Magnetophoresis separation device and method for paramagnetic micro-nano magnetic particles

Abstract

The invention provides a paramagnetic micro-nano magnetic particle magnetophoresis separation device and a paramagnetic micro-nano magnetic particle magnetophoresis separation method, and relates to the technical field of micro-nano magnetic particle separation and magnetic labeled biomolecule separation analysis. The separation device comprises a plurality of permanent magnets which have the same magnetism and the same size and are arranged above the separation channel at intervals in the direction of the separation channel, and a plurality of sets of mechanical structures which respectively drive each permanent magnet to move up and down in the vertical direction; the Hall sensor clings to the separation channel and is used for detecting the magnetic induction intensity at the separation channel; a liquid inlet device; a UV / Vis ultraviolet-visible light detector; a collection device and a computer. The magnetic induction intensity in the separation channel can be set, the critical diameter of the micro-nano magnetic particles capable of being captured by the magnetic field is determined, magnetophoresis separation of paramagnetic micro-nano magnetic particles is accurately achieved, the controllability of the magnetophoresis separation process is enhanced, and the separation effect of the micro-nano magnetic particles is improved.

Description

Technical Field

[0001] This invention relates to the technical field of separation of micro and nano magnetic particles and separation and analysis of magnetically labeled biomolecules, and particularly to a magnetophoretic separation device and method for paramagnetic micro and nano magnetic particles and magnetically labeled biomolecules. Background Technology

[0002] Paramagnetic micro / nano magnetic particles refer to magnetic material particles with paramagnetic properties, ranging in size from micrometers to nanometers (typically 1 nm to 100 μm). These particles exhibit near-zero remanence and zero coercivity in the absence of an external magnetic field (similar to paramagnetic materials), but can rapidly generate a strong magnetization response under an applied magnetic field (similar to ferromagnetic materials), and their magnetism essentially disappears after the magnetic field is removed, avoiding magnetic agglomeration. Magnetophoretic separation of paramagnetic micro / nano magnetic particles is mainly applied in magnetic materials, bioengineering, targeted drug delivery, clinical medicine, and environmental engineering. To obtain magnetic particles with uniform size and properties, it is necessary to perform magnetophoretic separation of micro / nano magnetic particles of different sizes in a sample based on the mechanism of magnetic interaction. In the biomedical field, proteins, nucleic acids, and other biomolecules or cells are magnetically labeled using paramagnetic micro / nano magnetic particles, and their magnetic properties are used to separate them from biological samples. Improving the separation accuracy of biological samples is crucial for increasing the purity of the separated samples and ensuring the smooth and effective execution of subsequent processing steps.

[0003] Magnetophoretic separation, based on the principle of magnetic capture and release, involves magnetic particles being carried by a flowing carrier liquid through a separation channel near a magnetic field. Samples with magnetic responsiveness experience a magnetic force greater than viscous resistance, causing the particles to be attracted to the separation channel wall on the magnetic field side – this is called "capture." When the flow rate is increased or the magnetic induction intensity at the separation channel is decreased, the magnetic force experienced by magnetically weaker particles becomes less than the viscous resistance, and the particles are eluted from the magnetic field under the influence of viscous resistance – this is called "release." The magnetic capture and release separation method utilizes the retention of magnetic particles by the magnetic field. A single permanent magnet first captures all magnetic particles flowing into the separation channel, then the magnetic field at the separation channel is gradually weakened, selectively allowing weaker magnetic particles to flow out while retaining stronger ones, thus achieving magnetophoretic separation of magnetic particles.

[0004] Currently, the magnetophoretic separation method for magnetic capture and release lacks an effective mechanical structure for adjusting the magnetic induction intensity at the separation channel, and there is no quantitative detection of the magnetic induction intensity at the separation channel. Instead of setting the magnetic induction intensity at the separation channel before the magnetic particles separate, the method continuously adjusts the magnetic induction intensity of a single permanent magnet at the separation channel during the magnetophoretic separation process. This results in low controllability of the magnetic particle magnetophoretic separation process, poor accuracy in the size of the separated magnetic particles, and affects the separation effect. Furthermore, the repeatability of magnetophoretic separation is poor. Summary of the Invention

[0005] In view of this, the present invention provides a magnetophoretic separation device and method for paramagnetic micro / nano magnetic particles, mainly solving the problem of magnetophoretic separation of paramagnetic micro / nano magnetic particles. A permanent magnet provides a magnetic field for magnetophoretic separation of the paramagnetic micro / nano magnetic particles. By setting the magnetic induction intensity of the magnetic field generated by the permanent magnet at the separation channel, the critical diameter for separation of the micro / nano magnetic particles is accurately controlled. Using two or more permanent magnets and employing a two-stage or multi-stage "capture-release" principle, magnetophoretic separation of micro / nano magnetic particles of different sizes is achieved, improving the separation effect and increasing the repeatability of magnetophoretic separation. The present invention designs a mechanical structure in which a servo motor drives a permanent magnet to move vertically up and down above the separation channel in the magnetophoretic separation device, changing the distance between the permanent magnet and the separation channel, and adjusting the magnetic induction intensity in the separation channel. A Hall sensor measures the magnetic induction intensity in the separation channel, and the micro / nano magnetic particles are separated by magnetophoretic separation using the two-stage or multi-stage magnetic field "capture-release" principle. By setting the magnetic induction intensity in the separation channel and determining the critical diameter of micro- and nano-magnetic particles that the magnetic field can capture, the magnetophoretic separation of paramagnetic micro- and nano-magnetic particles can be accurately achieved, enhancing the controllability of the magnetophoretic separation process and improving the separation effect of micro- and nano-magnetic particles.

