that in step S1, 5 mg of vanadium dichloride is changed to 15 mg of vanadium dichloride, and 10 mg of ferric chloride hexahydrate is changed to 0 mg of ferric chloride hexahydrate. The rest of the method is exactly the same as that of Example 1, and is recorded as V2O5-c.

[0054] Comparative Example 4 The only difference from Example 1 is that in step S1, 5 mg of vanadium dichloride is changed to 0 mg of vanadium dichloride, and 10 mg of ferric chloride hexahydrate is changed to 15 mg of ferric chloride hexahydrate. The rest of the method is exactly the same as that of Example 1, which is recorded as Fe3O4-d.

[0055] Experimental Results Figure 1 The X-ray powder diffraction pattern of Example 1 is shown. The results show that the Fe3O4-V2O5-1 prepared in Example 1 is composed of two phases, Fe3O4 and V2O5. The synergistic effect between different components can optimize the intrinsic nanozyme activity of the active substance, thereby improving the creatinine detection performance.

[0056] Figure 2The scanning electron microscope image and element distribution diagram of Example 1 are shown. The results show that Example 1 is an ultrafine composite nano foam structure composed of nanoparticles, and the particle size of a single nanoparticle is about 100nm. In addition, Fe and V elements are evenly distributed in the ultrafine nano composite foam, indicating that the two phases of Fe3O4 and V2O5 have good dispersibility in Fe3O4-V2O5-1, which is conducive to the synergistic effect between different phases. At the same time, this ultrafine composite nano foam structure can effectively prevent the agglomeration of nanoenzymes and maintain its good dispersibility and stability. In addition, the porous characteristics of the ultrafine composite foam structure can provide more channels for the rapid identification and reaction of serum creatinine, effectively shortening the detection time.

[0057] Figure 3 The scanning electron microscope image of Comparative Example 1 is shown. The main difference between Comparative Example 1 and Example 1 is that sucrose is not added during the preparation of the nanozyme. The results show that Comparative Example 1 presents a block structure that is adhered to each other, rather than the ultrafine nano-composite foam structure of Example 1. This shows that sucrose is conducive to the formation of ultrafine composite nanostructures, mainly because sucrose is oxidized by oxygen in the air during the calcination process to form a large amount of carbon dioxide, which can act as a pore-forming agent to promote the formation of ultrafine nano-composite foam structures.

[0058] Figure 4 The scanning electron microscope image of comparative example 2 is shown. The main difference between comparative example 2 and example 1 is that the nanozyme is not heated by Joule heat during preparation, but by a muffle furnace. Figure 4 It can be seen that the nanozymes prepared by the muffle furnace heating method have fewer foamy structures and more blocky materials. This is mainly because the heating and cooling rates of the muffle furnace are slow, the crystal nucleation and growth time is long, and it is easy to agglomerate and form large block materials. The Joule heat heating method has ultra-fast heating and cooling rates, which can inhibit the agglomeration of crystals during growth and the formation of large particles, and is more conducive to the formation of ultra-micro-nano composite foam structures.

[0059] To further analyze the pore structure of Fe3O4-V2O5-1, N2 adsorption-desorption tests were carried out. Figure 5 Table 1 shows the N2 adsorption-desorption test results of Example 1 and Comparative Examples 1 and 2. Figure 5 It can be seen from the figure that the adsorption-desorption curve of Example 1 shows an H3-type hysteresis loop, indicating that the material has a rich mesoporous structure. The Barrett-Joyner-Halenda (BJH) analysis results in the illustration show that the pore size distribution is relatively wide, further proving that the material is mainly a mesoporous structure. As can be seen from Table 1, the specific surface areas are as follows from large to small: Example 1 (45.23 m 2 / g)>Comparative Example 2 (18.65 m 2 / g)>Comparative Example 1 (8.69 m 2 / g). This indicates that during the synthesis of nanozymes, sucrose and Joule heat work together to promote the formation of ultrafine nano foam structure, and the contribution of sucrose is greater than that of Joule heat. This rich pore structure helps to disperse the active substances, expose more enzyme active sites, effectively prevent the aggregation of nanozymes, maintain good dispersibility and stability, and provide more channels for the rapid recognition and reaction of serum creatinine, shortening the detection time.

[0060] Table 1 N2 adsorption-desorption test results name Example 1 Comparative Example 1 Comparative Example 2 <![CDATA[Specific surface area (m 2 / g)]]> 45.23 8.69 18.65 Figure 6 The XPS spectra of Example 1, Comparative Example 3 and Comparative Example 4 are shown in FIG. Figure 6 It can be seen that compared with Comparative Examples 3 and 4, the binding energies of V and Fe elements in Example 1 shift toward low binding energy and high binding energy, respectively, indicating that there is a synergistic effect between Fe3O4 and V2O5, which optimizes the electronic structure of Fe and V elements, and can reduce the adsorption, activation and conversion energy barriers of reactants in enzyme-catalyzed reactions, thereby significantly improving the catalytic activity of enzyme active sites.

