Preparation method of three-mode sensor based on multifunctional Au (at) CeO2 and AuPt (at) Zn-C composite material

Abstract

The invention designs a preparation method of a three-mode sensor based on a multifunctional Au (at) CeO2 and AuPt (at) Zn-C composite material. A double-chain structure formed by an aptamer chain and a complementary chain is connected to the surface of the magnetic bead, and when beta-lactoglobulin exists, the complementary chain falls off due to specific binding of the aptamer. In an electrochemical mode, a high-conductivity AuPt-coated Zn-C modified electrode is used, a complementary chain is combined with a DNA hairpin HP1 connected to the surface of the electrode and sheared under the action of Exo III, and MB / S1-Au-coated CeO2 is connected to the surface of the electrode through a part of left single-chain structures. In a blood glucose meter and a colorimetric mode, a complementary chain in an unopened double-chain structure is subjected to a hybridization chain reaction after HP2-Au at CeO2 and HP3 are added, cascade catalysis is carried out after a glucose solution is added, the change of the glucose concentration is caused, and a colorimetric reaction is further carried out. The beta-lactoglobulin is detected through electrochemical-glucometer-colorimetric signal responses, and the method has the advantages of being good in specificity, high in accuracy and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of food safety detection, and in particular to a method for preparing a three-mode sensor based on a multifunctional Au@CeO2 and AuPt@Zn-C composite material. Background Art

[0002] Food allergy is a global public health concern. It is an immune response triggered by the ingestion of food protein antigens, involving both specific immunoglobulin E-mediated and non-immunoglobulin E-mediated immune mechanisms. Cow's milk, one of the eight major food allergens listed by the Food and Agriculture Organization (FAO), causes approximately one-third of allergic reactions. β-Lactoglobulin (β-LG) is the primary allergen in milk, accounting for 10% of total milk protein and 60% of total whey protein. A milk-specific protein synthesized by mammary epithelial cells, β-LG consists of an α-helix and nine antiparallel β-sheets, forming a calyx-shaped β-barrel structure with two disulfide bonds and a free cysteine ​​residue. As a protein relatively resistant to acid hydrolysis and protease activity, β-LG retains a certain degree of activity after digestion. After digestion and absorption, relatively intact β-LG and peptide fragments remain in the body, leading to allergic reactions. Since food allergies are incurable, the only option for people with milk allergies is to avoid exposure to the triggering ingredient. Therefore, it is of great significance to develop a convenient, accurate and efficient method for β-LG detection.

[0003] Traditional methods for detecting β-LG include chromatography, enzyme-linked immunosorbent assay (ELISA), capillary electrophoresis, and molecular imprinting. Although these traditional methods have high accuracy and sensitivity, they also have disadvantages such as high cost, complex pre-treatment, poor stability, false positives, and false negatives. Aptamers are a class of single-stranded oligonucleotides with strong affinity and specificity. They are obtained in vitro through exponential enrichment ligand system evolution technology and have the advantages of being easy to synthesize and modify. Composite nanomaterials have obtained richer functions and more excellent properties, such as conductivity, catalytic activity, and biocompatibility, by combining different nanomaterials. Biosensors that combine aptamers Apt and nanomaterials have good specificity, stability, and sensitivity, and are a β-LG detection method with broad application prospects.

[0004] To further improve the sensor's detection performance for β-LG, this method constructed a trimodal sensor: electrochemical, blood glucose meter, and colorimetric. The multifunctional Au@CeO2 substrate, which exhibits dual nanoenzyme activity of glucose oxidase and peroxidase to generate both blood glucose meter and colorimetric signals, also has a large relative surface area capable of loading a large number of signal molecules to generate electrochemical signals. AuPt@Zn-C was used as the electrode modification material to enhance the sensing performance of the electrode surface. Simultaneously, the combination of exonuclease III (Exo III) and hybridization chain reaction (HCR) further improved the sensor's sensitivity and accuracy. The trimodal sensor based on the present invention exhibits excellent selectivity, strong stability, and high sensitivity, facilitating its widespread application. Summary of the Invention

