CN111562381A - Antibody array card for detecting three fungaltoxins by bifunctional antigen-guided universal signal - Google Patents

Antibody array card for detecting three fungaltoxins by bifunctional antigen-guided universal signal Download PDF

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CN111562381A
CN111562381A CN202010310617.9A CN202010310617A CN111562381A CN 111562381 A CN111562381 A CN 111562381A CN 202010310617 A CN202010310617 A CN 202010310617A CN 111562381 A CN111562381 A CN 111562381A
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郭杰标
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Shaoguan University
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Abstract

The invention relates to an antibody array card for detecting three fungaltoxins by using bifunctional antigen-guided universal signals, which comprises a lining plate, and a bifunctional antigen release pad, a universal fluorescent probe release pad, a chromatographic membrane and a water absorption pad which are sequentially adhered to the lining plate and partially overlapped between the adjacent lining plate; the bifunctional antigen release pad comprises a specific marker coupled on the basis of detection antigens respectively coupled by ovalbumin and FB1, DON and F-2; the universal fluorescent probe release pad comprises a universal fluorescent probe labeled with an anti-specific marker antibody; the chromatographic membrane is provided with a detection line A, B, C and a quality control line, wherein the detection line A, B, C is respectively fixed with an anti-FB 1 antibody, an anti-DON antibody and an anti-F-2 antibody, and the quality control line is fixed with an anti-specific marker antibody. The invention can solve the production of all detection reagents by using a universal fluorescent probe, thereby reducing the cost and improving the quality control reliability; but also increases the signal intensity and stability of detection, and improves the detection sensitivity and the quantitative precision.

Description

Antibody array card for detecting three fungaltoxins by bifunctional antigen-guided universal signal
Technical Field
The invention relates to the field of food and drug safety detection, in particular to an antibody array card for detecting three fungaltoxins by using bifunctional antigen-guided universal signals.
Background
The mycotoxins are secondary metabolites produced by fungi, more than 300 mycotoxins with different chemical structures are known at present, and the mycotoxins produced by more than 30 fungal strains have carcinogenicity, genetic toxicity and teratogenicity on human and livestock, can also cause liver toxicity, kidney toxicity and abnormal reproduction and inhibit immune response, and are huge in toxicity and harmfulness.
There is global concern that agricultural products may be contaminated with various fungi and thus metabolically produce a mixed contamination of various mycotoxins. Authoritative research at home and abroad shows that grain and oil crops such as peanuts, corns, soybeans and the like are possibly polluted by F-2 toxin generated by fumonisin B1(FB1), Deoxynivalenol (DON) and fusarium graminearum.
At present, the confirmation method for detecting the illegal addition of FB1, DON and F-2 is high performance liquid chromatography and liquid-mass spectrometry detection. However, the methods have the disadvantages of large equipment investment, high operating cost, complex sample pretreatment, incapability of on-site detection and difficulty in large-scale screening of basic samples. The immunofluorescence detection method based on the nano material is sensitive, specific, rapid and cheap, has been widely applied in the fields of environmental monitoring and food safety, and is more and more hopeful in rapid detection of food and drug safety. The existing fast detection methods of FB1, DON and F-2 have fast development of immunofluorescence detection methods, but each immunoreagent can only detect 1-2 mycotoxins.
The high-throughput detection is a detection which simultaneously provides various information, improves the information throughput of an immunological detection technology, and is a popular subject for ensuring the food safety guarantee level. Aiming at the characteristics of universality, diversity of types and residual trace of mycotoxin sources, the corresponding immunoassay detection technology is developing towards the direction of high flux, high sensitivity, high specificity, high efficiency-cost ratio and high reliability. The immune array is also called as an immune chip, integrates a plurality of immune detection elements through a specific technical form to form a superposition of a series of immune detection technologies, and is a promising high-throughput biological detection technology.
The immune array comprises a plurality of immune detection units, and each detection unit is provided with a detection antigen, a detection antibody and a signal probe. Signal probes are important factors affecting detection performance and are usually prepared specifically for each unit requirement. The ordered release, specific identification and background control of the signal probes on the immune chip are relatively complex problems, and mutual interference among the probes is easy to cause misjudgment of results. If a working mechanism is innovated, signals of all the immunodetection units can be ensured by using the universal probe, and the method has positive significance for reducing the production cost of the array and improving the performance and quality stability of the chip.
Disclosure of Invention
Based on the defects of the detection method, the invention aims to provide an antibody array card for detecting three fungaltoxins by using a bifunctional antigen-guided universal signal.
