CN114471752A - Chip and preparation method thereof - Google Patents

Abstract

The application relates to the field of magnetic control micro-fluidic chips and discloses a chip and a preparation method thereof, wherein the chip comprises: the glass substrate, soft magnetic metal layer and micro-fluidic channel, wherein, micro-fluidic channel and glass substrate bonding are so that soft magnetic metal layer is located between glass substrate and micro-fluidic channel. The chip disclosed by the application improves the capture rate of magnetic beads in the nucleic acid extraction process and improves the experimental recovery rate by arranging the soft magnetic metal layer between the glass substrate and the microfluidic channel. In addition, the integrated design reduces the dependence on an external magnetic field, so that the adaptability of the chip and the device is higher.

Description

A kind of chip and preparation method thereof

technical field

The present application relates to the field of magnetron microfluidic chips, in particular to a chip and a preparation method thereof.

Background technique

As a kind of microbead shape, magnetic materials are widely used in bioseparation, targeted drug loading, and MRI because of their large surface area, good magnetic guidance, and strong operability. The magnetron microfluidic chip can be used for the mixing and transportation of liquids in the microfluidic chip, the switch and valve of the chip, and the transportation, separation and capture of magnetic objects.

Molecular diagnosis uses nucleic acid as the detection object, and is mainly used in the diagnosis of various clinical departments, such as tumors, infectious diseases, genetics, etc. Nucleic acid extraction is the "first step" of molecular diagnosis. Magnetic beads are biofunctional materials based on nanotechnology, which encapsulate magnetic nanoparticles into microspheres, and then undergo surface treatment (biochemical modification) to enable them to bind to various target detection substances. Under the action of the lysate, the DNA/RNA of cells or tissues is released and specifically combined with the modified magnetic beads to form a "magnetic bead-nucleic acid complex". Under the action of an external magnetic field, when the magnetic bead solution flows through the microchannel at a certain flow rate, it will be adsorbed and captured by the force of the magnetic field. When the external magnetic field is withdrawn, the magnetic beads are released and resuspended in the solution to realize the separation and purification of nucleic acids.

At present, the magnetic field in the microfluidic chip is mainly generated by external magnets or integrated soft magnets. The above methods are all conventional permanent magnets or electromagnets or soft magnets placed outside the microfluidic chip, and the magnetic field strength is used to control the magnetic particles. The method is simple in processing technology and low in cost, but has low integration and a limited range of magnetic field control, which limits the capture rate of magnetic beads during nucleic acid extraction. Therefore, how to improve the capture rate of magnetic beads in the nucleic acid extraction process of the microfluidic chip is a problem that needs to be solved by those skilled in the art.

SUMMARY OF THE INVENTION

The invention provides a chip. By placing a soft magnet inside the chip, the capture rate of magnetic beads in the nucleic acid extraction process is improved, and the experimental recovery rate is improved.

In order to achieve the above object, the present invention provides a chip, comprising:

A glass substrate, a soft magnetic metal layer, and a microfluidic channel, the microfluidic channel is bonded to the glass substrate so that the soft magnetic metal layer is located between the glass substrate and the microfluidic channel.

In the above chip, the soft magnetic metal layer is arranged between the glass substrate and the microfluidic channel. When the magnetic beads move in the microfluidic channel, the movement of the magnetic beads is controlled by applying an external magnetic field. When the external magnetic field is applied, the magnetic beads are adsorbed At the bottom of the micro-controlled flow channel, when the external magnetic field is removed, the magnetic beads return to a suspended state, and in this way, the magnetic beads are captured and released, and the separation and purification of substances in nucleic acid extraction experiments are completed. Since the soft magnetic metal layer is located inside the chip, when an external magnetic field is applied, the control range of the magnetic field can be enhanced, thereby enhancing the magnetic field strength, thereby increasing the capture rate of the magnetic beads. In addition, the integrated design of the above-mentioned chip can reduce the dependence on the external magnetic field, so that the adaptability of the chip and the device is higher.

Therefore, in the chip provided by the present invention, by arranging a soft magnetic metal layer between the glass substrate and the microfluidic channel, the capture rate of magnetic beads in the nucleic acid extraction process is improved, and the experimental recovery rate is improved.

Preferably, an insulating layer is also included between the soft magnetic metal layer and the microfluidic channel.

Preferably, it also includes titanium seeds located between the soft magnetic metal layer and the glass substrate, sequentially arranged along the direction from the glass substrate to the soft magnetic metal layer, and corresponding to the soft magnetic metal layer one-to-one layer and copper seed layer.