[0005] A method for preparing a tri-mode sensor based on a multifunctional Au@CeO2 and AuPt@Zn-C composite material is carried out according to the following steps: (1) Preparation of CeO2: Cerium nitrate hexahydrate and polyvinylpyrrolidone were dissolved in ethylene glycol, hydrochloric acid solution was added and ultrasonic treatment was performed, the solution was transferred to an autoclave, and the reaction was followed by high-speed centrifugation to collect the product, which was then centrifuged to remove the unreacted solvent and dried under vacuum at a constant temperature to a constant weight to obtain CeO2; (2) Preparation of multifunctional Au@CeO2 and signal probe: CeO2 was ultrasonically dispersed in water, chloroauric acid solution was added under stirring, and after mixing evenly, sodium hydroxide solution was added to adjust the pH. Stirring was continued, and the product was collected by high-speed centrifugation and washed to remove the unreacted solvent. The product was dried under vacuum at a constant temperature to a constant weight to obtain multifunctional Au@CeO2; Au@CeO2 was incubated with DNA chain S1, methylene blue MB, and DNA hairpin HP2, respectively, and combined to form signal probes MB / S1-Au@CeO2 and HP2-Au@CeO2; (3) Preparation of Zn-C: Zinc nitrate hexahydrate and 2-methylimidazole were dissolved in equal volumes of methanol, stirred, and then allowed to stand for aging. The product was collected by high-speed centrifugation and washed by centrifugation to remove unreacted solvent. The product was dried at a constant temperature under vacuum to a constant weight to obtain the precursor ZIF-8. ZIF-8 was calcined at a high temperature to obtain the derived carbon material Zn-C. (4) Preparation of AuPt@Zn-C composite material: Zn-C was ultrasonically dispersed in water, and equal volumes of chloroauric acid solution and chloroplatinic acid solution were added under magnetic stirring. After mixing, the reducing agent was slowly added with continuous stirring. The product was collected by high-speed centrifugation and washed to remove the unreacted solvent. The product was then dried under vacuum at a constant temperature to a constant weight to obtain the AuPt@Zn-C composite material. (5) Construction of the tri-mode sensor: First, a magnetic separation system was constructed. The aptamer Apt was connected to the surface of the magnetic beads through the specific binding of streptavidin and biotin. Then, the complementary chain cDNA was added and incubated to form a double-stranded structure. When the target β-LG was present, the specific binding of β-LG and the aptamer Apt would cause the complementary chain cDNA to fall off. After magnetic separation, free complementary chain cDNA existed in the supernatant and unopened double-stranded structure existed in the precipitate. In the electrochemical mode, the AuPt@Zn-C composite material was first added to the surface of the gold electrode. Then, the DNA hairpin HP1 was added and incubated to connect it to the electrode surface through gold-sulfur bonds and platinum-sulfur bonds. The supernatant and Exo III were added to the electrode surface. Exo III will cut the part where the complementary chain cDNA and DNA hairpin HP1 are bound and eventually leave a single-stranded structure that is not cut on the electrode surface. After adding the signal probe MB / S1-Au@CeO2, the electrochemical signal is measured using square wave voltammetry. In the blood glucose meter and colorimetric mode, the signal probe HP2-Au@CeO2 and DNA hairpin HP3 are added to the precipitate and incubated to produce HCR reaction. After magnetic separation, glucose solution is added to the precipitate. After incubation, magnetic separation is performed again and the supernatant is collected. The change in glucose concentration is directly measured using a blood glucose meter, and 3,3',5,5'-tetramethylbenzidine (TMB) and Au@CeO2 are added to produce a color reaction to measure the change in absorbance.

[0006] It is further defined that in step (1), the ultrasonic treatment time is 20 to 40 minutes; the reaction temperature in the high-pressure reactor is 140 to 180° C., and the reaction time is 2 to 4 hours.

[0007] It is further defined that in step (2), the mass of CeO2 dispersed in water is 30 to 50 mg; the volume of the chloroauric acid solution is 1 to 3 mL; the pH value is 9 to 13; the concentrations of the DNA chain S1 and the DNA hairpin HP2 are 1 to 2 μM; and the concentration of methylene blue MB is 5 to 10 mM.

[0008] It is further defined that in step (3), the mass ratio of zinc nitrate hexahydrate to 2-methylimidazole is 1:4 to 1:6; the static aging time is 12 to 24 hours; and the high-temperature calcination temperature is 400 to 800°C and the time is 2 to 6 hours.

[0009] It is further defined that in step (4), the mass of Zn-C dispersed in water is 2 to 5 mg; the volume of chloroauric acid and chloroplatinic acid is 150 μL to 250 μL; and the reducing agent is sodium borohydride.

[0010] It is further defined that in step (5), the volume of the magnetic beads is 2 to 10 μL; the concentrations of the aptamer Apt and the complementary chain cDNA are 1 to 2 μM; the volume of the AuPt@Zn-C added to the electrode surface is 2 to 8 μL; and the concentrations of the DNA hairpins HP1 and HP3 are 1 to 2 μM.

