Colorimetric sensing array based on hierarchical pore nano-enzyme as well as construction method and application of colorimetric sensing array

Abstract

The invention discloses a colorimetric sensing array based on hierarchical pore nano-enzyme as well as a construction method and application of the colorimetric sensing array, and belongs to the technical field of analysis and detection. According to the array, two cerium-based MOF nano-enzymes, namely micropore UiO-66 and hierarchical pore HP-UiO-66, are respectively combined with TMB (tetramethylbenzidine) and ABTS (2, 2, 6, 6-tetramethylbenzidine) chromogenic substrates to form a four-channel sensing system. The method comprises the following steps: synthesizing hierarchical pore HP-UiO-66 by a template method; collecting the absorbance of each channel under the characteristic wavelength by using an array, and generating a specific fingerprint spectrum of the to-be-detected object; by combining mode recognition technologies such as linear discriminant analysis and the like, rapid and synchronous distinguishing and quantitative detection of at least eight antioxidants with similar structures such as glycyrrhizic acid and caffeic acid in the traditional Chinese medicine decoction are realized. According to the method, the catalysis and mass transfer efficiency is improved by regulating and controlling the pore structure of the nano-enzyme, the problem of multi-target synchronous recognition in a complex matrix is solved by utilizing array cross response, and the method has the advantages of simplicity and convenience in operation, high flux and good accuracy.

Description

Technical Field

[0001] This invention relates to the field of nanoanalysis and detection, and more specifically, to a colorimetric sensing array based on hierarchical porous nanozymes, its construction method, and its application. Background Technology

[0002] Antioxidant therapy plays a crucial role in the prevention and treatment of oxidative stress-related diseases, prompting increasing attention to Traditional Chinese Medicine (TCM), which is rich in various natural antioxidants. TCM decoctions are complex matrices containing a variety of compounds with antioxidant activity, including phenolic acids (such as caffeic acid, ferulic acid, and gallic acid), flavonoids (such as naringenin), and alkaloids (such as berberine). Rapid and accurate identification and detection of these specific components are essential for the quality control of TCM, the elucidation of its pharmacodynamic material basis, and standardization research.

[0003] Currently, the qualitative and quantitative analysis of antioxidants in traditional Chinese medicine mainly relies on chromatographic techniques (such as high-performance liquid chromatography (HPLC) and gas chromatography (GC) coupled with mass spectrometry. While these methods offer high sensitivity, they typically require complex sample pretreatment, expensive instruments, specialized operators, and lengthy analysis times, making it difficult to achieve high-throughput, rapid, on-site detection. More importantly, these methods are mostly targeted analyses of single or a few target analytes, and their ability to simultaneously identify and differentiate between multiple structurally similar compounds in complex systems within traditional Chinese medicine is limited.

[0004] To simulate the ability of biological sensory systems (such as smell and taste) to perceive and distinguish complex mixtures, sensor array (or "electronic tongue" or "electronic nose") technology has emerged. This technology utilizes a series of cross-reactive sensing units to respond to the analyte, generating multi-dimensional signal patterns (i.e., "fingerprints"), which are then differentiated and identified using pattern recognition algorithms. Among these, colorimetric sensor arrays based on nanozymes exhibit unique advantages due to their intuitive signal output (color changes), simple equipment (commonly using ELISA readers), and tunable catalytic activity of the nanozymes themselves. Various nanomaterials, including noble metal nanoparticles, metal oxides, and carbon materials, have been used to construct sensing channels for nanozymes.

[0005] Metal-organic frameworks (MOFs) are a class of porous crystalline materials formed by the self-assembly of metal ions / clusters and organic ligands. Among them, cerium-based UiO-66, as a structurally stable MOF, has been reported to possess oxidase-like activity, catalyzing color reactions with chromogenic substrates such as 3,3',5,5'-tetramethylbenzidine (TMB) or 2,2'-azino-bis-(3-ethylbenzodihydrothiazoline-6-sulfonic acid) (ABTS), thus showing potential applications in biosensing. However, existing research on using MOFs as nanozymes for sensing largely focuses on their composition and macroscopic morphology, while the crucial physical property of their internal pore structure (such as pore size and channel distribution) often neglects its impact on substrate mass transfer efficiency and ultimately catalytic and sensing performance. In particular, how to design sensing units with differentiated performance by finely controlling the pore structure of MOFs, and thus construct efficient sensor arrays, has not yet been fully explored.

