CN116984041A - Method and device for controlling liquid to flow back and forth based on magnetic force and application - Google Patents
Method and device for controlling liquid to flow back and forth based on magnetic force and application Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
- G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
- G01N33/53—Immunoassay; Biospecific binding assay; Materials therefor
- G01N33/5302—Apparatus specially adapted for immunological test procedures
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
- B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
- B01L3/50—Containers for the purpose of retaining a material to be analysed, e.g. test tubes
- B01L3/502—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures
- B01L3/5027—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip
- B01L3/502707—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip characterised by the manufacture of the container or its components
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
- B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
- B01L3/50—Containers for the purpose of retaining a material to be analysed, e.g. test tubes
- B01L3/502—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures
- B01L3/5027—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip
- B01L3/50273—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip characterised by the means or forces applied to move the fluids
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- Life Sciences & Earth Sciences (AREA)
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Abstract
The invention discloses a method, a device and application for controlling liquid to flow back and forth based on magnetic force. The method provided by the invention uses the interfacial capillary force generated on the gas/liquid/solid three-phase interface formed before the hydrophilic magnet is separated from the liquid as the traction force for liquid movement, so as to realize the flow control of the liquid. The method has the advantages that: 1) Non-contact flow control, which can avoid pollution caused by contact control (such as mechanical probe control); 2) The liquid can stably and rapidly move, bubbles and a new gas-liquid interface are not generated, severe friction and vibration on the gas-liquid interface are avoided, and the generation probability of aerosol is reduced; 3) Compared with the existing magnetic control mode of moving or disturbing liquid by driving force, the risk of aerosol pollution is greatly reduced. In addition, the beneficial effects that one round of antigen-antibody combination only needs 1-2 minutes and one time detection only needs 5-15 minutes are realized, and the detection speed is far higher than that of the traditional immunoassay method based on a reaction cup or a micro-pore plate.
Description
Technical Field
The invention belongs to the technical field of immunodetection. And more particularly to a method and apparatus for controlling the reciprocation of a liquid based on magnetic force and application thereof.
Background
Aerosol pollution is an important problem in the biomedical diagnosis field and is also an important factor affecting detection safety and accuracy of detection results. Aerosols are colloidal dispersions of air with solid and liquid particles suspended therein. In general, aerosols with small liquid particles as the dispersed phase may be generated by friction or vibration at the gas-liquid interface. These aerosols are easily dispersed in small spaces and reattached to solid surfaces or fall back into the liquid.
In the medical detection process, most detection operations can cause friction or vibration of a gas-liquid interface, such as repeated sucking, injecting, shaking and vibrating of a sample solution or a reaction reagent, rapid transportation of the sample solution, rapid movement of a reaction vessel (such as a 96-well plate, a reaction cup or a microfluidic chip) containing the sample solution, and the like, so as to generate aerosol of the sample solution or the reaction reagent. The sample solution typically contains marker molecules, cells, viruses or microorganisms of the disease, and the original sample that is not inactivated may still be infectious. When these aerosols adhere to the surfaces of the instruments or vessels, they will cause sample contamination and reagent contamination on the instruments and vessels; sample contamination can cause the instrument and vessel to be infectious, resulting in infection of the inspector, and reagent contamination can cause corrosion of the instrument and vessel. When these aerosols fall back into the sample solution, they cause cross-contamination of the sample solution and minor changes in the amount of reagents used, which may deviate the results of the sample detection from the actual sample conditions.
In order to solve the problem of aerosol contamination during medical testing, in laboratory manual testing, the inspector typically provides sealing conditions for the reaction vessel in which the sample solution is loaded, reducing the efficiency of aerosol release into the environment. However, in automated detection devices (e.g., fully automated enzyme-linked immunosorbent assay (elisa), fully automated luminescence (alfa) assay, microfluidic immunoassay (afi) assay, etc.), the reaction vessel is typically open for automated pipetting, sample addition, washing, etc. steps by the device. In addition, in the automatic detection device, especially in the small-sized automatic detection device with small operable space, a flow control mode such as magnetic stirring, centrifugation and the like capable of causing severe friction and oscillation of a gas-liquid interface is generally introduced to improve the sample capturing efficiency and the detection speed, and the operations can lead to generation of aerosol of a sample solution and possibly lead to serious consequences such as sample cross contamination and instrument contamination.
In view of the foregoing, there is a need for a method of introducing a gentle and efficient flow control in a fully automated detection device, particularly a small fully automated detection device, that reduces the risk of aerosol generation while providing higher sample capture efficiency and detection speed. For example, the inventor performs early-stage research to obtain a reciprocating flow type enzyme-linked immunoassay method (Chinese patent number: 202010116126.0), develops a small portable full-automatic enzyme-linked immunoassay instrument (Chinese patent number: 202110063475.5) based on the control principle of air pressure change, provides liquid flow control of stable flow speed change based on the reciprocating flow strategy of air pressure control, and realizes rapid immunodetection, so that in order to further reduce the generation of aerosol caused by friction and collision of an air-liquid interface, development and research of more new methods and means are needed to overcome the problem of aerosol pollution hidden trouble in the existing biomedical detection field.
Disclosure of Invention
The invention aims to solve the technical problem of hidden danger of aerosol pollution in the existing biomedical detection field, and provides a magnetic force-based liquid reciprocating flow control method and a magnetic force-based liquid reciprocating flow control device based on the mode of magnetic control dragging liquid movement, so that stable and rapid liquid flow control is realized, aerosol pollution is avoided, and the risk of aerosol pollution caused by friction and collision of liquid on an air-liquid interface is greatly reduced.
The invention aims to provide a method for controlling liquid to flow back and forth based on magnetic force.
It is another object of the present invention to provide a magnetically controlled reciprocation device.
It is a further object of the present invention to provide a method of controlling the reciprocation of a liquid based on a magnetically controlled reciprocation device.
It is a further object of the present invention to provide a magnetically controlled reciprocation based method and use of the apparatus.
It is yet another object of the present invention to provide an immunoassay method.
