Preparation method and application of cell three-dimensional peppery taste sensor based on bimetal organic framework

Abstract

The invention belongs to the technical field of biosensing, and particularly relates to a preparation method and application of a cell three-dimensional peppery taste sensor based on a bimetal organic framework. A ZrCu-MOF / ILs compound material with stable electrochemical signals and low biotoxicity is synthesized, and is combined with A549 cells wrapped by GelMA to be loaded on an electrochemical sensor to obtain a cell electrochemical sensor with high selectivity and high sensitivity, and the cell electrochemical sensor is used for detecting capsaicin. The method has the outstanding advantages of low cost, high detection speed, simplicity in operation, high miniaturization capability and the like; on one hand, due to the synergistic material science effect of ZrCu-MOF and ILs, capsaicin molecules can be effectively enriched, and the detection sensitivity is directly improved; on the other hand, the wrapping protection effect of the GelMA hydrogel ensures the long-term health and function of A549 living cells, so that the stability, reliability and physiological correlation of a detection mode based on cell response are ensured.

Description

Technical Field

[0001] The present invention belongs to the field of biosensor technology, and specifically relates to a preparation method and application of a cell three-dimensional spicy taste sensor based on a bimetallic organic framework. Background Art

[0002] As a member of the Capsicum genus of the Solanaceae family, chili peppers, with their unique spicy taste, have become one of the most important spices on people's tables. The spiciness of chili peppers is mainly caused by the capsaicinoids they contain, of which capsaicin is the most effective and stimulating active compound. Although the content of capsaicinoids in chili peppers is less than 1%, they are indeed the key compounds that give chili peppers their spicy and hot sensation, giving the peppers a strong stimulating taste, triggering the body to produce heat and endorphin rushes, and giving the body an exciting experience and pleasure. In addition, the capsaicin content is one of the important indicators for evaluating the quality of chili peppers. Since the currently developed methods for detecting capsaicin cannot reflect the human body's response to spicy stimuli, it is of great significance to develop a capsaicin detection method that is consistent with human sensory organs, simple, fast, and low-cost.

[0003] The main methods for detecting capsaicin include high-performance liquid chromatography, spectrophotometry, enzyme-linked immunosorbent assay (ELISA), and electrochemical methods. However, the main drawbacks of these methods are complex pretreatment, reliance on large and expensive equipment, long detection times, high costs, inability to conduct rapid on-site detection, and a lack of information on biological activity. Electrochemical detection, on the other hand, offers advantages such as continuous real-time analysis, simple operation, strong specificity, high sensitivity, and fast response. In particular, when living cells are loaded onto an electrochemical working electrode as recognition elements, capsaicin binds to the TRPV1 receptor on the cell membrane, triggering channel opening and leading to a rapid influx of large amounts of cations. This acts as a natural, powerful signal amplification mechanism, converting trace amounts of capsaicin into a significant electrochemical signal.

[0004] Among existing technologies, the patent "A Reduced Graphene Oxide Sensor, Preparation Method, and Method for Rapidly Detecting Capsaicin Content" (CN114324545A) discloses a low-cost, fast, and safe reduced graphene oxide sensor, but this sensor is not suitable for testing complex samples. The patent "A Method for Detecting Capsaicin Content Using Botrytis Cinerea" (CN113403363A) discloses a detection method in which Botrytis Cinerea is inoculated into V8 culture medium containing varying concentrations of capsaicin. While this method improves accuracy, it cannot achieve non-destructive detection of capsaicin. Summary of the Invention

[0005] The purpose of the present invention is to address the shortcomings of existing capsaicin detection methods and provide an electrochemical detection method for capsaicin that is compatible with human senses. By synthesizing a ZrCu-MOF / ILs composite material with stable electrochemical signals and low biotoxicity, combining it with GelMA-wrapped A549 cells, and loading it onto an electrochemical sensor, a highly selective and sensitive cell electrochemical sensor is obtained for the detection of capsaicin.