[0006] Therefore, the present invention provides the following technical solution: On one hand, the present invention provides a magnetophoretic separation device for paramagnetic micro / nano magnetic particles, comprising: Separate channels; The separation device includes: multiple permanent magnets of the same magnetic properties and size, which are spaced apart above the separation channel along the separation channel direction, and multiple sets of mechanical structures that drive each permanent magnet to move up and down in the vertical direction. A Hall sensor, placed close to the permanent magnet in the separation channel, is used to detect the magnitude of the magnetic induction intensity at that location in the separation channel. The liquid inlet device allows the carrier liquid and paramagnetic micro / nano magnetic particle samples to converge and flow into the separation channel; A UV / Vis ultraviolet-visible light detector is connected to the end of the separation channel to detect the separation of paramagnetic micro and nano magnetic particles after separation by the separation channel. A collection device is used to collect the separated paramagnetic micro / nano magnetic particles and unwanted carrier liquid. The computer is electrically connected to the mechanical structure, Hall sensor, liquid inlet device, UV / Vis ultraviolet-visible light detector, and collection device, respectively.

[0007] Furthermore, the permanent magnet is a neodymium iron boron permanent magnet.

[0008] Furthermore, the separation channel includes: a cover plate, a microchannel, and a substrate. The cover plate has a mobile phase inlet and an outlet above it, and the microchannel is located between the cover plate and the substrate.

[0009] Furthermore, each mechanical structure includes: a servo motor, a driver, a coupling, a lead screw, a nut seat, a linear guide, a slider, and a support rod; the servo motor is connected to and coaxial with the lead screw via the coupling, and the servo motor and the lead screw are located on the rear side of the separation channel and arranged perpendicular to the separation channel; the linear guide and the slider are located on the front side of the separation channel and arranged perpendicular to the separation channel; the nut seat on the lead screw and the slider on the linear guide are connected via the support rod, which is used to fix the permanent magnet.

[0010] Furthermore, the liquid inlet device includes: an infusion pump, a three-way valve, and a sample injector.

[0011] Furthermore, the number of permanent magnets is two.

[0012] Furthermore, the collection device includes: a first collection bottle and its corresponding first solenoid valve, a second collection bottle and its corresponding second solenoid valve, a third collection bottle and its corresponding third solenoid valve, and a waste liquid bottle and its corresponding fourth solenoid valve.

[0013] Furthermore, when the UV / Vis ultraviolet-visible light detector detects unwanted carrier liquid flowing through the detector, the fourth solenoid valve opens, and the first, second, and third solenoid valves close, allowing the carrier liquid mobile phase to flow into the waste liquid bottle. When the UV / Vis ultraviolet-visible light detector detects micro-nano magnetic particles with a diameter less than or equal to the first threshold flowing through the detector, the fourth solenoid valve closes, the first solenoid valve opens, and the second and third solenoid valves close, allowing the mobile phase of micro-nano magnetic particles with a diameter less than or equal to the first threshold to flow into the first collection bottle. When the UV / Vis ultraviolet-visible light detector detects micro-nano magnetic particles with a diameter greater than the first threshold and less than or equal to the second threshold flowing through the detector, the fourth solenoid valve closes, the second solenoid valve opens, and the first and third solenoid valves close, allowing the mobile phase containing the micro-nano magnetic particles with a diameter greater than the first threshold and less than or equal to the second threshold to flow into the second collection bottle; after collection is completed, the second solenoid valve closes, the fourth solenoid valve opens, and the mobile phase flows into the waste liquid bottle. When the UV / Vis ultraviolet-visible light detector detects micro-nano magnetic particles with a diameter greater than the second threshold flowing through the detector, the fourth solenoid valve closes, the third solenoid valve opens, and the first and second solenoid valves close. The mobile phase containing micro-nano magnetic particles with a diameter greater than the second threshold flows into the third collection bottle. After collection is completed, the third solenoid valve closes, the fourth solenoid valve opens, and the mobile phase flows into the waste liquid bottle.

[0014] Furthermore, the computer detects and displays the magnetic induction intensity of the permanent magnet's magnetic field at the separation channel, which is used to accurately set the magnetic field size at the separation channel.

[0015] In another aspect, the present invention also provides a method for magnetophoretic separation of paramagnetic micro / nano magnetic particles, comprising: S1. Multiple permanent magnets of the same magnetism and size are arranged at intervals above the separation channel along the separation channel direction, and the magnetic induction intensity of the magnetic field of each permanent magnet at the separation channel is set respectively. S2. Open the fourth solenoid valve corresponding to the waste liquid bottle and close the solenoid valves of each collection bottle; turn on the infusion pump to make the deionized water carrier liquid flow in the device pipeline, pass through the three-way valve, the separation channel and the UV-Vis ultraviolet-visible light detector, and flow into the waste liquid bottle; inject the paramagnetic micro-nano magnetic particles to be separated into the three-way valve with the sample syringe, and together with the carrier liquid, they become the mobile phase and enter the separation channel through the mobile phase inlet. S3. The carrier liquid carrying the paramagnetic micro-nano magnetic particles to be separated first passes through the first permanent magnet. The first critical diameter, determined by the magnetic induction intensity of the first permanent magnet at the separation channel, captures micro-nano magnetic particles larger than the first critical diameter. Micro-nano magnetic particles smaller than the first critical diameter flow out from the mobile phase outlet of the separation channel through the magnetic field of the first permanent magnet and are collected by the first collection bottle. S4. Remove the first permanent magnet. The magnetic field of the first permanent magnet at the separation channel disappears, and the micro-nano magnetic particles captured by the first permanent magnet are released. Driven by the flowing carrier liquid, they pass through the magnetic field of the second permanent magnet. Based on the second critical diameter determined by the magnetic induction intensity of the second permanent magnet at the separation channel, micro-nano magnetic particles larger than the second critical diameter are captured, while micro-nano magnetic particles smaller than the second critical diameter flow out from the mobile phase outlet of the separation channel through the magnetic field of the second permanent magnet and are collected by the second collection bottle. S5. Remove the second permanent magnet. The magnetic field of the second permanent magnet at the separation channel disappears, and the micro-nano magnetic particles captured by the second permanent magnet are released. Driven by the flowing carrier liquid, they are captured and released by the magnetic field of other permanent magnets at the separation channel for magnetophoretic separation. If there is no other permanent magnet magnetic field, the micro-nano magnetic particles released by the second permanent magnet will flow out of the mobile phase outlet of the separation channel under the drive of the carrier liquid and be collected by the third collection bottle. S6. The magnetophoretic separation process of paramagnetic micro- and nano-magnetic particles is completed. Turn off the power to the magnetophoretic separation device.