The above object of the present invention is achieved by the following technical scheme:
the invention provides a method for controlling liquid to flow reciprocally based on magnetic force, which is characterized in that a hydrophilic magnet is added into liquid to be detected, the hydrophilic magnet is moved to the edge of a gas-liquid interface of the liquid through an external magnetic field, a gas/liquid/solid three-phase interface is formed on the surface of the hydrophilic magnet, and before the hydrophilic magnet is separated from the liquid, the three-phase interface on the surface of the hydrophilic magnet generates interface capillary force, namely traction force for controlling the liquid to flow, and magnetic control driving force is provided through the external magnetic field to control the hydrophilic magnet to drag the liquid to move in a state of incompletely separating from the liquid, so that the liquid to flow reciprocally can be controlled;
The invention attempts to remove the hydrophilic magnet from the liquid by moving the hydrophilic magnet to the gas-liquid interface edge of the liquid after the liquid is contacted with the hydrophilic magnet and wrapped, and then trying to continue to move the hydrophilic magnet to the outside of the liquid. At this time, the hydrophilic magnet breaks through the gas-liquid interface of the liquid, so that a gas/liquid/solid three-phase interface is formed on the surface of the hydrophilic magnet, and the solid/liquid contact line is embodied in such a way that the liquid edge surrounds the surface of the hydrophilic magnet. Subsequently, when the hydrophilic magnet tries to continue to separate from the liquid, the interface energy change is caused on the gas/liquid/solid three-phase interface; the change in interfacial energy in turn translates into interfacial capillary forces on the solid/liquid contact line that are simultaneously applied to the hydrophilic magnet and the liquid. For the liquid, the interfacial capillary force points to the outside of the liquid along the movement direction of the hydrophilic magnet, so that the liquid is driven to move along the movement direction of the hydrophilic magnet as traction force, and the control of the liquid flow is realized. In brief, the reciprocation control of the liquid is accomplished by moving the hydrophilic magnet to drag the liquid.
Specifically, the interfacial capillary force needs to overcome the sliding friction force between the liquid end and the inner wall of the pipeline and the total surface tension generated by the contact line of the edge of the liquid end on the inner wall of the pipeline, so that the liquid can be pulled by the interfacial capillary force to move, and the hydrophilic magnet needs to drive the liquid to move under the following stress conditions:
F Interfacial capillary force ＞f Liquid sliding friction force +f Surface tension of liquid
Meanwhile, in order to enable the hydrophilic magnet to continuously provide interfacial capillary force for the movement of the liquid, the hydrophilic magnet needs to be kept in a state of magnetically controllable movement but not being separated from the liquid; at this time, after the sliding friction force between the hydrophilic magnet and the inner wall of the pipeline is overcome, the magnetic control driving force for driving the hydrophilic magnet to move can not further overcome the interfacial capillary force of the liquid on the hydrophilic magnet; the magnetic control driving force needs to meet the following stress conditions:
0＜F magnetic control driving force -f Sliding friction force of magnet ≤F Interfacial capillary force
In addition, after the hydrophilic magnet is added into the liquid to be detected, the magnetic control driving force is required to further overcome the resistance of the liquid moving in the pipeline after overcoming the sliding friction force between the hydrophilic magnet and the inner wall of the pipeline; therefore, the magnetic control driving force also needs to meet the following stress conditions:
F magnetic control driving force -f Sliding friction force of magnet ＞f Liquid sliding friction force +f Surface tension of liquid
Compared with the existing magnetic control mode that the liquid is moved or disturbed by the driving force generated by the movement of the magnet, the method provided by the invention has the characteristics of stable and rapid liquid flow, and is not easy to cause severe friction and vibration of a liquid interface, so that the generation probability of aerosol and the pollution risk of the aerosol can be greatly reduced.
In particular, the interface capillary force is influenced by the property of the hydrophilic magnet and the property of the liquid, and is limited by the property of the hydrophilic magnet, the property of the liquid, the size and the property of the pipeline, and the definition of the interface capillary force value can be regulated according to different conditions such as the size, the type and the volume of the pipeline, so that the interface capillary force is suitable for other application scenes. Preferred ranges of interfacial capillary forces provided by the invention: 1.251×10 -4 N＜F Interfacial capillary force ＜4.171×10 -3 N。
In particular, the magnetic driving force is limited by the properties of the hydrophilic magnet, the liquid property, the pipeline size and the property, and the limitation of the magnetic driving force can be adjusted according to different conditions such as the pipeline size, the liquid type and the volume, so as to adapt to other requirementsThe scene is used. The preferred range of the magnetic control driving force provided by the invention is as follows: 4.5605 ×10 -4 N＜F Magnetic control driving force ＜1.138×10 -2 N。
Preferably, the hydrophilic magnet is a magnetic material, and is selected from one of a magnetic alnico material, a magnetic ferrite material and a magnetic neodymium-iron-boron alloy.
More preferably, the hydrophilic magnet can be flexibly varied according to the use requirements, and the shape of the hydrophilic magnet can also be flexibly varied according to the use requirements, including but not limited to cylinders, spheres, cubes and the like.
More preferably, the hydrophilic magnet used in the invention is a cylinder of neodymium iron boron alloy material.
The invention is based on the principle of magnetic force control of liquid reciprocating flow, and also provides a magnetic force control-based reciprocating flow device, which comprises a support base, a micro-fluidic chip platform, a magnetic control driving device, an external controller and a micro-fluidic chip; the magnetic control driving device, the microfluidic chip platform and the microfluidic chip are arranged above the supporting base, and the microfluidic chip platform is arranged on two sides of the supporting base and used for supporting the microfluidic chip; the magnetic control driving device is fixed on the supporting base, and one end of the magnetic control driving device is electrically connected with the external controller; the microfluidic chip comprises a bottom chip serving as a substrate, a middle chip providing a micro-channel and a top chip with holes; the middle chip is provided with micro-channels which are arranged in parallel, and each micro-channel contains a hydrophilic magnet which is used for being matched with magnetic force control.
Preferably, the magnetic control driving device controls magnetic force based on a stepping motor, and comprises the stepping motor, a transmission rod and a magnetic plate; the stepping motor, the transmission rod and the magnetic plate are arranged above the supporting base; the stepping motor is fixed on the supporting base, one end of the stepping motor is mechanically connected with the transmission rod, and the other end of the stepping motor is electrically connected with the external controller; the transmission rod is arranged in parallel with the supporting base, and the other end of the transmission rod is fixed with a magnetic plate.
Preferably, the magnetic control driving device controls magnetic force based on the array inductor, and the magnetic control driving device comprises the array inductor and a circuit board connected with the array inductor; a circuit board is arranged above the support base, and an array inductor is connected above the circuit board in an electrified manner; the circuit board is fixed on the supporting base, and one end of the circuit board is electrically connected with the external controller; the array inductors are arranged in parallel with the support base, the arrangement positions of the array inductors correspond to the positions of the micro-flow channels which are arranged in parallel in the micro-flow control chip, the inductors which are parallel to the micro-flow channel direction are connected in parallel, the inductors which are perpendicular to the micro-flow channel direction are connected in series, and the interval between the array inductors is equal to the interval distance between the micro-flow channels.
Preferably, the array inductance is sufficient to provide a sufficient F Magnetic control driving force In the case of (2) the dimensions are as small as possible.
Preferably, the array inductor needs to be an unshielded or semi-shielded inductor, and may be specifically one of a wound type, a patch type and a woven type inductor.