[0006] This method offers significant advantages, including low cost, rapid detection, simple operation, and robust miniaturization. The synergistic materials effects of ZrCu-MOF and ILs effectively enrich capsaicin molecules, directly enhancing detection sensitivity. Furthermore, the protective encapsulation of the GelMA hydrogel ensures the long-term health and function of living A549 cells, thus guaranteeing the stability, reliability, and physiological relevance of this cell-based detection model.

[0007] In order to achieve the above objectives, the present invention adopts the following technical solutions:

[0008] A method for preparing a cell-based three-dimensional spicy taste sensor based on a bimetallic organic framework comprises the following steps:

[0009] (1) preparing a chloroauric acid solution: mixing chloroauric acid and concentrated sulfuric acid, adding deionized water, and mixing uniformly to obtain a mixed solution;

[0010] (2) Preparation of Cu-MOF: copper nitrate is dissolved in pure water to obtain a copper nitrate solution; terephthalic acid is dissolved in anhydrous ethanol to obtain a terephthalic acid solution; then, the copper nitrate solution is added to the terephthalic acid solution, stirred to obtain a mixed solution, and placed in a reactor for heating reaction. After the reaction, crystals are collected and dried to obtain a sample; then, the sample is immersed in dichloromethane for activation, and then vacuum dried to finally obtain Cu-MOF crystals;

[0011] (3) Preparation of ZrCu-MOF: adding zirconium oxychloride octahydrate to a mixed solution containing N,N-diethylformamide and trifluoroacetic acid to obtain solution A; dissolving 4,4'-biphenyldicarboxylic acid in N,N-diethylformamide to obtain solution B; ultrasonically treating solution A and solution B respectively; combining solution A and solution B after treatment to obtain solution C; adding the Cu-MOF crystal obtained in step (2) to solution C for a second ultrasonic treatment; stirring the reaction after treatment; collecting the precipitate by centrifugation after the reaction, washing with dimethylformamide and anhydrous ethanol (to remove residual precursors), and finally drying to obtain ZrCu-MOF;

[0012] (4) Preparation of ZrCu-MOF / ILs: [BMIM][PF6] (1-butyl-3-methylimidazolium hexafluorophosphate) was dissolved in acetone, and then the ZrCu-MOF obtained in step (3) was added and stirred at room temperature. After stirring, the mixture was dried to obtain a dry product, namely ZrCu-MOF / ILs.

[0013] (5) Preparation of cell-methacrylated gelatin hydrogel (GelMA): gelatin was dissolved in PBS and stirred to obtain a gelatin solution; methacrylate anhydride was then added dropwise to the gelatin solution and stirred continuously. PBS was added again after stirring to terminate the reaction and obtain a reaction solution; the reaction solution was dialyzed, sterilized by filtration, and freeze-dried to obtain a GelMA prepolymer;

[0014] Then, the GelMA prepolymer was added to the photoinitiator, and the GelMA was dissolved in a warm bath. Then, A549 cells in the logarithmic growth phase were added to form a cell-methacrylated gelatin hydrogel.

[0015] (6) Preparation of spicy taste sensor based on modified glassy carbon electrode:

[0016] Immerse the glassy carbon electrode, platinum wire electrode and reference electrode in the chloroauric acid solution prepared in step (1) for electroplating, and take out the electrodes after treatment and let them air dry naturally;

[0017] The ZrCu-MOF / ILs prepared in step (4) was added to pure water and stirred evenly to obtain a ZrCu-MOF / ILs solution, and the ZrCu-MOF / ILs solution was dropped on a glassy carbon electrode and blown dry with nitrogen. Then, the cell-methacrylated gelatin hydrogel prepared in step (5) was dropped on the glassy carbon electrode and photocured under ultraviolet light to finally form a cell-GelMA hydrogel, thereby obtaining a cell-based three-dimensional spicy taste sensor based on a bimetallic organic framework.