[0011] It is further defined that in the steps (2) and (5), the incubation time is 0.5 to 8 h; the incubation temperature is 20 to 50°C; the sequence of the DNA chain S1 is 5'-ATG TTA GCA GGA AAA A -3', wherein the 5' end is modified with a thiol group; the sequence of the DNA hairpin HP2 is 5'-ACA GGA GAG TGT GAT GCT CTC CTG TCC TA -3', wherein the 5' end is modified with a thiol group; the sequence of the aptamer Apt is 5'-CGA CGA TCG GAC CGC AGT ACC CAC CCA CCA GCC CCA ACA TCA TGC CCATCC GTG TGT G -3', wherein the 3' end is modified with biotin; the sequence of the complementary chain cDNA is 5'-CTC TAC CAT GTCGCG GTC CGA TCG TCG TAG GAC AGG AGA GCA T -3'; the sequence of the DNA hairpin HP1 is 5'-AAA CGTCCT GCT AAC ATG AAA AAC ATG TTA GCA GGA CGG ACA TGG TAG AG -3', wherein the 5' end is modified with a sulfhydryl group; the sequence of the DNA hairpin HP3 is 5'- CAC ACT CTC CTG TAT AGG ACA GGA GAG CAT -3'. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 Schematic diagram of a tri-mode sensor based on multifunctional Au@CeO2 and AuPt@Zn-C composite materials.

[0013] Figure 2 This is the signal response diagram of the tri-mode sensor constructed in Example 1 of the present invention before and after the addition of 50 ng / mL β-LG.

[0014] Figure 3 This is the standard curve for detecting β-LG using the three-mode sensor constructed in Example 1 of the present invention.

[0015] Figure 4 This is the specificity of the tri-mode sensor constructed in Example 1 of the present invention for β-LG in the presence of other interfering factors. DETAILED DESCRIPTION

[0016] The specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings and specific examples, but it should be understood that the scope of protection of the present invention is not limited by the specific embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. The experimental methods described in the embodiments of the present invention are all conventional methods unless otherwise specified. Example

[0017] A method for preparing a three-mode sensor based on a multifunctional Au@CeO2 and AuPt@Zn-C composite material, the implementation method of which is as follows Figure 1 shown.

[0018] A method for preparing a tri-mode sensor based on a multifunctional Au@CeO2 and AuPt@Zn-C composite material comprises the following steps: (1) Preparation of CeO2: 1 g of cerium nitrate hexahydrate and 0.4 g of polyvinylpyrrolidone were completely dissolved in 30 mL of ethylene glycol solution. 2 mL of 1 M hydrochloric acid solution was added and ultrasonicated for 30 min. The solution was transferred to an autoclave and reacted at 160°C for 3 h. The product was collected by centrifugation at 8000 rpm for 5 min and washed with water and ethanol to remove the unreacted solvent. The product was dried in a vacuum oven at 60°C for 12 h to obtain CeO2.

[0019] (2) Preparation of multifunctional Au@CeO2 and signal probe: 40 mg CeO2 was ultrasonically dispersed in 40 mL water, and 2 mL of 25 mM chloroauric acid solution was added under stirring. After mixing, the pH was adjusted to 12 with 1 M sodium hydroxide solution, and stirring was continued for 4 h. The product was collected by centrifugation at 8000 rpm for 5 min and washed with water to remove the unreacted solvent. It was dried in a vacuum drying oven at 60 °C for 12 h to obtain Au@CeO2; 200 μL of 2 mg / mL Au@CeO2 was incubated with 200 μL of 2 μM DNA chain S1 at 37 °C for 2 h, centrifuged, and 200 μL of 10 mM methylene blue MB was added and incubated for 6 h, centrifuged again, and 200 μL of buffer solution was added to obtain the signal probe MB / S1-Au@CeO2; 200 μL of 2 mg / mL Au@CeO2 was incubated with 200 μL of 2 μM DNA hairpin HP2 at 37 °C for 2 h. h, and after centrifugation, 200 μL of buffer solution was added to obtain the signal probe HP2-Au@CeO2.