The device provided by the invention provides a magnetic control driving force through the magnetic control driving device, the stepping motor is connected with an external controller, and the driving rod is driven to enable the magnetic plate to move so as to drive the hydrophilic magnet in the microfluidic chip to move to drag the liquid to move; or the outer controller is connected with the array inductance circuit board, and the inductance is connected line by line to generate a changing magnetic field so as to drive the hydrophilic magnet in the microfluidic chip to move to drag the liquid to move; moving the hydrophilic magnet to the gas-liquid interface edge of the liquid, and trying to continuously move the hydrophilic magnet to the outside of the liquid so as to separate the hydrophilic magnet from the liquid, wherein the hydrophilic magnet and the liquid have to overcome the adhesion force between the hydrophilic magnet and the liquid to do work, and the adhesion force becomes the traction force of the liquid movement; the movement amplitude of the hydrophilic magnet is controlled within the bearing range of the adhesion force between the hydrophilic magnet and the liquid, so that the hydrophilic magnet continuously provides traction force for the movement of the liquid under the state of not completely separating from the liquid, thereby realizing the control of the liquid flow.
Further, the motion parameters are set through an external controller, and the motion parameters are input into a magnetic control driving device, so that a stepping motor drives a transmission rod to drive a magnetic plate to return to a starting position after the support base moves forwards at a constant speed, or the array inductor is sequentially and reciprocally connected line by line, and a motion cycle is completed.
Still further, the motion parameters include a motion speed, a motion distance, and a motion cycle number.
Preferably, the height of the hydrophilic magnet is smaller than the height of the micro flow channel, and the width is smaller than the width of the micro flow channel.
The invention provides a manufacturing method of a microfluidic chip, which comprises the following steps:
s1, manufacturing strip holes parallel to each other on the surface of a flat plastic sheet, so as to obtain a middle-layer chip;
s2, manufacturing a plurality of groups of round holes on the surface of the other flat plastic sheet, so as to obtain a top chip;
and S3, sequentially attaching the flat bottom chip, the middle chip and the top chip together in an adhesive bonding mode, and assembling to obtain the microfluidic chip.
Preferably, the plastic sheet is one of polydimethylsiloxane, polystyrene, polypropylene, polymethyl methacrylate, polyethylene terephthalate, polyethylene, polyvinyl chloride and polyurethane.
More preferably, the strip holes on the middle chip and the round holes on the top chip with holes of the micro-channel can be manufactured by a mechanical method, a laser cutting method and other processes.
Further preferably, the strip hole on the middle chip is a square hole with two round holes connected to two ends respectively, the diameter of the round hole is 0.4cm, the length of the square hole is 2.0cm, and the width of the square hole is 0.2cm.
More specifically, the diameter of the round hole on the top chip is 0.4cm, and the position of the round hole corresponds to the position of the round hole on the middle chip.
Preferably, the adhesive used for assembling the bottom chip, the middle chip and the top chip can be various quick-drying adhesives, photo-curing adhesives and the like, and can be flexibly changed according to actual use requirements.
More preferably, when the bottom chip, the middle chip and the top chip are assembled, the bottom chip and the top chip respectively form the bottom and the top of the square hole of the middle chip, thereby forming a micro flow channel; at this time, the round holes of the top chip are in one-to-one correspondence with the round holes of the middle chip.
The invention provides a method for controlling liquid to flow back and forth based on a magnetic force control liquid back and forth flow device, which specifically comprises the following steps:
s1, placing a microfluidic chip above a microfluidic chip platform;
s2, injecting liquid to be controlled into a micro-channel of the micro-fluidic chip;
S3, inputting motion parameters including motion speed, motion distance and motion cycle number to the magnetic control driving device through an external controller;
s4, starting a reciprocating flow device, enabling a stepping motor to drive a transmission rod to drive a magnetic plate to move, or enabling a circuit board to be connected with an array inductor line by line to generate a variable magnetic field, so that a hydrophilic magnet in a microfluidic chip moves forwards at a constant speed from a starting position according to the movement speed set in S3 under the action of a magnetic control driving force, wherein the movement distance is equal to the movement distance set in S3;
s5, after the hydrophilic magnet in the microfluidic chip moves at a constant speed to reach the set movement distance, the magnetic control driving device drives the hydrophilic magnet to move backwards at a constant speed according to the set speed in S3 and return to the initial position, so that one movement period is completed;
and S6, sequentially repeating the steps S4 and S5 by the reciprocating flow device, wherein the repetition number is equal to the movement cycle number set in the step S3, so that reciprocating flow control is realized.
The invention also provides an application of the magnetic force control liquid reciprocating flow method or the magnetic force control liquid reciprocating flow device in liquid control, immunodetection, nucleic acid detection and biological particle detection.
The invention also provides an immune detection method, which comprises the following steps:
S1, preparing a microfluidic chip and placing the microfluidic chip above a microfluidic chip platform;
s2, injecting a sample solution to be detected into a micro-channel of the micro-fluidic chip;
s3, setting motion parameters of an external controller, inputting the motion parameters into a magnetic control driving device, starting a reciprocating flow device, enabling a stepping motor to drive a transmission rod to drive a magnetic plate to move, or enabling a circuit board to be connected with an array inductor line by line to generate a variable magnetic field, so that a hydrophilic magnet in a microfluidic chip moves forwards at a constant speed from a starting position according to the motion speed set in S3, wherein the motion distance is equal to the motion distance set in S3; after the hydrophilic magnet in the micro-fluidic chip moves at a constant speed to reach the set movement distance, the magnetic control driving device drives the hydrophilic magnet to move backwards at a constant speed according to the set speed in the step S3 and return to the initial position, so that one movement period is completed;
and S4, sequentially repeating the steps of S2 and S3 according to the detection method, wherein the repetition number is equal to the movement cycle number set in S3, so that reciprocating flow control is realized and detection is carried out.
Preferably, in the step S1, a specific antibody or antigen is coated on the bottom chip at a position corresponding to the micro flow channel of the middle chip.
Preferably, in step S2, a sample solution to be measured is added into the micro flow channel from the top circular hole of the top chip of the micro flow control chip, capturing the sample to be measured, cleaning the sample solution, capturing the second antibody, cleaning the second antibody solution are sequentially performed, and the reciprocating flow device is started for detection.
The above detection method, the present invention also provides a most preferred embodiment, specifically comprising the following steps:
s1, coating a specific antibody or antigen on a bottom chip. Before assembling the microfluidic chip, the bottom chip is partially coated with specific antibodies or antigens in advance, and the coated antibodies or antigens can specifically identify the molecules of the sample to be detected. The size of the coating area is 0.2×0.4mm, and the position of the coating area corresponds to the middle position of the square hole above the middle layer chip.
S2, capturing a sample to be detected. And adding the sample solution to be tested into the micro-channel in the top layer round hole, then starting the reciprocating flow device to enable the sample solution to flow reciprocally for 5 periods, and then discharging the sample solution.
