CN115126931B

CN115126931B - Microfluidic chip, manufacturing method thereof and electromagnetic control valve device

Info

Publication number: CN115126931B
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: 2023-08-11
Anticipated expiration: 2042-06-08
Also published as: CN115126931A

Abstract

The application relates to the technical field of microfluidic chips and microfluidic valves, in particular to a microfluidic chip, a manufacturing method thereof and a device for controlling an electromagnetic valve, wherein the microfluidic chip comprises a first layer, a second layer and a third layer which are sequentially bonded, a microchannel is arranged on the first layer, a fifth through hole is arranged on the third layer, a magnetic ball is arranged in the fifth through hole, the device for controlling the electromagnetic valve comprises a centrifugal turntable, the microfluidic 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 microfluidic valve comprises a plurality of electromagnets and signal transmission components which are electrically communicated with the electromagnets; a plurality of 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 arranged opposite to the magnetic balls; the electromagnet is electrified through the signal transmission component and forms an electromagnetic valve with the magnetic ball, so as to control the on-off of the micro-channel.

Description

Microfluidic chip, manufacturing method thereof and electromagnetic control valve device

Technical Field

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

Background

The centrifugal microfluidic chip system integrates reagent, pretreatment, mixing, sequential loading of various liquids, valve control, metering in immunoassay and other experiments on a chip laboratory, 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 method onto a single disk without an external pump so as to realize the purposes of reaction, culture, mixing and the like.

The design and manufacture of effective valves to regulate the position and time sequence of fluid in a microfluidic system is important, and the existing centrifugal microfluidic valves have the problems that the valves are opened and closed under the condition that the rotation speed is difficult to be unchanged by mechanical flyballs and mechanical sliding blocks, and complicated alignment systems are needed in the manners of bolt pretension, laser ablation and the like.

Disclosure of Invention

The application provides a microfluidic chip, a manufacturing method thereof and an electromagnetic control valve device, which solve the problem that the valve can be opened and closed only by adjusting the rotating speed of the conventional centrifugal valve, and the valve can be repeatedly opened and closed to realize the opening and blocking of fluid in a plurality of chips. The following technical scheme is adopted:

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

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 at the middle part of the micro-channel;

the third layer is provided with a fourth through hole, a fifth through hole and a sixth through hole which correspond 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 far away from the second layer is sealed and fixed by a sealing piece;

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

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

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

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

the third layer is a glass plate.

The device for electromagnetically controlling the valve comprises a centrifugal turntable, a microfluidic 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;

the microfluidic chips of any one of the above are uniformly arranged on the turntable along the circumference;

the microfluidic valve comprises a plurality of electromagnets and a signal transmission component which is electrically communicated with the electromagnets;

a plurality of 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 arranged opposite to the magnetic balls;

the electromagnet is electrified through the signal transmission component and forms an electromagnetic valve with the magnetic ball, so as to control the on-off of the micro-channel.

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

the electromagnets are respectively connected with the conductive slip rings through wires, the electric brushes are connected with a power supply, and the electromagnets are connected through the conductive slip rings.

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

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

an output shaft of the driving motor penetrates through the workbench, and a conductive slip ring, a first disc and a second disc are sequentially arranged along 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 conductive rings along the axis, and the electric brush is provided with a plurality of conductive wires in line contact with the conductive rings;

and the conducting ring is always in contact conduction with the conducting wire when rotating along with the conducting slip ring and along the axial direction.

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

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 magnetic force to enable the magnetic ball to move towards the direction of the arc-shaped seat and be adsorbed on the arc-shaped seat, so that circulation of the micro-channel is cut off.

Optionally, 1-4 electromagnetic valves can be arranged in the same micro-channel.

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

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

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

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

step 4, spin-coating a thin layer of polydimethylsiloxane 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, the first layer and the second layer are simultaneously uncovered 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 adopting laser;

and 8, processing the first through hole and the second through hole on the second layer through the third through hole and the fourth through hole by using a punching needle, putting the 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.

In summary, the application has the following beneficial effects:

1. the application discloses a device for an electromagnetic control valve of a microfluidic chip, which is applied to a centrifugal microfluidic chip system, wherein the electromagnetic valve is formed by a magnetic ball and an electromagnet, the movement of the magnetic ball is controlled to realize the opening and blocking of fluid in a micro-channel, and an electric signal is converted into magnetic force to realize the opening and closing of the valve.

2. The rotary table is provided with a plurality of chips with electromagnetic valves through the circumferential array, and the corresponding electromagnets and magnetic balls can centrifugally move along with the rotary table, so that the opening and blocking of fluid in micro-channels of the chips can be realized under the condition that the centrifugal speed is not changed.

