CN110736829A

CN110736829A - Method for rapidly detecting T-2 toxin in food based on nucleic acid hydrogel

Info

Publication number: CN110736829A
Application number: CN201910919297.4A
Authority: CN
Inventors: 梁俊; 李双; 孙云凤; 陈瑞鹏
Original assignee: Tianjin University of Science and Technology
Current assignee: Tianjin University of Science and Technology
Priority date: 2019-09-26
Filing date: 2019-09-26
Publication date: 2020-01-31

Abstract

The invention belongs to the technical field of food detection, and discloses methods for rapidly detecting T-2 toxin in food based on nucleic acid hydrogel, which comprises the following steps of constructing the nucleic acid hydrogel taking T-2 toxin aptamer as linker cross-linking agent, uniformly embedding horseradish peroxidase in the nucleic acid hydrogel, and adding a sample to be detected into the nucleic acid hydrogel, wherein the concentration of T-2 toxin in the sample to be detected is 0.01ng mL^‑1‑10000ng mL^‑1The T-2 toxin aptamer is combined with the T-2 toxin, the gel is broken, horseradish peroxidase is released, hydrogen peroxide and potassium iodide are catalyzed by the horseradish peroxidase within time to react to generate iodine simple substance etched gold nanorods, and the content of the T-2 toxin is calculated according to an absorption peak of the gold nanorods under an ultraviolet spectrophotometer.

Description

Method for rapidly detecting T-2 toxin in food based on nucleic acid hydrogel

Technical Field

The invention relates to the technical field of food detection, in particular to methods for rapidly detecting T-2 toxin in food based on nucleic acid hydrogel.

Background

The description of the background of the invention pertaining to the related art to which this invention pertains is given for the purpose of illustration and understanding only of the summary of the invention and is not to be construed as an admission that the applicant is explicitly or implicitly admitted to be prior art to the date of filing this application as first filed with this invention.

In recent years, food safety problems related to mycotoxin residues emerge endlessly, and common trichothecenes, aflatoxins, zearalenone and the like are available, wherein T-2 toxin is the most main and with the highest toxicity in trichothecene A-type toxins, the T-2 toxin mainly acts on tissues and organs with vigorous cell division, can inhibit the synthesis of DNA, RNA and protein, has stronger genotoxicity, immunotoxicity, blood toxicity, carcinogenesis and teratogenesis, has lethal effect, also has toxicity to skin cells and heredity, and can also induce apoptosis, the pure product of the T-2 toxin is white crystal, and the molecular formula is C₂₄H₃₄O₉The molecular weight is 466.51, the food preservative has stable property, strong heat resistance and ultraviolet tolerance, is stable at room temperature, and has no toxicity reduction after being placed for 6-7 years or heated to 100-120 ℃ for 1 hour, so that the food preservative is not easy to inactivate in the process of food production and processing through high-pressure sterilization. Studies have shown that T-2 toxin may have close relationship with human food toxic leucocyte deficiency disease, Kaschin-Beck disease and keshan disease.

Currently, many analytical techniques have been used for T-2 toxin detection, including Thin-layer Chromatography (TLC), High Performance Liquid Chromatography (HPLC), Gas Chromatography-Mass Spectrometry (GC-MS), and Enzyme-Linked Immunosorbent Assay (ELISA), and these methods have High sensitivity and selectivity, which are the most commonly used methods for quantitative analysis of T-2 toxin. In addition, an immunological analysis method based on antigen-antibody specific recognition also provides technical support for establishment of a T-2 toxin quantitative rapid detection method. However, these methods are expensive in instruments and equipment, high in detection cost, require strict pretreatment of the sample, and have a long detection time.

Disclosure of Invention

The invention aims to provide methods for rapidly detecting T-2 toxin in food based on nucleic acid hydrogel.

The embodiment of the invention provides methods for rapidly detecting T-2 toxin in food based on nucleic acid hydrogel, which comprises the following steps:

constructing nucleic acid hydrogel taking T-2 toxin aptamer as linker cross-linking agent, wherein horseradish peroxidase is uniformly embedded in the nucleic acid hydrogel;

adding a sample to be detected into the nucleic acid hydrogel, wherein the concentration of the T-2 toxin in the sample to be detected is 0.01ng mL^-1-10000ng mL^-1The T-2 toxin aptamer is combined with the T-2 toxin, the gel is broken, and horseradish peroxidase is released;

in time, horseradish peroxidase catalyzes hydrogen peroxide and potassium iodide to react to generate iodine simple substance etching gold nanorods, and the content of T-2 toxin is calculated according to the absorption peak of the gold nanorods under an ultraviolet spectrophotometer.