S3, cleaning the sample solution. And adding cleaning liquid into the micro-flow channel in the round hole of the top layer, and starting the reciprocating flow device to enable the cleaning liquid to move unidirectionally and discharge. The washing was repeated 3 times.
S4, capturing a second antibody. Subsequently, a secondary antibody solution labeled with a signaling probe was added to the micro flow channel in the top-layer well. The reciprocating flow device was started to reciprocate the second antibody solution for 5 cycles, and then the second antibody solution was discharged.
S5, cleaning the secondary antibody solution. And adding cleaning liquid into the micro-flow channel in the round hole of the top layer, and starting the reciprocating flow device to enable the cleaning liquid to move unidirectionally and discharge. The washing was repeated 3 times.
S6, detecting results. According to different detection methods, a plurality of detection means can be selected.
The invention also provides an application of the method for controlling the liquid to flow back and forth by magnetic force or the magnetic force-controlled back and forth flowing device in enzyme-linked immunosorbent assay, fluorescence immunoassay, chemiluminescence immunoassay or local surface plasmon resonance detection.
The invention has the following beneficial effects:
the invention provides a method for controlling liquid to flow back and forth based on magnetic force based on a mode of magnetically controlling liquid to move, which utilizes interfacial capillary force generated on a gas/liquid/solid three-phase interface formed before a hydrophilic magnet is separated from liquid as traction force for liquid movement to realize liquid flow control. The method has the characteristics of stable and rapid liquid flow, greatly reduces the intense friction and vibration of a liquid interface, and avoids the generation of aerosol pollution, thereby avoiding the risk of aerosol pollution. The invention also provides a magnetic force control-based reciprocating flow device. Meanwhile, the invention also provides an immune detection method, which uses a reciprocating flow device for detection, can be applied to various microfluidic immune detection and has the following characteristics:
1) A non-contact flow control method can avoid solid pollution and liquid pollution (such as mechanical probe control) caused by conventional contact control.
2) The flow control method can enable the liquid to move stably and rapidly, and bubbles are not generated so as to form a new gas-liquid interface, thereby avoiding severe friction and vibration on the gas-liquid interface.
3) Compared with the existing magnetic control mode that the liquid is moved or disturbed by the driving force generated by the movement of the magnet, the magnetic control-based reciprocating flow device greatly reduces the probability of generating aerosol, thereby reducing the risk of aerosol pollution.
4) The magnetic force control-based reciprocating flow device is applied to various microfluidic immunodetection, only 1-2 minutes is needed for finishing one round of antigen-antibody combination, only 5-15 minutes is needed for finishing one round of immunodetection, and the detection speed is far higher than that of the traditional immunodetection method based on a reaction cup or a micro-pore plate.
Drawings
Fig. 1 is a schematic diagram of a reciprocating flow method of a reciprocating flow device provided by the invention.
Fig. 2 is a schematic diagram of a reciprocating flow device based on control of a stepper motor (a supporting base-1, a micro-fluidic chip platform-11, a stepper motor-21, a transmission rod-22, a magnetic plate-23, an external controller-3 and a micro-fluidic chip-4) provided by the invention.
Fig. 3 is a schematic structural diagram of a microfluidic chip (microfluidic chip-4, bottom chip-41, middle chip-42, top chip-43, micro flow channel-421, hydrophilic magnet-422) provided by the present invention.
FIG. 4 is a flow control process of the magnetic force control-based reciprocating flow device in example 1.
Fig. 5 is a schematic diagram of a reciprocating flow device based on array inductance control (support base-1, microfluidic chip platform-11, circuit board-24, array inductance-25, external controller-3, microfluidic chip-4) provided by the invention.
FIG. 6 is a qualitative result of ELISA detection of human immunoglobulin G (IgG) based on magnetically controlled shuttle devices in example 2.
FIG. 7 is the quantitative results of ELISA detection of human IgG based on magnetically controlled shuttle device of example 2.
FIG. 8 is a qualitative result of fluorescence immunoassay of human IgG based on magnetically controlled shuttle device in example 3.
Detailed Description
The invention is further illustrated in the following drawings and specific examples, which are not intended to limit the invention in any way. Unless specifically stated otherwise, the reagents, methods and apparatus employed in the present invention are those conventional in the art.
Reagents and materials used in the following examples are commercially available unless otherwise specified.
Example 1A method for controlling liquid reciprocation based on magnetic force
Aiming at the problem of hidden danger of aerosol pollution in the biomedical detection field, the invention provides a method for controlling liquid to flow back and forth based on magnetic force, which comprises the steps of adding a hydrophilic magnet into liquid to be detected, moving the hydrophilic magnet to the edge of a gas-liquid interface of the liquid through an external magnetic field, forming a gas/liquid/solid three-phase interface on the surface of the hydrophilic magnet, and generating interface capillary force on the three-phase interface on the surface of the hydrophilic magnet before the hydrophilic magnet is separated from the liquid, namely controlling the traction force of liquid flow, and controlling the movement of the hydrophilic magnet through the magnetic control driving force provided by the external magnetic field, so that the liquid to flow back and forth can be controlled;
the invention attempts to remove the hydrophilic magnet from the liquid by moving the hydrophilic magnet to the gas-liquid interface edge of the liquid after the liquid is contacted with the hydrophilic magnet and wrapped, and then trying to continue to move the hydrophilic magnet to the outside of the liquid. At this time, the hydrophilic magnet breaks through the gas-liquid interface of the liquid, so that a gas/liquid/solid three-phase interface is formed on the surface of the hydrophilic magnet, and the solid/liquid contact line is embodied in such a way that the liquid edge surrounds the surface of the hydrophilic magnet. Subsequently, when the hydrophilic magnet tries to continue to separate from the liquid, the interface energy change is caused on the gas/liquid/solid three-phase interface; the change in interfacial energy in turn translates into interfacial capillary forces on the solid/liquid contact line that are simultaneously applied to the hydrophilic magnet and the liquid. For the liquid, the interfacial capillary force points to the outside of the liquid along the movement direction of the hydrophilic magnet, so that the liquid is driven to move along the movement direction of the hydrophilic magnet as traction force, and the control of the liquid flow is realized. In brief, the reciprocation control of the liquid is accomplished by moving the hydrophilic magnet to drag the liquid.
The principle of controlling the liquid to flow back and forth based on the magnetic force is shown in figure 1, the hydrophilic magnet and the liquid have to overcome the interfacial capillary force between the hydrophilic magnet and the liquid to do work, and the interfacial capillary force becomes the traction force for the liquid to move; the movement amplitude of the hydrophilic magnet is controlled within the bearing range of the interfacial capillary force between the hydrophilic magnet and the liquid, so that the hydrophilic magnet is in a critical state of incompletely separating from the liquid, and traction force is continuously provided for the movement of the liquid, thereby realizing the control of the liquid flow.
