CN115126931A

CN115126931A - Micro-fluidic chip, manufacturing method thereof and device of electromagnetic control valve

Info

Publication number: CN115126931A
Application number: CN202210641042.8A
Authority: CN
Inventors: 赵才明; 夏雁鸣; 王楠鑫; 马盛林
Original assignee: Xiamen University
Current assignee: Xiamen University
Priority date: 2022-06-08
Filing date: 2022-06-08
Publication date: 2022-09-30
Anticipated expiration: 2042-06-08
Also published as: CN115126931B

Abstract

The application relates to the technical field of microfluidic chips and miniflow valves, in particular to a microfluidic chip, a manufacturing method thereof and a device of an electromagnetic control valve, wherein the microfluidic chip comprises a first layer, a second layer and a third layer which are sequentially bonded, a miniflow channel is arranged on the first layer, a fifth through hole is formed in the third layer, a magnetic ball is arranged in the fifth through hole, the device of the electromagnetic control valve comprises a centrifugal turntable, a miniflow valve and a driving motor, and an output shaft of the driving motor is connected with the centrifugal turntable and drives the centrifugal turntable to rotate; the micro-fluidic chips are uniformly arranged on the rotary disc along the circumference, and the micro-fluidic valve comprises a plurality of electromagnets and signal transmission parts electrically communicated with the electromagnets; the electromagnets are uniformly fixed on the turntable along the circumference, are positioned on one side of the microfluidic chip close to the arc-shaped seat and are opposite to the magnetic balls; the electromagnet is electrified through the signal transmission component and forms an electromagnetic valve with the magnetic ball, and the electromagnetic valve is used for controlling the on-off of the micro-channel.

Description

Micro-fluidic chip, manufacturing method thereof and device of electromagnetic control valve

Technical Field

The present invention relates to the technical field of microfluidic chips and microfluidic valves, and in particular, to a microfluidic chip, a method for manufacturing the same, and a device for electromagnetically controlling a valve.

Background

The centrifugal microfluidic chip system integrates reagents, pretreatment, mixing, sequential loading of various liquids, valve control, metering in immunoassay and other experiments in a lab-on-a-chip, can be applied to reaction, culture, mixing and the like of fluids in biological and chemical analysis, and can integrate the traditional biological and chemical analysis methods into a single disc without an external pump to achieve the purposes of reaction, culture, mixing and the like.

The design and manufacture of an effective valve to adjust the position and time sequence of fluid in a microfluidic system are very important, the existing centrifugal microfluidic valve comprises a mechanical ball-type valve and a mechanical slide-type valve which are difficult to open and close under the condition of constant rotating speed, and the modes of bolt pre-tightening, laser ablation and the like need complicated alignment systems and other problems.

Disclosure of Invention

In order to solve the above problems, the present application provides a microfluidic chip, a method for manufacturing the same, and an apparatus for electromagnetically controlling a valve, which solves the problem that the existing centrifugal valve needs to adjust the rotation speed to open and close the valve, and the valve can be repeatedly opened and closed, so that the opening and blocking of the fluid in multiple chips can be realized. The following technical scheme is adopted:

a microfluidic chip comprises a first layer, a second layer and a third layer which are bonded in sequence;

the first layer is provided with a micro-channel, and the second layer is provided with a first through hole, a second through hole and a third through hole;

the first through hole and the second through hole are respectively positioned at two ends of the micro-channel, and the third channel is positioned in the middle of the micro-channel;

the third layer is provided with a fourth through hole, a fifth through hole and a sixth through hole corresponding to the through holes of the second layer in sequence;

the magnetic ball is arranged in a fifth through hole, and one side of the fifth through hole, which is far away from the second layer, is sealed and fixed by a sealing element;

the first layer is provided with an arc-shaped seat at the position opposite to the third through hole and used for matching with the limiting magnetic ball.

Optionally, the height of the micro flow channel is 10-100 um; the width is 50-1000 nm;

the thickness of the first layer is 1-2 mm; the thickness of the second layer is more than 10 um.

Optionally, the first layer and the second layer are made of polydimethylsiloxane;

the third layer is a glass plate.

