Integrated food-borne pathogenic bacterium magnetic separation pretreatment system and target bacterium magnetic separation method based on magnetic covalent organic framework material

Abstract

The invention discloses an integrated food-borne pathogenic bacterium magnetic separation pretreatment system and a target bacterium magnetic separation method based on a magnetic covalent organic framework material, relates to the technical field of food safety detection, and solves the problem that a magnetic separation device in the prior art is difficult to meet high-throughput detection requirements. The system comprises a plurality of sample containers, the sample containers are connected with a peristaltic pump through a pipe network, the sample containers are respectively used for storing sample liquid and reaction liquid, the peristaltic pump is communicated with a dynamic magnetic field reaction chamber, and the dynamic magnetic field reaction chamber is connected with a sample collection container; an electromagnetic coil is arranged outside the dynamic magnetic field reaction chamber and is connected with a magnetic control module, and the magnetic control module can control the direction and the magnetic field intensity of a magnetic field generated by the electromagnetic coil. The electromagnetic coil is arranged outside the dynamic magnetic field reaction chamber, so that a magnetic field with controllable direction and strength can be provided for the dynamic magnetic field reaction chamber under the action of the magnetic control module, and the separation and enrichment process can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of food safety detection, and in particular to an integrated foodborne pathogenic bacteria magnetic separation pretreatment system and a target bacteria magnetic separation method based on a magnetic covalent organic framework material. Background Art

[0002] Foodborne pathogens are a significant contributor to foodborne illness, posing a serious threat to food safety and human health and posing a significant challenge to healthcare systems worldwide. While existing technologies offer several methods for detecting foodborne pathogens, these methods are often susceptible to interference from complex food matrices, resulting in insufficient sensitivity and accuracy. Effective sample pretreatment is required for accurate and reliable detection results. Traditional pretreatment methods, such as enrichment culture, centrifugation, and filtration, are time-consuming, non-targeted, and present significant limitations. Magnetic separation technology offers the advantages of targeted recognition and rapid separation, enabling the selective isolation and concentration of target bacteria from complex food matrices. It offers advantages such as ease of use and high separation efficiency. Combined with existing high-sensitivity detection methods, it can enable rapid early detection of foodborne pathogens. However, traditional magnetic separation devices rely on small sample volumes (typically ≤5 mL) and a fixed magnetic field, resulting in low mixing efficiency and prolonged separation times, making them unsuitable for high-throughput detection. Probe synthesis and target bacteria capture require separate, step-by-step procedures, relying on manual intervention, which can introduce contamination and reduce efficiency.

[0003] The Chinese invention patent with publication number CN114657063A discloses a magnetic separation device for foodborne pathogens, including: an enrichment mechanism and a magnetic adsorption mechanism. The enrichment mechanism includes a fixed frame, a centrifuge tube and a driver. The centrifuge tube is fixed to the fixed frame and is suitable for holding food sample liquid and immunomagnetic beads; the driver is connected to the fixed frame and is suitable for driving the fixed frame to rotate so that the immunomagnetic beads enrich the pathogens in the food sample liquid; the magnetic adsorption mechanism is detachably arranged on the fixed frame and close to the centrifuge tube, and is used to adsorb the immunomagnetic beads that enrich pathogens to the inner wall of the centrifuge tube.

[0004] This invention utilizes a magnetic adsorption mechanism to effectively improve the separation of foodborne pathogens. However, its reliance on centrifugal and rotary drives makes it difficult to achieve real-time, flexible magnetic field adjustment. Furthermore, it requires an additional step to attach the magnetic beads to the inner wall of the centrifuge tube, increasing operational complexity and time costs. Furthermore, the device requires a significant amount of manual operation. While simple in structure, some operations still require human intervention, which can easily introduce operational errors and affect the accuracy and repeatability of experimental results.

[0005] The present invention aims to provide a rapid and efficient magnetic separation system for foodborne pathogens to meet the urgent needs of food safety testing. Summary of the Invention

[0006] In response to the deficiencies in the above-mentioned background technology, the present invention proposes an integrated foodborne pathogenic bacteria magnetic separation pretreatment system and a target bacteria magnetic separation method based on magnetic covalent organic framework materials, which solves the problem that the magnetic separation devices in the existing technology are difficult to adapt to high-throughput detection requirements.