, the method for constructing the nucleic acid hydrogel with the T-2 toxin aptamer as the cross-linking agent comprises the following steps:

adding acrylamide with final concentration of 4 wt% into the complementary strand A100. mu.M and the complementary strand B100. mu.M modified with acrylamide, respectively, and then exhausting air at 35-40 deg.C for 10-15min to remove oxygen;

adding freshly prepared ammonium persulfate with a final concentration of 1.4% and freshly prepared tetramethylethylenediamine with a final concentration of 2.8%; pumping air at 35-40 deg.C, and reacting for 10-15min to obtain high-molecule complementary strand A and complementary strand B;

and (3) uniformly mixing the high-molecule complementary strand A and the complementary strand B, incubating for 5-10min at the temperature of 60-65 ℃, and repeatedly heating twice to ensure that the reagents are completely and uniformly mixed. Then adding cross-linking agent (30, 35, 40, 45 μ M) and horseradish peroxidase with different concentrations, incubating at 60-65 deg.C for 5-10min, repeatedly heating for 3 times to ensure mixing of reagents, and cooling to room temperature to form nucleic acid hydrogel.

The glue plane was washed with phosphate buffer solution to remove excess horseradish peroxidase from the glue surface.

, the gold nano-rod is prepared by the following method:

preparing gold seeds: adding 0.5-1.0mL of 0.2M hexadecyl trimethyl ammonium bromide solution into 0.5-1.0mL of 0.5mM tetrachloroauric acid solution; after shaking and mixing evenly, 0.1-0.2mL of 6mM freshly prepared sodium borohydride solution is added immediately; oscillating vigorously for 2-5min to turn the seed solution from yellow to brown, standing at room temperature for 30-45min to obtain gold seed, and storing at room temperature;

preparing a growth solution: weighing 0.9-1.1g of hexadecyl trimethyl ammonium bromide and 0.11-0.13g of 5-bromosalicylic acid into a 250mL round-bottom flask, and dissolving with 25-30mL warm water (50-70 ℃); then 1.2-1.5mL of 4.0mM silver nitrate solution was added. Placing the obtained solution in a water bath kettle at 30-37 deg.C, standing for 15-20min, adding 25mL of 1.0mM tetrachloroauric acid solution, and stirring for 15-20 min; finally, 0.2mL of 0.064-0.072M ascorbic acid is added, and the mixture is uniformly mixed for 30-60s until the solution becomes colorless, so that a growth solution can be obtained;

and (3) growing the gold nanorods: adding 80-85 μ L of the prepared seed solution into the obtained growth solution, mixing uniformly, placing in a 30-37 deg.C water bath, and standing for 12-14h to obtain the desired gold nanorods. Finally, the resulting gold nanorods were centrifuged and resuspended 3 times with 0.05M cetyltrimethylammonium bromide to remove the growth medium.

, when the ratio of the high-molecule complementary chain A to the high-molecule complementary chain B to the cross-linking agent is 110: 100: 45, the response time of the nucleic acid hydrogel is 15 min.

Further , the concentration of potassium iodide is 0.10M.

Further , the hydrogen peroxide concentration is 0.075M.

, calculating the content of T-2 toxin according to the absorption peak of the gold nanorod under an ultraviolet spectrophotometer comprises the steps of establishing a standard curve, adding 10 mul of T-2 toxin standard samples with different concentrations into the hydrogel, standing for 15min at room temperature, removing the supernatant into 2mL of 0.05mg/mL gold nanorod and 5mL of 0.10M potassium iodide 20mL of 0.075M hydrogen peroxide, standing for 3min at room temperature, and performing ultraviolet spectrum scanning.

The embodiment of the invention has the following beneficial effects:

the method is based on gold nanorods and nucleic acid hydrogelConstructing nucleic acid hydrogel taking T-2 toxin aptamer as linker, uniformly embedding Horseradish Peroxidase (HRP) in the hydrogel, combining the toxin aptamer with the toxin, breaking the gel to release the Horseradish Peroxidase, catalyzing hydrogen peroxide and potassium iodide to react to generate iodine simple substance etching gold nanorods within time to enable the gold nanorods to present different colors, and presenting absorption peaks at different positions under an ultraviolet spectrophotometer^-1. Compared with the prior art, the method is simple, rapid and quick, has good selectivity and sensitivity, and can be used for analyzing actual samples in food safety detection.