A device for electromagnetically controlling a valve comprises a centrifugal turntable, a micro-flow valve and a driving motor, wherein an output shaft of the driving motor is connected with the centrifugal turntable and drives the centrifugal turntable to rotate;

a plurality of the microfluidic chips are uniformly arranged on the turntable along the circumference;

the micro-flow valve comprises a plurality of electromagnets and a signal transmission component electrically communicated with the electromagnets;

the electromagnets are uniformly fixed on the turntable along the circumference, are positioned on one side of the microfluidic chip close to the arc-shaped seat and are opposite to the magnetic balls;

the electromagnet is electrified through the signal transmission component and forms an electromagnetic valve with the magnetic ball, and the electromagnetic valve is used for controlling the on-off of the micro-channel.

Optionally, the signal transmission component includes a conductive slip ring and an electric brush, the conductive slip ring is sleeved on the output shaft of the driving motor and rotates with the output shaft, and the conductive slip ring is in line contact with the electric brush;

the electromagnets are respectively connected with a conductive slip ring through leads, the electric brush is connected with a power supply, and the electromagnets are conducted through the conductive slip ring.

Optionally, the device further comprises a workbench, and the driving motor is fixed on the bottom surface of the workbench;

the centrifugal turntable comprises a first disk for fixing the electromagnet and a second disk for fixing the microfluidic chip;

an output shaft of the driving motor penetrates through the workbench, and the conductive slip ring, the first disc and the second disc are sequentially installed in the vertical direction of the workbench;

the electric brush is fixed on the workbench and is positioned on one side of the conductive slip ring.

Optionally, the slip ring is provided with a plurality of conducting rings along the axis, and the electric brush is provided with a plurality of conducting wires in line contact with the conducting rings;

when the conducting ring rotates along with the conducting slip ring and along the axial direction, the conducting ring is always in line contact with and conducted with the conducting wire.

Optionally, each two of the conducting rings are in a group, and each group of conducting rings is in line contact with a positive conducting wire and a negative conducting wire respectively;

each conducting ring is provided with a conducting needle head, and each group of conducting rings is connected with the same electromagnet through the conducting needle head;

the electromagnet is electrified to generate a magnetic force action so that the magnetic ball moves towards the arc-shaped seat and is adsorbed on the arc-shaped seat to be used for cutting off the circulation of the micro-channel.

Optionally, 1-4 solenoid valves may be disposed in the same microchannel.

A method of manufacturing a microfluidic chip according to any one of the above, comprising the steps of;

step 1, preparing a mould structure of a first layer of arc-shaped seat on a No. 1 silicon wafer by using AZ series photoresist and a photoetching technology, and preparing a structure of a micro-channel by using SU8 series photoresist to obtain a mould of the first layer;

step 2, pouring polydimethylsiloxane with a certain proportion on the mould of the first layer;

step 3, cooling and solidifying, and removing the polydimethylsiloxane from the mold, namely completing the preparation of the first layer;

step 4, spin-coating a thin polydimethylsiloxane layer on the No. 2 silicon wafer to process a second layer;

step 5, bonding the lower surface of the first layer with the upper surface of the second layer by adopting a plasma method;

step 6, simultaneously removing the first layer and the second layer from the silicon wafer;

step 7, bonding the lower surface of the second layer and the upper surface of the third layer after plasma treatment, and processing a third through hole, a fourth through hole and a fifth through hole by using laser;

and 8, processing a first through hole and a second through hole on the second layer by using a punching needle through the third through hole and the fourth through hole, putting a magnetic metal ball into the fifth through hole from the lower surface side of the third layer, and sealing the fifth through hole by using a sealing element.

To sum up, the present application includes the following beneficial effects:

1. the invention discloses a device of an electromagnetic control valve for a microfluidic chip, which is applied to a centrifugal microfluidic chip system.

2. A plurality of chips with electromagnetic valves can be arranged on the rotary disc through the circumferential array, and corresponding electromagnets and magnetic balls can do centrifugal motion along with the rotary disc, so that the opening and the blocking of fluid in micro-channels of the chips can be realized under the condition of not changing the centrifugal speed.

