Dual-mode analysis and detection method for simultaneously detecting ricin and abrus precatorius toxin

Abstract

The invention belongs to the technical field of environmental pollution detection, and particularly relates to a dual-mode analysis and detection method for simultaneously detecting ricin and abrus precatorius toxin. The functional optical fiber probe prepared by the invention depends on an evanescent wave two-color optical fiber sensor, realizes dual-mode simultaneous detection of ricin and abrus precatorius toxin on the basis of a size effect and a complementary chain hybridization strategy, and can realize simultaneous detection of ricin and abrus precatorius toxin through two different modes; the two toxins can be detected at the same time without mutual interference, the requirements of different application scenes are met, only the biological recognition element needs to be replaced, simultaneous detection of multiple biotoxins or environmental pollutants can be broadened, the detection requirements of different application scenes can be met, and support can be provided for on-site rapid detection of high-risk chemical toxins and guarantee of personnel health.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental pollution detection, and particularly relates to a dual-mode analysis and detection method for the simultaneous detection of ricin and abrin. Background Art

[0002] Ricin and abrin are two highly toxic plant protein toxins derived from castor beans and abrin seeds, respectively. Due to their potential lethality and easy availability, these two toxins are widely considered to be significant threats in bioterrorism and food safety incidents. Ricin and abrin have stable tertiary structures and maintain stable activity even after high-temperature treatment. Currently, there is a lack of effective antidotes, vaccines, or other specific therapies for these two toxins. The development of highly sensitive detection methods for these two toxins is of great significance for timely protection and prevention of personnel and for reducing the probability of toxin poisoning incidents.

[0003] Currently reported detection methods can only detect a single toxin, making it difficult to meet the requirements for the simultaneous detection of multiple toxins, and are not suitable for the detection of water bodies or food samples contaminated by mixed toxins. The simultaneous detection of multiple biological toxins has several significant advantages: first, it can greatly improve detection efficiency and reduce detection time and manpower investment; second, it can effectively reduce costs and reduce the use of reagents and consumables; third, by optimizing detection methods and sample pretreatment technologies, cross-interference between different toxins can be avoided, ensuring the reliability and sensitivity of the test results. In addition, the field environment is complex and diverse, and the construction of a simultaneous detection method that can meet a variety of application scenarios has important practical significance and application value.

[0004] Evanescent wave fiber biosensing technology, based on the principle of laser-induced evanescent wave fields generated on the surface of solid-state optical fibers, stands out among numerous sensing technologies due to its high sensitivity, fast response speed, and high selectivity. Because the evanescent field decays exponentially in optically sparse media, its effective penetration depth is only a few hundred nanometers. This effectively isolates and reduces background interference in the sample being tested, improving detection sensitivity. This type of sensor uses the energy of the evanescent field to activate fluorescent markers attached to the sensing element, thereby establishing a quantitative relationship between the concentration of the target analyte in the sample. By optimizing the surface of the optical fiber through corrosion, the surface is modified to possess different pore structures. When fluorescently labeled nucleic acid aptamers enter the excitation range of the evanescent wave field through the nanopores on the fiber surface, the fluorescently labeled nucleic acid aptamers produce a distinct fluorescent signal under the excitation of the evanescent wave field. Ricin and abrin are large protein molecules with diameters ranging from tens to hundreds of nanometers, far larger than the size of nucleic acid aptamers. When ricin and abrin toxin specifically bind to the corresponding nucleic acid aptamers, they cannot pass through the nanopores into the evanescent wave field, making it difficult to excite the fluorescence signal and weakening the signal.