[0018] Preferably, the concentration of HAuCl4 in the mixed solution of step (1) is 5 mmol / L, and the concentration of concentrated sulfuric acid is 0.5 mol / L.

[0019] Preferably, in step (2), the ratio of copper nitrate to pure water is 2.61 g:36 mL, and the amounts of terephthalic acid and anhydrous ethanol are 0.996 g:36 mL; the volume ratio of the copper nitrate solution to the terephthalic acid solution is 1:1, and the stirring time is 1 hour; the heating reaction conditions are 120° C. and 12 hours; the crystal drying conditions are: 80° C. and drying for 12 hours; the obtained sample is immersed in dichloromethane for activation for 24 hours, and the vacuum drying conditions are 150° C. and 12 hours.

[0020] Preferably, in step (3), the amount ratio of zirconium oxychloride octahydrate, N,N-diethylformamide and trifluoroacetic acid is 175 mg:3 mL:0.5 mL; the amount ratio of 4,4'-biphenyldicarboxylic acid:N,N-diethylformamide is 80 mg:3 mL; the volume ratio of solution A and solution B is 1:1; the amount relationship of 4,4'-biphenyldicarboxylic acid and Cu-MOF crystals in solution C is 80 mg:60 mg; the ultrasonic treatment time is 15 minutes, the stirring reaction temperature is 50°C, and the stirring reaction time is 48 hours; the drying conditions are 60°C and 12 hours.

[0021] Preferably, the amount of [BMIM][PF6], acetone and ZrCu-MOF in step (4) is 60 mg:6 mL:0.14 g; the stirring time at room temperature is 1 h; and the drying conditions are 60° C. and 12 h.

[0022] Preferably, the amount of gelatin, PBS, methacrylate anhydride and PBS added again in step (5) is 5g:50mL:4mL:200mL, and the stirring conditions are all 50°C and 2h; the dialysis conditions are 50°C and 7 days; the filtration sterilization is performed by filtering with a 0.22μm membrane filter; and the freeze-drying treatment conditions are -80°C and freeze-drying for 5 days.

[0023] Preferably, the ratio of the amount of GelMA prepolymer to the photoinitiator in step (5) is 0.05 g: 1 mL, wherein the photoinitiator is Irgacure 2959 at a concentration of 0.5% (w / v); the temperature of the warm bath is 40°C; the final density of A549 cells in the cell-methacrylic acid acylated gelatin hydrogel is 10 6 pieces / mL.

[0024] Preferably, the scanning speed of the electroplating treatment in step (6) is 0.05 V / s, and the number of scanning circles is set to 20 circles.

[0025] Preferably, the ratio of ZrCu-MOF / ILs to pure water in step (6) is 1 mg:1 mL; the amount of ZrCu-MOF / ILs solution dropped on the glassy carbon electrode is 5 μl; the amount of cell-methacrylic acid acylated gelatin hydrogel added is 5 μl; the UV curing conditions are: 405 nm, 50 m W / cm 2 , light curing for 30 seconds.

[0026] The three-dimensional cell spiciness sensor prepared by the present invention is used for detecting capsaicin.

[0027] Beneficial effects:

[0028] (1) ZrCu-MOF itself has a high specific surface area, a rich porous structure, and potential catalytic active sites provided by the Zr and Cu bimetallic nodes. These properties are conducive to the effective adsorption and enrichment of capsaicin molecules. The introduction of ionic liquids (ILs) further enhances the conductivity of the composite material and may enhance the specific recognition ability of the electrode interface for capsaicin through its unique ionic environment and hydrogen bonding and π-π stacking interactions with capsaicin molecules, which can greatly reduce the interference of other detection conditions.

[0029] (2) GelMA hydrogel provides a highly biomimetic 3D microenvironment for the embedded A549 lung cancer cells, with excellent hydrophilicity, permeability, and biocompatibility; ensuring the long-term health and function of the living A549 cells, thereby guaranteeing the stability, reliability, and physiological relevance of the cell-based response detection model. It has good prospects in detecting capsaicin content. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is the H NMR spectrum of GelMA.