The technical scheme adopted by the invention is as follows:
an antibody array card for detecting three fungaltoxins by bifunctional antigen-guided universal signals comprises a lining plate, and a bifunctional antigen release pad, a universal fluorescent probe release pad, a chromatographic membrane and a water absorption pad which are sequentially adhered to the lining plate and partially overlapped between the adjacent lining plate; the bifunctional antigen release pad comprises a specific marker coupled on the basis of detection antigens respectively coupled by ovalbumin and FB1, DON and F-2; the universal fluorescent probe release pad comprises a universal fluorescent probe labeled with an anti-specific marker antibody; the chromatographic membrane is provided with a detection line A, a detection line B, a detection line C and a quality control line, wherein the detection line A, the detection line B and the detection line C are respectively fixed with anti-FB 1, anti-DON and anti-F-2 antibodies, and the quality control line is fixed with an anti-specific marker antibody.
Preferably, the specific marker is 7-amino-4-hydroxy-2-naphthalenesulfonic acid.
The bifunctional antigen is simultaneously connected with a hapten (FB1, DON or F-2) and a plurality of markers (7-amino-4-hydroxy-2-naphthalenesulfonic acid) on a carrier protein (OVA). The double-function characteristic is that: the hapten is combined with a detection antibody, the label is combined with the bifunctional antigen-guided universal probe, and a detection signal is formed by stacking the universal probes mediated by a sandwich immune complex formed on the detection line A, the detection line B and the detection line C respectively; the plurality of markers on the bifunctional antigen are respectively combined with the bifunctional antigen guide on the quality control line and the universal probe to form another sandwich immune complex on the quality control line to mediate the universal probe to accumulate to form a detection signal.
Compared with the traditional binary system immune competition method, the detection card provided by the invention utilizes the principle of the sandwich immune competition method, and adds a universal antibody aiming at the bifunctional antigen marker 7-amino-4-hydroxy-2-naphthalenesulfonic acid in addition to two immune detection elements of the bifunctional antigen and the detection antibody. The invention synthesizes bifunctional antigen by respectively and covalently connecting detection substances FB1, DON and F-2 on carrier protein (ovalbumin), marking a general antibody (an anti-7-amino-4-hydroxy-2-naphthalenesulfonic acid antibody) on a quantum dot, fixing a detection antibody 1 (an anti-FB 1 antibody) on a detection line A of a chromatographic membrane, fixing a detection antibody 2 (an anti-DON antibody) on a detection line B of the chromatographic membrane, fixing a detection antibody 3 (an anti-F-2 antibody) on a detection line C of the chromatographic membrane, therefore, the detection substance coupled on the bifunctional antigen is captured by the detection antibody, the universal antibody is combined with the '7-amino-4-hydroxy-2-naphthalenesulfonic acid' coupled on the bifunctional antigen to form a sandwich immune complex, and a fluorescence detection signal is generated on a corresponding detection line. When the detection antibody is bound by the free detection substance, the fluorescence intensity on the corresponding detection line will be suppressed, thereby generating an suppressed detection signal.
Specifically, a sample solution is dripped onto the bifunctional antigen release pad during detection, the bifunctional antigen and the general fluorescent probe are dissolved in the movement process of the sample solution and are carried to a detection line A, a detection line B, a detection line C and a quality control line, and an anti-7-amino-4-hydroxy-2-naphthalenesulfonic acid antibody and the bifunctional antigen which are marked by the carried general fluorescent probe respectively form a sandwich immuno conjugate with an anti-FB 1 antibody on the detection line A, an anti-DON on the detection line B and an anti-F-2 antibody on the detection line C, so that the detection line generates a fluorescent signal; the carried general fluorescent probe labeled antibody of 7-amino-4-hydroxy-2-naphthalenesulfonic acid is combined with the antibody of 7-amino-4-hydroxy-2-naphthalenesulfonic acid fixed on the quality control line, and is accumulated on the quality control line to form a fluorescent signal. When free FB1, DON and F-2 in the sample reach a certain concentration, immunoreactions on the detection line A, the detection line B and the detection line C are competitively blocked by corresponding detection products, and a fluorescence signal is inhibited; while the fluorescence signal on the quality control line is generated based on the 7-amino-4-hydroxy-2-naphthalenesulfonic acid and is not affected by the concentration of three mycotoxins.