Drawings

FIG. 1 is a schematic diagram of the process for rapid detection of T-2 toxin in food based on nucleic acid hydrogel according to the present invention;

FIG. 2 is a TEM image before gold nanorods etching;

FIG. 3 is a TEM image of gold nanorods after etching;

FIG. 4 is an ultraviolet absorption spectrum of gold nanorods before and after etching;

FIG. 5 is a non-etchability verification diagram;

FIG. 6 is an optimization of hydrogel gelling conditions;

FIG. 7 is an optimization of hydrogel hydrolysis time;

FIG. 8 is an optimization of potassium iodide concentration;

FIG. 9 is an optimization of hydrogen peroxide concentration;

FIG. 10 is a TEM image of an unbroken hydrogel;

FIG. 11 is a TEM image of a fully collapsed hydrogel;

FIG. 12 is a UV spectrum of nucleic acid hydrogel-based rapid detection of T-2 toxin in food products;

FIG. 13 is a graph of a standard curve for rapid detection of T-2 toxin in food based on nucleic acid hydrogels;

FIG. 14 is a graph of the stability of hydrogels at different residence times;

FIG. 15 is a specificity profile for other mycotoxins;

FIG. 16 is a scaled recovery plot.

Detailed Description

The present application is further described in with reference to the following examples.

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, in the following description, different " embodiment" or "embodiment" means is different from embodiment.

With reference to fig. 1, methods for rapidly detecting T-2 toxin in food based on nucleic acid hydrogel, comprising the following steps:

In examples of the present invention, the construction of the nucleic acid hydrogel using the T-2 toxin aptamer as a cross-linking agent comprises the following steps:

In examples of the present invention, the gold nanorods were prepared by the following method:

In examples of the invention, when the ratio of the amounts of the high-molecular complementary strand a, the high-molecular complementary strand B and the crosslinker is 110: 100: 45, the response time of the nucleic acid hydrogel is 15 min.

In examples of the present invention, the concentration of potassium iodide was 0.10M.

In examples of the present invention, the concentration of hydrogen peroxide was 0.075M.

In examples of the present invention, the calculation of the content of T-2 toxin based on the absorption peak of gold nanorods under UV spectrophotometer comprises the steps of establishing a standard curve, adding 10 μ L of T-2 toxin standard samples with different concentrations into the above hydrogel, standing at room temperature for 15min, removing the supernatant into 2mL of 0.05mg/mL gold nanorods, 5mL of 0.10M potassium iodide, 20mL of 0.075M hydrogen peroxide, standing at room temperature for 3min, and performing UV spectrum scanning.

Preparation of gold nanorods

And (4) preparing gold seeds. 0.5-1.0mL of 0.2M cetyltrimethylammonium bromide solution was added to 0.5-1.0mL of 0.5mM chloroauric acid solution. After shaking and mixing, 0.1-0.2mL of 6mM freshly prepared sodium borohydride solution was immediately added. Shaking vigorously for 2-5min to change the seed solution from yellow to brown, standing at room temperature for 30-45min to obtain gold seed, and storing at room temperature.

And (4) preparing a growth liquid. 0.9-1.1g of cetyltrimethylammonium bromide and 0.11-0.13g of 5-bromosalicylic acid are weighed into a 250mL round bottom flask and dissolved with 25-30mL warm water (50-70 ℃). Then 1.2-1.5mL of 4.0mM silver nitrate solution was added. Placing the obtained solution in a water bath at 30-37 deg.C, standing for 15-20min, adding 25mL of 1.0mM tetrachloroauric acid solution, and stirring for 15-20 min. And finally, adding 0.2mL of 0.064-0.072M ascorbic acid, and uniformly mixing for 30-60s until the solution becomes colorless to obtain the growth solution.

And (4) growing the gold nanorods. Adding 80-85 μ L of the prepared seed solution into the obtained growth solution, mixing uniformly, placing in a 30-37 deg.C water bath, and standing for 12-14h to obtain the desired gold nanorods. Finally, the obtained gold nanorods were centrifuged and resuspended 3 times with 0.05M cetyltrimethylammonium bromide to remove the growth solution for subsequent experiments.

The TEM before etching the gold nanorods is shown in FIG. 2, the TEM after etching is shown in FIG. 3, the corresponding ultraviolet absorption spectrograms are shown in FIG. 4, and the non-etchability verification is carried out as shown in FIG. 5, so that hydrogen peroxide and potassium iodide do not react within time without existence of horseradish peroxidase, no iodine simple substance is formed, and the gold nanorods are not etched to generate peak shift.