3. The conductive slip ring is in line contact with the brush holder and rotates along with the driving motor, synchronous centrifugal motion of the electromagnet and the chip can be achieved, the electromagnet can be ensured to be powered on to generate magnetism in the centrifugal motion, the conductive rings of the conductive slip ring are matched with the conductive wires of the brush holder, each conductive ring is connected with the electromagnet in a matching mode, every two conductive rings (which are in line contact with one positive conductive wire and one negative conductive wire respectively) are independently connected with one electromagnet, different electromagnets are independent, namely the current conduction of each electromagnet is independent, the two electromagnets are mutually independent and do not interfere with each other, the conduction current of each electromagnet can be independently adjusted, and the electromagnets can generate different magnetic forces.

Drawings

FIG. 1(a) is a schematic diagram of the structure of the electromagnetic valve of the present embodiment;

FIG. 1(b) is a schematic diagram of the structure of the present embodiment in which the solenoid valve is closed;

FIG. 2 is a schematic diagram of the structure of the microfluidic chip of the present embodiment;

fig. 3 to 10 are flow charts of the manufacturing of the microfluidic chip of this embodiment.

FIG. 11 is a diagram of a centrifugal microfluidic device according to the present embodiment;

fig. 12 is a signal transmission structure diagram of the centrifugal microfluidic device of the present embodiment.

Description of reference numerals: 100. a microfluidic valve; 101. an electromagnet; 200. a microfluidic chip; 201. a right side channel; 202. an arc-shaped seat; 203. an electromagnetic valve; 204. a left side channel; 300. a first layer; 301. a micro flow channel; 310. a first layer lower surface; 400. a second layer; 401. a first through hole; 402. a second through hole; 410. a second layer upper surface; 420. a second layer lower surface; 500. a third layer; 501. a third through hole; 502. a fifth through hole; 503. a fourth via hole; 504. a seal member; 505. a magnetic ball; 600. a mold; 601. silicon wafer No. 1; 602. an arc seat mold; 603. a microchannel mold; 700. silicon wafer No. 2; 800. a centrifugal turntable support; 801. a flat plate; 802. a longitudinal frame; 803. a transverse frame; 900. a drive motor; 1000. an electric brush; 1001. connecting a lead externally; 1002. an electric brush holder; 1003. a conductive wire; 1004. a slip ring; 1005. a conductive needle head; 1100. a first disc; 1201. a wire; 1300. a second disk.

Detailed Description

The present application is described in further detail below with reference to figures 1-12.

The embodiment of the application discloses a micro-fluidic chip, a manufacturing method thereof and a device of an electromagnetic control valve.

As shown in fig. 2, the microfluidic chip 200 includes a first layer 300, a second layer 400, and a third layer 500 bonded in sequence, a micro channel 301 is located on the first layer 300, the second layer 400 is provided with a first through hole 401 and a second through hole 402, the first through hole 401 and the second through hole 402 are respectively located at two ends of the micro channel 301, the third layer 500 is provided with a third through hole 501 and a fourth through hole 503 corresponding to the two through holes of the second layer 400 in sequence, a fifth through hole 502 is located in the middle of the third layer 500, a magnetic ball 505 is installed in the fifth through hole 502, one side of the fifth through hole 502 away from the second layer 400 is sealed and fixed by a sealing element 504, so as to prevent the magnetic ball 505 from falling, and the sealing element 504 may be an adhesive tape or a sealing film.

Preferably, the first layer 300 and the second layer 400 are made of polydimethylsiloxane, so that the first layer 300 and the second layer 400 have certain elasticity, the first through hole 401 and the third through hole 501 are arranged oppositely to form a fluid inlet, the second through hole 402 and the fourth through hole 503 are arranged oppositely to form a fluid outlet, and the first layer 300 is provided with an arc-shaped seat 202 at a position opposite to the fifth through hole 502 for matching with the limiting magnetic ball 505.

As shown in fig. 1, the electromagnetic control valve device includes a centrifugal turntable, an electromagnet module, a microfluidic chip module, and a driving motor 900, wherein the electromagnet module and the microfluidic chip module are mounted and fixed on the centrifugal turntable, the driving motor 900 is used for driving the centrifugal turntable to rotate circumferentially, the electromagnet module and the microfluidic chip module can rotate circumferentially with the centrifugal turntable, and the centrifugal turntable includes a first disc 1100 and a second disc 1300, which are respectively used for fixing the electromagnet 101 and the microfluidic chip 200.