[0006] Furthermore, applying MOF-based nanozyme sensor arrays to traditional Chinese medicine systems with extremely complex compositions to achieve simultaneous identification and quantitative detection of multiple specific antioxidants remains challenging. This is mainly due to severe interference from the traditional Chinese medicine matrix and the need for the sensor array to have sufficient distinguishing ability among multiple target substances with similar structures.

[0007] Therefore, developing a colorimetric sensor array and method based on novel nanoenzyme materials, with a simple construction method, capable of effectively overcoming interference from traditional Chinese medicine matrices, and simultaneously identifying and detecting multiple antioxidants from traditional Chinese medicines, is of significant scientific importance and application value. Summary of the Invention

[0008] To overcome the shortcomings of existing chromatographic methods in detecting multi-component antioxidants in traditional Chinese medicine (TCM), such as complex operation and low throughput, as well as the limited distinguishing ability of existing sensor arrays, this invention provides a colorimetric sensor array based on hierarchical porous nanozymes, its construction method, and its application. By designing UiO-66 and HP-UiO-66 nanozymes with different pore structures, and constructing a four-channel array with two substrates, specific fingerprint spectra are generated, thereby achieving rapid, simultaneous identification and quantitative detection of multiple structurally similar antioxidants in TCM.

[0009] This invention provides a colorimetric sensing array based on hierarchical porous nanozymes, comprising: a microporous cerium-based metal-organic framework material UiO-66, a hierarchical porous cerium-based metal-organic framework material HP-UiO-66, a chromogenic substrate 3,3',5,5'-tetramethylbenzidine, and a chromogenic substrate 2,2'-azino-bis-(3-ethylbenzodihydrothiazoline-6-sulfonic acid); the microporous cerium-based metal-organic framework material UiO-66 and the hierarchical porous cerium-based metal-organic framework material HP-UiO-66 are respectively combined with 3,3',5,5'-tetramethylbenzidine and the 2,2'-azino-bis-(3-ethylbenzodihydrothiazoline-6-sulfonic acid) to form four signal output channels; the hierarchical porous cerium-based metal-organic framework material HP-UiO-66 is synthesized by a surfactant template method, and its pore size is larger than that of the microporous cerium-based metal-organic framework material UiO-66.

[0010] Compared with existing technologies, the core advantage of this invention lies in the innovative synthesis and combination of cerium-based MOF nanozymes (microporous UiO-66 and hierarchical HP-UiO-66) with different pore structures, and the construction of a four-channel sensing array with two chromogenic substrates. This design utilizes the hierarchical pore structure to enhance catalytic activity and substrate mass transfer efficiency, forming performance complementarity and signal differentiation with the microporous materials, thereby generating information-rich specific fingerprint spectra. Ultimately, it achieves efficient, rapid, simultaneous differentiation and accurate detection of multiple structurally similar antioxidants in complex systems such as traditional Chinese medicine, overcoming the limitations of low throughput and cumbersome operation of traditional methods.

[0011] In one possible implementation, the synthesis method of the hierarchical porous cerium-based metal-organic framework material HP-UiO-66 includes the following steps: a) Dissolve template agent P123 in deionized water, add glacial acetic acid and 1,3,5-trimethylbenzene to form a microemulsion; b) Add cerium source (NH4)2Ce(NO3)6 and organic ligand terephthalic acid to the microemulsion of step a); c) The system was stirred at 50°C. After the stirring reaction was completed, the product was centrifuged, washed and vacuum dried.