3. The conductive slip ring is in line contact fit with the brush seat, the conductive slip ring rotates along with the driving motor, synchronous centrifugal movement of the electromagnets and the chip can be realized, magnetism can be generated by electrifying the electromagnets in the centrifugal movement, the conductive rings of the conductive slip ring are mutually matched with conductive wires of the brush seat, each conductive ring is connected with the matched electromagnet, each two conductive rings (one positive conductive wire and one negative conductive wire are respectively in line contact with the two conductive rings) are respectively connected with one electromagnet, different electromagnets are independent, namely current conduction of each electromagnet is an independent circuit, and the electromagnets are mutually independent and noninterfere, so that conduction currents of each electromagnet can be independently adjusted to generate different magnetic forces.

Drawings

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

fig. 1 (b) is a schematic structural diagram of the electromagnetic valve closure of the present embodiment;

fig. 2 is a schematic structural diagram of the microfluidic chip of the present embodiment;

fig. 3 to 10 are flowcharts of the fabrication of the microfluidic chip of the present embodiment.

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

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

Reference numerals illustrate: 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 microchannel; 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 through hole; 504. a seal; 505. a magnetic ball; 600. a mold; 601. a silicon wafer No. 1; 602. arc seat mould; 603. a micro flow channel mold; 700. a No. 2 silicon wafer; 800. a centrifugal turntable bracket; 801. a flat plate; 802. a vertical frame; 803. a transverse frame; 900. a driving motor; 1000. a brush; 1001. externally connecting a wire; 1002. a brush holder; 1003. a conductive wire; 1004. a slip ring; 1005. a conductive needle; 1100. a first disc; 1201. a wire; 1300. and a second disc.

Detailed Description

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

The embodiment of the application discloses a microfluidic chip, a manufacturing method thereof and a device for controlling a valve by electromagnetic waves.

As shown in fig. 2, the microfluidic chip 200 includes a first layer 300, a second layer 400 and a third layer 500 that are sequentially bonded, the micro flow 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 flow channel 301, the third layer 500 is sequentially provided with a third through hole 501 and a fourth through hole 503 corresponding to two through holes of the second layer 400, a fifth through hole 502 is provided 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 far from the second layer 400 is sealed and fixed by a sealing member 504, the sealing member 504 can be an adhesive tape or a sealing film, and the magnetic ball 505 is prevented from falling.

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 opposite to each other to form a fluid inlet, the second through hole 402 and the fourth through hole 503 are opposite to each other 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 being matched with the limit magnetic ball 505.

As shown in fig. 1, the device for controlling the valve by using the electromagnetic method comprises 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 installed and fixed on the centrifugal turntable, the driving motor 900 is used for driving the centrifugal turntable to do circumferential rotation, the electromagnet module and the microfluidic chip module can do circumferential rotation along with the centrifugal turntable, and the centrifugal turntable comprises 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 plurality of microfluidic chips 200 are mounted on the first disc 1100 through a circumferential array, the microfluidic chips 200 include a micro flow channel 301 for fluid flow and a magnetic ball 505 disposed on one side of the micro flow channel 301, the magnetic ball 505 is of a metal structure, it should be noted that the shape of the magnetic ball 505 can be any geometric shape of other magnetic metals besides a spherical shape, which belongs to parameters that can be modified arbitrarily by a person skilled in the art according to different usage scenarios, and belongs to simple replacement under the technical concept of the present embodiment.

The microfluidic valve 100 comprises a plurality of electromagnets 101 and a signal transmission component electrically connected with the electromagnets 101, wherein an external power supply of the signal transmission component supplies power to the electromagnets 101 to enable on-current of the electromagnets 101 to generate magnetism, the electromagnets 101 are circumferentially arranged on the second disc 1300, the electromagnets 101 are positioned on one side of the microfluidic 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 opposite to the magnetic ball, one electromagnet 101 is arranged corresponding to one microfluidic chip 200, the electromagnets 101 are parallel and collinear with the magnetic ball 505 in the microfluidic chip 200, namely, the electromagnets 101 and the magnetic ball 505 are respectively positioned on two sides of the micro-channel 301 to form an electromagnetic valve 203, and the electromagnetic valve 203 is positioned close to the middle position of the micro-channel 301 and is used for controlling on-off of the micro-channel 301.

The electromagnetic control valve structure is controlled to be opened and closed, when the electromagnet 101 is not electrified, the valve is in an opened state, fluid in the micro-channel 301 can normally circulate, and fluid in the left channel 204 can flow to the right channel 201; when the electromagnet 101 is electrified, the electromagnet 101 moves the magnetic ball 505 towards the arc-shaped seat 202 under the action of magnetic force, and simultaneously the second layer 400 is elastically deformed at the position where the magnetic ball 505 is positioned, and the magnetic ball 505 adsorbs the second layer on the arc-shaped seat 202, so that the electromagnetic valve 203 is closed, and the communication between the middle left channel 204 and the right channel 201 of the micro flow channel 301 is cut off. When the electromagnet 101 is electrified reversely, the electromagnet generates repulsive force to push the magnetic ball 505 to reset and open the valve, the fluid in the micro-channel 301 is recovered to normally circulate, the valve can be opened and closed by controlling the electric signal input into the electromagnet 101, the conversion from the electric signal to the mechanical signal is realized, and the repeated switching of the valve can be realized. In a preferred embodiment, two, three or even more arc-shaped seats and magnetic balls can be disposed in the same micro flow channel 301.