Preparation of nucleic acid hydrogels

Acrylamide-modified complementary strand A and complementary strand B (each 100. mu.M) were each added to acrylamide at a final concentration of 4 wt%, followed by evacuation of air at 35-40 ℃ for 10-15min to remove oxygen.

Freshly prepared ammonium persulfate at a final concentration of 1.4% and freshly prepared tetramethylethylenediamine at a final concentration of 2.8% were added. Exhausting air at 35-40 deg.C, and reacting for 10-15min to obtain high-molecule complementary strand A and complementary strand B.

Washing the glue plane with phosphate buffer solution to remove excess horseradish catalase on the glue surface.

Optimization of hydrogel forming conditions

The ratio of the amounts of the high-molecular complementary chain A, the high-molecular complementary chain B and the cross-linking agent is optimized, and the ratio ranges from 100: 100: 40-100: 100: 55, respectively. As shown in fig. 6, when the ratio of the amounts of the high-molecular complementary strand a, the high-molecular complementary strand B, and the crosslinking agent is 100: 100: at 40 hours, after 20min, the light absorption value of the experimental group supernatant at 310nm is larger, which indicates that the hydrogel is fully disintegrated; however, the absorbance of the control group at 310nm increased significantly with time after standing for 20min, which indicates that when the ratio of the amounts of the high-molecular complementary chain a, the high-molecular complementary chain B and the crosslinker is 100: 100: at 40, the hydrogel was unstable and collapsed upon itself even in the absence of the target. As shown in fig. 6B, when the ratio of the amounts of the high-molecular complementary strand a, the high-molecular complementary strand B and the crosslinker is 100: 100: 45 hours, the absorption value of horseradish peroxidase in the supernatant of the experimental group is gradually increased along with the increase of time, and the absorption value is almost kept unchanged after 20 minutes, which indicates that the hydrogel is basically fully disintegrated after 20 minutes; meanwhile, the 310nm absorbance of the control group supernatant remained substantially unchanged within 20min, indicating that the hydrogel was very stable under these conditions. As shown in fig. 6c and 6d, when the ratio of the amounts of the high-molecular complementary strand a, the high-molecular complementary strand B and the crosslinker is 100: 100: 50/55, although the 310nm absorption values of the supernatants of the two control groups are almost unchanged within 40min, the hydrogel is very stable, however, after standing for 40min, the 310nm absorption values of the supernatants of the corresponding experimental groups are small, which indicates that under the condition, the hydrogel is too stable, and 1 μ M toxin can only slightly break down the hydrogel, so that the response effect is poor. In summary, when the ratio of the amounts of the high-molecular complementary chain a, the high-molecular complementary chain B and the crosslinker is 100: 100: 45, the nucleic acid hydrogel responded optimally to the toxin.

Optimization of hydrogel hydrolysis time

The ratio of the amounts of the high-molecular complementary chain A, the high-molecular complementary chain B and the cross-linking agent is optimized, and the ratio ranges from 90: 100: 45-120: 100: 45, respectively. As shown in fig. 7, when the ratio of the amounts of the high-molecular complementary strand a, the high-molecular complementary strand B, and the crosslinking agent is 90: 100: at 45 hours, the 310nm absorption value of the control group supernatant is almost unchanged after 10min, and the hydrogel is very stable, however, after standing for 10min, the 310nm absorption value of the corresponding experimental group supernatant is smaller, which indicates that under the condition, the hydrogel is too stable, 1 mu M toxin can only cause the hydrogel to be slightly disintegrated, and the response effect is poor. As shown in fig. 7B, when the ratio of the amounts of the high-molecular complementary strand a, the high-molecular complementary strand B and the crosslinker is 100: 100: 45 hours, the absorption value of horseradish peroxidase in the supernatant of the experimental group is gradually increased along with the increase of time, and the absorption value is almost kept unchanged after 20 minutes, which indicates that the hydrogel is basically fully disintegrated after 20 minutes; meanwhile, the 310nm absorbance of the control group supernatant remained substantially unchanged within 20min, indicating that the hydrogel was very stable under these conditions. However, referring to fig. 7c, when the ratio of the amounts of the high-molecular complementary strand a, the high-molecular complementary strand B and the crosslinker is 110: 100: at 45 hours, the phenomenon was essentially the same as in FIG. 7b, but at 15min the absorbance of horseradish peroxidase in the assay supernatant remained almost unchanged, indicating that the hydrogel had essentially collapsed sufficiently after 15 min. The time is shorter. As shown in fig. 7d, when the ratio of the amounts of the high-molecular complementary strand a, the high-molecular complementary strand B, and the crosslinker is 120: 100: at 45 hours, after 15min, the light absorption value of the experimental group supernatant at 310nm is larger, which indicates that the hydrogel is fully disintegrated; however, the absorbance of the control group at 310nm of the supernatant increased significantly with time after standing for 15min, indicating that the hydrogel was unstable at a linker concentration of 40. mu.M and collapsed itself even in the absence of the target. In summary, when the ratio of the amounts of the high-molecular complementary chain a, the high-molecular complementary chain B and the crosslinker is 110: 100: at 45 hours, the nucleic acid hydrogel has the best response to the toxin, and the response time is 15 min.