[0012] Compared with existing technologies, the above synthesis method achieves precise control over the hierarchical pore structure of HP-UiO-66 by employing a P123 surfactant template and a microemulsion system. This process can be rapidly completed under mild conditions (50°C), is simple to operate, and has good reproducibility. The resulting material possesses open hierarchical channels, significantly improving substrate mass transfer efficiency and the accessibility of catalytic active sites, thus exhibiting superior oxidase-like activity compared to traditional microporous UiO-66, providing a key material foundation for constructing high-performance sensor arrays.

[0013] A second objective of this invention is to provide a method for constructing a colorimetric sensor array, comprising the following steps: a) Add buffer solution, chromogenic substrate, test sample and nanozyme solution sequentially to a reaction vessel to form a reaction system. The chromogenic substrate is 3,3',5,5'-tetramethylbenzidine or 2,2'-azinyl-bis-(3-ethylbenzodihydrothiazoline-6-sulfonic acid). The nanozyme solution is an aqueous dispersion of microporous cerium-based metal-organic framework material UiO-66 or hierarchical porous cerium-based metal-organic framework material HP-UiO-66. b) After the reaction, the absorbance of the reaction system at a specific wavelength was measured; when the chromogenic substrate was 3,3',5,5'-tetramethylbenzidine, the measurement wavelength was 652 nm; when the chromogenic substrate was 2,2'-azino-bis-(3-ethylbenzodihydrothiazoline-6-sulfonic acid), the measurement wavelength was 425 nm. c) Combine the absorbance signals from the four signal output channels to generate a specific fingerprint spectrum of the sample to be tested.

[0014] Compared to existing technologies, a stable and efficient four-channel colorimetric sensing array was rapidly constructed by standardizing the combination and operation of two nanozymes (UiO-66 and HP-UiO-66) with different catalytic properties and two substrates (TMB and ABTS). This construction process is simple and rapid (reaction time is only 5 minutes), easily implemented in conventional 96-well plates, and achieves high-throughput detection. By acquiring the absorbance signals of the four channels at characteristic wavelengths and integrating them into a multi-dimensional specific fingerprint spectrum, a rich and reliable data foundation is provided for subsequent pattern recognition-based accurate differentiation and identification.

[0015] In one possible implementation, in step a), the buffer solution is a NaAc-HAc buffer solution with pH=4.0, the concentration of the chromogenic substrate is 5 mM, and the concentration of the nanozyme solution is 1 mg / mL.

[0016] The third objective of this invention is to provide a method for detecting antioxidants in traditional Chinese medicine, which employs a colorimetric sensor array to simultaneously identify at least one antioxidant selected from glycyrrhizic acid, caffeic acid, coumaric acid, vanillic acid, ferulic acid, gallic acid, naringenin, and berberine.

[0017] Compared with existing technologies, this invention utilizes a constructed four-channel colorimetric sensor array to achieve rapid and simultaneous identification of eight key phenolic acids, flavonoids, and alkaloid antioxidants (such as glycyrrhizic acid, ferulic acid, and naringenin) in complex matrices such as traditional Chinese medicine decoctions. It avoids the cumbersome separation steps and high costs of traditional chromatographic methods, acquiring multidimensional fingerprint signals through a single detection and effectively distinguishing structurally similar substances using pattern recognition algorithms. This provides an efficient and reliable new tool for multi-index quality control and high-throughput screening of active ingredients in traditional Chinese medicine.

[0018] In one possible implementation, the detection method is used for the quantitative detection of glycyrrhizic acid, caffeic acid, ferulic acid and gallic acid; Among them, the concentration of glycyrrhizic acid in the range of 0-50 μM showed a linear relationship with the linear discriminant factor Factor 1, and the linear regression equation was y = 1.3689x - 28.3486, R0. 2 =0.994; The caffeic acid concentration showed a linear relationship with Factor 1 in the range of 0-25 μM, with a linear regression equation of y = 6.7574x - 109.0898, R0. 2 =0.992; Ferulic acid concentration showed a linear relationship with Factor 1 in the range of 0-50 μM, with a linear regression equation of y = 1.2407x - 20.0008, R0. 2 =0.996; Gallic acid concentration showed a linear relationship with Factor 1 in the range of 0-25 μM, with a linear regression equation of y = 4.3039x - 63.9522, R0. 2 =0.990; where y represents the value of Factor 1 and x represents the antioxidant concentration.