Specifically, the interfacial capillary force needs to overcome the sliding friction force between the liquid end and the inner wall of the pipeline and the total surface tension generated by the contact line of the edge of the liquid end on the inner wall of the pipeline, so that the liquid can be pulled by the interfacial capillary force to move, and the hydrophilic magnet needs to drive the liquid to move under the following stress conditions:
F interfacial capillary force ＞f Liquid sliding friction force +f Surface tension of liquid
Meanwhile, in order to enable the hydrophilic magnet to continuously provide interfacial capillary force for the movement of the liquid, the hydrophilic magnet needs to be kept in a state of magnetically controllable movement but not being separated from the liquid; at this time, after the sliding friction force between the hydrophilic magnet and the inner wall of the pipeline is overcome, the magnetic control driving force for driving the hydrophilic magnet to move can not further overcome the interfacial capillary force of the liquid on the hydrophilic magnet; the magnetic control driving force needs to meet the following stress conditions:
0＜F Magnetic control driving force -f Sliding friction force of magnet ≤F Interfacial capillary force
In addition, after the hydrophilic magnet is added into the liquid to be detected, the magnetic control driving force is required to further overcome the resistance of the liquid moving in the pipeline after overcoming the sliding friction force between the hydrophilic magnet and the inner wall of the pipeline; therefore, the magnetic control driving force also needs to meet the following stress conditions:
F magnetic control driving force -f Sliding friction force of magnet ＞f Liquid sliding friction force +f Surface tension of liquid
And the interface capillary force and the magnetic control driving force are influenced by the property of the hydrophilic magnet and the property of the liquid, are limited by the property of the hydrophilic magnet, the property of the liquid, the size and the property of the pipeline, and can be adjusted according to different conditions such as the size, the type and the volume of the pipeline, so that the device is suitable for other application scenes.
The invention is studied to obtainThe preferred range of interfacial capillary forces is: 1.251×10 -4 N＜F Interfacial capillary force ＜4.171×10 -3 N, preferred range of magnetic driving force: 4.5605 ×10 -4 N＜F Magnetic control driving force ＜1.138×10 -2 N。
The hydrophilic magnet used in the invention is a magnetic material, is selected from one of a magnetic alnico material, a magnetic ferrite material and a magnetic neodymium-iron-boron alloy, can flexibly change according to the use requirement, and can also flexibly change according to the use requirement, including but not limited to a cylinder, a sphere, a cube and the like. Preferably, the hydrophilic magnet used in the invention is a cylinder made of neodymium-iron-boron alloy material.
The invention provides a method for controlling liquid to flow back and forth based on magnetic force, which realizes stable and rapid liquid flow control, and can be applied to microfluidic immunodetection with various low aerosol pollution risks, such as enzyme-linked immunodetection, fluorescence immunodetection, chemiluminescence immunodetection or local surface plasmon resonance detection. Unlike available magnetic control mode, which produces driving force to move or disturb liquid, the present invention has the magnetic control mode of providing liquid with capillary force to move in critical state before the hydrophilic magnet in the liquid is separated from the liquid, so as to control the liquid flow.
Example 2A magnetic force controlling reciprocating flow device based on a stepper Motor
The embodiment provides a device for controlling liquid to flow back and forth based on magnetic force, and a schematic diagram of the device is shown in fig. 2, and the device comprises the following main structures: the micro-fluidic chip comprises a support base 1, a micro-fluidic chip platform 11, a magnetic control driving device 2, an external controller 3 and a micro-fluidic chip 4; the magnetic control driving device 2 comprises a stepping motor 21, a transmission rod 22 and a magnetic plate 23; a micro-fluidic chip platform 11 is arranged above the support base 1 and used for supporting the micro-fluidic chip 4, and the micro-fluidic chip platform 11 is arranged above the stepper motor 21, the transmission rod 22 and the magnetic plate 23 assembly; the stepping motor 21 is fixed on the supporting base 1, one end of the stepping motor is mechanically connected with the transmission rod 22, and the other end of the stepping motor is electrically connected with the external controller 3; the transmission rod 22 is parallel to the support base 1, and a magnetic plate 23 is fixed at the other end.
The schematic diagram of the microfluidic chip 4 is shown in fig. 3, and the microfluidic chip 4 is divided into three layers including a bottom chip 41 as a substrate, a middle chip 42 providing a micro flow channel, and a top chip 43 with holes; the middle chip 42 is provided with micro-channels 421 which are arranged in parallel, and hydrophilic magnets 422 for matching magnetic force control are arranged in each micro-channel in advance;
further, the hydrophilic magnet is characterized by dimensions: the height is smaller than the height of the micro flow channel, and the width is smaller than the width of the micro flow channel.
The device of the invention is realized by the following principle: after the liquid is injected into the micro flow channel, the liquid is contacted with the hydrophilic magnet and wrapped. The invention is achieved by moving the hydrophilic 422 magnet to the gas-liquid interface edge of the liquid; and attempts to continue moving the hydrophilic magnet 422 toward the outside of the liquid to disengage it from the liquid. At this time, the hydrophilic magnet 422 breaks through the gas-liquid interface of the liquid, thereby forming a gas/liquid/solid three-phase interface on the surface of the hydrophilic magnet 422, which is embodied as a solid/liquid contact line where the liquid edge surrounds the surface of the hydrophilic magnet 422. Subsequently, as the hydrophilic magnet 422 attempts to continue to disengage from the liquid, a change in interfacial energy will be induced at the gas/liquid/solid three-phase interface; the change in interfacial energy in turn translates into interfacial capillary forces on the solid/liquid contact lines that are simultaneously applied to the hydrophilic magnet 422 and the liquid. For the liquid, the interfacial capillary force is directed to the outside of the liquid along the movement direction of the hydrophilic magnet 422, so that the liquid is driven to move along the movement direction of the hydrophilic magnet 422 as a traction force, and the control of the liquid flow is realized. In brief, the reciprocation control of the liquid is accomplished by moving the hydrophilic magnet 422 to drag the liquid movement.
The operation method of the device based on magnetic force control for reciprocating flow comprises the following steps: placing the microfluidic chip 4 above the microfluidic chip platform 11, and injecting liquid to be controlled into the micro flow channel 421 of the microfluidic chip 4; inputting motion parameters including motion speed, motion distance and motion cycle number to the stepper motor 21 through the external controller 3; starting the reciprocating flow device to enable the stepping motor 21 to drive the transmission rod 22 to move, so as to drive the magnetic plate 23 to move forwards at a constant speed from the initial position according to the movement speed and distance set in the external controller 3;
after the magnetic plate 23 moves at a constant speed to reach the set movement distance, the stepping motor 21 drives the transmission rod 22 to move, so that the magnetic plate 23 moves back at a constant speed according to the speed set by the external controller 3 and returns to the initial position, thereby completing one movement period; the reciprocation device sequentially repeats the above operations for a number of times equal to the number of movement cycles set in the external controller 3, thereby realizing reciprocation control.