[0005] Detection methods based on size effects are not conducive to the simultaneous detection of low-concentration toxins, as fluorescently labeled nucleic acid aptamers only adhere to the optical fiber surface through diffusion and non-specific adsorption. To this end, the complementary DNA chains of nucleic acid aptamers of two toxins can be modified simultaneously on the optical fiber surface. Based on the principle of complementary chain hybridization, fluorescently labeled nucleic acid aptamers can be specifically captured, so that more nucleic acid aptamers are within the excitation range of the evanescent wave field, thereby improving detection sensitivity. Relying on the evanescent wave two-color optical fiber biosensor, based on the size effect and complementary chain hybridization strategy, two different modes of simultaneous detection technology for biological toxins can be constructed to meet the detection needs of different application scenarios, and can provide new support for on-site rapid detection of high-risk chemical and biological toxins, protecting personnel health, and maintaining national security. Summary of the Invention

[0006] The purpose of the present invention is to solve the problem that traditional detection technology is complicated in operation and single in detection, and it is difficult to meet the requirements of rapid, sensitive and simultaneous detection of two toxins, castor and abrin seed. Relying on the evanescent wave two-color fiber optic biosensor, nucleic acid aptamers labeled with different fluorescent molecules are used as specific recognition probes for the two toxins, so as to realize the simultaneous detection of two biological toxins by a single fiber optic probe. By effectively regulating or modifying the biorecognition molecules at the fiber optic interface, two functionalized fiber optic probes are prepared, and a multimodal simultaneous detection technology for castor and abrin seed toxins is constructed based on the size effect and complementary chain hybridization strategy. Among them, the detection mode based on the size effect is simple, fast and stable in preparation of the fiber optic probe, and has good application potential in the field of rapid on-site detection; the detection mode based on the complementary chain hybridization strategy relies on the high affinity between the complementary DNA chain at the fiber optic interface and the nucleic acid aptamer, and has a lower detection limit, which can be applied to the highly sensitive simultaneous detection of trace toxins.

[0007] The technical solution adopted in the present invention is:

[0008] In a first aspect, the present invention provides a dual-mode analytical detection method for the simultaneous detection of ricin and abrin, wherein the dual mode is a mode based on size effect and a mode based on complementary chain hybridization strategy, comprising the following steps:

[0009] S1 Preparation of functionalized fiber optic probe:

[0010] The functionalized optical fiber probes include bare optical fiber probes and optical fiber probes modified with complementary DNA chains;

[0011] The bare fiber probe is prepared by removing a portion of the coating of a multimode quartz optical fiber, and then etching the portion removed by immersing it in a mixed solution of hydrofluoric acid and HNO3; after removing the coating of the remaining portion of the multimode quartz optical fiber, the portion is cleaned with piranha solution to obtain a bare fiber probe;

[0012] The preparation method of a fiber optic probe modified with complementary DNA chains is as follows: based on a bare fiber optic probe, the fiber optic probe is first immersed in a toluene solution containing γ-aminopropyltriethoxysilane for reaction for 2 hours, and after drying, it is immersed in a glutaraldehyde aqueous solution for reaction; after the reaction, it is immersed in a mixed solution of ricin and abrin complementary DNA chains, and after sufficient reaction, it is washed with a buffer to remove excess complementary DNA chains; then the fiber optic probe is immersed in a blocking solution for sufficient reaction to block nonspecific adsorption sites, and after washing with a buffer, the fiber optic probe modified with complementary DNA chains is obtained;

[0013] The sequences of the complementary DNA chains of the ricin toxin and abrinus toxin nucleic acid aptamers are 5′-TTTTAGTCTCCGGAGGCGTTGCGTCTGCCTGCGGTGGGAAAAAA-3′ and 5′-TTTCCTTGCTATGCATGAGCATTCCTCACAGAAAAAA-3′ respectively;

[0014] Preparation of S2 standard curve:

[0015] Sample a: several groups of ricin nucleic acid aptamer and abrin nucleic acid aptamer solutions with different concentrations;

[0016] The sequences of the ricin toxin and abrinus toxin nucleic acid aptamers are 5′-TTTTTTCCCACCGCAGGCAGACGCAACGCCTCGGAGACTAAAA-3′ and are labeled with Cy5.5 fluorescent dye, and 5′-TTTTTTCTGTGAGGAATGCTCATGCATAGCAAGGAAA-3′ and are labeled with Cy3 fluorescent dye;

[0017] Sample b: several groups of solutions containing ricin and abrin at different concentrations;

[0018] After mixing several groups of sample a and sample b, a bare fiber probe standard solution is prepared and a standard curve of the bare fiber probe is measured;

[0019] Sample a is used as a standard solution of the optical fiber probe for modifying complementary DNA chains, the concentration of the target substance in the standard solution is measured, and a standard curve based on the optical fiber probe for modifying complementary DNA chains is established.