[0020] (3) Preparation of Zn-C: 0.6375 g of zinc nitrate hexahydrate and 3.1875 g of 2-methylimidazole were dissolved in 15 mL of methanol, stirred and mixed, and then aged at room temperature for 24 h. The product was collected by centrifugation at 8000 rpm for 5 min, washed with methanol to remove the unreacted solvent, and dried in a vacuum drying oven at 60°C for 12 h to obtain the precursor material ZIF-8; ZIF-8 was calcined at 600°C for 180 min to obtain the derived carbon material Zn-C.

[0021] (4) Preparation of AuPt@Zn-C composite material: 3 mg Zn-C was ultrasonically dispersed in 1 mL water. 200 μL 25 mM chloroauric acid and 200 μL 25 mM chloroplatinic acid were added under magnetic stirring and stirred for 20 min. After mixing, 2 mL 0.1 M sodium borohydride solution was added and stirring was continued for 30 min. The product was collected by centrifugation at 8000 rpm for 10 min, washed with ultrapure water to remove unreacted solvent, and dried in a vacuum drying oven at 60 °C for 12 h to obtain the AuPt@Zn-C composite material.

[0022] (5) Construction of the three-mode sensor: First, 5 μL of magnetic beads MBs and 10 μL of 4 μM aptamer Apt were incubated at 37°C for 1 h. The aptamer Apt was connected to the surface of the magnetic beads MBs through the specific binding of streptavidin and biotin. After magnetic separation, 20 μL of 2 μM complementary chain cDNA was added to the precipitate and incubated at 37°C for 1 h to form a double-stranded structure. After magnetic separation, 20 μL of β-LG was added to the precipitate and incubated at 37°C for 1 h. The specific binding of β-LG and aptamer Apt caused the complementary chain cDNA to fall off. After magnetic separation, free complementary chain cDNA existed in the supernatant and unreleased double-stranded structure existed in the precipitate. In the electrochemical mode, 5 μL of AuPt@Zn-C composite material was first added to the pretreated gold electrode surface and incubated at 37°C for 1 h. 5 μL of 2 μM DNA hairpin HP1 was added and incubated at 37°C for 1.5 h. h to connect it to the electrode surface through gold-sulfur bonds and platinum-sulfur bonds; 5 μL 0.1 mM MCH blocking agent was added and incubated at 37°C for 1 h; 5 μL supernatant and 2 μL 5U / μL Exo III were added dropwise to the electrode surface and incubated at 37°C for 1 h. The complementary chain cDNA and DNA hairpin HP1 were partially bound and cut by Exo III, leaving a partially uncut single-stranded structure on the electrode surface; 5 μL signal probe MB / S1-Au@CeO2 was added and incubated at 37°C for 1 h, and finally the electrochemical signal was measured by square wave voltammetry; in the blood glucose meter and colorimetric mode, 40 μL signal probe HP2-Au@CeO2 and 40 μL 2 μM DNA hairpin HP3 were added to the precipitate and incubated at 37°C for 2 h to produce HCR reaction. After magnetic separation, 1 mL 50 mg / mL glucose solution was added to the precipitate, incubated at 50°C for 2 h, and magnetic separation was performed again to collect the supernatant; 1 The change in glucose concentration was directly measured using a blood glucose meter from 20 μL of supernatant. 20 μL of supernatant was added with 20 μL of 20 mM TMB, 7 μL of 2 mg / mL Au@CeO2, and 153 μL of acetate buffer solution. The reaction was carried out in a 37°C water bath for 10 min, and the change in absorbance was measured.

[0023] (6) Establishment of standard curve: β-LG standard solutions of different concentrations were added to step (5), and electrochemical-glucose meter-colorimetric tri-mode signals were obtained through subsequent reactions. The logarithmic value of β-LG concentration was used as the horizontal axis and the signal value as the vertical axis for linear fitting to establish the standard curve of the tri-mode sensor for β-LG.

[0024] like Figure 2 , which is a signal response diagram of the tri-mode sensor constructed in Example 1 of the present invention before and after the addition of 50 ng / mL β-LG.