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

The plurality of 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 electromagnet 101 through conducting wires 1201, the conducting wires 1201 can transmit electric signals from the conducting needles 1005 to the electromagnet 101, the external conducting wires 1001 can be connected with a power supply to transmit signals from the external conducting wires 1001 to the parallel conducting wires 1003, and electric signals between the conducting rings in the conducting slip rings 1004 and the conducting needles 1005 can be conducted. The conductive slip ring 1004 rotates along with the driving motor 900, and the parallel conductive wires 1003 and the conductive ring 1004 are conducted in a wire contact mode, namely after the external conductive wire 1001 is connected to a direct current power supply, signals can be transmitted to the electromagnet through the external conductive wire 1001. The preferred side-by-side wires 1003 employ hard wires to facilitate line contact with the conductive ring 1101.

The electromagnets 101 are made to generate magnetic force through conducted current, each conducting ring is independently connected with one electromagnet 101, the electromagnets 101 are independent, the conducting rings are matched with the electromagnets 101, every two conducting rings are in a group, each group of conducting rings are respectively in line contact with a positive conducting wire 1003 and a negative conducting wire 1003, 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 respectively in line contact with one positive conducting wire and one negative conducting wire, each conducting ring is independently connected with one electromagnet 101, the different electromagnets 102 are independent, and the conducting wires 1003 are preferably hard conducting wires 1201 and are convenient to be in line contact with the conducting rings.

The electric signal is conducted to the electromagnet 101 through the external lead 1001, and the valve is opened and closed through the interaction between the magnetic force and the magnetic ball 505, so that the conversion from the electric signal to the mechanical signal is realized, and in the embodiment, preferably, the external lead 1001 has 6 paths or multiple paths, so that three or more electromagnets 101 can be controlled to block and pass through the fluid in three or more chips respectively.

The device for electromagnetically controlling a valve further includes a working table for mounting the centrifugal turntable, the working table includes a centrifugal turntable support 800, the centrifugal turntable support 800 includes a flat plate 801, a longitudinal frame 802 and a transverse frame 803, other structures can be fixed and supported, 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 an electrically conductive slip ring 1004, a first disc 1100 and a second disc 1300 are sequentially mounted along a vertical direction of the working table, and the electrically conductive slip ring 1004, the first disc 1100 and the second disc 1300 can synchronously rotate along with the driving motor 900.

When the electromagnet 101 is not electrified, the valve is in an open 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 is electrified, the electromagnet generates attractive force, the attraction magnetic ball 505 closes the valve, fluid in the micro-channel 301 is blocked, 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 reversely, the electromagnet generates repulsive force, the magnetic ball 505 is pushed to reset and open the valve, the fluid in the micro-channel 301 is recovered to flow normally, the valve can be opened and closed by controlling an electric signal input into the electromagnet 101, the conversion from the electric signal to a mechanical signal is realized, and the repeated switching of the valve can be realized.

As shown in fig. 3 to 10, the manufacturing method of 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 silicon wafer No. 1 601 by utilizing AZ series photoresist and a photoetching technology, and preparing a structure of a micro-channel mold 603 by utilizing SU8 series photoresist to obtain a mold 600 of the first layer 300;

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

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

step 4, spin coating a thin layer of polydimethylsiloxane 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, the first layer 300 and the second layer 400 are simultaneously uncovered 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;

in step 8, the first through hole 401 and the second through hole 402 are formed in the second layer 400 by punching the third through hole 501 and the fourth through hole 503, the 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 the sealing member 504.

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

preferably, the height of the micro flow channel 301 is 30um; the width is 90nm and the thickness of the first layer 300 is 2mm; 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 all belong to parameters that can be modified by those skilled in the art according to different usage scenarios, and belong to simple replacement under the technical concept of the present embodiment.

The above embodiments are not intended to limit the scope of the present application, so: all equivalent changes in structure, shape and principle of the application should be covered in the scope of protection of the application.

Claims

1. A manufacturing method of a micro-fluidic chip is characterized in that: the microfluidic chip comprises a first layer, a second layer and a third layer which are sequentially bonded;

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 in the middle of the third layer;

the first layer is provided with an arc-shaped seat at the position opposite to the fifth through hole and used for being matched with the limit magnetic ball;

the manufacturing method comprises the following steps of;

2. The method for manufacturing a microfluidic chip according to claim 1, wherein: the height of the micro flow channel is 10-100um, and the width is 50-1000nm;

3. The method for manufacturing 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.