[0019] Compared with existing technologies, this invention successfully transforms the recognition capability of sensor arrays into precise and simultaneous quantitative analysis of four key antioxidants: glycyrrhizic acid, caffeic acid, ferulic acid, and gallic acid. By establishing a highly reliable (R²≥0.990) linear model between the concentration of each substance and the linear discriminant factor (Factor 1), this method achieves excellent accuracy over a wide linear range. This avoids the cumbersome process of separate detection required by traditional chromatography, significantly improving the throughput and efficiency of multi-indicator quality control of traditional Chinese medicine.

[0020] In one possible implementation, the detection limit for glycyrrhizic acid is 2.66 μM, the detection limit for caffeic acid is 0.57 μM, the detection limit for ferulic acid is 1.69 μM, and the detection limit for gallic acid is 0.78 μM.

[0021] In one possible implementation, the following sample pretreatment steps are also included: the raw Chinese medicine to be tested is mixed with water, heated under reflux at 100°C, then filtered and centrifuged to obtain the supernatant, which is then diluted and added to the reaction system as the sample to be tested.

[0022] In one possible implementation, the heating reflux time is 1 hour. Attached Figure Description

[0023] Figure 1 Scanning electron microscope images of UiO-66 and HP-UiO-66 materials in Example 1.

[0024] Figure 2 Absorption spectra and reaction kinetic curves of TMB and ABTS oxidation by UiO-66 and HP-UiO-66 materials.

[0025] Figure 3 LDA diagrams of eight antioxidants at the same concentration, based on a colorimetric sensing array of cerium-based hierarchical porous nanoparticles.

[0026] Figure 4 HCA diagram of eight antioxidants at the same concentration, based on a colorimetric sensing array of cerium-based hierarchical porous nanoparticles.

[0027] Figure 5 LDA diagrams for identifying different concentrations of the same antioxidant using a colorimetric sensing array based on cerium-based hierarchical porous nanoparticles.

[0028] Figure 6 Standard curves for the detection of glycyrrhizic acid, caffeic acid, ferulic acid and gallic acid.

[0029] Figure 7 LDA plot and standard curve for the identification of binary mixtures of oxidants by colorimetric sensor array.

[0030] Figure 8 : LDA and HCA diagrams of the colorimetric sensor array for distinguishing actual samples. Detailed Implementation

[0031] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. It should be noted that the following embodiments are only used to illustrate the implementation methods and typical parameters of the present invention, and are not intended to limit the parameter range described in the present invention. Reasonable variations derived therefrom are still within the protection scope of the present invention.

[0032] It should be noted that the endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0033] Unless otherwise defined, all terms, symbols, and other scientific terms used herein are intended to have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In some instances, terms having a conventional meaning are defined herein for clarification or ease of reference, and such definitions should not be construed as indicating a significant difference from conventional understanding in the art. The technical methods described or referenced herein are generally well understood by those skilled in the art and employed by conventional methods. Unless otherwise stated, the use of commercially available kits, reagents, and instruments shall be performed according to the manufacturer's instructions and parameters.

[0034] Example 1: Preparation of Materials 1) Synthesis of nanoenzyme material 1-microporous cerium-based metal-organic framework material UiO-66: 50 mg of block copolymer F127 and 500 μL of 1,3,5-trimethylbenzene were dissolved in 6 mL of deionized water and vigorously shaken to form a nanoemulsion. Then, 100 μL of glacial acetic acid and 0.5480 g of cerium ammonium hexanitrate were added, and the mixture was stirred to homogenize it. Next, 0.1660 g of terephthalic acid was added, and the reaction was carried out in an oil bath at 30 °C with continuous stirring at 800 rpm for 3 hours. The product was centrifuged, washed three times each with N,N-dimethylformamide (DMF) and anhydrous ethanol, and dried overnight in a vacuum oven at room temperature to obtain a material with a microporous octahedral structure (see [link to product description]). Figure 1 ).