[0031] Figure 2 TEM image of ZrCu-MOF / ILs.

[0032] Figure 3 CV and EIS characterization of the assembly process of cell electrochemical sensors.

[0033] Figure 4 DPV curve of GelMA-A549 / ZrCu-MOF / ILs / AuNPs / GCE for the detection of capsaicin. DETAILED DESCRIPTION

[0034] The present invention is described in detail below with reference to the accompanying drawings, but the present invention is not limited to these embodiments. It should be noted that those skilled in the art may make various modifications and improvements without departing from the scope of the present invention. Such modifications and improvements are all within the scope of protection of the present invention.

[0035] Example 1:

[0036] (1) Preparation of chloroauric acid solution:

[0037] Measure 1 mL of 50 mmol / L chloroauric acid and 272 μL of concentrated sulfuric acid into a 10 mL volumetric flask, dilute to the mark with deionized water, and shake well to obtain a mixed solution; the final concentration of HAuCl4 in the mixed solution is 5 mmol / L, and the final concentration of concentrated sulfuric acid is 0.5 mol / L;

[0038] (2) Synthesis of Cu-MOF:

[0039] 2.61g of Cu(NO3)2·3H2O was dissolved in 36mL of pure water to obtain a copper nitrate solution; 0.996g of terephthalic acid was dissolved in 36mL of anhydrous ethanol to obtain a terephthalic acid solution; then, the copper nitrate solution was mixed with the terephthalic acid solution in a volume ratio of 1:1 and stirred for 1h. The mixture was then placed in a polytetrafluoroethylene-lined stainless steel hydrothermal reactor and heated at 120°C for 12h. After the reaction, the crystals were collected and dried at 80°C for 12h to obtain a sample; then, the sample was immersed in dichloromethane for activation for 24h and then vacuum dried at 150°C for 12h to finally obtain Cu-MOF crystals;

[0040] (3) Synthesis of ZrCu-MOF:

[0041] 175 mg of zirconium oxychloride octahydrate was added to a solution containing 3 mL of N,N-diethylformamide and 0.5 mL of trifluoroacetic acid to obtain solution A; 80 mg of 4,4'-biphenyldicarboxylic acid was dissolved in 3 mL of N,N-diethylformamide in another beaker to obtain solution B. Solution A and solution B were ultrasonically treated for 15 minutes respectively. After treatment, solution A and solution B were combined in a volume ratio of 1:1, and 60 mg of the Cu-MOF crystal obtained in step (2) was added and ultrasonicated for a second time for 15 minutes. The mixture was stirred at 50°C for 48 hours and then centrifuged to collect the precipitate; the precipitate was washed with dimethylformamide and anhydrous ethanol to remove the residual precursor, and finally dried at 60°C for 12 hours to obtain ZrCu-MOF;

[0042] (4) Preparation of ZrCu-MOF / ILs:

[0043] 60 mg of [BMIM][PF6] was dissolved in 6 mL of acetone; then, 0.14 g of ZrCu-MOF prepared in step (3) was added and stirred at room temperature until the acetone was completely evaporated. Finally, the mixture was dried in an oven at 60 ° C for 12 h to obtain the dry product, namely ZrCu-MOF- / ILs; TEM image is shown as follows Figure 2 As shown, it is a quadrilateral.

[0044] (5) Preparation of cell-methacrylic acid acylated gelatin hydrogel:

[0045] 5 g of gelatin was dissolved in 50 mL of PBS and stirred gently to obtain a gelatin solution. Then, 4 mL of methacrylate anhydride was added dropwise and stirred at 50°C for 2 h. After stirring, 200 mL of 50°C PBS solution was added to dilute the solution to terminate the reaction and obtain a reaction solution. The reaction solution was dialyzed at 50°C for 7 days. After dialysis, the dialyzate was sterilized by passing through a 0.22 μm membrane filter and freeze-dried at -80°C for 5 days to obtain a GelMA prepolymer. The H NMR spectrum was as follows: Figure 1 shown.