[0016] Advantages and positive effects of this invention: This invention provides a magnetophoretic separation device and method for paramagnetic micro / nano magnetic particles. This device has a mechanical structure for adjusting the magnetic field strength of a permanent magnet at the separation channel. A Hall sensor measures the magnetic induction intensity of the magnetic field at the separation channel, quantitatively adjusting the magnetic field strength to determine the critical diameter of the micro / nano magnetic particles that the permanent magnet's magnetic field can capture. The device uses two or more permanent magnets with identical magnetism and dimensions. Through two or more stages of capture-release of paramagnetic micro / nano magnetic particles, the magnetophoretic separation of paramagnetic micro / nano magnetic particles with the same magnetic susceptibility but different sizes is precisely achieved based on the critical diameter determined by the magnetic induction intensity of the magnetic field at the separation channel. After magnetophoretic separation, the micro / nano magnetic particles of different sizes are collected into different collection bottles by controlling the on / off state of various solenoid valves. The magnetophoretic separation device and method of this invention improve the accuracy of magnetophoretic separation of micro / nano magnetic particles, enhance the separation effect, increase the controllability of the magnetophoretic separation process, and ensure the repeatability of the magnetophoretic separation. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the paramagnetic micro / nano magnetic particle capture-release magnetophoretic separation device in an embodiment of the present invention; Figure 2 This is a schematic diagram of the basic structure of the separation channel in an embodiment of the present invention; Figure 3 This is a schematic diagram of the computer control interface of the magnetic separation device in an embodiment of the present invention; Figure 4 This is a schematic diagram of the separation results of paramagnetic micro / nano magnetic particles separated by two-stage "capture-release" magnetophoretic separation in an embodiment of the present invention; In the diagram, 1. Separation channel; 2. Separation device; 3. Hall sensor; 4. Liquid inlet device; 5. UV / Vis ultraviolet-visible light detector; 6. Collection device; 7. Computer; 11. Cover plate; 12. Microchannel; 13. Substrate; 14. Mobile phase inlet; 15. Mobile phase outlet; 20. Permanent magnet; 21. Servo motor; 22. Driver; 23. Coupling; 24. Lead screw; 25. Nut seat; 26. Linear guide; 27. Slider; 28. Support rod; 41. Infusion pump; 42. Three-way valve; 43. Injector; 61. First collection bottle; 62. Second collection bottle; 63. Third collection bottle; 64. Waste bottle; 65. First solenoid valve; 66. Second solenoid valve; 67. Third solenoid valve; 68. Fourth solenoid valve. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0020] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0021] The characteristics of paramagnetic micro / nano magnetic particles are: they exhibit significant magnetism when placed in an external magnetic field; once the magnetic field disappears, their magnetism tends to vanish. For paramagnetic micro / nano magnetic particles with the same magnetic susceptibility but different diameters, in the magnetic field of a permanent magnet, larger particles experience a greater magnetic force, while smaller particles experience a smaller magnetic force. By setting the magnetic induction intensity of the magnetic field in the separation channel, the critical diameter of the captured micro / nano magnetic particles can be determined. Micro / nano magnetic particles with a diameter larger than the critical diameter experience a greater magnetic force and are captured on the channel wall of the separation channel on the permanent magnet side; micro / nano magnetic particles with a diameter smaller than the critical diameter experience a smaller magnetic force and can continue to move along the separation channel under the influence of the flowing carrier liquid, leaving the magnetic field region where the permanent magnet is located. When magnetic particles captured by the magnetic field of a permanent magnet are removed from the separation channel, the magnetic field it provides near the separation channel disappears. The magnetism of the paramagnetic micro / nano magnetic particles captured on the channel wall tends to disappear, and they are released from the channel wall. Driven by the carrier liquid, they move along the separation channel and flow out from the channel's mobile phase outlet. Thus, when paramagnetic micro / nano magnetic particles with the same magnetic susceptibility but different diameters pass through the magnetic field generated by the permanent magnet above the separation channel, those with diameters smaller than the critical diameter flow out from the mobile phase outlet first, while those with diameters larger than the critical diameter flow out from the mobile phase outlet later. Magnetophoretic separation of micro / nano magnetic particles is achieved by using the critical diameter as the boundary.

[0022] like Figure 1 As shown, a paramagnetic micro / nano magnetic particle magnetophoretic separation device mainly includes: a separation channel 1, a separation device 2, a Hall sensor 3, a liquid inlet device 4, a UV / Vis ultraviolet-visible light detector 5, a collection device 6, and a computer 7.