[0035] 2) Synthesis of nanozyme material 2-hierarchical porous cerium-based metal-organic framework material HP-UiO-66: 0.0833 g of template agent P123 was dissolved in 5 ml of deionized water. 83 μL of glacial acetic acid and 1 mL of 1,3,5-trimethylbenzene were added with stirring to form a microemulsion. Then, 0.0457 g of cerium ammonium hexanitrate and 0.1383 g of terephthalic acid were added to the microemulsion. The mixture was stirred at 800 rpm for 1 hour at 50 °C. After the reaction, the product was centrifuged and repeatedly washed with DMF and anhydrous ethanol. Finally, it was vacuum dried overnight at room temperature to obtain a material with a hierarchical porous spherical structure (see [link to product description]). Figure 1 ).

[0036] Example 2 Characterization of material-based oxidase activity and reaction kinetics Characterization of oxidase-like catalytic properties: Prepare aqueous dispersions of nanozyme 1-UiO-66 and nanozyme 2-HP-UiO-66 at concentrations of 1 mg / mL, respectively. For testing, mix 200 μL NaAc-HAc buffer (100 mM, pH 4.0), 200 μL TMB substrate solution (5 mM), and 1500 μL deionized water in a cuvette. Add 100 μL of the above nanozyme dispersion to initiate the reaction. After incubation at room temperature for 5 minutes, immediately record the absorption spectrum in the 400-900 nm range using a UV-Vis spectrophotometer. The procedure is the same when using ABTS (5 mM) as the substrate (see [link to relevant documentation]). Figure 2 ).

[0037] Catalytic reaction kinetics test: In a 96-well plate, add 150 μL of deionized water, 20 μL of NaAc-HAc buffer (100 mM, pH 4.0), and 20 μL of TMB substrate solution (5 mM) sequentially. Then add 10 μL of nanozyme aqueous dispersion (1 mg / mL) to initiate the reaction. Immediately place the plate in a microplate reader and measure the absorbance at 652 nm at 0, 0.5, 1, 2, 4, 6, 8, 10, and 12 minutes after the start of the reaction to plot the reaction kinetics curve. When using ABTS as the substrate, the measurement wavelength is 425 nm, and the procedure is similar (see [link to article]). Figure 2 ).

[0038] Example 3: Detection Method for Antioxidants in Traditional Chinese Medicine 1) Single antioxidant identification based on sensor array: Two nanozymes, namely microporous cerium-based metal-organic framework material UiO-66 and hierarchical porous cerium-based metal-organic framework material HP-UiO-66, were combined with two chromogenic substrates, TMB and ABTS, respectively, to construct a four-channel colorimetric sensor array. The array was used to detect eight target antioxidants (glycyrrhizic acid, caffeic acid, coumaric acid, vanillic acid, ferulic acid, gallic acid, naringenin, and berberine).

[0039] The specific operation is as follows: Using a multichannel pipette, add an appropriate amount of deionized water, 20 μL of NaAc-HAc buffer (100 mM, pH 4.0), 20 μL of TMB or ABTS substrate solution (5 mM), and an antioxidant sample solution of a certain concentration to each well of a 96-well plate in sequence. Finally, add 10 μL of nanozyme aqueous dispersion (1 mg / mL) to make the total system volume 200 μL. After incubating at room temperature for 5 minutes, immediately measure the absorbance using a microplate reader: the TMB system was measured at 652 nm, and the ABTS system was measured at 425 nm. Each antioxidant was tested 5 times, and finally a data matrix of 8 target substances × 4 signal channels × 5 repetitions was obtained. Linear discriminant analysis (LDA) and hierarchical clustering analysis (HCA) were used to process the data. Finally, the colorimetric sensor array achieved the identification of eight antioxidants at the same concentration (see Figure 3 and Figure 4 Meanwhile, the colorimetric sensing array also demonstrated good differentiation between different concentrations of the same target analyte (see [reference]). Figure 5 ).