The microfluidic chip module includes a plurality of microfluidic chips 200, the microfluidic chips 200 are mounted on the first disc 1100 through a circumferential array, the microfluidic chip 200 includes a micro channel 301 for fluid flow and a magnetic ball 505 disposed on one side of the micro channel 301, the magnetic ball 505 is a metal structure, it should be noted that the shape of the magnetic ball 505 may be any geometric shape of other magnetic metals besides a ball shape, and the magnetic ball belongs to parameters that can be arbitrarily modified by a person skilled in the art according to different use scenarios, and belongs to simple replacement under the technical concept of the present embodiment.

The miniflow valve 100 comprises a plurality of electromagnets 101 and signal transmission components electrically connected with the electromagnets, an external power supply of the signal transmission components supplies power to the electromagnets 101 to enable the electromagnets 101 to generate magnetism when conducting current, a circumferential array of the electromagnets 101 is installed on the second disc 1300, the electromagnets 101 are located on one side of the miniflow control chip 200 close to the arc-shaped seat 202, namely, one side of the arc-shaped seat 202 far away from the third through hole 402 and are arranged opposite to the magnetic balls, one electromagnet 101 is arranged corresponding to one miniflow control chip 200, the electromagnets 101 and the magnetic balls 505 in the miniflow control chip 200 are parallel and collinear, namely, the electromagnets 101 and the magnetic balls 505 are respectively located on two sides of the miniflow channel 301 to form an electromagnetic valve 203, and the position of the electromagnetic valve 203 is close to the middle position of the miniflow channel 301 and is used for controlling the on-off of the miniflow channel 301.

Controlling the opening and closing of the electromagnetic control valve structure, wherein when the electromagnet 101 is not electrified, the valve is in an opening state, the fluid in the micro-channel 301 can normally circulate, and the fluid in the left channel 204 can flow to the right channel 201; when the electromagnet 101 is energized, the electromagnet 101 moves the magnetic ball 505 toward the arc-shaped seat 202 by magnetic force, and at the same time, the second layer 400 is elastically deformed at the position of the magnetic ball 505, and the magnetic ball 505 adsorbs the second layer onto the arc-shaped seat 202, so as to close the electromagnetic valve 203 and cut off the communication between the left channel 204 and the right channel 201 of the micro channel 301. When the electromagnet 101 is energized in the reverse direction, the electromagnet generates a repulsive force to push the magnetic ball 505 to reset and open the valve, the fluid in the micro flow channel 301 returns to normal circulation, the valve can be opened and closed by controlling the electric signal input to the electromagnet 101, the conversion from the electric signal to the mechanical signal is realized, and the valve can be repeatedly opened and closed. In a preferred embodiment, two, three or even more arc-shaped seats and magnetic balls may be disposed in the same microchannel 301.

In the structure of the device, the signal transmission component comprises a conductive slip ring 1004 and a brush 1000, the conductive slip ring 1004 comprises a plurality of conductive rings and a conductive needle 1005, the brush 1000 comprises a brush holder 1002, an external lead 1001 fixed on two sides of the brush holder 1002 and parallel leads 1003, wherein the brush holder 1002 and the leads 1003 are fixed on a flat plate 801, the conductive rings rotate together with a driving motor 900, the leads 1003 and the conductive rings are conducted in a line contact mode, the external lead 1001 can be connected with a direct current power supply, and the electric signals can be conducted between the conductive rings rotating along with the motor through the leads 1003.

The conducting rings are arranged along the axis, each conducting ring is provided with a conducting needle 1005, the conducting needles 1005 are connected with the electromagnets 101 through conducting wires 1201, the conducting wires 1201 can transmit electric signals from the conducting needles 1005 to the electromagnets 101, the external conducting wires 1001 can be connected with a power supply to transmit the signals from the external conducting wires 1001 to the parallel conducting wires 1003, and the conducting rings in the conducting slip rings 1004 can be connected with the conducting needles 1005 in electric signals. The conductive slip ring 1004 rotates together with the driving motor 900, and the parallel conductive wires 1003 and the conductive ring 1004 are conducted in a line contact manner, that is, after the external wire 1001 is connected to a direct current power supply, a signal can be transmitted to the electromagnet through the external wire 1001. The preferred side-by-side wire 1003 is a hard wire to facilitate wire contact with the conductive ring 1101.