Optimization of potassium iodide concentration

The 5 concentrations were optimized to be 0.08M, 0.09M, 0.10M, 0.11M, and 0.12M, respectively, and as shown in fig. 8, the peak shift gradually increased when the potassium iodide concentration was 0.08M to 0.10M, and reached the maximum value when the potassium iodide concentration was 0.10M, so the optimum concentration was 0.10M.

Optimization of hydrogen peroxide concentration

The 5 concentrations, 0.065M, 0.070M, 0.075M, 0.080M and 0.085M, were optimized, as shown in fig. 9, the peak shift gradually increased when the hydrogen peroxide concentration was 0.065M to 0.075M, and reached the maximum when the hydrogen peroxide concentration was 0.075M, so the optimum concentration was 0.075M.

Establishment of a Standard Curve

Adding 10 mu L of T-2 toxin standard samples with different concentrations into the hydrogel, standing for 15min at room temperature, removing the supernatant into 2mL of 0.05mg/mL gold nanorods, 5mL of 0.10M potassium iodide and 20mL of 0.075M hydrogen peroxide, standing for 3min at room temperature, and then carrying out ultraviolet spectrum scanning. Wherein FIG. 10 is a TEM image of an unbroken hydrogel and FIG. 11 is a TEM image of a fully collapsed hydrogel.

In the case of the above experimental conditions, a standard curve was plotted using serially diluted concentrations of T-2 toxin standard, as shown in FIG. 12, the trend of increasing peak shift with increasing T-2 toxin concentration can be explained by the fact that when different concentrations of T-2 toxin were added to the hydrogel, the hydrogel was in a state where different concentrations of T-2 toxin were added to the hydrogelThe cross-linking agent can be specifically combined with the toxin, so that the hydrogel is broken and becomes solution, horseradish peroxidase embedded in the hydrogel is released, and the amount of the released horseradish peroxidase is in direct proportion to the content of the toxin. Liquid in the hydrogel system is transferred into the gold nanorods, horseradish peroxidase catalyzes hydrogen peroxide and potassium iodide to react to generate iodine elementary substance to etch the gold nanorods, so that the gold nanorods are in different colors and show absorption peaks at different positions under an ultraviolet spectrophotometer, and the peak displacement of the gold nanorods is in direct proportion to the concentration of T-2 toxin. As shown in fig. 13, the concentration of T-2 toxin was plotted on the abscissa and the peak shift of the gold nanorods was plotted on the ordinate, and the obtained standard curve was represented by Y-32.3129 lgX +54.0285, R²When the concentration of the T-2 toxin is 0.9991, the T-2 toxin is in a good linear relation between 0.01ng/mL and 10000ng/mL, and the lowest detection limit is 0.87pgmL^-1。

Stability of the detection method

In order to evaluate the stability of the method, 30-day, 20-day, 10-day and 1-day hydrogels are respectively prepared, and T-2 toxin standard samples with different concentrations in high, medium and low are added. As shown in FIG. 14, the peak shifts obtained from the detection of hydrogels at different storage times were not very different. The stability of the hydrogel prepared by the method is good.

Specificity of the detection method

To evaluate the specificity of the method of the present invention, we selected the interferents Ochratoxin (OTA), Fusarium oxysporum (FB1), Aflatoxin B1(AFB1), vomitoxin (DON), zearalenone toxin (ZEN) which are mycotoxins together with T-2 toxin, and theoretically, the specificity of the method mainly depends on the specific binding of T-2 toxin and T-2 toxin aptamer, and if T-2 toxin aptamer binds with other mycotoxins, a false positive signal is generated. As shown in FIG. 15, the peak shift of T-2 toxin was most pronounced after addition of 10ng/mL of the different toxins. The hydrogel prepared by the method has good specificity.