[0040] 2) Quantitative detection proficiency testing: Quantitative analysis was performed on glycyrrhizic acid, caffeic acid, ferulic acid, and gallic acid. The experimental procedure was the same as above, measuring the response signals at different concentrations and performing LDA analysis. The results showed that the concentrations of the four substances within the specified range exhibited a good linear relationship with the first discriminant factor (Factor 1) obtained from LDA (see [link to study]). Figure 6 The linear regression equations are: y = 1.3689x - 28.3486, R0 2 = 0.994, detection range is 0-50 μM; y = 6.7574x -109.0898, R 2 = 0.992, detection range is 0-25 μM; y = 1.2407x -20.0008, R 2 = 0.996, detection range is 0-50 μM; y = 4.3039x -63.9522, R 2 = 0.990, detection range is 0-25 μM.

[0041] 3) Identification of binary mixtures: Six binary mixed solutions of glycyrrhizic acid (Gly) and gallic acid (Gal) were prepared at different concentration ratios (20:0, 16:4, 12:8, 8:12, 4:16, 0:20 μM). These solutions were detected using the aforementioned sensor array, resulting in a training data matrix of 6 concentration ratios × 4 signals × 5 sets of repetitions. Origin linear discriminant analysis (LDA) was performed on the data. The ratio of Gly to Gal showed a good linear relationship with Factor 1, with the linear regression equations being: y = 0.4544x - 22.4246, R0. 2 = 0.989 (see Figure 7 This demonstrates that the array can be used to analyze component ratios.

[0042] 4) Determination of actual Chinese herbal medicine samples: Weigh different mass ratios of licorice tablets and gallnut mixtures (6:0, 2.4:1.2, 1.2:1.6, 0:2 g), add 30 ml of deionized water, and heat under reflux at 100℃ for 1 hour. Filter and centrifuge to obtain four supernatants. Take 100 μL of the supernatant and dilute to 1 ml to obtain four dilutions. Then, add deionized water, buffer solution (100 mM NaAc-HAc, pH = 4.0), substrate (5 mM TMB or ABTS), four dilutions, and nanozyme (1 mg / mL) sequentially to a 96-well plate, and use a multichannel pipette to obtain a 200 μL system. Finally, analyze the training data matrix of 4 dilutions × 4 signals × 5 repetitions according to the above steps, and perform linear discriminant analysis (LDA) and hierarchical clustering analysis (HCA) on the data in Origin (see [link to Origin]). Figure 8 The four sets of actual samples can be clearly distinguished.

[0043] The inventors also conducted identification experiments on unknown samples, and the results are summarized in Table 1. All 20 unknown samples were successfully categorized with 100% accuracy. Furthermore, calculations showed that the results for these four groups of actual samples corroborated each other. Therefore, it can be concluded that sensor arrays based on UiO-66 and HP-UiO-66 have strong applicability and high accuracy in analyzing antioxidants in traditional Chinese medicine. While the disclosure is as stated above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the protection scope of this invention.

Claims

1. A colorimetric sensing array based on hierarchical porous nanozymes, characterized in that, include: The study comprises a microporous cerium-based metal-organic framework (MORF) UiO-66, a hierarchical porous cerium-based MORF HP-UiO-66, a chromogenic substrate 3,3',5,5'-tetramethylbenzidine, and a chromogenic substrate 2,2'-azino-bis-(3-ethylbenzodihydrothiazoline-6-sulfonic acid). The microporous cerium-based MORF UiO-66 and the hierarchical porous cerium-based MORF HP-UiO-66 are combined with 3,3',5,5'-tetramethylbenzidine and the 2,2'-azino-bis-(3-ethylbenzodihydrothiazoline-6-sulfonic acid), respectively, to form four signal output channels. The hierarchical porous cerium-based MORF HP-UiO-66 is synthesized using a surfactant template method, and its pore size is larger than that of the microporous cerium-based MORF UiO-66.