[0020] S3 Simultaneous detection of ricin and abrin based on size effect and complementary chain hybridization strategy:

[0021] The evanescent wave dual-color fiber optic biosensor includes an all-fiber optical system and a microfluidic sampling module; the all-fiber optical system includes a laser, an optical switch, a single / multimode fiber coupler for fluorescence coupling and transmission, a filter, a functionalized fiber optic probe, and a photodetector; the microfluidic sampling module includes a pump, a multi-position valve, and a microchannel sample cell; the functionalized fiber optic probe is immersed in the microchannel sample cell;

[0022] S3-1: adding an excess of ricin and abrin nucleic acid aptamers of known concentrations to a biological sample solution containing ricin and abrin to obtain a test sample c;

[0023] S3-2: Installing a bare fiber probe and a fiber probe modified with complementary DNA chains into an evanescent wave dual-color fiber biosensor; passing Tris-HCl buffer into the evanescent wave dual-color fiber biosensor, and using laser excitation to generate baseline signals;

[0024] The wavelength of the laser for detecting ricin is 620-680nm, and the wavelength for detecting abrin toxin is 510-570nm;

[0025] S3-3: The sample c to be tested is introduced into the microchannel detection module of the sensor, reacting with the bare optical fiber probe and the optical fiber probe modified with complementary DNA strands, respectively, and the instrument detects the signal;

[0026] During this process, for the bare fiber probe, the size of the formed complex is much larger than the nanopore at the fiber interface of the bare fiber probe, resulting in a decrease in the free nucleic acid aptamer that enters the evanescent wave field on the surface of the bare fiber probe through the nanopore, and a decrease in the signal;

[0027] For the fiber optic probe modified with complementary DNA chains, ricin and abrin toxin specifically bind to the corresponding aptamers, resulting in a decrease in the free aptamers bound to the complementary DNA chains immobilized on the fiber and a decrease in the signal;

[0028] S4: Determine the concentrations in the two modes based on the prepared standard curve.

[0029] Preferably, when detecting ricin and abrin, the wavelengths of the lasers of the evanescent wave dual-color optical fiber biosensor are 635 nm and 520 nm, respectively, to excite the labeled nucleic acid aptamers.

[0030] Preferably, when the concentration of ricin and abrin is above 4 ng / mL, dual-mode detection using a bare fiber probe and modified complementary DNA chains is used; when the concentration of ricin and abrin is below 4 ng / mL, detection based on a complementary chain hybridization strategy using a fiber optic probe with modified complementary DNA chains is used.

[0031] Preferably, in the detection mode based on the complementary chain hybridization strategy, the detection range of ricin is 0.05-147.84 ng / mL, and the detection limit is 0.0086 ng / mL; the detection range of abrin toxin is 0.04-140.25 ng / mL, and the detection limit is 0.004 ng / mL.

[0032] Preferably, in the detection mode based on size effect, the detection range of ricin is 4.09-123.30 ng / mL, and the detection limit is 2.32 ng / mL; the detection range of abrin toxin is 4.47-173.78 ng / mL, and the detection limit is 2.56 ng / mL.

[0033] Preferably, the buffer solution is Tris-HCl buffer.

[0034] Preferably, the bare optical fiber probe and the optical fiber probe modified with complementary DNA chain are regenerated with SDS regeneration solution and Tris-HCl buffer after use.

[0035] Preferably, the mixed solution of hydrofluoric acid and HNO 3 is V(HNO 3 ):V(HF)=1:10-1:2, and the etching treatment is performed for 2-4 hours.