[0023] Separation channel 1 allows paramagnetic micro / nano magnetic particles to separate within it; such as Figure 2 As shown, the separation channel 1 includes a cover plate 11, a microchannel 12, and a substrate 13. Above the cover plate 11 are a flow phase inlet 14 and an outlet 15. Between the cover plate 11 and the substrate 13 is the microchannel 12. A Hall sensor 3 for detecting the magnitude of the magnetic field at the separation channel is embedded in the substrate 13, close to the upper surface of the substrate 13, and close to the position corresponding to the permanent magnet on the separation channel 1. It is used to measure the magnitude of the magnetic induction intensity at this location.

[0024] Separation device 2 achieves two-stage "capture-release" separation of paramagnetic micro / nano magnetic particles; it includes: two permanent magnets 20 with identical magnetic properties and dimensions, and mechanical structures that drive the two permanent magnets 20 to move vertically up and down. In this embodiment, the permanent magnets 20 are neodymium iron boron permanent magnets, providing a magnetic field for magnetophoretic separation of paramagnetic micro / nano magnetic particles; utilizing the "capture-release" magnetophoresis principle, two or more permanent magnets 20 with identical magnetic properties and dimensions are used to achieve two-stage or multi-stage "capture-release" separation of micro / nano magnetic particles. Two sets of mechanical structures are used to adjust the distance between the two permanent magnets 20 and the separation channel 1, driving the permanent magnets 20 above the separation channel 1 to move vertically up and down, changing the distance between the permanent magnets 20 and the separation channel 1, and setting the magnetic induction intensity of the magnetic field in the separation channel 1. Specifically, each set of mechanical structures includes: a servo motor 21, a driver 22, a coupling 23, a lead screw 24, a nut seat 25, a linear guide rail 26, a slider 27, and a support rod 28. The separation channel 1 is placed horizontally. A servo motor 21 is connected to a lead screw 24 via a coupling 23 and remains coaxial. The servo motor 21 and lead screw 24 are located at the rear of the separation channel 1, arranged perpendicular to the separation channel 1. A linear guide rail 26 and a slider 27 are located at the front of the separation channel 1, also arranged perpendicular to the separation channel 1. The nut seat 25 on the lead screw 24 and the slider 27 on the linear guide rail 26 are connected via a support rod 28, and a permanent magnet 20 is fixed to the support rod 28. Thus, when the servo motor 21 drives the lead screw 24 to rotate, the lead screw 24 drives the nut seat 25 on it to move up and down. The support rod 28 fixed to the nut seat 25 drives the permanent magnet 20 and the slider 27 on the linear guide rail 26 to move up and down together. The linear guide rail 26 ensures structural rigidity, parallelism between the permanent magnet 20 and the separation channel 1, and motion accuracy. The computer 7 transmits commands to the driver 22 of the servo motor 21, and the driver 22 drives the servo motor 21 to rotate according to the commands. The lead screw 24 and the servo motor 21 rotate together. The nut seat 25 on the lead screw 24 drives the permanent magnet 20 to move up and down in the vertical direction above the separation channel 1. The magnetic induction intensity of the magnetic field at the separation channel is set to determine the critical diameter at which the permanent magnet 20 can capture micro-nano magnetic particles, or the permanent magnet 20 is moved away from the separation channel 1 so that the micro-nano magnetic particles in the separation channel 1 are not affected by the magnetic field of the permanent magnet 20.

[0025] Hall sensor 3 detects the magnitude of the magnetic field strength of the permanent magnet 20 at the separation channel; specifically, Hall sensor 3, which measures the magnetic field strength, is embedded below the substrate 13 and close to the separation channel 1 to detect the magnetic field strength at this location in the separation channel.

[0026] The liquid inlet device 4 includes an infusion pump 41, a three-way valve 42, and a sample injector 43. The carrier liquid and the micro / nano magnetic particle sample converge at the three-way valve 42 and flow into the separation channel 1. Specifically, the infusion pump 41 delivers deionized water as the carrier liquid to one inlet of the three-way valve 42, while the sample injector 43 injects paramagnetic micro / nano magnetic particle samples with the same magnetic susceptibility but different diameters into the other inlet of the three-way valve 42. The deionized water and the paramagnetic micro / nano magnetic particles converge within the three-way valve 42 and, under the pressure of the infusion pump 41, flow out from the outlet of the three-way valve 42 into the mobile phase inlet 14 of the separation channel 1. After passing through the separation channel 1, the particles undergo magnetophoretic separation. The separated micro / nano magnetic particles flow out from the mobile phase outlet 15 of the separation channel 1 at different times and enter the UV / Vis ultraviolet-visible light detector 5.

[0027] UV / Vis ultraviolet-visible light detector 5 is used to detect the separation of micro and nano magnetic particles.