Preferably, the thickness of the titanium seed layer is 0.8-1.2um, and the thickness of the copper seed layer is 0.8-1.2um.

Preferably, along the length direction of the glass substrate, the flow channel includes a plurality of S-shaped sub-channels connected end to end in sequence.

Preferably, the height of the channel is 0.5-3 mm.

Preferably, the thickness of the soft magnetic metal layer is 50um.

Preferably, the material of the soft magnetic metal layer is one of iron-nickel alloy, pure iron and low carbon steel, iron-silicon alloy, iron-aluminum alloy, soft ferrite ti3, and amorphous soft magnetic alloy.

Preferably, the present invention also provides a method for preparing a chip as described in any of the above, comprising:

forming a soft magnetic metal layer on a glass substrate;

form microfluidic channels;

The microfluidic channel is bonded to the glass substrate such that the soft magnetic metal layer is located between the glass substrate and the microfluidic channel.

Preferably, the forming the soft magnetic metal layer on the glass substrate comprises:

Coating positive photoresist on glass substrate;

Using a patterning process to develop and expose the positive photoresist to obtain a recessed portion, and fill the recessed portion with a soft magnetic metal material to form a soft magnetic metal layer;

Remove the remaining positive photoresist.

Preferably, after removing the remaining positive photoresist, the method further includes depositing a silicon oxide layer on the soft magnetic metal layer to form an insulating layer.

Preferably, before coating the positive photoresist on the glass substrate, the method further comprises: sequentially sputtering a titanium seed layer and a copper seed layer on the glass substrate;

When the remaining positive photoresist is removed, the titanium seed layer and the copper seed layer corresponding to the positive photoresist are simultaneously removed.

Preferably, the forming the microfluidic channel comprises:

Coating SU-8 photoresist on silicon wafer;

Using a patterning process to develop and expose the SU-8 photoresist so that the SU-8 photoresist is in the shape of a microfluidic channel;

Pouring a PDMS layer on the SU-8 photoresist;

Remove the SU-8 photoresist.

Description of drawings

1 is a schematic diagram of a film layer structure of a chip in an embodiment of the present invention;

2 is a schematic diagram of a working principle of a chip in an embodiment of the present invention;

3 is a schematic structural diagram of a chip in an embodiment of the present invention;

Fig. 4 is a kind of sectional structure schematic diagram of A direction in Fig. 3;

Fig. 5 is a kind of sectional structure schematic diagram of B direction in Fig. 3;

6 is a schematic diagram of a step of a method for preparing a chip in an embodiment of the present invention;

FIG. 7 is a schematic diagram of a specific step of step S100 in FIG. 6;

FIG. 8 is a schematic diagram of a specific step of step S200 in FIG. 6 .

In the picture:

10-glass substrate; 20-soft magnetic metal layer; 30-titanium seed layer; 40-copper seed layer; 50-insulating layer; 60-microfluidic channel; 70-magnetic bead; 80-PDMS.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Please refer to FIG. 1 and FIGS. 3 to 5 , the present invention provides a chip including: a glass substrate 10 , a soft magnetic metal layer 20 and a microfluidic channel 60 , wherein the microfluidic channel 60 is bonded to the glass substrate 10 So that the soft magnetic metal layer 20 is located between the glass substrate 10 and the microfluidic channel 60 .

In the above chip, as shown in FIG. 2 , the soft magnetic metal layer 20 is disposed between the glass substrate 10 and the microfluidic channel 60 , and the magnetic beads 70 are captured in the microfluidic channel by using a method of magnetron capture. To move, the movement of the magnetic beads 70 is controlled by applying an external magnetic field. When the external magnetic field is applied, the magnetic beads 70 are adsorbed at the bottom of the micro-controlled flow channel. The capture and release of the magnetic beads 70 complete the separation and purification of substances in the nucleic acid extraction experiment. Since the soft magnetic metal layer 20 is located inside the chip, when an external magnetic field is applied, the control range of the magnetic field can be enhanced, thereby enhancing the magnetic field strength, thereby increasing the capture rate of the magnetic beads 70 . In addition, the integrated design of the above-mentioned chip can reduce the dependence on the external magnetic field, so that the adaptability of the chip and the device is higher.

Therefore, in the chip provided by the present invention, by arranging the soft magnetic metal layer 20 between the glass substrate 10 and the microfluidic channel 60, the capture rate of the magnetic beads 70 in the nucleic acid extraction process is improved, and the experimental recovery rate is improved.