The implementation also provides a manufacturing method of the microfluidic chip 4:
s1, manufacturing 3 mutually parallel strip holes on the surface of a flat polymethyl methacrylate (PMMA) sheet by laser cutting, so as to obtain a middle-layer chip 42; the strip hole consists of square holes with two ends respectively connected with two round holes, wherein the diameter of the round hole is 0.4cm, the length of the square hole is 2.0cm, and the width of the square hole is 0.2cm;
S2, manufacturing 3 groups of round holes with the diameter of 0.4cm on the surface of the other flat PMMA sheet by laser cutting, so as to obtain a top chip 43;
and S3, using photo-curing glue as an adhesive, and attaching the flat bottom chip 41 (flat PMMA sheet), the middle chip 42 and the top chip 43 together under the condition of illumination to assemble the microfluidic chip 4.
The device of the invention is adopted to control the flowing process of liquid: placing the assembled microfluidic chip 4 on a microfluidic chip platform 11 of a reciprocating flow device, and adding 40 mu L of red water into a micro-channel 421 of a middle chip 42 through a round hole on a top chip 43; the external controller 3 inputs motion parameters including a motion speed (3.11 mm/s), a motion distance (2.0 cm) and a motion cycle number to the stepper motor 21, and the reciprocating flow device is started to start flow control.
As a result of the flow control, as shown in fig. 4, there is no pushing action on the liquid when the hydrophilic magnet 422 moves inside the liquid during the reciprocation of the magnetic force control. When the hydrophilic magnet 422 moves to the boundary of the gas-liquid interface of the liquid, the liquid of each channel can be pulled to move at the same speed at a uniform speed. When the hydrophilic magnet 422 stops moving, the liquid also immediately stops moving. The above process remains consistent during flow control in different flow directions.
The result shows that the magnetic force control-based reciprocating flow method can realize flow control that the magnet drags liquid to move instead of pushing or disturbing. In the control process, the movement of the liquid is smooth and rapid, and no severe friction and oscillation of a gas-liquid interface occur; and no bubbles are generated to form a new gas-liquid interface, so that the method meets the requirement of reducing the generation probability of aerosol and has the capability of reducing the pollution risk of the aerosol.
Example 3A magnetic force controlling device for reciprocating flow based on array inductance
The embodiment provides a device for controlling magnetic force to drive liquid to flow back and forth based on array inductance, a schematic diagram of the device is shown in fig. 5, and the device comprises the following main structures: the micro-fluidic chip comprises a support base 1, a micro-fluidic chip platform 11, a magnetic control driving device 2, an external controller 3 and a micro-fluidic chip 4, wherein the magnetic control driving device 2 comprises a circuit board 24 and an array inductor 25; a micro-fluidic chip platform 11 is arranged above the support base 1 and used for supporting the micro-fluidic chip 4, and the micro-fluidic chip platform 11 is arranged above the circuit board 24 and the array inductor 25 assembly; the circuit board 24 is fixed on the supporting base 1, the upper end of the circuit board is electrically connected with the array inductor 25, and one end of the circuit board is electrically connected with the external controller 3; the array inductors 25 are arranged in parallel with the support base 1, the arrangement positions of the array inductors correspond to the positions of the micro flow channels 421 which are arranged in parallel in the micro flow control chip 4, the inductors parallel to the micro flow channels 421 are connected in parallel, the interval is as small as possible, the inductors perpendicular to the micro flow channels 421 are connected in series, and the interval is equal to the distance between the micro flow channels 421; the array inductor 25 is sufficient to provide enough F Magnetic control driving force In the case of (2), the dimensions are as small as possible; the array inductor 25 is required to be an unshielded or semi-shielded inductor, specifically one of a wound type, a patch type, and a woven type.
The structure and manufacturing method of the microfluidic chip 4 in this embodiment, hydrophilic magnet selection, and liquid control principles and parameters are the same as those in embodiment 2.
The operation method of the device based on magnetic force control for reciprocating flow comprises the following steps: placing the microfluidic chip 4 above the microfluidic chip platform 11, and injecting liquid to be controlled into the micro flow channel 421 of the microfluidic chip 4; inputting motion parameters including motion speed, motion distance and motion cycle number to the circuit board 24 through the external controller 3; starting the reciprocating flow device, enabling the circuit board 24 to be connected with the array inductor 25 row by row according to the movement speed and the movement distance set in the external controller 3 to generate a variable magnetic field, and driving the hydrophilic magnet in the micro-channel 421 to move forwards at a constant speed from the initial position;
after the hydrophilic magnet moves at a constant speed to reach the set movement distance, the circuit board 24 is reversely connected with the array inductor 25 line by line to generate a variable magnetic field, so that the hydrophilic magnet in the micro-channel 421 is driven to move backwards at a constant speed according to the set speed of the external controller 3 and return to the initial position, and a movement period is completed; the reciprocation device sequentially repeats the above operations for a number of times equal to the number of movement cycles set in the external controller 3, thereby realizing reciprocation control.
Example 4 ELISA based on magnetic flow-back device
1. Manufacturing a microfluidic chip for immunodetection:
s1, partially coating goat anti-human IgG antibody on a flat PMMA sheet, wherein the size of a coating area is 0.2 multiplied by 0.4mm, and the position of the coating area corresponds to the middle position of a square hole on a middle chip 42, so that a bottom chip 41 coated with specific antibody is obtained;
s2, 6 mutually parallel strip holes are manufactured on the surface of the other flat PMMA sheet by laser cutting, so that a middle-layer chip 42 is obtained; the strip hole consists of square holes with two ends respectively connected with two round holes, wherein the diameter of the round hole is 0.4cm, the length of the square hole is 2.0cm, and the width of the square hole is 0.2cm;
s3, manufacturing 6 groups of round holes on the surface of the flat plastic sheet by laser cutting, so as to obtain round holes with the diameter of 0.4cm, and obtaining a top chip 43;
and S4, using photo-curing adhesive as an adhesive, and attaching the bottom chip 41, the middle chip 42 and the top chip 43 together under the condition of illumination to assemble the microfluidic chip 4.
2. ELISA method for detecting human IgG:
(1) Capturing a sample to be tested. The magnetic force-based reciprocating flow device is adopted, 40 mu L of human IgG solution is respectively added into the micro-flow channel 421 in the top round hole of the top chip 43 on the micro-fluidic chip 4, then an external controller 3 is arranged (the reciprocating flow control motion parameter setting is the same as that of the embodiment 1) to start the reciprocating flow device, so that the sample solution flows back and forth for 5 periods, and then the sample solution is discharged.