2. The colorimetric sensor array as described in claim 1, characterized in that, The synthesis method of the hierarchical porous cerium-based metal-organic framework material HP-UiO-66 includes the following steps: a) Dissolve template agent P123 in deionized water, add glacial acetic acid and 1,3,5-trimethylbenzene to form a microemulsion; b) Add cerium source (NH4)2Ce(NO3)6 and organic ligand terephthalic acid to the microemulsion of step a); c) The system was stirred at 50°C. After the stirring reaction was completed, the product was centrifuged, washed and vacuum dried.

3. A method for constructing a colorimetric sensor array as described in any one of claims 1-2, characterized in that, Includes the following steps: a) Add buffer solution, chromogenic substrate, test sample and nanozyme solution sequentially to a reaction vessel to form a reaction system. The chromogenic substrate is 3,3',5,5'-tetramethylbenzidine or 2,2'-azinyl-bis-(3-ethylbenzodihydrothiazoline-6-sulfonic acid). The nanozyme solution is an aqueous dispersion of microporous cerium-based metal-organic framework material UiO-66 or hierarchical porous cerium-based metal-organic framework material HP-UiO-66. b) After the reaction, the absorbance of the reaction system at a specific wavelength was measured; when the chromogenic substrate was 3,3',5,5'-tetramethylbenzidine, the measurement wavelength was 652 nm; when the chromogenic substrate was 2,2'-azino-bis-(3-ethylbenzodihydrothiazoline-6-sulfonic acid), the measurement wavelength was 425 nm. c) Combine the absorbance signals from the four signal output channels to generate a specific fingerprint spectrum of the sample to be tested.

4. The construction method as described in claim 3, characterized in that, In step a), the buffer solution is a NaAc-HAc buffer solution with pH=4.0, the concentration of the chromogenic substrate is 5 mM, and the concentration of the nanozyme solution is 1 mg / mL.

5. A method for detecting antioxidants in traditional Chinese medicine, characterized in that, Using the colorimetric sensor array as described in any one of claims 1-2, at least one antioxidant selected from glycyrrhizic acid, caffeic acid, coumaric acid, vanillic acid, ferulic acid, gallic acid, naringenin, and berberine can be simultaneously identified.

6. The detection method as described in claim 5, characterized in that, The detection method is used for the quantitative detection of glycyrrhizic acid, caffeic acid, ferulic acid and gallic acid; Among them, the concentration of glycyrrhizic acid in the range of 0-50 μM showed a linear relationship with the linear discriminant factor Factor 1, and the linear regression equation was y = 1.3689x - 28.3486, R0. 2 =0.994; The concentration of caffeic acid showed a linear relationship with Factor 1 in the range of 0-25 μM, with a linear regression equation of y = 6.7574x - 109.0898 and R0. 2 =0.992; The concentration of ferulic acid showed a linear relationship with Factor 1 in the range of 0-50 μM, with a linear regression equation of y = 1.2407x - 20.0008, R0. 2 =0.996; Gallic acid concentration showed a linear relationship with Factor 1 in the range of 0-25 μM, with a linear regression equation of y = 4.3039x - 63.9522, R0. 2 =0.990; where y represents the value of Factor 1 and x represents the antioxidant concentration.

7. The detection method as described in claim 6, characterized in that, The detection limit for glycyrrhizic acid is 2.66 μM, the detection limit for caffeic acid is 0.57 μM, the detection limit for ferulic acid is 1.69 μM, and the detection limit for gallic acid is 0.78 μM.

8. The detection method as described in claim 5, characterized in that, The sample pretreatment steps also include the following: the raw Chinese medicine to be tested is mixed with water, heated under reflux at 100°C, then filtered and centrifuged to obtain the supernatant, which is then diluted and added to the reaction system as the sample to be tested.

9. The detection method as described in claim 8, characterized in that, The heating reflux time is 1 hour.

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