Specifically, referring to FIG. 1, the above-mentioned chip may further include an insulating layer 50 between the soft magnetic metal layer 20 and the microfluidic channel 60, and the insulating layer 50 may be used to protect the soft magnetic metal layer 20 to ensure the soft magnetic Magnetic properties of metal layer 20 . It should be noted that the material of the insulating layer 50 may be silicon oxide or other materials.

Further, the above-mentioned chip may include titanium seed layers 30 which are located between the soft magnetic metal layer 20 and the glass substrate 10 and are sequentially arranged along the direction from the glass substrate 10 to the soft magnetic metal layer 20 in one-to-one correspondence with the soft magnetic metal layers 20 . and the copper seed layer 40, by using the above-mentioned titanium seed layer 30 and copper seed layer 40, the soft magnetic metal layer 20 can be better attached to the glass substrate 10, so as to ensure that the chip can be used better in the process of capturing the magnetic beads 70. Effect.

It should be noted that the thicknesses of the titanium seed layer 30 and the copper seed layer 40 are 0.8-1.2um, which ensures that the soft magnetic metal layer 20 is adhered to the glass substrate 10 and the thickness of the chip is not too large. Wherein, as a preferred solution, the thickness of the titanium seed layer 30 and the copper seed layer 40 may be 1 um.

It should be noted that, referring to FIG. 3 , the microfluidic channel 60 in the above-mentioned chip has a longer length in the direction along which the magnetic beads 70 move, so as to increase the movement of the magnetic beads 70 in the microfluidic channel 60 as much as possible. This ensures that more magnetic beads 70 are captured when an external magnetic field is applied, so as to complete the separation and purification of substances in the nucleic acid extraction experiment. In one embodiment, the above-mentioned microfluidic channel 60 may be composed of a plurality of sub-channels connected end to end along the length of the glass substrate 10, and the form of the above-mentioned microfluidic channel 60 greatly increases the performance of the magnetic beads 70. move the distance, thereby further improving the capture rate of the magnetic beads 70 .

Further, the height of the microfluidic channel 60 should be determined according to the diameter of the magnetic beads 70 to be captured. When the diameter of the magnetic beads 70 is relatively large, the microfluidic channel 60 is correspondingly higher, so that the magnetic beads 70 can Move smoothly in the microfluidic channel 60 . Wherein, the height of the microfluidic channel 60 is specifically set in the range of 0.5-3 mm.

In a factual solution, the height of the soft magnetic metal layer 20 in the above chip can be set to 50um to ensure that when a corresponding external magnetic field is applied, the soft magnetic metal layer 20 can have sufficient magnetic force on the magnetic beads 70, so that the magnetic beads 70 can have sufficient magnetic force. is adsorbed on the bottom of the microfluidic channel 60 .

It should be noted that the material of the soft magnetic metal layer 20 in the chip in the present application can be iron-nickel alloy, pure iron and low carbon steel, iron-silicon alloy, iron-aluminum alloy, soft ferrite ti3, amorphous One of the soft magnetic alloys, and the shape of the soft magnetic metal layer 20 can be set according to different requirements, and has high universality.

Based on the same inventive idea, the present application can also provide a method for preparing a chip, please refer to FIG. 6 , which specifically includes the following steps:

S100: forming a soft magnetic metal layer 20 on the glass substrate 10;

S200: forming a microfluidic channel 60;

S300 : Bond the microfluidic channel 60 with the glass substrate 10 so that the soft magnetic metal layer 20 is located between the glass substrate 10 and the microfluidic channel 60 .

As described above, by forming the soft magnetic metal layer 20 inside the chip, when an external magnetic field is applied, the magnetic field strength of the soft magnetic metal layer 20 can be increased, thereby improving the capture rate of the magnetic beads 70 . In addition, the chip prepared by the above method can also reduce the dependence on the external magnetic field, and the adaptability of the chip and the device is improved.

Specifically, in the above step S100, as shown in FIG. 7, forming the soft magnetic metal layer 20 on the glass substrate 10 may include the following steps:

S101: coating positive photoresist on the glass substrate 10;

S102: developing and exposing the positive photoresist by a patterning process to obtain a recessed portion, and filling the recessed portion with a soft magnetic metal material to form the soft magnetic metal layer 20;

S103: Remove the remaining positive photoresist.

It should be noted that, in the above step S101, the glass substrate 10 needs to be strictly cleaned before the positive photoresist is applied on the glass substrate 10, and the thickness of the glass substrate 10 can be selected to be about 0.5 mm.

Specifically, after the above-mentioned step S103 is completed, that is, after removing the remaining positive photoresist, a silicon oxide layer may also be deposited on the formed soft magnetic metal layer 20 to form an insulating layer 50 to protect the soft magnetic metal layer 20, When depositing the silicon oxide layer, vapor deposition can be used.