[0028] The collection device 6 collects the separated micro / nano magnetic particles and unwanted carrier liquid. It mainly consists of collection bottles 61, 62, and 63, a waste liquid bottle 64, and solenoid valves 65, 66, 67, and 68. Solenoid valves are installed before the waste liquid bottle 64 and the pipelines of each collection bottle. When the UV / Vis ultraviolet-visible light detector 5 detects unwanted carrier liquid flowing through it, the fourth solenoid valve 68 of the waste liquid bottle 64 opens, and the solenoid valves of the collection bottles close, allowing the carrier liquid mobile phase to flow into the waste liquid bottle 64. When smaller diameter micro / nano magnetic particles are detected flowing through the detector, the fourth solenoid valve 68 of the waste liquid bottle 64 closes, the first solenoid valve 65 of the first collection bottle 61 opens, and the solenoid valves of the other collection bottles close, allowing the mobile phase containing the smaller diameter micro / nano magnetic particles to flow into the first collection bottle 61. After collection, the second solenoid valve 65 of the first collection bottle 61 closes, and the fourth solenoid valve 68 of the waste liquid bottle 64 opens, allowing the mobile phase to flow into the waste liquid bottle 64. When larger diameter micro / nano magnetic particles are detected flowing through the detector, the fourth solenoid valve 68 of waste bottle 64 closes, the second solenoid valve 66 of the second collection bottle 62 opens, and the solenoid valves of the other collection bottles close. The mobile phase containing the larger diameter micro / nano magnetic particles flows into the second collection bottle 62. After collection, the second solenoid valve 66 of the second collection bottle 62 closes, and the fourth solenoid valve 68 of waste bottle 64 opens, allowing the mobile phase to flow into waste bottle 64. When even larger diameter micro / nano magnetic particles are detected flowing through the detector, the fourth solenoid valve 68 of waste bottle 64 closes, the third solenoid valve 67 of the third collection bottle 63 opens, and the solenoid valves of the other collection bottles close. The mobile phase containing even larger diameter micro / nano magnetic particles flows into the third collection bottle 63. After collection, the third solenoid valve 67 of the third collection bottle 63 closes, and the fourth solenoid valve 68 of waste bottle 64 opens, allowing the mobile phase to flow into waste bottle 64.

[0029] Computer 7 controls the flow rate of the infusion pump 41, drives the servo motor 21, displays the magnetic induction intensity at the separation channel 1, and controls the opening and closing of the solenoid valve. Specifically, computer 7 controls the rotation of servo motor 21 via driver 22, driving permanent magnet 20 to move vertically up and down above separation channel 1, adjusting the vertical distance between permanent magnet 20 and separation channel 1 to set the magnetic induction intensity of the magnetic field generated by permanent magnet 20 at separation channel 1, and determining the critical diameter of paramagnetic micro / nano magnetic particles that can be captured at separation channel 1. When releasing the paramagnetic micro / nano magnetic particles captured at separation channel 1, permanent magnet 20 is moved away from separation channel 1. Computer 7 detects and displays the magnetic induction intensity of the magnetic field of permanent magnet 20 at the corresponding position in separation channel 1 to accurately set the magnetic field magnitude at separation channel 1. Computer 7 controls the opening and closing of the solenoid valves before the pipelines of each collection bottle and waste bottle 64 to achieve the collection of paramagnetic micro / nano magnetic particles after magnetophoretic separation. Figure 3 As shown, the computer control interface 7 for the magnetophoretic separation of micro- and nano-magnetic particles displays the magnetic induction intensity of each permanent magnet 20 at the separation channel 1. The distance between each permanent magnet 20 and the separation channel 1 is adjusted by using the "Increase Magnetic Induction Intensity" and "Decrease Magnetic Induction Intensity" buttons, respectively. The magnetic field of the permanent magnet 20 is quickly added to or removed from the separation channel 1 by using the "Add Magnetic Field" and "Remove Magnetic Field" buttons. The on / off status of each solenoid valve is displayed by the indicator lights, and the switches corresponding to the waste liquid bottle 64 and each collection bottle control the opening and closing of their solenoid valves.

[0030] This invention employs two or more permanent magnets of identical magnetic properties and dimensions, placed above the separation channel 1. Sufficient horizontal distance is maintained between the permanent magnets to ensure their magnetic fields do not overlap at the separation channel 1. Each permanent magnet has an independent mechanical structure for adjusting the distance between itself and the separation channel 1, and the magnetic induction intensity of each permanent magnet's magnetic field at the separation channel 1 is set accordingly. Generally, the permanent magnet closest to the mobile phase inlet 14 of the separation channel 1 has the highest magnetic induction intensity at the separation channel 1, while other permanent magnets farther from the mobile phase inlet have lower magnetic induction intensities at the separation channel 1. The permanent magnet closest to the mobile phase outlet 15 of the separation channel 1 has the lowest magnetic induction intensity at the separation channel 1. Thus, during the magnetophoretic separation process, when the mobile carrier liquid carrying the paramagnetic micro / nano magnetic particle sample to be separated enters the separation channel 1 as the mobile phase, it first passes through the first permanent magnet. Using the critical diameter of the micro / nano magnetic particles determined by the magnetic induction intensity of the first permanent magnet at the separation channel 1 as a boundary, micro / nano magnetic particles with a diameter larger than the critical diameter are captured, while those smaller than the critical diameter pass through the magnetic field of the first permanent magnet. Because the magnetic induction intensity of the magnetic field of the other permanent magnets at separation channel 1 is less than that of the first permanent magnet, the micro-nano magnetic particles flowing through the first permanent magnet will not be captured by the other permanent magnets. These micro-nano magnetic particles flow out from the flow phase outlet 15 of separation channel 1 through the other permanent magnets, achieving separation. Next, the first permanent magnet is removed, and the magnetic field of the first permanent magnet at separation channel 1 disappears. The micro-nano magnetic particles captured by the first permanent magnet are released and do not exhibit external magnetism. Driven by the carrier liquid, they pass through the magnetic field of the second permanent magnet. Using the critical diameter determined by the magnetic induction intensity of the second permanent magnet at separation channel 1 as the boundary, micro-nano magnetic particles with a diameter larger than the critical diameter are captured by the second permanent magnet, while micro-nano magnetic particles with a diameter smaller than the critical diameter pass through the other permanent magnets and flow out from the flow phase outlet 15 of separation channel 1, separating. Then, the second permanent magnet is removed, and its magnetic field at separation channel 1 disappears. The micro-nano magnetic particles captured by the second permanent magnet are released and do not exhibit external magnetism. Driven by the carrier liquid, they pass through the magnetic fields of the other permanent magnets at separation channel 1 to continue the "capture-release" magnetophoretic separation. If there is no other permanent magnet magnetic field behind, the micro-nano magnetic particles released by the second permanent magnet will flow out of the mobile phase output port 15 of the separation channel 1 under the drive of the carrier liquid, and the magnetophoretic separation process of the paramagnetic micro-nano magnetic particles will end.