(2) And (5) cleaning the sample solution. 40 mu L of cleaning liquid is respectively added into the micro-channels 421 from the top round holes of the top chip 43, and then the reciprocating flow device is started to enable the cleaning liquid to move unidirectionally and be discharged; the cleaning solution is phosphate buffer solution containing Tween-20. The washing was repeated 3 times.
(3) Capture of the second antibody. Subsequently, 40. Mu.L of horseradish peroxidase-labeled rabbit anti-human IgG antibody solution was added to the micro flow channel 421 from the top-layer well of the top-layer chip 43, respectively. The reciprocating flow device was started to reciprocate the second antibody solution for 5 cycles, and then the second antibody solution was discharged.
(4) Washing of the secondary antibody solution. 40. Mu.L of the cleaning liquid (the cleaning liquid component is the same as (2) above) was added to the micro flow channels 421 from the top circular holes of the top chip 43, and the reciprocating flow device was started to move the cleaning liquid in one direction and discharge the cleaning liquid. The washing was repeated 3 times.
(5) And (5) detecting results. 40. Mu.L of the color-developing solution was added to each of the micro flow channels 421 from the top circular hole of the top chip 43, and the reciprocating flow device was started to allow the color-developing solution to be circulated for 5 cycles. Subsequently, 20. Mu.L of the stop solution was added to each of the micro flow channels 421 from the top circular hole of the top chip 43, and the shuttle was started to allow the color development solution to be circulated for 5 cycles. And carrying out data analysis on the color of the liquid in each channel to obtain a detection result.
The results of qualitative detection of ELISA using a shuttle device are shown in FIG. 6. The left side of fig. 6 is a physical diagram of a qualitative detection result, in which information includes 6 micro channels parallel to each other, wherein the three micro channels on the left side are detection channels of negative samples, and the three micro channels on the right side are detection channels of positive samples. Obviously, the color results in the negative sample detection channel and the positive sample detection channel have stronger differentiation, and can be effectively applied to qualitative detection. The color data of the detection channels are extracted, classified and compared according to the sample types, namely the histogram on the right side of fig. 6. According to the histogram, the color gray scales of the negative sample and the positive sample are obviously different, so that the negative and positive results have strong distinction, and the detection method in the embodiment can be effectively applied to qualitative detection for distinguishing the negative and positive samples.
The results of quantitative detection by ELISA using a shuttle device are shown in FIG. 7. The left graph of fig. 7 is a physical graph of quantitative detection results, in which the information includes 6 parallel microchannels, and the microchannels are from left to right and are respectively detection channels of blank samples and IgG samples with different concentrations, and are ordered according to concentration increase. Obviously, the color results in the 6 detection channels are enhanced with the increase of the concentration of IgG in the sample, which indicates that the detection method in this embodiment can provide a visual result for quantitative detection. The color data of the detection channels are extracted, and the change of the color intensity along with the concentration of the sample is analyzed and fitted, namely, a linear fitting curve on the right side of fig. 7. According to the graph, the detection results of positive samples with different concentrations have obvious linear relation with the change of the concentrations, and can be effectively applied to quantitative detection.
Example 5 fluorescent immunodetection based on magnetic flow-back device
The preparation of the microfluidic chip 4 for immunodetection was the same as example 2 using the magnetic-force-based flow-back device of example 3 for fluorescence immunodetection. The procedure for the capture of the sample to be tested, the washing of the sample solution and the capture of the second antibody using the shuttle device for detection of human IgG was the same as in example 4. Subsequently, 40. Mu.L of a fluorescent microsphere-labeled rabbit anti-human IgG antibody solution was added to the micro flow channel from the top chip 43 in the top sample well, and the secondary antibody solution was reciprocally flowed for 5 cycles by starting the reciprocal flow device, followed by discharging the secondary antibody solution. And then cleaning the second antibody solution, wherein the method is the same as that of the embodiment 2, and placing the processed microfluidic chip 4 into an ultraviolet camera bellows, and analyzing the detection result according to the fluorescence intensity in the coating area.
The results of qualitative detection of fluorescence immunoassay using a reciprocating flow device are shown in fig. 8. Fig. 8 is a bottom chip physical diagram of the microfluidic chip after fluorescence detection in this embodiment, where the result of fluorescence detection should appear in the middle of each detection channel, i.e. the area between each set of opposite circular holes. The micro-flow channel between the three groups of round holes on the left side carries out the detection of the negative sample, and no obvious fluorescent speckles appear in the middle of the detection channel; in contrast, the micro flow channels between the three groups of round holes on the right side respectively carry out human IgG detection with the concentrations of 7.3, 73 and 730ng/mL, fluorescent spots which can be distinguished by naked eyes appear in the middle of the detection channel, and the fluorescence intensity is obviously changed along with the increase of the concentration of the human IgG. The result shows that the negative sample result, the low-concentration positive sample result and the high-concentration positive sample result in the embodiment have stronger differentiation degree, and can effectively develop the immune detection.
In summary, the magnetic force control-based reciprocating flow method and device provided by the invention can be applied to various microfluidic immunodetection, and interface capillary force generated by a gas/liquid/solid three-phase interface formed before a hydrophilic magnet leaves liquid is used as liquid movement traction force to realize liquid flow control, so that non-contact flow control is realized, and pollution caused by contact control (such as mechanical probe control) can be avoided; meanwhile, the liquid can stably and rapidly move, bubbles and a new gas-liquid interface are not generated, severe friction and vibration on the gas-liquid interface are avoided, and the generation probability of aerosol is reduced; compared with the existing magnetic control mode of moving or disturbing liquid by driving force, the method greatly reduces the risk of aerosol pollution. In addition, the microfluidic immunodetection device provided by the invention only needs 1-2 minutes for antigen-antibody combination and 5-15 minutes for one-time detection, and the detection speed is far higher than that of the traditional immunodetection method based on a reaction cup or a micro-pore plate.
The above examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above examples, and any other changes, modifications, substitutions, combinations, and simplifications that do not depart from the spirit and principle of the present invention should be made in the equivalent manner, and the embodiments are included in the protection scope of the present invention.