Further, before the above step S101, that is, before coating the positive photoresist on the glass substrate 10, the titanium seed layer 30 and the copper seed layer 40 may be sputtered on the glass substrate 10 in sequence, and in step S103, namely When removing the remaining positive photoresist, the titanium seed layer 30 and the copper seed layer 40 corresponding to the positive photoresist are simultaneously removed. The titanium seed layer 30 and the copper seed layer 40 are formed in the above-described manner, so that the formed soft magnetic metal layer 20 can better adhere to the glass substrate 10 .

Specifically, in the above step S200, as shown in FIG. 8, forming the microfluidic channel 60 may specifically include the following steps:

S201: Coating SU-8 photoresist on the silicon wafer;

S202: using a patterning process to develop and expose the SU-8 photoresist to make the SU-8 photoresist take the shape of the microfluidic channel 60;

S203: pour 80 layers of PDMS (ie polydimethylsiloxane) on the SU-8 photoresist;

S204: Remove the SU-photoresist.

It should be noted that, in the above step S201, that is, before coating the SU-8 photoresist on the silicon wafer, the silicon wafer needs to be cleaned.

It should also be noted that, in the above step S300, before the microfluidic channel is bonded to the glass substrate, the formed PDMS chip (that is, the formed microfluidic channel) needs to be cleaned, and the surface is subjected to oxygen plasma treatment .

Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present invention without departing from the spirit and scope of the present invention. Thus, provided that these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims (13)

1. a chip, is characterized in that, comprises: A glass substrate, a soft magnetic metal layer, and a microfluidic channel, the microfluidic channel is bonded to the glass substrate so that the soft magnetic metal layer is located between the glass substrate and the microfluidic channel. 2 . The chip according to claim 1 , further comprising an insulating layer between the soft magnetic metal layer and the microfluidic channel. 3 . 3 . The chip according to claim 1 , further comprising being located between the soft magnetic metal layer and the glass substrate, arranged in sequence along the direction from the glass substrate to the soft magnetic metal layer, and 3 . The soft magnetic metal layers correspond to a titanium seed layer and a copper seed layer one by one. The chip according to claim 3, wherein the thickness of the titanium seed layer is 0.8-1.2um, and the thickness of the copper seed layer is 0.8-1.2um. 5 . The chip according to claim 1 , wherein, along the length direction of the glass substrate, the microfluidic channel comprises a plurality of S-shaped sub-channels connected end to end in sequence. 6 . 6. The chip according to claim 5, wherein the height of the microfluidic channel is 0.5-3 mm. 7. The chip according to claim 1, wherein the thickness of the soft magnetic metal layer is 50um. 8. The chip according to any one of claims 1-7, wherein the soft magnetic metal layer is made of iron-nickel alloy, pure iron and low-carbon steel, iron-silicon alloy, iron-aluminum alloy, Soft ferrite ti3, a kind of amorphous soft magnetic alloy. 9. a preparation method of the chip as described in any one of claim 1-8, is characterized in that, comprising: forming a soft magnetic metal layer on a glass substrate; form microfluidic channels; The microfluidic channel is bonded to the glass substrate such that the soft magnetic metal layer is located between the glass substrate and the microfluidic channel. 10. The preparation method according to claim 9, wherein the forming a soft magnetic metal layer on the glass substrate comprises: Coating positive photoresist on glass substrate; Using a patterning process to develop and expose the positive photoresist to obtain a recessed portion, and fill the recessed portion with a soft magnetic metal material to form a soft magnetic metal layer; Remove the remaining positive photoresist. 11 . The preparation method according to claim 10 , wherein after removing the remaining positive photoresist, the method further comprises depositing a silicon oxide layer on the soft magnetic metal layer to form an insulating layer. 12 . 12 . The preparation method according to claim 10 , wherein before coating the positive photoresist on the glass substrate, the method further comprises: sputtering a titanium seed layer and a copper seed layer on the glass substrate in sequence; 12 . When the remaining positive photoresist is removed, the titanium seed layer and the copper seed layer corresponding to the positive photoresist are simultaneously removed. 13. The preparation method according to claim 9, wherein the forming a microfluidic channel comprises: Coating SU-8 photoresist on silicon wafer; Using a patterning process to develop and expose the SU-8 photoresist so that the SU-8 photoresist is in the shape of a microfluidic channel; Pouring a PDMS layer on the SU-8 photoresist; Remove the SU-8 photoresist.

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