[0036] Preferably, after the bare optical fiber is aldehyde-treated, it is immersed in a mixed solution of 1-5 μmol / L ricin and abrin complementary DNA chains and reacted at 4° C. overnight.

[0037] Preferably, the blocking solution is a 0.1-2 wt.% bovine serum solution.

[0038] In a second aspect, the present invention provides a functionalized optical fiber probe for the simultaneous detection of ricin and abrin, comprising a bare optical fiber probe and an optical fiber probe modified with a complementary DNA chain;

[0039] The bare fiber probe is prepared by removing a portion of the coating of a multimode quartz optical fiber, and then etching the portion removed by immersing it in a mixed solution of hydrofluoric acid and HNO3; after removing the coating of the remaining portion of the multimode quartz optical fiber, the portion is cleaned with piranha solution to obtain a bare fiber probe;

[0040] The preparation method of the fiber optic probe modified with complementary DNA chains is as follows: based on a bare fiber optic probe, the fiber optic probe is first immersed in a toluene solution containing γ-aminopropyltriethoxysilane for reaction, and after drying, it is immersed in a glutaraldehyde aqueous solution for reaction; after the reaction is completed, it is immersed in a mixed solution of ricin and abrin complementary DNA chains, and after sufficient reaction, it is washed with a buffer to remove excess complementary DNA chains; then the fiber optic probe is immersed in a blocking solution for sufficient reaction to block nonspecific adsorption sites, and after washing with a buffer, a fiber optic probe modified with complementary DNA chains is obtained; the fiber optic probe modified with two toxin complementary DNA chains is referred to as a functionalized fiber optic probe;

[0041] The sequences of the complementary DNA chains of the ricin toxin and abrinus toxin nucleic acid aptamers are 5′-TTTTAGTCTCCGGAGGCGTTGCGTCTGCCTGCGGTGGGAAAAAA-3′ and 5′-TTTCCTTGCTATGCATGAGCATTCCTCACAGAAAAAA-3′ respectively.

[0042] The beneficial effects of the present invention are as follows: the present invention prepares a bare optical fiber probe and a functionalized optical fiber probe modified with a complementary chain, relies on an evanescent wave two-color optical fiber sensor, and realizes dual-mode simultaneous detection of ricin and abrin based on the size effect and complementary chain hybridization strategy. The simultaneous detection of ricin and abrin can be achieved through two different modes, and the simultaneous detection of the two toxins will not interfere with each other, meeting the needs of different application scenarios. Only by replacing the biorecognition element, the application of the simultaneous detection of multiple biological toxins or environmental pollutants can be expanded to meet the detection needs of different application scenarios, which can provide new support for on-site rapid detection of high-risk chemical and biological toxins and protection of personnel health. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematic diagram of the simultaneous detection of ricin and abrin based on size effect (left) and complementary strand hybridization strategy (right).

[0044] Figure 2 Signal curves of simultaneous detection of ricin (A) and abrin (B) based on size effect.

[0045] Figure 3 Signal curves of simultaneous detection of ricin (A) and abrin (B) based on the complementary chain hybridization strategy; standard curves of simultaneous detection of ricin (C) and abrin (D) based on the complementary chain hybridization strategy. DETAILED DESCRIPTION

[0046] Example 1

[0047] (1) Preparation of functionalized fiber optic probes:

[0048] The functionalized optical fiber probes include bare optical fiber probes and optical fiber probes modified with complementary DNA chains;

[0049] The bare fiber probe is prepared by removing a portion of the coating of a multimode quartz optical fiber, and then etching the portion removed by immersing it in a mixed solution of hydrofluoric acid and HNO3; after removing the coating of the remaining portion of the multimode quartz optical fiber, the portion is cleaned with piranha solution to obtain a bare fiber probe;