[0025] like Figure 3As shown, this is the standard curve for detecting β-LG using the three-mode sensor constructed in Example 1 of the present invention. Example

[0026] A method for preparing a tri-mode sensor based on a multifunctional Au@CeO2 and AuPt@Zn-C composite material, and its practical application, comprises the following steps: (1) In order to verify that the prepared trimodal sensor based on the multifunctional Au@CeO2 and AuPt@Zn-C composite material has specific recognition for β-LG, the β-LG standard was accurately weighed and dissolved in ultrapure water to make the concentration of β-LG in the sample 50 ng / mL; ultrapure water or Tris-HCl buffer solution was used to prepare other interfering substance standard solutions, and the concentration was 50 ng / mL. The above different standards were detected according to the detection system constructed in Example 1, and the results are shown as follows: Figure 4 As shown, it is shown that the method of the present invention has good specificity for β-LG. Example

[0027] A method for preparing a tri-mode sensor based on a multifunctional Au@CeO2 and AuPt@Zn-C composite material is described. The practical application thereof is carried out according to the following steps: (1) Food sample processing: Accurately weigh 1 mg of solid sample amino acid formula milk powder and dissolve it in 1 mL of ultrapure water. Then, take 1 μL and mix it with 999 μL of ultrapure water. Finally, take 100 μL of the mixed solution and mix it with 900 μL of ultrapure water. Take 100 μL of the above mixed solution and mix it with 100 μL of β-LG standard samples of different concentrations to obtain milk powder spiked samples.

[0028] (2) Sample detection: The three-mode signal was measured according to the steps of Example 1 and the concentration of β-LG in the sample was obtained by substituting the standard curve into the signal.

[0029] (3) When amino acid formula milk powder was used as the actual sample for measurement, different concentrations of β-LG standard were added to the sample. 20 μL of sample solution was taken, and the three-mode signal was measured according to steps (1) to (5) of Example 1. The standard curve detected in Example 1 was used to obtain the β-LG concentration in the sample. Each sample was measured three times and the average value was taken. The average recovery rate was calculated to be 94.73%-104.33%.

[0030] The prepared trimodal sensor has been verified to have the advantages of simple operation, good stability, high specificity and wide detection range for the detection of β-LG. The detection of actual samples shows that the prepared trimodal sensor has good practical application value.

[0031] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above-described embodiments. The above-described embodiments and descriptions are merely illustrative of the principles of the present invention and do not limit the present invention in any way. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a tri-mode sensor based on a multifunctional Au@CeO2 and AuPt@Zn-C composite material, characterized in that: The following steps are involved: (1) Preparation of multifunctional Au@CeO2 and signal probe: Cerium nitrate hexahydrate and polyvinylpyrrolidone were dissolved in ethylene glycol, hydrochloric acid was added and ultrasonic treatment was carried out, and then the mixture was transferred to a high-pressure reactor for high-temperature reaction to obtain CeO2; CeO2 was dispersed in water and chloroauric acid solution was added under stirring, and sodium hydroxide solution was added to adjust the pH after mixing. After continued stirring, the mixture was centrifuged and dried to obtain multifunctional Au@CeO2, which has both glucose oxidase activity and peroxidase activity and has a rich relative surface area for loading methylene blue MB; Au@CeO2 was incubated with DNA chain S1, methylene blue MB and DNA hairpin HP2, respectively, to form signal probes MB / S1-Au@CeO2 and HP2-Au@CeO2; (2) Preparation of AuPt@Zn-C composite material: Zinc nitrate hexahydrate and 2-methylimidazole were dissolved in equal volumes of methanol, stirred, and then allowed to stand for aging to obtain the precursor ZIF-8. ZIF-8 was calcined at high temperature to obtain the derived carbon material Zn-C; Zn-C was ultrasonically dispersed in water, and equal volumes of chloroauric acid solution and chloroplatinic acid solution were added under magnetic stirring. After thorough mixing, a reducing agent was added and stirring was continued to obtain a highly conductive AuPt@Zn-C composite material; (3) Construction of a three-mode sensor: First, the aptamer Apt is connected to the surface of the magnetic beads through the specific binding of streptavidin and biotin, and the complementary chain cDNA is added and incubated to form a double-stranded structure. When the target β-lactoglobulin is present, the aptamer Apt and β-lactoglobulin preferentially bind specifically and cause the complementary chain cDNA to fall off. After magnetic separation, free complementary chain cDNA exists in the supernatant and unopened double-stranded structure exists in the precipitate. In the electrochemical mode, the AuPt@Zn-C composite material is dropped on the pretreated gold electrode surface, and the DNA hairpin HP1 is added to connect to the modified material through gold-sulfur bonds and platinum-sulfur bonds. The supernatant and Exo ExoIII was added to the electrode surface, where the complementary cDNA and DNA hairpin HP1 bound and were subsequently cleaved by ExoIII, ultimately leaving a partially single-stranded structure on the electrode surface. After the addition of the signal probe MB / S1-Au@CeO2, the electrochemical signal was measured using square wave voltammetry. In the blood glucose meter and colorimetric modes, the signal probe HP2-Au@CeO2 and the DNA hairpin HP3 were added to the precipitate to undergo a hybridization chain reaction. After magnetic separation, the glucose solution was added to the precipitate. After incubation, magnetic separation was repeated and the supernatant was collected. The change in glucose concentration was directly measured using a blood glucose meter, and 3,3',5,5'-tetramethylbenzidine was added to react with Au@CeO2 to produce a colorimetric reaction, which was then used to measure the change in absorbance. By using the multifunctional Au@CeO2 and highly conductive AuPt@Zn-C composite material and introducing two cyclic amplification strategies, ExoIII and hybridization chain reaction, an electrochemical-blood glucose meter-colorimetric tri-mode sensor was constructed for the detection of β-lactoglobulin.