Because the marker molecules are introduced into the bifunctional antigens and the anti-marker molecule antibody is used for constructing the universal fluorescent probe, the production of all detection reagents can be realized by using one universal fluorescent probe, so that the cost is reduced and the quality control reliability is improved; and the signal intensity and stability of detection can be increased, and the detection sensitivity and the quantitative precision are improved.
Further, the bifunctional antigen release pad is prepared by absorbing PBS (phosphate buffer solution) containing three bifunctional antigens, a surfactant, mannitol and sucrose by adopting a glass cellulose membrane. Preferably, PBS solutions containing two concentrations of 20. mu.g/mL labeled diclofenac detection antigen, 25. mu.g/mL labeled indomethacin detection antigen, 50. mu.g/mL surfactant, 30mg/mL mannitol, 50mg/mL sucrose, respectively, are well absorbed by a 0.85mm thick glass cellulose membrane. Wherein, mannitol is used as a freeze-drying bracket for ensuring that the bifunctional antigen is rapidly dissolved in the detection process; the sucrose is used for adjusting the viscosity of the detection solution and controlling the chromatographic development speed; the surfactant is used for eliminating non-specific adsorption in the detection process, and preferably polyethylene glycol octyl phenyl ether (Triton X-100); the three bifunctional antigens are respectively synthesized by OVA/FB1, OVA/DON and OVA/F-2 through covalent coupling, and then are marked with 7-amino-4-hydroxy-2-naphthalenesulfonic acid to become the bifunctional antigen. The detection antibody can be combined on the membrane, and can also be combined by the universal antibody on the quantum dot.
Furthermore, the universal fluorescent probe release pad is prepared by absorbing PBS (phosphate buffer solution) containing the quantum dot fluorescent probe, polyethylene glycol, mannitol, sucrose and glycine by adopting a cellulose membrane. Preferably, a PBS solution containing 30. mu.g/mL universal quantum dot fluorescent probe, 60. mu.g/mL polyethylene glycol (PEG-500), 10mg/mL mannitol, 60mg/mL sucrose, 10mg/mL glycine is absorbed by a cellulose-based membrane with a thickness of 0.34 mm. Wherein, the mannitol is used as a freeze-drying bracket for ensuring that the universal fluorescent probe is quickly dissolved in the detection process; the polyethylene glycol and the sucrose are used for adjusting the viscosity of the detection solution and controlling the chromatographic development speed; glycine is used for eliminating nonspecific adsorption in the detection process; the quantum dot fluorescent probe is formed by labeling an anti-7-amino-4-hydroxy-2-naphthalenesulfonic acid antibody on the surface of a quantum dot, and can be combined with a bifunctional antigen captured on three detection lines and the anti-7-amino-4-hydroxy-2-naphthalenesulfonic acid antibody fixed on a quality control line to respectively generate fluorescent detection signals.
Further, the chromatographic membrane adopts a nitrocellulose membrane, and the detection line A is prepared by spraying a PBS solution containing an anti-FB 1 antibody and sucrose on the nitrocellulose membrane; the detection line B is prepared by spraying a PBS solution containing an anti-DON antibody and sucrose on a nitrocellulose membrane; the detection line C is prepared by spraying a PBS solution containing an anti-F-2 antibody and sucrose on a nitrocellulose membrane. Preferably, a 0.05MPBS solution (pH 7.4) containing 0.3mg/mL of anti-FB 1, anti-DON, anti-F-2 antibody, and 10mg/mL of sucrose is sprayed onto a nitrocellulose membrane in an amount of 3.0. mu.g/cm. The basis for the formation of the fluorescence signal of the detection line is the immunoreaction of the antibody and three fungaltoxins coupled with the bifunctional antigen, and the corresponding free fungaltoxins in the detected product compete for inhibition.
Further, the control line was prepared by spraying a PBS solution containing an anti-7-amino-4-hydroxy-2-naphthalenesulfonic acid antibody and sucrose on a nitrocellulose membrane. Preferably, a 0.05M PBS solution (pH 7.4) containing 0.3mg/mL 7-amino-4-hydroxy-2-naphthalenesulfonic acid antibody and 10mg/mL sucrose is sprayed on a nitrocellulose membrane in an amount of 1.0 to 3.0. mu.g/cm. The basis of the formation of the fluorescence signal of the quality control line is that the quantum dots and the quality control line both contain anti-7-amino-4-hydroxy-2-naphthalenesulfonic acid antibodies, and respectively generate immunoreaction with the 7-amino-4-hydroxy-2-naphthalenesulfonic acid antibodies on the detection antigen to form a sandwich immune complex, so that the detection signal generated on the quality control line is irrelevant to a target detection product and can not compete and inhibit three free mycotoxins in the detected product.