[0007] The technical solution of the present invention is implemented as follows: an integrated foodborne pathogenic bacteria magnetic separation pretreatment system includes several sample containers, each of which is connected to a peristaltic pump through a pipe network. The sample containers are used to store sample liquid and reaction liquid respectively. The peristaltic pump is connected to a dynamic magnetic field reaction chamber, and the dynamic magnetic field reaction chamber is connected to a sample collection container; an electromagnetic coil is provided outside the dynamic magnetic field reaction chamber, and the electromagnetic coil is connected to a magnetic control module. The magnetic control module can control the direction and intensity of the magnetic field generated by the electromagnetic coil.

[0008] Preferably, the dynamic magnetic field reaction chamber is a cylindrical chamber, and both ends of the dynamic magnetic field reaction chamber are provided with pipe openings and are respectively connected to the peristaltic pump and the sample collection container through the pipe openings.

[0009] Preferably, the pipe network includes an inlet pipe connected to the liquid inlet of the peristaltic pump, the inlet pipe is connected to a multi-way pipe joint, the multi-way pipe joint is respectively connected to several pipes, and respectively connected to the liquid outlet ends of several sample containers through several pipes.

[0010] Preferably, valves are provided on the pipeline and at the pipe openings at both ends of the dynamic magnetic field reaction chamber; the sample collection container includes a fixing frame on which a centrifuge tube is provided.

[0011] Preferably, the magnetic control module includes a power supply, the power supply is connected to the control unit, the control unit is connected to the electromagnetic coil, and the control unit can control the magnetic field direction and magnetic field strength of the electromagnetic coil.

[0012] Preferably, the electromagnetic coil includes a first coil and a second coil, which are alternately spirally wound on the outside of the dynamic magnetic field reaction chamber, and the two ends of the first coil and the second coil are electrically connected to the control unit through wires; the control unit adjusts the magnetic field direction and magnetic field strength by controlling the current in different directions to be passed into the first coil and the second coil respectively.

[0013] Preferably, the electromagnetic coil includes a solenoid spirally wound on the outside of the dynamic magnetic field reaction chamber, and the two ends of the solenoid are electrically connected to the control unit through wires; the control unit adjusts the magnetic field direction and magnetic field strength by controlling the direction and current magnitude of the current passed into the electromagnetic coil.

[0014] Preferably, the electromagnetic coil includes an inner coil and an outer coil, the inner coil and the outer coil have opposite rotation directions and are sequentially arranged layer by layer on the outside of the dynamic magnetic field reaction chamber.

[0015] A method for magnetic separation of target bacteria based on magnetic covalent organic framework materials, using the above-mentioned integrated foodborne pathogenic bacteria magnetic separation pretreatment system, comprises the following steps: A number of sample containers are respectively filled with a magnetic covalent organic framework material sample solution, a target bacteria antibody solution and a PBS reaction buffer solution, a BSA blocking solution, and a sample solution to be tested; The peristaltic pump was turned on to quantitatively inject the magnetic covalent organic framework material sample liquid, target bacteria antibody solution and PBS reaction buffer in the sample container into the dynamic magnetic field reaction chamber respectively. The magnetic control module provided a mixed mode magnetic field for the dynamic magnetic field reaction chamber through the electromagnetic coil. The reaction was carried out at room temperature for 20-60 minutes to obtain the antibody-modified magnetic covalent organic framework.

[0016] The BSA blocking solution in the sample container is injected into the dynamic magnetic field reaction chamber through a peristaltic pump. The magnetic control module provides a mixed mode magnetic field for the dynamic magnetic field reaction chamber. The reaction is carried out at room temperature for 20-60 minutes to complete the blocking of the antibody-modified magnetic covalent organic framework.

[0017] The PBS reaction buffer in the sample container is injected into the dynamic magnetic field reaction chamber for washing through a peristaltic pump. The magnetic control module provides a separation mode magnetic field for the dynamic magnetic field reaction chamber module. The separation is carried out at room temperature for 2-5 minutes. The BSA blocking solution and PBS reaction buffer are removed by a peristaltic pump to obtain the capture probe.

[0018] The sample liquid to be tested is injected into the dynamic magnetic field reaction chamber through a peristaltic pump, and a mixed mode magnetic field is provided to the dynamic magnetic field reaction chamber through a magnetic control module. After reacting at room temperature for 20-60 minutes, the capture probe captures the target bacteria in the sample liquid to be tested, and a complex of the target bacteria and the capture probe is obtained.