[0061] Figure 7 The peroxidase-like activity of Example 1 and Comparative Examples 1-4 samples was compared. The intensity of the absorption peak at 652 nm of the example is proportional to the enzyme activity. As can be seen from the figure, the material of Example 1 exhibits the highest nanozyme activity, which is much better than the nanozyme activity of the comparative example. In addition, the size of the nanozyme activity of the comparative example is Comparative Example 2>Comparative Example 4>Comparative Example 3>Comparative Example 1. It shows that sucrose, Joule heat, and multi-metal elements are essential for the improvement of nanozyme activity, and the synergistic effect of multiple factors significantly improves the activity of the nanozyme in Example 1.

[0062] Figure 8 The UV absorption spectra of the Fe3O4-V2O5-1 system under different creatinine (CR) concentrations were displayed. The results showed that as the creatinine concentration of the solution increased from 0.4 to 550 µM, the absorbance value of the TMB solution increased steadily, indicating that the absorbance value of the TMB solution can be used to quantify the concentration of the creatinine solution.

[0063] According to the Lambert-Beer law, the absorbance data of the Fe3O4-V2O5-1 system at different creatinine (CR) concentrations were converted to obtain Fig. 9 The relationship between UV absorption and creatinine concentration. In the range of 0.4-250µM, the UV absorption intensity and creatinine concentration show a good linear relationship (see Fig. 9 Illustration), the linear equation is: y=0.00339x+0.00407 (R 2=0.996), the detection limit (LOD) was calculated to be 0.179µM using the calculation method of LOD = 3σ / K, where σ is the standard deviation of the blank sample and K is the slope of the linear equation. Therefore, the detection limit (LOD) of the Fe3O4-V2O5 ultrafine composite foam nanozyme material is as low as 0.179µM, indicating that the colorimetric sensing method based on this material has excellent detection limit and high sensitivity for creatinine.

[0064] Fig.10 This is the active peroxidase activity diagram of Example 1 after 9 cycles of detecting creatinine. It can be seen from the figure that Example 1 still exhibits excellent enzyme activity after 9 cycles of detecting creatinine, indicating that Example 1 has excellent enzyme activity stability and can be reused many times.

[0065] Fig.11 This is a scanning electron microscope image of Example 1 after 9 cycles of creatinine detection. The results show that the microstructure of Example 1 has not changed significantly after 9 cycles of creatinine detection, and the ultrafine composite foam nanostructure is still maintained, indicating that Example 1 has excellent structural stability, which is beneficial to the stability of its enzyme activity.

[0066] The rapid Joule thermal shock technology in the embodiment of the present invention comes from a Joule thermal rapid heating device, which is composed of an electrode, a 316L vacuum chamber, a gas path device, a vacuum pump, a graphite sample stage, a temperature measurement module, and a data collection system; the output voltage is 0~40V, the output current is 0~375A, the current ramp time is 1000ms, the model is JH3.2, and the power supply is single-phase 220V / 40A.

[0067] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation methods of the present invention. For ordinary technical users in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is not necessary and impossible to list all the implementation methods here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for preparing Fe3O4-V2O5 ultrafine composite foam nanozyme for serum creatinine detection, characterized in that: The following steps are involved: (1) dissolving vanadium dichloride, ferric chloride hexahydrate and sucrose in an ethanol solution, then adding a phytic acid aqueous solution, and drying to obtain a first solid; (2) Placing the first solid object in a graphite sample stage of a Joule heat device and subjecting it to rapid Joule heat shock in an air atmosphere to obtain the Fe3O4-V2O5 ultrafine composite foam nanozyme.

2. The preparation method according to claim 1, characterized in that: The mass ratio of the vanadium dichloride, ferric chloride hexahydrate, sucrose and phytic acid is 1:(1-3):(10-20):(8-12).

3. The preparation method according to claim 1, characterized in that: The mass concentration of the ethanol solution is 40%; the mass concentration of the phytic acid aqueous solution is 50%.

4. The preparation method according to claim 1, characterized in that: The drying conditions are: keeping warm at 90° C. for 24 hours.

5. The preparation method according to claim 1, characterized in that: The temperature of the rapid Joule thermal shock is 550-900°C, the heating rate is 1000-2000°C / s, and the number of times is 1-10 times.

6. The Fe3O4-V2O5 ultrafine composite foam nanozyme prepared by the preparation method according to any one of claims 1 to 5.

7. Use of the Fe3O4-V2O5 ultrafine composite foam nanozyme as described in claim 6 in the preparation of a product for detecting serum creatinine.

8. A product for detecting serum creatinine, characterized in that: Including the Fe3O4-V2O5 ultrafine composite foam nanozyme as described in claim 6.

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