[0031] In another embodiment, the method for magnetophoretic separation of paramagnetic micro / nano magnetic particles using the magnetophoretic separation device for paramagnetic micro / nano magnetic particles described in the above embodiments includes the following steps: S1. Two or more permanent magnets of different magnetic properties and sizes are placed above the separation channel 1, and the magnetic induction intensity of the magnetic field of each permanent magnet at the separation channel 1 is set. Along the flow phase inlet 14 to the flow phase outlet 15 of the separation channel 1, the set value of the magnetic induction intensity of the magnetic field of each permanent magnet at the separation channel 1 decreases sequentially.

[0032] S2. Open the solenoid valve of waste bottle 64 and close the solenoid valves of all collection bottles. Turn on the infusion pump 41 to allow the deionized water carrier liquid to flow in the device pipeline, passing through the three-way valve 42, separation channel 1, and UV-Vis ultraviolet-visible light detector 5, and flowing into waste bottle 64. The paramagnetic micro / nano magnetic particles to be separated are injected into the three-way valve 42 using a sample syringe, and together with the carrier liquid, they serve as the mobile phase, entering separation channel 1 through the mobile phase inlet 14.

[0033] S3. The carrier liquid carrying the paramagnetic micro / nano magnetic particles to be separated enters the separation channel 1. It first passes through the first permanent magnet. The critical diameter of the micro / nano magnetic particles is determined by the magnetic induction intensity of the first permanent magnet at the separation channel 1. Micro / nano magnetic particles larger than the critical diameter are captured, while those smaller than the critical diameter pass through the magnetic field of the first permanent magnet and flow out from the mobile phase outlet 15 of the separation channel 1. After passing through the UV-Vis ultraviolet-visible light detector 5, the detector closes the fourth solenoid valve 68 and opens the first solenoid valve 65 to collect these micro / nano magnetic particles. After collection, the first solenoid valve 65 is closed and the fourth solenoid valve 68 is opened.

[0034] S4. Remove the first permanent magnet. The magnetic field of the first permanent magnet at separation channel 1 disappears, and the micro-nano magnetic particles captured by the first permanent magnet are released. Driven by the flowing carrier liquid, they pass through the magnetic field of the second permanent magnet. Using the critical diameter determined by the magnetic induction intensity of the second permanent magnet at separation channel 1 as the boundary, micro-nano magnetic particles with a diameter larger than this critical diameter are captured by the second permanent magnet, while those smaller than this critical diameter flow out from the flowing phase outlet 15 of separation channel 1 through other permanent magnets. After passing through the UV-Vis ultraviolet-visible light detector 5, the fourth solenoid valve 68 is closed and the second solenoid valve 66 is opened to collect these micro-nano magnetic particles. After collection, the second solenoid valve 66 is closed and the fourth solenoid valve 68 is opened.

[0035] S5. Remove the second permanent magnet. Its magnetic field at separation channel 1 disappears, releasing the micro / nano magnetic particles captured by the second permanent magnet. Driven by the carrier liquid, these particles continue to be captured and released through the magnetic fields of other permanent magnets at separation channel 1, undergoing further magnetophoretic separation. If there are no other permanent magnets, the micro / nano magnetic particles released by the second permanent magnet flow out of the mobile phase outlet 15 of separation channel 1 under the influence of the carrier liquid. After passing through the UV-Vis ultraviolet-visible light detector 5, the detector closes the fourth solenoid valve 68 and opens the third solenoid valve 67 to collect these micro / nano magnetic particles. After collection, the third solenoid valve 67 is closed, and the fourth solenoid valve 68 is opened.

[0036] S6. The magnetophoretic separation process of paramagnetic micro-nano magnetic particles ends. Turn off the power to the magnetophoretic separation device 2, liquid inlet device 4, UV-Vis ultraviolet-visible light detector 5, collection device 6 and computer 7.

[0037] Figure 4 In the separation device, two permanent magnets are set up to achieve two-stage "capture-release" magnetophoretic separation. With critical diameters of 3.05μm and 4.26μm respectively, the separation of paramagnetic micro- and nano-magnetic particles with diameters of 3.00-5.50μm is completed. The separated micro- and nano-magnetic particles flow out from separation channel 1 at different times and are detected by UV-Vis visible-ultraviolet light detectors and collected into corresponding collection bottles.