[0050] The preparation method of a fiber optic probe for modifying complementary DNA chains is as follows: based on a bare fiber optic probe, the fiber optic probe is first immersed in a toluene solution containing γ-aminopropyltriethoxysilane for a reaction of 2 hours, and after drying, immersed in a 25% glutaraldehyde aqueous solution for a reaction of 1 hour; after the reaction, the fiber optic probe is immersed in a mixed solution of ricin and abrin complementary DNA chains, and after sufficient reaction, it is washed with a buffer to remove excess complementary DNA chains; the fiber optic probe is then immersed in a blocking solution for a sufficient reaction to block nonspecific adsorption sites, and washed with a buffer to obtain a fiber optic probe for modifying complementary DNA chains;

[0051] The sequences of the complementary DNA chains of the ricin toxin and abrinus toxin nucleic acid aptamers are 5′-TTTTAGTCTCCGGAGGCGTTGCGTCTGCCTGCGGTGGGAAAAAA-3′ and 5′-TTTCCTTGCTATGCATGAGCATTCCTCACAGAAAAAA-3′ respectively.

[0052] Example 2

[0053] (1) Establish a standard curve:

[0054] Sample a: a mixed solution of several groups of ricin nucleic acid aptamers and abrin nucleic acid aptamers with different concentrations, ranging from 400 to 800 nM;

[0055] The sequences of the ricin toxin and abrinus toxin nucleic acid aptamers are 5′-TTTTTTCCCACCGCAGGCAGACGCAACGCCTCGGAGACTAAAA-3′ and are labeled with Cy5.5 fluorescent dye, and 5′-TTTTTTCTGTGAGGAATGCTCATGCATAGCAAGGAAA-3′ and are labeled with Cy3 fluorescent dye;

[0056] Sample b: several groups of solutions containing ricin and abrin at different concentrations;

[0057] Prepare ricin and abrin toxin solutions with a concentration of 0.02 to 2000 ng / mL.

[0058] The evanescent wave two-color fiber optic biosensor includes an all-fiber optical system and a microfluidic sampling module; the all-fiber optical system includes a laser, an optical switch, a single / multimode fiber optic coupler for fluorescence coupling and transmission, a filter, a functionalized fiber optic probe, and a photodetector; the microfluidic sampling module includes a pump, a multi-position valve, and a microchannel sample cell; the functionalized fiber optic probe is placed in the microchannel sample cell.

[0059] After mixing sample a and sample b, a bare fiber probe standard solution is prepared, the concentration of the target substance in the standard solution is measured, and a standard curve based on the bare fiber probe is established;

[0060] Sample a is used as a standard solution of the optical fiber probe for modifying the complementary DNA chain, the concentration of the target substance in the standard solution is measured, and a standard curve based on the optical fiber probe for modifying the complementary DNA chain is established.

[0061] (2) Detection of ricin and abrin in Tris-HCl buffer based on size effect

[0062] First, ricin and abrinus samples were prepared at concentrations of 0, 2.5, 5, 10, 50, 100, 500, and 1000 ng / mL using Tris-HCl buffer. A biological sample c, i.e., a mixed solution of two nucleic acid aptamers with ricin and abrinus toxin, was prepared. The mixed solution was reacted for 1 hour.

[0063] Tris-HCl buffer was passed into the biosensor to clean the optical fiber and obtain a baseline signal for 40 seconds. Next, samples b and c were respectively passed into the biosensor microchannel detection module. At this time, the free aptamer entered the nanopore area on the surface of the bare optical fiber and reacted for 150 seconds. The obtained real-time fluorescence signal was recorded by the built-in computer. After that, SDS and Tris-HCl buffer solutions were passed into the optical fiber probe to clean it in preparation for the next detection.

[0064] Test results such as Figure 2 As shown in the figure, analysis of the test data shows that the detection range for ricin based on the size effect detection mode is 4.09-123.30 ng / mL, with a detection limit of 2.32 ng / mL; the detection range for abrin is 4.47-173.78 ng / mL, with a detection limit of 2.56 ng / mL. Furthermore, the detection of ricin and abrin using the size effect detection mode does not interfere with each other, ensuring accurate data.