Detection of actual samples

A spiking recovery experiment was used. Corn, soybean and coffee are selected as actual samples. Weighing 1-1.5g of corn flour, soybean flour and coffee powder, adding into a 5mL centrifuge tube, adding 2-3mL of T-2 toxin solution with the concentration of 100ng/mL (diluting with methanol: PBS (7: 3)), vortexing and shaking for 5-7min, centrifuging at 10000rpm/min for 15-20min, taking supernatant, filtering with a 0.45 mu m filter membrane, and diluting to 50ng/mL, 1ng/mL and 0.1ng/mL (diluting with methanol: PBS (7: 3)) for labeling recovery experiment. The concentration of each concentration was measured 3 times in parallel, and the recovery rate of spiking was calculated by setting different concentrations (50ng/mL, 1ng/mL, 0.1ng/mL) in the detection range, as shown in FIG. 16, the recovery rate of spiking of the present invention was 93.72% to 103.07%, with the Relative Standard Deviation (RSD) of 3.87% to 7.07%. The method is accurate and reliable.

It should be noted that the above embodiments can be freely combined as necessary. The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1, A method for rapidly detecting T-2 toxin in food based on nucleic acid hydrogel, which is characterized by comprising the following steps:

2. The method for rapidly detecting T-2 toxin in food based on nucleic acid hydrogel of claim 1, wherein the step of constructing the nucleic acid hydrogel with T-2 toxin aptamer as a cross-linking agent comprises the following steps:

mixing the high-molecular complementary strand A and the complementary strand B, incubating at 60-65 ℃ for 5-10min, and repeatedly heating twice to ensure that the reagents are completely mixed; adding cross-linking agent (30, 35, 40, 45 μ M) and horse radish peroxidase with different concentrations, incubating at 60-65 deg.C for 5-10min, repeatedly heating for 3 times to ensure mixing of reagents, and cooling to room temperature to form nucleic acid hydrogel;

3. The method for rapidly detecting T-2 toxin in food based on nucleic acid hydrogel of claim 1, wherein the gold nanorods are prepared by the following method:

preparing a growth solution: weighing 0.9-1.1g of hexadecyl trimethyl ammonium bromide and 0.11-0.13g of 5-bromosalicylic acid into a 250mL round-bottom flask, and dissolving with 25-30mL warm water (50-70 ℃); then 1.2-1.5mL of 4.0mM silver nitrate solution is added; placing the obtained solution in a water bath kettle at 30-37 deg.C, standing for 15-20min, adding 25mL of 1.0mM tetrachloroauric acid solution, and stirring for 15-20 min; finally, 0.2mL of 0.064-0.072M ascorbic acid is added, and the mixture is uniformly mixed for 30-60s until the solution becomes colorless, so that a growth solution can be obtained;

and (3) growing the gold nanorods: adding 80-85 μ L of the prepared seed solution into the obtained growth solution, mixing uniformly, placing in a 30-37 deg.C water bath, and standing for 12-14h to obtain the desired gold nanorods; finally, the resulting gold nanorods were centrifuged and resuspended 3 times with 0.05M cetyltrimethylammonium bromide to remove the growth medium.

4. The method for rapidly detecting T-2 toxin in food based on nucleic acid hydrogel of claim 2, wherein the ratio of the amounts of the high-molecular complementary chain A, the high-molecular complementary chain B and the crosslinking agent is 110: 100: at 45 deg.C, the response time of the nucleic acid hydrogel is 15 min.

5. The method for rapidly detecting T-2 toxin in food based on nucleic acid hydrogel of claim 1, wherein the concentration of potassium iodide is 0.10M.

6. The method for rapid detection of T-2 toxin in food based on nucleic acid hydrogel of claim 1, wherein the concentration of hydrogen peroxide is 0.075M.

7. The method for rapidly detecting T-2 toxin in food based on nucleic acid hydrogel of claim 1, wherein the step of calculating the content of T-2 toxin according to the absorption peak of gold nanorods under an ultraviolet spectrophotometer comprises the steps of: establishing a standard curve: adding 10 mu L of T-2 toxin standard samples with different concentrations into the hydrogel, standing for 15min at room temperature, removing the supernatant into 2mL of 0.05mg/mL gold nanorods, 5mL of 0.10M potassium iodide and 20mL of 0.075M hydrogen peroxide, standing for 3min at room temperature, and then carrying out ultraviolet spectrum scanning.