The invention also comprises a detection method for simultaneously detecting three mycotoxins of cereal crops, which comprises the following steps:
s1, preparing a bifunctional antigen, a general fluorescent probe, a detection line and a quality control line; the three bifunctional antigens are respectively coupled with FB1, DON and F-2 by ovalbumin and then labeled with 7-amino-4-hydroxy-2-naphthalenesulfonic acid, the universal fluorescent probe is labeled with an anti-7-amino-4-hydroxy-2-naphthalenesulfonic acid antibody, the detection line A is fixed with an anti-FB 1 antibody, the detection line B is fixed with an anti-DON antibody, and the detection line C is fixed with an anti-F-2 antibody; the quality control line is fixed with an anti-7-amino-4-hydroxy-2-naphthalenesulfonic acid antibody;
s2: mixing a sample solution, three bifunctional antigens and a universal fluorescent probe, conveying the mixture to a detection line A, a detection line B, a detection line C and a quality control line together, judging whether the sample contains FB1, DON and F-2 or not according to fluorescent signals of the three detection lines and the quality control line, and determining the concentrations of the three mycotoxins.
FB1, DON and F-2 mycotoxin are small molecular compounds, the immunodetection principle of the conventional detection of small molecular compounds is a binary system immune competition method formed by a bifunctional antigen and a detection antibody, and aiming at the defects of the method in quantum dot lateral immunochromatography, the invention adds a universal antibody on the basis of the bifunctional antigen to form a double-antibody immune competition method with the detection antibody, and adjusts the combination of various immune reaction elements in a chromatographic system.
Taking the signal of detection line a as an example: and fixing the FB1 antibody on the detection line A, and connecting labels on the quantum dots to form a universal probe. The FB1 bifunctional antigen is respectively combined and 'bridged' with two antibodies to form an 'double antibody' immune complex of [ FB1 antibody- (FB1 hapten-OVA-marker) -marker antibody ], and the marker antibody mediates the accumulation of a universal probe to form a fluorescent signal. When the FB1 antibody is bound by free FB1 toxin, the fluorescence intensity will be suppressed, thereby generating an inhibitory detection signal.
Similarly, a [ DON antibody- (DON hapten-OVA-marker) -marker antibody ] double-antibody immune complex is formed on the detection line B, and a [ F-2 antibody (F-2 hapten-OVA-marker) -marker antibody ] "double-antibody immune complex" is formed on the detection line C, so that a fluorescence signal which can be inhibited by free mycotoxin is generated.
Further, step S2 is performed to determine whether the sample contains three mycotoxins by the following method: the detection line A, the detection line B, the detection line C and the quality control line all display fluorescence signals, the result is judged to be negative, and the sample does not contain FB1, DON and F-2; the detection line A does not display a fluorescence signal, the quality control line displays a fluorescence signal, and FB1 in the sample is judged; the detection line B does not display a fluorescence signal, the quality control line displays a fluorescence signal, and the DON in the sample is judged; the detection line C does not display a fluorescence signal, the quality control line displays a fluorescence signal, and the sample is judged to contain F-2. The quality control line is set for checking whether the method is effective or not, the quality control line displays a fluorescent signal to indicate that the method is effective, and the quality control line does not display the fluorescent signal to indicate that the method is ineffective.
Further, step S2 determines the concentrations of the three mycotoxins by: the fluorescence signal intensity detection value of the quality control line is defined as a C value, the fluorescence signal intensity detection values of 3 detection lines are respectively defined as a T1 value, a T2 value and a T3 value, and a standard curve is established according to the T/C ratio of each detection line so as to measure the specific concentration.
As the toxin concentration increases, the detection line signal is suppressed and the T/C ratio tends to 0. The range of toxin concentrations from inhibition of production to complete disappearance of signal is defined as the linear range. Linear range of FB 1: 0.01-3.0 ng/mL; linear range of DON: 0.01-3.0 ng/mL; f-2 Linear Range: 0.01-3.0 ng/mL. In the actual detection, the concentration of mycotoxin is calculated on a standard curve according to the T/C ratio of each detection line actually measured.
Further, the universal fluorescent probe generates 630nm emitted light under the excitation of a 365nm light source.