[0046] 0.05 g of GelMA prepolymer was added to 1 mL of 0.5% (w / v) photoinitiator Irgacure 2959 and dissolved in a 40°C warm bath. Then, A549 cells in the logarithmic growth phase were added to form a cell density of 10 6 cells / mL of cell-methacrylated gelatin hydrogel.

[0047] (6) Preparation of spicy taste sensor based on modified glassy carbon electrode:

[0048] The glassy carbon electrode, platinum wire electrode and reference electrode were immersed in the chloroauric acid solution prepared in (1). The scanning speed of electroplating was 0.05 V / s, the number of scanning circles was set to 20 circles, and the electrodes were naturally air-dried.

[0049] 1 mg of ZrCu-MOF / ILs was weighed and dissolved in 1 mL of pure water, stirred evenly to obtain a ZrCu-MOF / ILs solution; 5 μl of the ZrCu-MOF / ILs solution was dropped on a glassy carbon electrode and dried with nitrogen; then 5 μl of the cell-methacrylic acid acylated gelatin hydrogel prepared in step (5) was dropped on the glassy carbon electrode and the solution was observed under ultraviolet light of 405 nm and 50 mW / cm 2 The mixture was photocured for 30 seconds to form a cell-GelMA hydrogel, and a cell-based three-dimensional spicy taste sensor based on a bimetallic organic framework was obtained, which was named GelMA-A549 / ZrCu-MOF / ILs / AuNPs / GCE cell electrochemical sensor.

[0050] Performance testing:

[0051] 1. CV and EIS characterization of the assembly process of the cell electrochemical sensor prepared in Example 1

[0052] (1) Figure 3 In Figure A, bare GCE (a), AuNPs / GCE (b), ZrCu-MOF / ILs / AuNPs / GCE (c) and GelMA-A549 / ZrCu-MOF / ILs / AuNPs / GCE (d) in the presence of 5 mM Fe(CN)6 3- / 4- There are obvious redox peaks in both (e) and (f), which proves their good electrical conductivity, while ZrCu-MOF / AuNPs / GCE (e) and GelMA-A549 / ZrCu-MOF / AuNPs / GCE (f) have no redox peaks, which is attributed to the poor conductivity caused by the high resistance of MOF structure.

[0053] (2) Figure 3The EIS data in Figure B is intuitively presented in the form of a Nyquist plot, where the Nyquist curve consists of two parts: a flat semicircle in the high-frequency region and a straight line in the low-frequency region. The flat semicircle part deeply reflects the electron transfer kinetics between the electrode and electrolyte interface, while the charge transfer resistance (Rct) is accurately quantified by the difference between the flat semicircle and the real axis intercept. Figure 3 In Figure B, the Rct of the bare GCE was estimated to be 105.24Ω, while that of the AuNPs / GCE was estimated to be 80.63Ω, indicating the good conductivity of AuNPs. The ZrCu-MOF / AuNPs / GCE resistance was estimated to be 1493.8Ω, and after loading with cells, the resistance reached 2225.39Ω. In contrast, the resistance of the ZrCu-MOF / ILs / AuNPs / GCE was only 358.01Ω, and when loaded with cells, the resistance dropped to 667.23Ω due to the insulating effect of the cells.

[0054] 2. Feasibility analysis of capsaicin detection using the GelMA-A549 / ZrCu-MOF / ILs / AuNPs / GCE cell electrochemical sensor prepared in Example 1

[0055] The GelMA-A549 / ZrCu-MOF / ILs / AuNPs / GCE cell electrochemical sensor was placed in different concentrations of capsaicin for DPV detection. Figure 4 As can be seen, as the capsaicin concentration gradually increases from 0, 10 μM, and 20 μM, the response current also increases. This is because, after cells are stimulated by pungent ingredients, they undergo varying degrees of cell contraction and apoptosis, accelerating electron transfer on the electrode surface and significantly increasing the DPV signal. This demonstrates that the GelMA-A549 / ZrCu-MOF / ILs / AuNPs / GCE prepared in this invention can be used to detect capsaicin concentration.