[0019] The magnetic control module provides a separation mode magnetic field for the dynamic magnetic field reaction chamber, and the separation is carried out for 2-5 minutes at room temperature. The sample liquid that is not magnetically separated is removed by a peristaltic pump.

[0020] The power supply to the electromagnetic coil is disconnected, and the PBS solution in the sample container is injected into the dynamic magnetic field reaction chamber through the peristaltic pump to collect the target bacteria and capture probe complex, thereby achieving separation and enrichment of the target bacteria.

[0021] Preferably, the magnetic covalent organic framework material is Fe3O4@TbBd; the antibody-modified magnetic covalent organic framework is Fe3O4@TbBd@antibody; the magnetic field in the mixed mode is an alternating magnetic field generated by adjusting the current direction of the electromagnetic coil at a frequency of 2-5 minutes per time, and the alternating magnetic field strength is 0.1 T; the magnetic field in the separation mode is a continuous unidirectional magnetic field of 0.5-1.5 T generated by the electromagnetic coil.

[0022] Beneficial effects of the present invention: By setting up several sample containers, sample liquid and multiple reaction liquids can be packaged. By using a peristaltic pump in conjunction with a pipe network, the sample liquid and reaction liquid can be pumped into the dynamic magnetic field reaction chamber. By setting up a dynamic magnetic field reaction chamber, a storage and reaction space can be provided. By setting up an electromagnetic coil outside the dynamic magnetic field reaction chamber, a magnetic field with controllable direction and intensity can be provided in the dynamic magnetic field reaction chamber under the action of the magnetic control module, so as to realize the separation and enrichment process.

[0023] This device uses electromagnetic coils to generate a magnetic field, and the magnetic field strength and direction can be flexibly adjusted in real time. When used, it improves the binding efficiency between the magnetic covalent organic framework material and the target, and improves the final capture effect. At the same time, it avoids the problem of reduced experimental stability and reliability caused by the current majority of magnetic separation systems that use a fixed magnetic field or only support simple manual adjustment of the magnetic field strength.

[0024] This device has a higher degree of integration and supports the continuous injection of sample liquids of different volumes, avoiding the operation process of frequent sample replacement; through the continuous sampling function of the peristaltic pump, this device can process large-volume samples at one time, significantly improving the detection throughput and efficiency, and is suitable for large-scale food safety screening.

[0025] This method can be used to prepare capture probes and separate and enrich target bacteria using capture probes. By switching the electromagnetic coils of the magnetic control module in two modes to generate a dynamic magnetic field, intelligent switching between mixing and separation modes is achieved. By allowing the magnetic covalent organic framework to adsorb antibodies in the mixing mode to prepare capture probes, and then using the capture probes in the separation mode to separate and enrich target bacteria, this method solves the difficulty of balancing mixing and separation in traditional devices, while reducing manual intervention and improving the device's automation.

[0026] The present invention can continuously inject reaction solutions such as reaction samples, test sample solutions, and eluents to achieve large-scale continuous testing, and utilizes a peristaltic pump to automate the injection reaction. The design of the present invention simplifies the magnetic separation process for foodborne pathogens, significantly improving the efficiency and accuracy of separation and enrichment compared to traditional methods. The device has a compact structure, a high degree of automation, and low cost, providing a reliable solution for efficient magnetic separation pretreatment of foodborne pathogens and can be widely used in fields such as food safety testing, clinical diagnosis, and environmental monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0028] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention; Figure 2 This is a schematic diagram of the connection structure between the pipe network and the peristaltic pump of the present invention; Figure 3 This is a schematic diagram of the external structure of the dynamic magnetic field reaction chamber of the present invention; Figure 4 This is a schematic diagram of the connection structure between the electromagnetic coil and the power supply of the present invention; Figure 5 Schematic diagram of the first electromagnetic coil structure; Figure 6 Schematic diagram of the second electromagnetic coil structure; Figure 7 Schematic diagram of the third electromagnetic coil structure; Figure 8 This is a diagram of the mixing effect in the dynamic magnetic field reaction chamber simulated by COMSOL of the present invention; Figure 9 The COMSOL simulation of the motion trajectory of the magnetic covalent organic framework (COF) in the dynamic magnetic field reaction chamber and the simulation configuration parameter diagram of the present invention; Figure 10 : This is the hysteresis curve of Fe3O4@TbBd of the present invention; Figure 11 These are the scanning electron microscope images and transmission electron microscope images of Fe3O4@TbBd of the present invention. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0030] like Figure 1 、 2As shown in Example 1, an integrated magnetic separation pretreatment system for foodborne pathogens includes several sample containers 1, each connected to a peristaltic pump 3 via a pipe network 2. The sample containers 1 are used to store sample liquids and multiple reaction liquids, ensuring stable storage and supply of the sample and reaction liquids. The peristaltic pump 3 is connected to a dynamic magnetic field reaction chamber 4, which provides a storage and reaction space for the sample and reaction liquids. The peristaltic pump 3 cooperates with the pipe network 2 to achieve continuous, controllable, and quantitative pumping of the sample and reaction liquids into the dynamic magnetic field reaction chamber 4.