Compared with the prior art, the invention has the following advantages:
1. the invention introduces a small molecular marker 7-amino-4-hydroxy-2-naphthalenesulfonic acid as an immune recognition site for detecting the antigen, and ensures the stability of the affinity of the universal antibody and the detection antigen. The labeled molecule has strong immunogenicity, high coupling efficiency and good hydrophilicity, can not appear in a sample, and is very suitable for the detection requirement of the invention. The 4-hydroxy-2-naphthalenesulfonic acid is used as an epitope, has super-strong immunogenicity and small steric hindrance, is easy to induce and obtain a high-affinity antibody, and is combined with a marker antibody to guide a universal probe to generate a detection signal, so that the detection signal strength and sensitivity are improved;
2. the quantum dots marked by the anti-7-amino-4-hydroxy-2-naphthalenesulfonic acid antibody are uniformly used for generating detection signals, and the production of reagents of different varieties and different batches can be met only by uniformly preparing the universal probes, so that the scale effect not only improves the production efficiency, but also is beneficial to ensuring the uniformity of the quality of products of different batches;
3. the detection antibody is fixed on the chromatographic membrane, and the activity protection effect on the antibody is more favorable by sealing and drying the membrane, so that the stability of the antibody is improved;
4. the specificity is strong, the detection time is short (5-10 minutes), the field operation can be realized, the fluorescent signal can be excited by means of a portable 360nm light source, the result can be read by naked eyes, the detection cost is low, the operation is simple and convenient, and the kit is suitable for basic level detection personnel to operate.
For a better understanding and practice, the invention is described in detail below with reference to the accompanying drawings.
Drawings
FIG. 1 is a schematic structural diagram of an antibody array card for detecting three mycotoxins by using the bifunctional antigen-guided universal signal.
FIG. 2 shows the diazotization method used to label 7-amino-4-hydroxy-2-naphthalenesulfonic acid onto the carrier protein OVA of the test antigen.
FIG. 3 is a schematic diagram of the formation of immune complexes and the generation of fluorescence signals on the detection lines A, B and C.
FIG. 4 is a schematic diagram of the principle that the fluorescent signals on the detection lines A, B and C are competitively blocked.
FIG. 5 is a schematic diagram of the generation of fluorescence signal due to immunoreaction on the control line.
FIG. 6 shows the principle of generation of the fluorescence immunoassay and the principle of determination of the detection result.
FIG. 7 is a competition inhibition curve of the fluorescent signal formed by FB1 in the detection process in the example.
FIG. 8 is a competition inhibition curve of fluorescence signals generated during the detection of DON in the example.
FIG. 9 is a competition inhibition curve of the fluorescence signal formed during the detection of F-2 in example.
Drawing notes: 1. bifunctional antigen release pad 2, universal fluorescent probe release pad 3, nitrocellulose membrane 31, detection line A311, anti-FB 1 antibody 32, detection line B321, anti-DON antibody 33, detection line C331, anti-F-2 antibody 34, quality control line 4, water absorption pad 5, lining plate 6, sample solution 61, quantum dot 62, "7-amino-4-hydroxy-2-naphthalenesulfonic acid" marker 63, OVA64, coupled FB 1641, free FB 165, anti-7-amino-4-hydroxy-2-naphthalenesulfonic acid "antibody 66, coupled DON 661, free DON 67, coupled F-2671, free F-2
Detailed Description
Example 1
An antibody array card for detecting three fungaltoxins by bifunctional antigen-guided universal signals comprises a lining plate 5, and a bifunctional antigen release pad 1, a universal fluorescent probe release pad 2, a cellulose acetate membrane 3 and a water absorption pad 4 which are sequentially adhered to the lining plate 5 and partially overlapped between the adjacent lining plates; the bifunctional antigen release pad comprises a detection antigen which is formed by respectively coupling ovalbumin, FB1, DON and F-2 and a '7-amino-4-hydroxy-2-naphthalenesulfonic acid' marker 62; the universal fluorescent probe release 1 pad comprises a universal fluorescent probe marked with an anti-7-amino-4-hydroxy-2-naphthalenesulfonic acid antibody 65, and the fluorescent probe is a quantum dot 61; the cellulose acetate membrane 3 is provided with a detection line A, a detection line B, a detection line C and a quality control line 34, wherein the detection line A, the detection line B and the detection line C are respectively fixed with an anti-FB 1 antibody 311, an anti-DON antibody 321 and an anti-F-2 antibody 331, and the quality control line 34 is fixed with an anti-7-amino-4-hydroxy-2-naphthalenesulfonic acid antibody 65.