The electromagnets 101 generate magnetic force through conducted current, each conducting ring is independently connected with one electromagnet 101, the electromagnets 101 are independent from each other, the conducting rings are paired with the electromagnets 101, every two conducting rings form a group, each group of conducting rings are in line contact with a positive conducting wire 1003 and a negative conducting wire 1003 respectively, each conducting ring is provided with a conducting needle 1005, each group of conducting rings is connected with the same electromagnet through the conducting needle 1005, namely, each two conducting rings are in line contact with one positive conducting wire and one negative conducting wire respectively and are connected with one electromagnet 101 independently, the different electromagnets 102 are independent from each other, and the preferred conducting wire 1003 is a hard conducting wire 1201, so that the conducting rings are in line contact with each other conveniently.

The electrical signal is conducted to the electromagnet 101 through the external lead 1001, and the valve is switched on and off through the interaction between the magnetic force and the magnetic ball 505, so as to realize the conversion from the electrical signal to the mechanical signal.

The device for electromagnetically controlling the valve further comprises a workbench for installing the centrifugal turntable, the workbench comprises a centrifugal turntable support 800, the centrifugal turntable support 800 is provided with a flat plate 801, a longitudinal frame 802 and a transverse frame 803, and can be used for fixing and supporting other structures, a driving motor 900 is fixed on the centrifugal turntable support 800, an output shaft of the driving motor 900 penetrates through the flat plate 801, and a conductive slip ring 1004, a first disk 1100 and a second disk 1300 are sequentially installed along the vertical direction of the workbench, and the conductive slip ring 1004, the first disk 1100 and the second disk 1300 can synchronously rotate along with the driving motor 900.

When the electromagnet 101 is not energized, the valve is in an open state, the fluid in the micro channel 301 can normally flow, and the fluid in the left channel 204 can flow to the right channel 201; when the electromagnet is electrified, the electromagnet generates an attraction force, the magnetic ball 505 is adsorbed to close the valve, the fluid in the micro-channel 301 is blocked, the fluid in the left channel 204 cannot flow to the right channel 201 through the middle of the micro-channel 301, when the electromagnet is electrified in the reverse direction, the electromagnet generates a repulsive force to push the magnetic ball 505 to reset and open the valve, the fluid in the micro-channel 301 returns to normal flow, the valve can be opened and closed by controlling an electric signal input to the electromagnet 101, the conversion from the electric signal to a mechanical signal is realized, and the repeated opening and closing of the valve can be realized.

Referring to fig. 3 to 10, a method for manufacturing the microfluidic chip 200 includes the following steps;

step 1, preparing a structure of an arc seat mold 602 on a first layer 300 on a No. 1 silicon wafer 601 by using AZ series photoresist and a photoetching technology, and preparing a structure of a micro-channel mold 603 by using SU8 series photoresist to obtain a mold 600 of the first layer 300;

step 2, pouring polydimethylsiloxane with a certain proportion on the mold 600 of the first layer 300;

step 3, cooling and solidifying, and removing the polydimethylsiloxane from the mold 600, namely, completing the preparation of the first layer 300;

step 4, spin-coating a thin polydimethylsiloxane layer on the No. 2 silicon wafer to process a second layer 400;

step 5, bonding the lower surface of the first layer 300 with the upper surface of the second layer 400 by using a plasma method;

step 6, simultaneously removing the first layer 300 and the second layer 400 from the silicon wafer;

step 7, bonding the lower surface of the second layer 400 and the upper surface of the third layer 500 after plasma treatment, wherein the third layer 500 is a glass plate, and a third through hole 501, a fourth through hole 503 and a fifth through hole 502 are processed by laser;

step 8, a first through hole 401 and a second through hole 402 are formed in the second layer 400 by punching needles through the third through hole 501 and the fourth through hole 503, a magnetic ball 505 is placed in the fifth through hole 502 from the lower surface side of the third layer 500, and the fifth through hole 502 is sealed by a sealing member 504.