[0031] An electromagnetic coil 5 is provided outside the dynamic magnetic field reaction chamber 4, and the electromagnetic coil 5 is connected to the magnetic control module 6. The electromagnetic coil 5 can provide a magnetic field with controllable direction and intensity in the dynamic magnetic field reaction chamber 4 under the control of the magnetic control module 6, so as to realize the separation and enrichment process of foodborne pathogens. The magnetic control module 6 can control the direction and intensity of the magnetic field generated by the electromagnetic coil 5. The dynamic magnetic field reaction chamber 4 is connected to the sample collection container 7, and the sample collection container can be used to accommodate and collect the separated samples. In this embodiment, the sample container 1 is integrated with the peristaltic pump 3. Through multiple or continuous sampling, large-volume samples of 10 mL or more can be processed at one time, avoiding the operation of frequently changing samples, significantly improving the detection throughput and efficiency, and being suitable for large-scale food safety screening.

[0032] As a further specific embodiment, the dynamic magnetic field reaction chamber 4 is a cylindrical chamber, which is opened inside the chamber shell. Both ends of the chamber shell are provided with a pipe mouth 41, and the pipe mouths at both ends are located at the lower position or lower side of the chamber shell to facilitate the entry and exit of the liquid. The two ends of the dynamic magnetic field reaction chamber 4 are respectively connected to the two pipe mouths 41, and are respectively connected to the peristaltic pump 3 and the sample collection container 7 through the pipe mouths 41. Specifically in this embodiment, the volume of the dynamic magnetic field reaction chamber is 10 ml, in order to increase the amount of sample processed in a single time, the inner diameter is 16.2 mm, the aspect ratio is 3:1, and the magnetic field coil layout is adapted to avoid edge magnetic field attenuation. The injection speed of the peristaltic pump 3 for the sample liquid and the reaction liquid is 80 mL / min to increase the flow rate, adapt to the needs of larger batches of sample processing, and support continuous sampling of large volume samples greater than or equal to 10 ml. The pumping rate of the peristaltic pump is adjusted according to the sample characteristics to achieve more accurate sample processing.

[0033] Furthermore, in this embodiment, the peristaltic pump, sample container 1, dynamic magnetic field reaction chamber 4, magnetron module 6, electromagnetic coil 5, and sample collection container 7 are all integrated on a support, which provides a stable support base. As a further option, one or more additional empty sample containers can be placed on the support and connected to the peristaltic pump via a pipe network. During actual use, the peristaltic pump can be used to reversely extract and store liquid in the dynamic magnetic field reaction chamber, thereby advancing the experimental progress.

[0034] Example 2, based on Example 1, Figure 2 As shown, the pipe network 2 includes a liquid inlet pipe 21 connected to the liquid inlet of the peristaltic pump 3. The liquid inlet pipe 21 is connected to a multi-way pipe connector 22. The multi-way pipe connector 22 is respectively connected to a plurality of pipes 23, and is respectively connected to the liquid outlet ends of a plurality of sample containers 1 through the plurality of pipes 23. In this embodiment, the multi-way pipe connector 22 can optionally be a Luer multi-way connector, and the pipes and sample containers are connected via a pagoda adapter.

[0035] As a further embodiment, valves are installed on the pipe 23 and at the ends of the dynamic magnetic field reaction chamber 4. In this embodiment, the valves are solenoid valves, which control the opening and closing of each pipe to meet the needs of the experimental process. The pipe 23 is made of food-grade silicone hose to ensure biocompatibility and pollution-free during the transmission process.

[0036] As a further optional implementation, in this embodiment, the peristaltic pump and solenoid valve are connected to a conventional single-chip microcomputer. The single-chip microcomputer can accurately control the opening and closing of each solenoid valve and peristaltic pump, and can accurately control the rotation speed of the peristaltic pump, thereby controlling the liquid supply speed of the peristaltic pump and achieving precise control of the flow rate and reaction process.