Referring to fig. 1, in this example, detection substances FB1, DON and F-2 are covalently linked to a carrier protein (ovalbumin) to synthesize a bifunctional antigen, and 7-amino-4-hydroxy-2-naphthalenesulfonic acid is labeled to the detection antigen to prepare a labeled detection antigen. Labeling a marker antibody on a quantum dot, fixing a detection antibody 1(FB1 antibody) on a detection line A of a chromatographic membrane, fixing a detection antibody 2(DON antibody) on a detection line B of the chromatographic membrane, and fixing a detection antibody 3(F-2 antibody) on a detection line C, so that the detection antibody captures a target toxin hapten coupled on the bifunctional antigen, and a general antibody is combined with the marker coupled on the bifunctional antigen to form a double-antibody immune complex, and a fluorescence detection signal is generated on the corresponding detection line. When the detection antibody is bound by the free detection substance, the fluorescence intensity on the corresponding detection line will be suppressed, resulting in an suppressed detection signal.
Referring to FIG. 2, this example uses diazotization to label 7-amino-4-hydroxy-2-naphthalenesulfonic acid marker 62 onto the carrier protein OVA of the test antigen to construct the bifunctional antigen.
Referring to fig. 3, in the present embodiment, a sample solution is dropped onto the bifunctional antigen release pad 1 during detection, three bifunctional antigens and a universal fluorescent probe are dissolved during the movement of the sample solution and are carried to the detection line a, the detection line B, the detection line C and the quality control line, and the anti-7-amino-4-hydroxy-2-naphthalenesulfonic acid antibody 65 and the bifunctional antigen labeled by the universal fluorescent probe form a double-antibody immunoconjugate with the FB1 antibody, the DON antibody and the F-2 antibody on the detection line a, the detection line B and the detection line C, respectively, so that the detection line generates a fluorescent signal.
Referring to fig. 4, the basis of the formation of the fluorescence signal of the quality control line in this embodiment is that the quantum dots 61 and the quality control line 34 both contain the anti-7-amino-4-hydroxy-2-naphthalenesulfonic acid antibody 65, and the anti-7-amino-4-hydroxy-2-naphthalenesulfonic acid antibody 65 on the detection antigen and respectively generate immunoreaction to form a "double antibody immune complex", so that the detection signal generated on the quality control line 34 is independent of the target test product. When free FB1, DON or F-2 in the sample reaches a certain concentration, immunoreactions on the detection line A, the detection line B and the detection line C are competitively blocked by corresponding detection products, and a fluorescence signal is inhibited; while the fluorescent signal on the control line 34 is not affected by the toxin in the sample.
Specifically, the preparation method of the bifunctional antigen release pad comprises the following steps: a PBS solution containing 30. mu.g/mL FB1 bifunctional antigen, 35. mu.g/mL DON bifunctional antigen, 25. mu.g/mL F-2 bifunctional antigen, 50. mu.g/mL Triton X-100, 30mg/mL mannitol and 50mg/mL sucrose was sufficiently absorbed by a 0.85mm thick glass cellulose membrane, and was freeze-dried for use.
Specifically, the preparation method of the universal fluorescent probe release pad comprises the following steps: a PBS solution containing 30. mu.g/mL universal fluorescent probe, 60. mu.g/mL PEG-500, 10mg/mL mannitol, 60mg/mL sucrose, 10mg/mL glycine was absorbed by a Whatman 85 cellulose membrane having a thickness of 0.34mm, and was lyophilized for use.
Specifically, the preparation method of the detection line is as follows: 0.20mg/mL FB1 antibody, 0.25mg/mL DON antibody, and 0.15mg/mL F-2 antibody were prepared from 10mg/mL sucrose in 0.05M PBS (pH 7.4), and sprayed onto the set areas on the nitrocellulose membrane in an amount of 3.0. mu.g/cm, respectively, to form test line A, test line B, and test line C.
Specifically, the preparation method of the quality control line comprises the following steps: A0.05M PBS solution (pH 7.4) containing 0.3mg/mL of an anti-7-amino-4-hydroxy-2-naphthalenesulfonic acid antibody and 10mg/mL of sucrose was sprayed on a nitrocellulose membrane in an amount of 1.0 to 3.0. mu.g/cm to form a quality control line.