[0038] In the two-stage "capture-release" paramagnetic micro / nano magnetic particle magnetophoretic separation device, the fourth solenoid valve 68 of the waste liquid bottle 64 is opened, and the solenoid valves of each collection bottle are closed. The magnetic induction intensity of the magnetic field of the first permanent magnet in separation channel 1 is set to 84 mT, and the magnetic induction intensity of the magnetic field of the second permanent magnet in separation channel 1 is set to 37 mT. Deionized water is used as the carrier liquid, and paramagnetic micro / nano magnetic particles with the same magnetic susceptibility but different sizes are used as samples to be separated. The diameter of the micro / nano magnetic particles is 3.00-5.50 μm. The infusion pump 41 is started, and the flow rate of the carrier liquid is set to 0.1 ml / min. The paramagnetic micro / nano magnetic particle sample is injected through the three-way valve 42 using the injection syringe 43, and the device begins magnetophoretic separation. The magnetic particle sample is carried into separation channel 1 by the flowing carrier liquid. After passing through the magnetic field of the first permanent magnet, some micro / nano magnetic particles are captured by the magnetic field, while the uncaptured micro / nano magnetic particles flow out of separation channel 1 through the second permanent magnet and are detected by the UV-Vis ultraviolet-visible light detector 5. Close the fourth solenoid valve 68 of waste liquid bottle 64 and open the first solenoid valve 65 of the first collection bottle 61 to collect these micro-nano magnetic particles. Then open the fourth solenoid valve 68 of waste liquid bottle 64 again and close the first solenoid valve 65 of the first collection bottle 61. After 6 minutes of magnetophoretic separation, the servo motor 21 drives the first permanent magnet to move rapidly away from the separation channel 1. The magnetic field of the first permanent magnet at the separation channel 1 disappears, releasing the micro-nano magnetic particles captured by the first permanent magnet. When these magnetic particles pass through the magnetic field of the second permanent magnet at the separation channel 1, some of them are captured, while the uncaptured micro-nano magnetic particles flow out of the separation channel 1 and are detected by the UV-Vis ultraviolet-visible light detector 5. Close the fourth solenoid valve 68 of waste liquid bottle 64 and open the second solenoid valve 66 of the second collection bottle 62 to collect these micro-nano magnetic particles. Then open the fourth solenoid valve 68 of waste liquid bottle 64 and close the second solenoid valve 66 of the second collection bottle 62. After 12 minutes, the servo motor 21 drives the second permanent magnet to quickly move away from the separation channel 1. The magnetic field of the second permanent magnet at the separation channel 1 disappears, releasing the micro-nano magnetic particles captured by the second permanent magnet. These magnetic particles flow out of the separation channel 1 and are detected when they pass through the UV-Vis ultraviolet-visible light detector 5. Close the fourth solenoid valve 68 of waste liquid bottle 64 and open the third solenoid valve 67 of the third collection bottle 63 to collect these micro-nano magnetic particles. Then open the fourth solenoid valve 68 of waste liquid bottle 64 and close the third solenoid valve 67 of the third collection bottle 63. The magnetophoretic separation of the paramagnetic micro-nano magnetic particle sample is completed, and the separation results are as follows. Figure 4As shown. Testing revealed that the diameter of the paramagnetic micro / nano magnetic particles in the first collection bottle 61 was less than 3.05 μm, the diameter of the paramagnetic micro / nano magnetic particles in the second collection bottle 62 was between 3.05 and 4.26 μm, and the diameter of the paramagnetic micro / nano magnetic particles in the third collection bottle 63 was between 4.26 and 5.38 μm, achieving magnetophoretic separation of paramagnetic micro / nano magnetic particles ranging from 3.00 to 5.50 μm.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A magnetophoretic separation device for paramagnetic micro / nano magnetic particles, characterized in that, include: Separate channel (1); The separation device includes: multiple permanent magnets (20) with the same magnetism and size and arranged at intervals above the separation channel (1) along the direction of the separation channel (1); and multiple sets of mechanical structures that drive each permanent magnet to move up and down in the vertical direction. Hall sensor (3) is attached to the position of the permanent magnet of the separation channel (1) to detect the magnitude of the magnetic induction intensity at that position of the separation channel (1); The liquid inlet device (4) allows the carrier liquid and paramagnetic micro / nano magnetic particle samples to flow into the separation channel (1) after they are combined. A UV / Vis ultraviolet-visible light detector (5) is connected to the end of the separation channel (1) to detect the separation of paramagnetic micro and nano magnetic particles after separation by the separation channel (1); Collection device (6) collects the separated paramagnetic micro / nano magnetic particles and unwanted carrier liquid; The computer (7) is electrically connected to the mechanical structure, Hall sensor (3), liquid inlet device (4), UV / Vis ultraviolet-visible light detector (5) and collection device (6), respectively.

2. The paramagnetic micro / nano magnetic particle magnetophoretic separation device according to claim 1, characterized in that, The permanent magnet (20) is a neodymium iron boron permanent magnet.

3. The paramagnetic micro / nano magnetic particle magnetophoretic separation device according to claim 1, characterized in that, The separation channel (1) includes: a cover plate (11), a microchannel (12) and a substrate (13). Above the cover plate (11) are the mobile phase inlet (14) and outlet (15) of the separation channel (1). The microchannel (12) is located between the cover plate (11) and the substrate (13).

4. The paramagnetic micro / nano magnetic particle magnetophoretic separation device according to claim 1, characterized in that, Each mechanical structure includes: a servo motor (21), a driver (22), a coupling (23), a lead screw (24), a nut seat (25), a linear guide (26), a slider (27), and a support rod (28); the servo motor (21) is connected to the lead screw (24) through the coupling (23) and kept coaxial; the servo motor (21) and the lead screw (24) are located on the rear side of the separation channel (1) and arranged in a direction perpendicular to the separation channel (1); the linear guide (26) and the slider (27) are located on the front side of the separation channel (1) and arranged in a direction perpendicular to the separation channel (1); the nut seat (25) on the lead screw (24) and the slider (27) on the linear guide (26) are connected through the support rod (28), which is used to fix the permanent magnet (20).

5. The paramagnetic micro / nano magnetic particle magnetophoretic separation device according to claim 1, characterized in that, The liquid inlet device (4) includes: an infusion pump (41), a three-way valve (42), and a sample injector (43).