[0056] Note: The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. Therefore, although this specification has described the present invention in detail with reference to the above embodiments, it should be understood by those skilled in the art that the present invention may still be modified or replaced by equivalents. All technical solutions and improvements that do not depart from the spirit and scope of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for preparing a cell-based three-dimensional spicy taste sensor based on a bimetallic organic framework, characterized in that: The following steps are involved: (1) preparing a chloroauric acid solution: mixing chloroauric acid and concentrated sulfuric acid, adding deionized water, and mixing uniformly to obtain a mixed solution; (2) Preparation of Cu-MOF: copper nitrate is dissolved in pure water to obtain a copper nitrate solution; terephthalic acid is dissolved in anhydrous ethanol to obtain a terephthalic acid solution; then, the copper nitrate solution is added to the terephthalic acid solution, stirred to obtain a mixed solution, and placed in a reactor for heating reaction. After the reaction, the crystals are collected and dried to obtain a sample; Afterwards, the sample was immersed in dichloromethane for activation and then vacuum dried to obtain Cu-MOF crystals. (3) Preparation of ZrCu-MOF: adding zirconium oxychloride octahydrate to a mixed solution containing N,N-diethylformamide and trifluoroacetic acid to obtain solution A; dissolving 4,4'-biphenyldicarboxylic acid in N,N-diethylformamide to obtain solution B; ultrasonically treating solution A and solution B respectively; combining solution A and solution B after treatment to obtain solution C; adding the Cu-MOF crystal obtained in step (2) to solution C for a second ultrasonic treatment; stirring the reaction after treatment; collecting the precipitate by centrifugation after the reaction, washing with dimethylformamide and anhydrous ethanol, and finally drying to obtain ZrCu-MOF; (4) Preparation of ZrCu-MOF / ILs: [BMIM][PF6] was dissolved in acetone, and then the ZrCu-MOF obtained in step (3) was added and stirred at room temperature. After stirring, the mixture was dried to obtain a dry product, namely ZrCu-MOF / ILs; (5) Preparation of cell-methacrylic acid acylated gelatin hydrogel: gelatin was dissolved in PBS and stirred to obtain a gelatin solution; methacrylic acid anhydride was then added dropwise to the gelatin solution and stirred continuously. PBS was added again after stirring to terminate the reaction and obtain a reaction solution; The reaction solution was dialyzed, sterilized by filtration, and freeze-dried to obtain a GelMA prepolymer; Then, GelMA prepolymer was added to the photoinitiator, GelMA was dissolved in a warm bath, and then A549 cells in the logarithmic growth phase were added to form a cell-methacrylated gelatin hydrogel; (6) Preparation of spicy taste sensor based on modified glassy carbon electrode: Immerse the glassy carbon electrode, platinum wire electrode and reference electrode in the chloroauric acid solution prepared in step (1) for electroplating, and take out the electrodes after treatment and let them air dry naturally; The ZrCu-MOF / ILs prepared in step (4) was added to pure water and stirred to obtain a ZrCu-MOF / ILs solution. The ZrCu-MOF / ILs solution was dropped onto a glassy carbon electrode and dried with nitrogen gas; Then, the cell-methacrylated gelatin hydrogel prepared in step (5) is dropped onto the glassy carbon electrode and photocured under ultraviolet light to finally form the cell-GelMA hydrogel, thereby obtaining a cell-based three-dimensional spicy taste sensor based on a bimetallic organic framework.