Example 2
The detection method for simultaneously detecting FB1, DON and F-2 is shown in FIG. 6, and comprises the following steps:
taking 5g of crushed cereal crop samples, fully extracting the samples in 25mL of 70% methanol-water solution, centrifuging at 5000rpm for 10 minutes, taking 2.0mL of supernatant, adding 8.0mL of PBS buffer solution, and fully shaking up to obtain sample solution; dripping 3-4 drops of sample solution on the bifunctional antigen release pad by a dropper, releasing the bifunctional antigen and the universal fluorescent probe in the process that the sample solution moves to the nitrocellulose membrane, sequentially crossing the detection line and the quality control line, and judging whether the sample contains FB1, DON and F-2 according to fluorescent signals on the detection line A, the detection line B, the detection line C and the quality control line.
See fig. 5. An FB1 antibody 311 fixed on a nitrocellulose membrane detection line A and an anti-7-amino-4-hydroxy-2-naphthalenesulfonic acid antibody 65 marked on a general fluorescent probe are respectively combined with bifunctional antigens to form a double-antibody immunoconjugate, so that the detection line generates a fluorescent detection signal. When free FB1 is present in the sample to a certain concentration, the immune response on the detection line is blocked by competition, and the fluorescence signal disappears. Similarly, for the detection lines B and C of DON and F-2, the formation and judgment of the detection signals are the same as those of the detection line A. The quality control line is set by providing a reference for the fluorescence signal, and the color development is effective, and the non-color development indicates that the method is not effective.
Referring to FIGS. 6-9, the universal fluorescent probe produces 630nm emission when excited by a 365nm light source.
In this embodiment, the principle of determining the detection result is as follows:
1) as shown in FIG. 6, the fluorescence signal intensity detection value of the quality control line is defined as a C value, the fluorescence signal intensity detection values of the 3 detection lines are defined as a T1 value, a T2 value and a T3 value, respectively, and the ratio of the detection line signal and the quality control line signal is defined as a T/C ratio.
According to the optimized target of the universal probe antibody array card, the concentrations of 3 mycotoxins are all equal to the reference value of 0, and the optimal situation is as follows: T1/C value T2/C value T3/C value 1. Due to microscopic deviation and steric hindrance of the solid phase carrier, deviation and fluctuation of 15-20% exist in T/C ratio of fluorescence immunochromatography reported in the literature. Due to the overcoming of steric hindrance caused by the uniform and double antibody effect of the universal signal, the T/C ratio deviation of the antibody array card is controlled to be 10-15%.
2) Based on the above, the detection result is shown as a in the schematic diagram 6: each detection line and quality control line show sufficient fluorescence signals, the T1/C value, the T2/C value and the T2/C value are all more than 85 percent, and the fact that the sample does not contain FB1, DON and F-2 can be judged;
3) according to the optimization result of the antibody array card, the concentration of FB1 in the sample solution is more than 3.0ng/mL, the concentration of DON is more than 3.0ng/mL, the concentration of F-2 is more than 3.0ng/mL, and the detection line corresponding to mycotoxin completely disappears. As shown in B-d in fig. 6, one of the detection lines a, B and C disappears, and the quality control line shows a fluorescence signal, which can determine the corresponding standard for completely blocking the content of mycotoxin;
4) as shown in FIG. 6 as e1-e 4: when the control line does not show a fluorescent signal, it indicates that the detection reagent has failed.
5) As shown in fig. 7-9, as toxin concentration increased, the detection line signal was suppressed and the T/C ratio tended to 0. The range of toxin concentrations from inhibition of production to complete disappearance of signal is defined as the linear range. Linear range of FB 1: 0.01-3.0 ng/mL; linear range of DON: 0.01-3.0 ng/mL; f-2 Linear Range: 0.01-3.0 ng/mL. In the actual detection, the concentration of mycotoxin is calculated on a standard curve according to the T/C ratio of each detection line actually measured.
Compared with the prior art, the ternary system immune competition method adopted by the embodiment has the following advantages: 1. the general probe for resisting the mark of the marked object is uniformly used, only one general probe is required to be intensively prepared to be used as a fluorescent probe, and the scale and standardization of the detection work are facilitated; 2. the detection antibody is fixed on the chromatographic membrane, and the activity protection effect on the antibody is more favorable by sealing and drying the membrane, so that the stability of the antibody is improved; 3. when the antibody is used for immune binding, the steric hindrance is smaller, and the detection signal intensity and sensitivity are improved.
In the above examples, the methods for inducing and generating antibodies specific to FB1, DON and F-2, the method for inducing and generating antibodies against 7-amino-4-hydroxy-2-naphthalenesulfonic acid, the method for labeling the antibodies against 7-amino-4-hydroxy-2-naphthalenesulfonic acid on quantum dots, and the method for preparing quantum dot fluorescent probes all adopt the prior art.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.