Wherein, the height of the micro-channel 301 is 10-100 um; the width is 50-1000nm, and the thickness of the first layer 300 is 1-2 mm; the second layer 400 is thicker than 10um, the third layer 500 is made of glass plate,

preferably, the height of the micro flow channel 301 is 30 um; the width is 90nm and the thickness of the first layer 300 is 2 mm; the second layer 400 is 12um thick. It should be noted that the height and width of the micro flow channel 301 and the thicknesses of the first layer 300 and the second layer 400 are parameters that can be arbitrarily modified by those skilled in the art according to different usage scenarios, and are simple alternatives under the technical concept of the present embodiment.

The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited by the above embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims

1. A microfluidic chip, characterized in that: comprises a first layer, a second layer and a third layer which are bonded in sequence;

the first layer is provided with a micro-channel, and the second layer is provided with a first through hole and a second through hole;

the first through hole and the second through hole are respectively positioned at two ends of the micro-channel;

the third layer is provided with a third through hole and a fourth through hole corresponding to the through holes of the second layer in sequence, and a fifth through hole is arranged at the middle position of the third layer;

the first layer is provided with an arc-shaped seat at the position opposite to the third through hole for matching with the limiting magnetic ball.

2. A microfluidic chip according to claim 1, wherein: the height of the micro flow channel is 10-100 um; the width is 50-1000 nm;

3. A microfluidic chip according to claim 1, wherein: the first layer and the second layer are made of polydimethylsiloxane;

the third layer is a glass plate.

4. An arrangement for electromagnetically controlling a valve, comprising: the micro-fluidic valve comprises a centrifugal turntable, a micro-fluidic valve and a driving motor, wherein an output shaft of the driving motor is connected with the centrifugal turntable and drives the centrifugal turntable to rotate;

a plurality of the microfluidic chips of any one of claims 1-3 are uniformly arranged on the rotating disc along the circumference;

the micro-flow valve comprises a plurality of electromagnets and signal transmission components electrically communicated with the electromagnets;

5. An arrangement of solenoid control valves according to claim 4, wherein: the signal transmission part comprises a conductive slip ring and an electric brush, the conductive slip ring is sleeved on an output shaft of the driving motor and rotates along with the output shaft, and the conductive slip ring is communicated with the electric brush through line contact;

6. An arrangement of solenoid control valves according to claim 5, wherein: the device also comprises a workbench, and the driving motor is fixed on the bottom surface of the workbench;

7. An arrangement of solenoid control valves according to claim 6, wherein: the conductive slip ring is provided with a plurality of conductive rings along the axis, and the electric brush is provided with a plurality of conductive wires in line contact with the conductive rings;

8. An arrangement of solenoid control valves according to claim 7, wherein: every two conducting rings are in a group, and each group of conducting rings is in line contact with a positive conducting wire and a negative conducting wire respectively;

each conducting ring is provided with a conducting needle, and each group of conducting rings is connected with the same electromagnet through the conducting needle;

the electromagnet is electrified to generate a magnetic force action to enable the magnetic ball to move towards the arc-shaped seat and be adsorbed on the arc-shaped seat for cutting off the circulation of the micro-channel.

9. An arrangement of solenoid control valves according to claim 5, characterized in that: 1-4 electromagnetic valves can be arranged in the same micro-channel.

10. A method of manufacturing a microfluidic chip according to any one of claims 1 to 4, wherein: comprises the following steps;

step 1, preparing a mold structure of a first layer of arc-shaped seat on a No. 1 silicon wafer by using AZ series photoresist and a photoetching technology, and preparing a structure of a micro-channel by using SU8 series photoresist to obtain a mold of the first layer;

step 3, cooling and solidifying, and removing the polydimethylsiloxane from the mold, namely the preparation of the first layer is finished;

step 4, spin-coating a thin polydimethylsiloxane layer on the No. 2 silicon wafer, and processing a second layer;

step 7, bonding the lower surface of the second layer and the upper surface of the third layer after plasma treatment, and processing a third through hole, a fourth through hole and a fifth through hole by laser;