Claims (10)
1. A method for controlling liquid to flow back and forth based on magnetic force is characterized in that a hydrophilic magnet is added into liquid to be detected, and the hydrophilic magnet is controlled by an external magnetic field to drag the liquid to move under the condition of incompletely separating from the liquid, so that the liquid to flow back and forth can be controlled; the capillary force of a gas/liquid/solid three-phase interface formed by the hydrophilic magnet on the edge surface of a gas-liquid interface of liquid is used as driving force for liquid movement, and the driving force and the sliding friction force of the hydrophilic magnet and the liquid sliding friction force, the liquid surface tension, and the magnetic control driving force and the magnet sliding friction force generated by an external magnetic field are required to meet the following stress conditions:
F interfacial capillary force >f Liquid sliding friction force +f Surface tension of liquid ；
0<F Magnetic control driving force -f Sliding friction force of magnet ≤F Interfacial capillary force ；
F Magnetic control driving force -f Sliding friction force of magnet >f Liquid sliding friction force +f Surface tension of liquid 。
2. The method of claim 1, wherein the hydrophilic magnet is a magnetic material selected from one of a magnetic alnico material, a magnetic ferrite material, and a magnetic neodymium-iron-boron alloy.
3. The magnetic force control-based reciprocating flow device is characterized by comprising a supporting base (1), a micro-fluidic chip platform (11), a magnetic control driving device (2), an external controller (3) and a micro-fluidic chip (4); a magnetic control driving device (2), a micro-fluidic chip platform (11) and a micro-fluidic chip (4) are arranged above the support base (1), and the micro-fluidic chip platform (11) is arranged on two sides of the support base (1) and used for supporting the micro-fluidic chip (4); the magnetic control driving device (2) is fixed on the supporting base (1), and one end of the magnetic control driving device is electrically connected with the external controller (3); the micro-fluidic chip (4) comprises a bottom chip (41) serving as a substrate, a middle chip (42) provided with a micro-channel and a top chip (43) with holes; the middle chip (42) is provided with micro-channels (421) which are arranged in parallel, and each micro-channel contains a hydrophilic magnet (422) for matching with magnetic force control.
4. A device according to claim 3, characterized in that the magnetically controlled drive means (2) comprise a stepper motor (21), a transmission rod (22), a magnetic plate (23); the stepping motor (21), the transmission rod (22) and the magnetic plate (23) are arranged above the supporting base (1); the stepping motor (21) is fixed on the supporting base (1), one end of the stepping motor is mechanically connected with the transmission rod (22), and the other end of the stepping motor is electrically connected with the external controller (3); the transmission rod (22) is arranged in parallel with the supporting base (1), and the other end is fixed with a magnetic plate (23).
5. A device according to claim 3, characterized in that the magnetically controlled drive means (2) comprise an array inductor (24) and a circuit board (25) connecting the inductors; a circuit board (25) is arranged above the support base (1), and an array inductor (24) is connected above the circuit board (25) in an electrified manner; the circuit board (25) is fixed on the supporting base (1), and one end of the circuit board is electrically connected with the external controller (3); the array inductor (24) is arranged in parallel with the support base (1), the arrangement position of the array inductor (24) corresponds to the position of the micro-flow channels (421) which are arranged in parallel in the micro-flow control chip (4), the inductors which are parallel to the micro-flow channels (421) are connected in parallel, the inductors which are perpendicular to the micro-flow channels (421) are connected in series, and the interval between the array inductors (24) is equal to the interval distance between the micro-flow channels (421).
6. A device according to claim 3, characterized in that the hydrophilic magnet (422) has a height smaller than the height of the microchannel (421) and a width smaller than the width of the microchannel (421).
7. A method for controlling the reciprocating flow of a liquid based on the device according to any one of claims 3 to 6, characterized in that it comprises the following steps:
s1, placing a microfluidic chip (4) above a microfluidic chip platform (11);
s2, injecting liquid to be controlled into a micro-channel (421) of the micro-fluidic chip (4);
s3, inputting motion parameters including motion speed, motion distance and motion cycle number into the magnetic control driving device (2) through the external controller (3);
s4, starting a reciprocating flow device to enable the magnetic control driving device (2) to generate a variable magnetic field, so that the hydrophilic magnet (422) in the micro-fluidic chip (4) moves forwards at a constant speed from a starting position according to the movement speed set in S3 under the action of the magnetic control driving force, and the movement distance is equal to the movement distance set in S3;
s5, after the hydrophilic magnet (422) in the microfluidic chip (6) moves at a constant speed to reach the set movement distance, the magnetic control driving device (2) drives the hydrophilic magnet (422) to move backwards at a constant speed according to the set speed in S3 and return to the initial position, so that one movement period is completed;
And S6, sequentially repeating the steps S4 and S5 by the reciprocating flow device, wherein the repetition number is equal to the movement cycle number set in the step S3, so that reciprocating flow control is realized.
8. Use of the method of claim 1 or 2, or the device of any one of claims 3 to 6 in fluid control, immunodetection, nucleic acid detection, bio-particle detection.
9. An immunoassay method, characterized in that it is carried out by using the device according to any one of claims 3 to 6 or the method according to claim 7, comprising the steps of:
s1, preparing a microfluidic chip (4), coating a specific antibody or antigen on a bottom chip (41) at a position corresponding to a micro-channel (421) of a middle chip (42), and placing the prepared microfluidic chip (4) above a microfluidic chip platform (11);
s2, injecting a sample solution to be detected into a micro-channel (421) of the micro-fluidic chip (4);
s3, setting motion parameters of an external controller (3), inputting the motion parameters into a magnetic control driving device (2), starting a reciprocating flow device, enabling a stepping motor (21) to drive a transmission rod (22) to drive a magnetic plate (23) to move, or enabling a circuit board (24) to be connected with an array inductor (25) row by row to generate a variable magnetic field, so that a hydrophilic magnet (422) in a microfluidic chip (4) moves forwards at a constant speed from a starting position according to the motion speed set in S3, wherein the motion distance is equal to the motion distance set in S3; after the hydrophilic magnet (422) in the micro-fluidic chip (4) moves at a constant speed to reach the set movement distance, the magnetic control driving device (2) drives the hydrophilic magnet (422) to move backwards at a constant speed according to the speed set in the step S3 and return to the initial position, so that one movement period is completed;
And S4, sequentially repeating the steps of S2 and S3 according to the detection method, wherein the repetition number is equal to the movement cycle number set in S3, so that reciprocating flow control is realized and detection is carried out.
10. The method according to claim 9, wherein in step S2, the sample solution to be measured is added to the micro flow channel (421) from the top circular hole of the top chip (43) of the microfluidic chip (4), capturing of the sample to be measured, cleaning of the sample solution, capturing of the second antibody, cleaning of the second antibody solution are sequentially performed, and the reciprocating flow device is started for detection.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310740090.7A CN116984041A (en) | 2023-06-20 | 2023-06-20 | Method and device for controlling liquid to flow back and forth based on magnetic force and application |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310740090.7A CN116984041A (en) | 2023-06-20 | 2023-06-20 | Method and device for controlling liquid to flow back and forth based on magnetic force and application |
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| CN202310740090.7A Pending CN116984041A (en) | 2023-06-20 | 2023-06-20 | Method and device for controlling liquid to flow back and forth based on magnetic force and application |
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