2. The method for preparing a cell-based three-dimensional spicy taste sensor based on a bimetallic organic framework according to claim 1, characterized in that: The concentration of HAuCl4 in the mixed solution of step (1) is 5 mmol / L, and the concentration of concentrated sulfuric acid is 0.5 mol / L.

3. The method for preparing a cell-based three-dimensional spicy taste sensor based on a bimetallic organic framework according to claim 1, characterized in that: In step (2), the ratio of copper nitrate to pure water is 2.61 g:36 mL, and the amounts of terephthalic acid and anhydrous ethanol are 0.996 g:36 mL; the volume ratio of the copper nitrate solution to the terephthalic acid solution is 1:1, and the stirring time is 1 hour; the heating reaction conditions are 120° C. and 12 hours; the crystal drying conditions are: 80° C. and drying for 12 hours; the obtained sample is immersed in dichloromethane for activation for 24 hours, and the vacuum drying conditions are 150° C. and 12 hours.

4. The method for preparing a cell-based three-dimensional spicy taste sensor based on a bimetallic organic framework according to claim 1, characterized in that: The amount ratio of zirconium oxychloride octahydrate, N,N-diethylformamide and trifluoroacetic acid in step (3) is 175 mg:3 mL:0.5 mL; the amount ratio of 4,4'-biphenyldicarboxylic acid:N,N-diethylformamide is 80 mg:3 mL; the volume ratio of solution A and solution B is 1:1; the amount relationship of 4,4'-biphenyldicarboxylic acid and Cu-MOF crystals in solution C is 80 mg:60 mg; the ultrasonic treatment time is 15 minutes, the stirring reaction temperature is 50°C, and the stirring reaction time is 48 hours; the drying conditions are 60°C and 12 hours.

5. The method for preparing a cell-based three-dimensional spicy taste sensor based on a bimetallic organic framework according to claim 1, characterized in that: The dosage of [BMIM][PF6], acetone and ZrCu-MOF in step (4) is 60 mg:6 mL:0.14 g; the stirring time at room temperature is 1 h; and the drying conditions are 60° C. and 12 h.

6. The method for preparing a cell-based three-dimensional spicy taste sensor based on a bimetallic organic framework according to claim 1, characterized in that: In step (5), the amount of gelatin, PBS, methacrylate anhydride and PBS added again is 5g:50mL:4mL:200mL, and the stirring conditions are all 50°C for 2h; the dialysis conditions are 50°C for 7 days; the filtration sterilization is performed by filtering with a 0.22μm membrane filter; the freeze-drying conditions are -80°C and freeze-dried for 5 days.

7. The method for preparing a cell-based three-dimensional spicy taste sensor based on a bimetallic organic framework according to claim 1, characterized in that: In step (5), the ratio of GelMA prepolymer to photoinitiator was 0.05 g:1 mL, wherein the photoinitiator was Irgacure 2959 at a concentration of 0.5% (w / v); the temperature of the warm bath was 40°C; the final density of A549 cells in the cell-methacrylic acid acylated gelatin hydrogel was 10 6 pieces / mL.

8. The method for preparing a cell-based three-dimensional spicy taste sensor based on a bimetallic organic framework according to claim 1, characterized in that: The scanning speed of the electroplating treatment in step (6) is 0.05 V / s, and the number of scanning circles is set to 20 circles.

9. The method for preparing a cell-based three-dimensional spicy taste sensor based on a bimetallic organic framework according to claim 1, characterized in that: The ratio of ZrCu-MOF / ILs to pure water in step (6) is 1 mg:1 mL; the amount of ZrCu-MOF / ILs solution dropped on the glassy carbon electrode is 5 μl; the amount of cell-methacrylic acid acylated gelatin hydrogel added is 5 μl; the UV curing conditions are: 405 nm, 50 m W / cm 2 , light curing for 30 seconds.

10. Use of the cellular three-dimensional spicy taste sensor prepared according to the method of any one of claims 1 to 9 for detecting capsaicin.

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