Claims (10)

1. An antibody array card for detecting three fungaltoxins by bifunctional antigen-guided universal signals is characterized by comprising a lining plate, and a bifunctional antigen release pad, a universal fluorescent probe release pad, a chromatographic membrane and a water absorption pad which are sequentially adhered to the lining plate and partially overlapped between the adjacent two; the bifunctional antigen release pad comprises a specific marker coupled on the basis of detection antigens respectively coupled by ovalbumin and FB1, DON and F-2; the universal fluorescent probe release pad comprises a universal fluorescent probe labeled with an anti-specific marker antibody; the chromatographic membrane is provided with a detection line A, a detection line B, a detection line C and a quality control line, wherein the detection line A, the detection line B and the detection line C are respectively fixed with anti-FB 1, anti-DON and anti-F-2 antibodies, and the quality control line is fixed with an anti-specific marker antibody.
2. The antibody array card of claim 1, wherein said specific label is 7-amino-4-hydroxy-2-naphthalenesulfonic acid.
3. The antibody array card of claim 1, wherein the bifunctional antigen releasing pad is prepared by absorbing a PBS solution containing three bifunctional antigens, a surfactant, mannitol, and sucrose with a glass cellulose membrane.
4. The antibody array card of claim 1, wherein the universal fluorescent probe releasing pad is made by absorbing PBS solution containing quantum dot fluorescent probes, polyethylene glycol, mannitol, sucrose and glycine with a cellulose membrane.
5. The antibody array card of claim 1, wherein the chromatographic membrane is nitrocellulose membrane; the detection line A is prepared by spraying a PBS solution containing an anti-FB 1 antibody and sucrose on a nitrocellulose membrane; the detection line B is prepared by spraying a PBS solution containing an anti-DON antibody and sucrose on a nitrocellulose membrane; the detection line C is prepared by spraying a PBS solution containing an anti-F-2 antibody and sucrose on a nitrocellulose membrane.
6. The antibody array card of claim 1, wherein said control line is prepared by spraying a PBS solution containing an anti-7-amino-4-hydroxy-2-naphthalenesulfonic acid antibody and sucrose on a nitrocellulose membrane.
7. The detection method for simultaneously detecting three mycotoxins of cereal crops is characterized by comprising the following steps:
s1, preparing a bifunctional antigen, a general fluorescent probe, a detection line and a quality control line; the three bifunctional antigens are respectively coupled with FB1, DON and F-2 by ovalbumin and then labeled with 7-amino-4-hydroxy-2-naphthalenesulfonic acid, the universal fluorescent probe is labeled with an anti-7-amino-4-hydroxy-2-naphthalenesulfonic acid antibody, the detection line A is fixed with an anti-FB 1 antibody, the detection line B is fixed with an anti-DON antibody, and the detection line C is fixed with an anti-F-2 antibody; the quality control line is fixed with an anti-7-amino-4-hydroxy-2-naphthalenesulfonic acid antibody;
s2: mixing a sample solution, three bifunctional antigens and a universal fluorescent probe, conveying the mixture to a detection line A, a detection line B, a detection line C and a quality control line together, judging whether the sample contains FB1, DON and F-2 or not according to fluorescent signals of the three detection lines and the quality control line, and determining the concentrations of the three mycotoxins.
8. The method for detecting according to claim 7, wherein the step S2 is performed by determining whether the sample contains three mycotoxins by: the detection line A, the detection line B, the detection line C and the quality control line all display fluorescence signals, the result is judged to be negative, and the sample does not contain FB1, DON and F-2; the detection line A does not display a fluorescence signal, the quality control line displays a fluorescence signal, and FB1 in the sample is judged; the detection line B does not display a fluorescence signal, the quality control line displays a fluorescence signal, and the DON in the sample is judged; the detection line C does not display a fluorescence signal, the quality control line displays a fluorescence signal, and the sample is judged to contain F-2.
9. The method according to claim 7, wherein the step S2 is performed by the following steps: the fluorescence signal intensity detection value of the quality control line is defined as a C value, the fluorescence signal intensity detection values of 3 detection lines are respectively defined as a T1 value, a T2 value and a T3 value, and a standard curve is established according to the T/C ratio of each detection line so as to measure the specific concentration.
10. The detection method according to claim 7, wherein the universal fluorescent probe generates 630nm of emission light under the excitation of 365nm light source.
CN202010310617.9A 2020-04-20 2020-04-20 Antibody array card for detecting three fungaltoxins by bifunctional antigen-guided universal signal Pending CN111562381A (en)

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