[0037] In addition, the sample collection container 7 includes a fixing frame, which is fixed on the ground or a bracket, and a centrifuge tube is arranged on the fixing frame.

[0038] Example 3, based on Example 2, Figure 3 、 4 As shown, the magnetic control module 6 includes a power supply 61, which is connected to a control unit, which is connected to the electromagnetic coil 5, and the control unit can control the direction and strength of the magnetic field of the electromagnetic coil 5, thereby providing a dynamic magnetic field according to actual needs during actual use to complete separation and enrichment. In this embodiment, the power supply can optionally adopt a conventional mobile power supply or battery to improve portability and maintenance convenience. The control unit adopts a conventional power management module or control knob. When the power management module is adopted, the power management module is connected to the single-chip microcomputer, and the single-chip microcomputer controls the direction and magnitude of the DC current output by the power management module through conventional program logic, thereby changing the magnitude and direction of the current passed into the electromagnetic coil. As a further optional solution, the power management module can optionally be controlled by a conventional bidirectional DC-DC converter, and the model can be TPS631000. As Figure 4 As shown, when the control knob 62 is used, the control knob is used to selectively connect different electromagnetic coils or change the connection relationship with the connected electromagnetic coils, thereby controlling the direction of the current in the magnetic induction coil and realizing dynamic adjustment of the magnetic field.

[0039] As an optional implementation, Figure 5 As shown, the electromagnetic coil 5 in this embodiment includes a first coil 51 and a second coil 52, which are alternately spirally wound around the outside of the dynamic magnetic field reaction chamber 4. Both ends of the first coil 51 and the second coil 52 are electrically connected to the control unit through wires. The control unit adjusts the direction and strength of the magnetic field by controlling the current in different directions to flow into the first coil 51 and the second coil 52.

[0040] As another optional embodiment, Figure 6 As shown, the electromagnetic coil 5 includes a solenoid spirally wound on the outside of the dynamic magnetic field reaction chamber, and both ends of the solenoid are electrically connected to the control unit through wires; the control unit adjusts the magnetic field direction and magnetic field strength by controlling the direction and current magnitude of the current passed into the electromagnetic coil 5.

[0041] As a third optional implementation, Figure 7 As shown, the electromagnetic coil 5 comprises an inner coil 53 and an outer coil 54, which rotate in opposite directions and are arranged layer by layer outside the dynamic magnetic field reaction chamber 4. Through the orthogonal double-layer helical winding structure of the inner and outer coils, the inner coils 53 and outer coils 54 are staggered along the chamber axis, forming a uniform gradient magnetic field. The pitch of the inner and outer coils 53 and 54 is 5 mm, ensuring that the magnetic field coverage is optimally matched to the material movement path within the dynamic magnetic field reaction chamber.

[0042] Furthermore, the first coil 51, the second coil 52, the solenoid, the inner coil 53, and the outer coil 54 are all wound in parallel using three strands of thickened copper wire. Each strand has a diameter of 1.5 mm, a cross-sectional area of ​​1.77 mm², a total number of turns of 200±10, a DC resistance of ≤0.5 Ω / m, and a maximum current carrying capacity of 50 A, ensuring that the magnetic field strength can reach 1.5 T, thereby improving the adsorption efficiency.

[0043] Example 4, a method for magnetic separation of target bacteria based on magnetic covalent organic framework materials, using the integrated foodborne pathogenic bacteria magnetic separation pretreatment system of any of the above embodiments, comprises the following steps: Step 1: Several sample containers 1 are filled with magnetic covalent organic framework material sample solution, target bacteria antibody solution and PBS reaction buffer, BSA blocking solution, and sample solution to be tested. In this embodiment, the magnetic covalent organic framework material is Fe3O4@TbBd.

[0044] Step 2: Turn on the peristaltic pump 3 and quantitatively inject the magnetic covalent organic framework material sample liquid, target bacteria antibody solution and PBS reaction buffer in the sample container 1 into the dynamic magnetic field reaction chamber 4 respectively. The magnetic control module 6 provides a mixed mode magnetic field to the dynamic magnetic field reaction chamber 4 through the electromagnetic coil 5. The reaction is carried out at room temperature for 20-60 minutes to obtain an antibody-modified magnetic covalent organic framework. The antibody-modified magnetic covalent organic framework obtained in this embodiment is Fe3O4@TbBd@antibody.