[0065] (3) Detection of ricin and abrin in Tris-HCl buffer based on complementary chain hybridization strategy

[0066] First, Tris-HCl buffer was used to prepare ricin and abrinus samples at concentrations of 0, 0.01, 0.1, 1, 10, 100, and 1000 ng / mL. Biological sample c, a mixed solution of two nucleic acid aptamers with ricin and abrinus toxin, was prepared. The mixed solution was reacted for 1 hour, and Tris-HCl buffer was passed into the biosensor to clean the optical fiber and obtain a baseline signal for 40 seconds. Next, sample b and sample c were respectively passed into the microchannel detection module of the biosensor. At this time, the free aptamer bound to the functionalized optical fiber probe modified with the complementary DNA chain and reacted for 500 seconds. The obtained real-time fluorescence signal was recorded by a built-in computer. Then, SDS was passed into the regenerated optical fiber probe 3, and Tris-HCl buffer solution was passed again to clean the optical fiber probe 3 for the next detection.

[0067] Test results such as Figure 3 As shown in the figure, analysis of the test data shows that the detection range for ricin based on the complementary strand hybridization strategy is 0.05-147.84 ng / mL, with a detection limit of 0.0086 ng / mL; the detection range for abrin is 0.04-140.25 ng / mL, with a detection limit of 0.004 ng / mL. Furthermore, the detection of ricin and abrin using the complementary strand hybridization strategy does not interfere with each other, ensuring accurate data.

Claims

1. A dual-mode analytical detection method for the simultaneous detection of ricin and abrin, characterized in that: The dual mode is a mode based on size effect and a mode based on complementary chain hybridization strategy, comprising the following steps: S1 Preparation of functionalized fiber optic probe: The functionalized optical fiber probes include bare optical fiber probes and optical fiber probes modified with complementary DNA chains; The bare fiber probe is prepared by removing a portion of the coating layer of the multimode quartz optical fiber and then etching the portion without the coating layer in a mixed solution of hydrofluoric acid and HNO3; After removing the coating layer of the remaining part of the multimode quartz optical fiber, it is cleaned with piranha solution to obtain a bare optical fiber probe; The preparation method of a fiber optic probe for modifying complementary DNA chains comprises the following steps: based on a bare fiber optic probe, the fiber optic probe is immersed in a toluene solution containing γ-aminopropyltriethoxysilane for reaction, and after drying, is immersed in a glutaraldehyde aqueous solution for reaction; after the reaction, the fiber optic probe is immersed in a mixed solution of ricin and abrin complementary DNA chains, and after sufficient reaction, it is washed with a buffer solution to remove excess complementary DNA chains; the fiber optic probe is then immersed in a blocking solution for sufficient reaction to block nonspecific adsorption sites, and is washed with a buffer solution to obtain a fiber optic probe for modifying complementary DNA chains; The sequences of the complementary DNA chains of the ricin and abrin toxin nucleic acid aptamers are respectively: 5′-TTTTAGTCTCCGGAGGCGTTGCGTCTGCCTGCGGTGGGAAAAAA-3′, 5′-TTTCCTTGCTATGCATGAGCATTCCTCACAGAAAAAA-3′; Preparation of S2 standard curve: Sample a: several groups of solutions containing ricin nucleic acid aptamers and abrin nucleic acid aptamers at different concentrations; The sequences of the ricin toxin and abrinus toxin nucleic acid aptamers are 5′-TTTTTTCCCACCGCAGGCAGACGCAACGCCTCGGAGACTAAAA-3′ and are labeled with Cy5.5 fluorescent dye, and 5′-TTTTTTCTGTGAGGAATGCTCATGCATAGCAAGGAAA-3′ and are labeled with Cy3 fluorescent dye; Sample b: several groups of solutions containing ricin and abrin at different concentrations; Standard concentration solutions were prepared by using gradient concentrations of sample a, sample b, and mixed solutions of sample a and sample b to determine standard curves for bare fiber probes and fiber probes modified with complementary DNA chains; S3 Simultaneous detection of ricin and abrin based on size effect and complementary chain hybridization strategy: The evanescent wave dual-color fiber optic biosensor includes an all-fiber optical system and a microfluidic sampling module; the all-fiber optical system includes a laser, an optical switch, a single / multimode fiber coupler for fluorescence coupling and transmission, a filter, a functionalized fiber optic probe, and a photodetector; the microfluidic sampling module includes a pump, a multi-position valve, and a microchannel sample cell; the functionalized fiber optic probe is immersed in the microchannel sample cell; S3-1: adding an excess of ricin and abrin nucleic acid aptamers to a biological sample solution containing ricin and abrin to obtain a test sample c; S3-2: Installing a bare fiber probe and a fiber probe modified with complementary DNA chains into an evanescent wave dual-color fiber biosensor; passing a buffer solution into the evanescent wave dual-color fiber biosensor, and using laser excitation to generate baseline signals; The wavelength for detecting ricin is 620-680nm, and the wavelength for detecting abrin toxin is 510-570nm; S3-3: The sample c to be tested is introduced into the microchannel detection module of the sensor, reacting with the bare optical fiber probe and the optical fiber probe modified with complementary DNA strands, respectively, and the instrument detects the signal; S4: Determine the concentrations of ricin and abrin based on the prepared standard curve.