6. The paramagnetic micro / nano magnetic particle magnetophoretic separation device according to claim 1, characterized in that, The number of permanent magnets (20) is two.

7. The paramagnetic micro / nano magnetic particle magnetophoretic separation device according to claim 6, characterized in that, The collection device (6) includes: a first collection bottle (61) and its corresponding first solenoid valve (65), a second collection bottle (62) and its corresponding second solenoid valve (66), a third collection bottle (63) and its corresponding third solenoid valve (67), and a waste liquid bottle (64) and its corresponding fourth solenoid valve (68).

8. The paramagnetic micro / nano magnetic particle magnetophoretic separation device according to claim 7, characterized in that, When the UV / Vis ultraviolet-visible light detector (5) detects unwanted carrier liquid flowing through the detector, the fourth solenoid valve (68) opens, and the first solenoid valve (65), the second solenoid valve (66) and the third solenoid valve (67) close, and the carrier liquid mobile phase flows into the waste liquid bottle (64). When the UV / Vis ultraviolet-visible light detector (5) detects micro-nano magnetic particles with a diameter less than or equal to the first threshold flowing through the detector, the fourth solenoid valve (68) closes, the first solenoid valve (65) opens, and the second solenoid valve (66) and the third solenoid valve (67) close, and the mobile phase of micro-nano magnetic particles with a diameter less than or equal to the first threshold flows into the first collection bottle (61). When the UV / Vis ultraviolet-visible light detector (5) detects micro-nano magnetic particles with a diameter greater than the first threshold and less than or equal to the second threshold flowing through the detector, the fourth solenoid valve (68) closes, the second solenoid valve (66) opens, and the first solenoid valve (65) and the third solenoid valve (67) close. The mobile phase of micro-nano magnetic particles with a diameter greater than the first threshold and less than or equal to the second threshold flows into the second collection bottle (62). After collection, the second solenoid valve (66) is closed, the fourth solenoid valve (68) is opened, and the mobile phase flows into the waste liquid bottle (64). When the UV / Vis ultraviolet-visible light detector (5) detects micro-nano magnetic particles with a diameter greater than the second threshold flowing through the detector, the fourth solenoid valve (68) closes, the third solenoid valve (67) opens, and the first solenoid valve (65) and the second solenoid valve (66) close. The mobile phase of micro-nano magnetic particles with a diameter greater than the second threshold flows into the third collection bottle (63). After collection, the third solenoid valve (67) is closed, the fourth solenoid valve (68) is opened, and the mobile phase flows into the waste liquid bottle (64).

9. The paramagnetic micro / nano magnetic particle magnetophoretic separation device according to claim 1, characterized in that, The computer (7) detects and displays the magnetic field strength of the permanent magnet (20) at the separation channel (1) to accurately set the magnetic field size at the separation channel (1).

10. A method for magnetophoretic separation of paramagnetic micro / nano magnetic particles, characterized in that, include: S1. Multiple permanent magnets (20) of the same magnetic properties and size are arranged at intervals above the separation channel (1) along the direction of the separation channel (1), and the magnetic induction intensity of the magnetic field of each permanent magnet at the separation channel (1) is set respectively. S2. Open the fourth solenoid valve (68) corresponding to the waste liquid bottle (64) and close the solenoid valves of each collection bottle; turn on the infusion pump (41) to make the deionized water carrier liquid flow in the device pipeline, through the three-way valve (42), the separation channel (1) and the UV-Vis ultraviolet-visible light detector (5), and flow into the waste liquid bottle (64); inject the paramagnetic micro-nano magnetic particles to be separated into the three-way valve (42) with the sample syringe, and together with the carrier liquid, as the mobile phase, enter the separation channel (1) through the mobile phase inlet (14); S3. The carrier liquid carrying the paramagnetic micro-nano magnetic particles to be separated first passes through the first permanent magnet. The first critical diameter is determined by the magnetic induction intensity of the first permanent magnet at the separation channel (1). Micro-nano magnetic particles larger than the first critical diameter are captured, while micro-nano magnetic particles smaller than the first critical diameter are passed through the magnetic field of the first permanent magnet and flow out from the mobile phase outlet (15) of the separation channel (1) and collected by the first collection bottle (61). S4. Remove the first permanent magnet. The magnetic field of the first permanent magnet at the separation channel (1) disappears. The micro-nano magnetic particles captured by the first permanent magnet are released and, driven by the flowing carrier liquid, pass through the magnetic field of the second permanent magnet. The second critical diameter, determined by the magnetic induction intensity of the second permanent magnet at the separation channel (1), captures micro-nano magnetic particles larger than the second critical diameter. Micro-nano magnetic particles smaller than the second critical diameter flow out from the mobile phase outlet (15) of the separation channel (1) through the magnetic field of the second permanent magnet and are collected by the second collection bottle (62). S5. Remove the second permanent magnet. The magnetic field of the second permanent magnet at the separation channel (1) disappears. The micro-nano magnetic particles captured by the second permanent magnet are released. Driven by the flowing carrier liquid, they are captured and released by the magnetic field of other permanent magnets at the separation channel (1) for further magnetophoretic separation. If there is no other permanent magnet magnetic field, the micro-nano magnetic particles released by the second permanent magnet will flow out of the separation channel (1) mobile phase outlet (15) under the drive of the carrier liquid and be collected by the third collection bottle (63). S6. The magnetophoretic separation process of paramagnetic micro-nano magnetic particles ends. Turn off the power to the magnetophoretic separation device (2), liquid inlet device (4), UV-Vis ultraviolet-visible light detector (5), collection device (6) and computer (7).

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