[0045] Step 3: The BSA blocking solution in the sample container 1 is injected into the dynamic magnetic field reaction chamber 4 through the peristaltic pump 3. The magnetic control module 6 provides a mixed mode magnetic field for the dynamic magnetic field reaction chamber 4. The reaction is carried out at room temperature for 20-60 minutes to complete the blocking of the Fe3O4@TbBd@ antibody to improve the specificity of magnetic separation.

[0046] Step 4: The PBS reaction buffer in the sample container 1 is injected into the dynamic magnetic field reaction chamber 4 for washing via the peristaltic pump 3 to obtain a mixed solution containing the capture probes. The magnetic control module 6 provides a separation mode magnetic field to the dynamic magnetic field reaction chamber 4, and the separation is carried out at room temperature for 2-5 minutes, thereby causing the capture probes to move and concentrate at the end away from the peristaltic pump 3. By starting the peristaltic pump 3 for periodic suction, part of the liquid in the dynamic magnetic field reaction chamber 4 flows back into the peristaltic pump in a single direction and is pumped into the empty sample container 1, thereby removing a large amount of BSA blocking solution and PBS reaction buffer that do not contain capture probes. According to the actual experimental design or actual verification, suction is stopped for a specified time or after the peristaltic pump flow rate reaches a specified capacity. The remaining small amount of solution is rich in capture probes, thus obtaining the capture probes.

[0047] Step 5: The sample liquid to be tested is injected into the dynamic magnetic field reaction chamber 4 through the peristaltic pump 3, and a mixed mode magnetic field is provided to the dynamic magnetic field reaction chamber 4 through the magnetic control module 6. After reacting at room temperature for 20-60 minutes, the capture probe captures the target bacteria in the sample liquid to be tested, and a complex of the target bacteria and the capture probe is obtained.

[0048] Step 6: Provide a separation mode magnetic field for the dynamic magnetic field reaction chamber 4 through the magnetic control module 6, and separate for 2-5 minutes at room temperature, so that the target bacteria and the capture probe complex move to one end away from the peristaltic pump. Start the peristaltic pump 3 for periodic suction, so that the liquid flows back to the peristaltic pump in a single direction and is pumped into the empty sample container 1. According to the actual experimental design or actual verification, the suction is stopped after a specified time or when the peristaltic pump flow rate reaches a specified capacity, thereby removing the sample liquid to be tested that has not been magnetically separated.

[0049] Step 7: Disconnect the power to electromagnetic coil 5 and use peristaltic pump 3 to inject 1-3 mL of PBS reaction buffer from sample container 1 into dynamic magnetic field reaction chamber 4. Simultaneously, open the valve between the dynamic magnetic field reaction chamber and the collection container, allowing the PBS reaction buffer to carry the target bacteria and capture probe complex into collection container 7, where the target bacteria and capture probe complex are collected and isolated and enriched. The collected target bacteria and capture probe complex is then passed into a centrifuge tube in sample collection container 7, allowing the isolated and enriched target bacteria to be collected for further testing and analysis.

[0050] As a further specific embodiment, when providing a mixed mode magnetic field for the dynamic magnetic field reaction chamber, the current direction of the electromagnetic coil 5 is adjusted at a frequency of every 2-5 minutes, thereby providing a magnetic field in the opposite direction for the dynamic magnetic field reaction chamber at a frequency of 2-5 minutes to promote the mixing of the internal liquid.

[0051] like Figure 8 、 9 As shown, when providing a separation mode magnetic field for the dynamic magnetic field reaction chamber, an electromagnetic coil is used to provide a constant unidirectional magnetic field for the dynamic magnetic field reaction chamber, so that the capture probe moves toward one end of the dynamic magnetic field reaction chamber under the action of the unidirectional magnetic field to achieve magnetic separation.

[0052] Specifically, in this example, the current flowing through the electromagnetic coil was adjusted to ensure that the magnetic field within the dynamic reaction chamber reached 150 mT or higher, enhancing the binding efficiency between the magnetic covalent organic framework Fe3O4@TbBd and the target bacteria. By switching between the magnetic control module and the electromagnetic coil in dual modes, a dynamic magnetic field was generated, enabling intelligent switching between mixing and separation modes, improving mixing efficiency and shortening separation time.