2. The dual-mode analysis and detection method for simultaneous detection of ricin and abrin according to claim 1, characterized in that: When detecting ricin and abrin, the wavelengths of the lasers of the evanescent wave dual-color fiber optic biosensor are 635nm and 520nm, respectively.

3. The dual-mode analysis and detection method for simultaneous detection of ricin and abrin according to claim 1, characterized in that: When the concentration of ricin and abrin is above 4 ng / mL, dual-mode detection using a bare fiber optic probe and modified complementary DNA chains is used; when the concentration of ricin and abrin is below 4 ng / mL, detection based on a complementary chain hybridization strategy using a fiber optic probe modified with complementary DNA chains is used.

4. The dual-mode analysis and detection method for simultaneous detection of ricin and abrin according to claim 1, characterized in that: Under the detection mode based on complementary chain hybridization strategy, the detection range of ricin is 0.05-147.84 ng / mL, and the detection limit is 0.0086 ng / mL; the detection range of abrin toxin is 0.04-140.25 ng / mL, and the detection limit is 0.004 ng / mL.

5. The dual-mode analysis and detection method for simultaneous detection of ricin and abrin according to claim 1, characterized in that: In the detection mode based on size effect, the detection range of ricin is 4.09~123.30ng / mL, and the detection limit is 2.32ng / mL; the detection range of abrin toxin is 4.47~173.78ng / mL, and the detection limit is 2.56ng / mL.

6. The dual-mode analysis and detection method for simultaneous detection of ricin and abrin according to claim 1, characterized in that: The buffer solution is Tris-HCl buffer.

7. The dual-mode analysis and detection method for simultaneous detection of ricin and abrin according to claim 1, characterized in that: The bare optical fiber probe and the optical fiber probe modified with complementary DNA chain are regenerated by SDS regeneration solution and Tris-HCl buffer after use.

8. The dual-mode analysis and detection method for simultaneous detection of ricin and abrin according to claim 1, characterized in that: The mixed solution of hydrofluoric acid and HNO3 is V(HNO3):V(HF)=1:10~1:2, and the corrosion treatment is 2~4h.

9. The dual-mode analysis and detection method for simultaneous detection of ricin and abrin according to claim 1, characterized in that: After the bare optical fiber is treated with aldehyde, it is immersed in a mixed solution of ricin and abrin complementary DNA chains at a concentration of 1 to 5 μmol / L and reacted at 4°C overnight.

10. A functionalized optical fiber probe for simultaneous detection of ricin and abrin, comprising a bare optical fiber probe and an optical fiber probe modified with a complementary DNA chain, prepared by step S1 of the method according to any one of claims 1 to 9.

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