2. The method for preparing a triple-mode sensor based on a multifunctional Au@CeO2 and AuPt@Zn-C composite material according to claim 1, characterized in that: In step (1), the ultrasonic treatment time is 20 to 40 min; the reaction temperature in the high-pressure reactor is 140 to 180°C, and the reaction time is 2 to 4 h; the mass of CeO2 dispersed in water is 30 to 50 mg; the volume of the chloroauric acid solution is 1 to 3 mL; the pH value is 9 to 13; the concentrations of the DNA chain S1 and the DNA hairpin HP2 are 1 to 2 μM; and the concentration of methylene blue MB is 5 to 10 mM.

3. The method for preparing a triple-mode sensor based on a multifunctional Au@CeO2 and AuPt@Zn-C composite material according to claim 1, characterized in that: In step (2), the mass ratio of zinc nitrate hexahydrate to 2-methylimidazole is 1:4 to 1:6; the static aging time is 12 to 24 hours; the high-temperature calcination temperature is 400 to 800°C and the time is 2 to 6 hours; the mass of Zn-C dispersed in water is 2 to 5 mg; the volume of chloroauric acid and chloroplatinic acid is 150 μL to 250 μL; and the reducing agent is sodium borohydride.

4. The method for preparing a triple-mode sensor based on a multifunctional Au@CeO2 and AuPt@Zn-C composite material according to claim 1, wherein: In step (3), the volume of the magnetic beads is 2 ~ 10 μL; the concentrations of the aptamer Apt and the complementary chain cDNA are 1 ~ 2 μM; the volume of AuPt@Zn-C added to the electrode surface is 2 ~ 8 μL; and the concentrations of the DNA hairpins HP1 and HP3 are 1 ~ 2 μM.

5. The method for preparing a tri-mode sensor based on a multifunctional Au@CeO2 and AuPt@Zn-C composite material according to claim 1, characterized in that: In steps (1) and (3), the incubation time is 0.5 to 8 hours and the incubation temperature is 20 to 50°C.

6. The method for preparing a triple-mode sensor based on a multifunctional Au@CeO2 and AuPt@Zn-C composite material according to claim 1, characterized in that: In step (1), the DNA chain S1 is as shown in SEQ ID NO. 1, and the specific sequence is 5'-ATG TTA GCA GGA AAA A -3', wherein the 5' end is modified with a thiol group; the DNA hairpin HP2 is as shown in SEQ ID NO. 2, and the specific sequence is 5'-ACA GGA GAG TGT GAT GCT CTC CTG TCC TA -3', wherein the 5' end is modified with a thiol group.

7. The method for preparing a triple-mode sensor based on a multifunctional Au@CeO2 and AuPt@Zn-C composite material according to claim 1, characterized in that: In step (3), the aptamer Apt is shown as SEQ ID NO.3, and the specific sequence is 5'- CGA CGA TCG GAC CGC AGT ACC CAC CCA CCA GCC CCA ACA TCA TGC CCA TCC GTGTGT G -3', wherein the 3' end is modified with biotin; the complementary chain cDNA is shown as SEQ ID NO.4, and the specific sequence is 5'-CTC TAC CAT GTC GCG GTC CGA TCG TCG TAG GAC AGG AGA GCA T -3'; the DNA hairpin HP1 is shown as SEQ ID NO.5, and the specific sequence is 5'- AAA CGT CCT GCT AAC ATG AAA AAC ATG TTAGCA GGA CGG ACA TGG TAG AG -3', wherein the 5' end is modified with a thiol group; the DNA hairpin HP3 is shown as SEQ ID NO.6, and the specific sequence is 5'- CAC ACT CTC CTG TAT AGG ACA GGA GAG CAT -3'. .

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