[0053] Compared with other detection technologies, the present invention can continuously inject magnetic covalent organic framework material sample liquid, target bacteria antibody solution, sample liquid to be tested, PBS reaction buffer, BSA blocking solution, etc., to achieve large-scale continuous detection, and use a peristaltic pump to complete the automated injection reaction, and achieve uniform mixing and separation and enrichment inside the dynamic magnetic field reaction chamber. Secondly, the present invention can achieve efficient separation and enrichment of pathogenic bacteria by precisely controlling the magnetic field and liquid flow, reduce costs and be easy to carry, do not have a constant magnetic field, and are protective for special populations. The design of the present invention simplifies the magnetic separation operation process of foodborne pathogens, and significantly improves the efficiency and accuracy of separation and enrichment compared to traditional methods. The device has a compact structure, a high degree of automation, and low cost, and provides a reliable solution for efficient magnetic separation pretreatment of foodborne pathogens. It can be widely used in food safety testing, clinical diagnosis, environmental monitoring and other fields.

[0054] Example 5, based on Example 4, the capture probe is prepared by adsorbing antibodies on a magnetic covalent organic framework in a hybrid mode. This is because Fe3O4@TbBd is a core-shell structure with the magnetic properties of the Fe3O4 core and the adsorption properties of the COF shell. Therefore, this system can prepare the capture probe by adsorbing antibodies on Fe3O4@TbBd and sealing with BSA in a hybrid mode. However, the immunomagnetic beads used in traditional magnetic separation devices cannot be prepared by direct mixed adsorption, but require complex chemical reaction processes such as covalent binding. Figure 10 As shown in FIG, the hysteresis loop diagram of Fe3O4@TbBd is shown, indicating that Fe3O4@TbBd has superparamagnetic properties and a saturation magnetization value of 41.4 emu / g, which enables Fe3O4@TbBd to respond quickly to the magnetic field outside the dynamic magnetic field reaction chamber 4. Figure 11 As shown, scanning electron microscopy and transmission electron microscopy images of Fe3O4@TbBd are shown, indicating the core-shell structure of Fe3O4@TbBd.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An integrated foodborne pathogenic bacteria magnetic separation pretreatment system, characterized by: The apparatus comprises a plurality of sample containers (1), each of which is connected to a peristaltic pump (3) via a pipe network (2), the sample containers (1) being used to store a sample liquid and a reaction liquid respectively, the peristaltic pump (3) being connected to a dynamic magnetic field reaction chamber (4), and the dynamic magnetic field reaction chamber (4) being connected to a sample collection container (7); An electromagnetic coil (5) is provided outside the dynamic magnetic field reaction chamber (4), and the electromagnetic coil (5) is connected to a magnetic control module (6). The magnetic control module (6) is capable of controlling the direction and intensity of the magnetic field generated by the electromagnetic coil (5).

2. The integrated foodborne pathogenic bacteria magnetic separation pretreatment system according to claim 1, characterized in that: The dynamic magnetic field reaction chamber (4) is a cylindrical chamber. Both ends of the dynamic magnetic field reaction chamber (4) are provided with pipe openings (41) and are respectively connected to the peristaltic pump (3) and the sample collection container (7) through the pipe openings (41).

3. The integrated foodborne pathogenic bacteria magnetic separation pretreatment system according to claim 2, characterized in that: The pipe network (2) includes a liquid inlet pipe (21) connected to the liquid inlet of the peristaltic pump (3), the liquid inlet pipe (21) is connected to a pipe multi-way connector (22), the pipe multi-way connector (22) is respectively connected to a plurality of pipes (23), and is respectively connected to the liquid outlet ends of a plurality of sample containers (1) through the plurality of pipes (23).

4. The integrated foodborne pathogenic bacteria magnetic separation pretreatment system according to claim 3, characterized in that: Valves are provided on the pipe (23) and at the pipe openings (41) at both ends of the dynamic magnetic field reaction chamber (4); the sample collection container (7) includes a fixing frame on which a centrifuge tube is provided.

5. The integrated foodborne pathogenic bacteria magnetic separation pretreatment system according to any one of claims 1 to 4, characterized in that: The magnetic control module (6) comprises a power supply (61), the power supply (61) is connected to a control unit, the control unit is connected to the electromagnetic coil (5), and the control unit is capable of controlling the magnetic field direction and magnetic field strength of the electromagnetic coil (5).

6. The integrated foodborne pathogenic bacteria magnetic separation pretreatment system according to claim 5, characterized in that: The electromagnetic coil (5) comprises a first coil (51) and a second coil (52), the first coil (51) and the second coil (52) being alternately spirally wound around the outside of the dynamic magnetic field reaction chamber (4), and both ends of the first coil (51) and the second coil (52) being electrically connected to a control unit via wires; the control unit adjusts the direction and intensity of the magnetic field by controlling currents in different directions to be passed through the first coil (51) and the second coil (52).

7. The integrated foodborne pathogenic bacteria magnetic separation pretreatment system according to claim 5, characterized in that: The electromagnetic coil (5) comprises a solenoid spirally wound outside the dynamic magnetic field reaction chamber, and both ends of the solenoid are electrically connected to a control unit via wires; the control unit adjusts the direction and intensity of the magnetic field by controlling the direction and magnitude of the current flowing into the electromagnetic coil (5).

8. The integrated foodborne pathogenic bacteria magnetic separation pretreatment system according to claim 5, characterized in that: The electromagnetic coil (5) comprises an inner coil (53) and an outer coil (54), wherein the inner coil (53) and the outer coil (54) have opposite rotation directions and are sequentially sleeved on the outside of the dynamic magnetic field reaction chamber (4).

9. A method for magnetic separation of target bacteria based on magnetic covalent organic framework materials, using the integrated foodborne pathogenic bacteria magnetic separation pretreatment system according to any one of claims 1 to 8, characterized in that: The steps include: A plurality of sample containers (1) are respectively filled with a magnetic covalent organic framework material sample solution, a target bacteria antibody solution and a PBS reaction buffer solution, a BSA blocking solution, and a sample solution to be tested; The peristaltic pump (3) is turned on to quantitatively inject the magnetic covalent organic framework material sample solution, the target bacteria antibody solution and the PBS reaction buffer in the sample container (1) into the dynamic magnetic field reaction chamber (4). The magnetic control module (6) provides a mixed mode magnetic field to the dynamic magnetic field reaction chamber (4) via the electromagnetic coil (5). The reaction is carried out at room temperature for 20-60 minutes to obtain the antibody-modified magnetic covalent organic framework. The BSA blocking solution in the sample container (1) is injected into the dynamic magnetic field reaction chamber (4) through the peristaltic pump (3), and a mixed mode magnetic field is provided to the dynamic magnetic field reaction chamber (4) through the magnetic control module (6). The reaction is carried out at room temperature for 20-60 minutes to complete the blocking of the antibody-modified magnetic covalent organic framework; The PBS reaction buffer in the sample container (1) is injected into the dynamic magnetic field reaction chamber (4) for washing by a peristaltic pump (3), and a magnetic control module (6) is used to provide a magnetic field in a separation mode for the dynamic magnetic field reaction chamber module (4). The separation is performed at room temperature for 2-5 minutes, and the BSA blocking solution and PBS reaction buffer are removed by a peristaltic pump (3) to obtain a capture probe; The sample liquid to be tested is injected into the dynamic magnetic field reaction chamber (4) through the peristaltic pump (3), and a mixed mode magnetic field is provided to the dynamic magnetic field reaction chamber (4) through the magnetic control module (6). After reacting at room temperature for 20-60 minutes, the capture probe captures the target bacteria in the sample liquid to be tested, and a complex of the target bacteria and the capture probe is obtained; The magnetic control module (6) provides a separation mode magnetic field for the dynamic magnetic field reaction chamber (4), separates for 2-5 minutes at room temperature, and removes the sample liquid that has not been magnetically separated by the peristaltic pump (3); The power supply to the electromagnetic coil (5) is disconnected, and the PBS solution in the sample container (1) is injected into the dynamic magnetic field reaction chamber (4) through the peristaltic pump (3) to collect the target bacteria and the capture probe complex, thereby achieving separation and enrichment of the target bacteria.

10. The method for magnetic separation of target bacteria based on magnetic covalent organic framework materials according to claim 9, characterized in that: The magnetic covalent organic framework material is Fe3O4@TbBd; the antibody-modified magnetic covalent organic framework is Fe3O4@TbBd@antibody; The magnetic field of the mixed mode is an alternating magnetic field generated by adjusting the current direction of the electromagnetic coil (5) at a frequency of 2-5 minutes / time, and the alternating magnetic field strength is 0.1 T; The magnetic field in the separation mode is a continuous unidirectional magnetic field of 0.5-1.5 T generated by an electromagnetic coil (5).

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