Bidirectional microfluid pump chip based on totally-enclosed microbubble structure and manufacturing method

Abstract

The invention discloses a two-way microfluid pump chip based on a totally-closed microbubble structure and a manufacturing method of the two-way microfluid pump chip. The microfluid pump chip comprises an annular flow channel, the annular flow channel comprises a first flow channel and a second flow channel which extend in a winding mode, convex banks on the two sides of the first flow channel are provided with first resonant cavities, and convex banks on the two sides of the second flow channel are provided with second resonant cavities. Due to the fact that the first resonance cavity and the second resonance cavity have different characteristic frequencies, fluid pumping can be achieved through selective excitation of ultrasound of different frequencies, and therefore the fluid in the first flow channel and the fluid in the second flow channel are driven to flow in different directions. The manufacturing method comprises photoetching, mold reversing and bonding processes. The flow direction of the liquid can be controlled by changing the ultrasonic frequency, and bidirectional pumping of the liquid is achieved.

Description

Technical Field

[0001] The invention belongs to the field of microfluidics technology, and in particular relates to a bidirectional microfluid pump chip based on a fully enclosed microbubble structure and a manufacturing method thereof. Background Art

[0002] Microfluidics refers to the manipulation of various tiny fluids in microchannels. Microfluidics technology has the advantages of small size, high precision and low material consumption. It is widely used in various disciplines such as chemistry, medicine, biology, etc.

[0003] In microfluidic technology, liquid driving is one of its core contents. Precise control of liquid movement is the main reason for the high precision of microfluidic technology. How to effectively and quickly drive liquid is the key technology of microfluidic technology. At present, the main driving methods for microfluidic technology are: external pump, magnetic field, electric field, ultrasonic drive, etc. There are some problems with the existing driving methods, such as: the use of external pumps requires the pump to have high precision and response speed and large volume, which weakens the advantage of small volume of microfluidic technology; magnetic field and electric field control requires complex structural design, and the microstructure is controlled by magnetic field and electric field to drive the fluid; the ultrasonic drive method mainly pumps the liquid through the acoustic streaming effect of microbubbles or sharp structures in the liquid, but the stability of the microbubbles is not enough to support long-term use, and the acoustic streaming effect is fixed to the driving direction of the liquid and lacks certain flexibility. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a bidirectional microfluidic pump chip based on a fully enclosed microbubble structure and a manufacturing method, which solves the problems in the above-mentioned background technology.

[0005] One of the technical solutions adopted by the present invention to solve its technical problems is: providing a bidirectional microfluidic pump chip based on a fully enclosed microbubble structure, including an annular flow channel, the annular flow channel including a first flow channel and a second flow channel extending in a winding manner, the convex banks on both sides of the first flow channel are provided with a first resonant cavity, the convex banks on both sides of the second flow channel are provided with a second resonant cavity, the first resonant cavity and the second resonant cavity realize fluid pumping through selective excitation of ultrasound of different frequencies, thereby driving the fluids in the first flow channel and the second flow channel to flow in different directions.

[0006] In a preferred embodiment of the present invention, a plurality of first resonance cavities are equidistantly disposed on both sides of the first flow channel, and a plurality of second resonance cavities are equidistantly disposed on both sides of the second flow channel.

[0007] In a preferred embodiment of the present invention, the first resonant cavity and the second resonant cavity are cylinders, and the radius of the second resonant cavity is greater than that of the first resonant cavity.

[0008] In a preferred embodiment of the present invention, the projections of the convex banks of the first flow channel and the second flow channel are composed of a section of circular arc thin wall and a slope.

[0009] In a preferred embodiment of the present invention, the tangent lines of the arcs of the first flow channel and the second flow channel at the starting points form an acute angle with the inner wall of the flow channel, and the line connecting the end point of the arc and the inner wall of the flow channel forms the slope.

[0010] In a preferred embodiment of the present invention, the first resonance cavity and the second resonance cavity are arranged in the arc and form an arc thin wall with the flow channel.

[0011] In a preferred embodiment of the present invention, the thickness of the thin-wall structure is no more than 3 microns.

[0012] In a preferred embodiment of the present invention, the arc thin wall formed by the first resonance cavity has a larger fan angle than the arc thin wall formed by the second resonance cavity.

[0013] In a preferred embodiment of the present invention, it comprises a main body and a packaging substrate, the annular flow channel, the first resonance cavity and the second resonance cavity are arranged in the main body, and the main body is bonded to the packaging substrate.

[0014] In a preferred embodiment of the present invention, an ultrasonic driving device is used as the external pump drive.

[0015] The second technical solution adopted by the present invention to solve the technical problem is: providing a method for manufacturing the above-mentioned bidirectional microfluidic pump chip based on a fully enclosed microbubble structure, comprising the following steps:

[0016] 1) Making a mold by photolithography;

[0017] 2) performing reverse molding of the elastic polymer from which bubbles have been removed;

[0018] 3) Encapsulate the formed body through a bonding process.

[0019] Compared with the background technology, this technical solution has the following advantages:

[0020] 1. The present invention integrates the resonant cavity as a driving device in the chip, and the fully enclosed setting reduces the volume while also ensuring the long-term stable performance of the chip.

[0021] 2. The present invention sets resonant cavities of different sizes beside different flow channels, and actively controls by changing the ultrasonic frequency, thus simply realizing the bidirectional flow of the liquid and improving the flexibility of the acoustic streaming effect drive;

[0022] 3. The manufacturing method of the present invention is simple, can accurately construct flow channels and cavities, flexibly set the size, shape, and position, ensure that the liquid is at the microfluidic level, ensure that the cavity position does not block the microchannel, and that the characteristic frequencies of the cavities on both sides of different flow channels are different. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the exploded structure of the bidirectional microfluidic pump chip of the embodiment;

[0024] Figure 2 is an overall schematic diagram of a bidirectional microfluidic pump chip according to an embodiment;

[0025] Figure 3 A schematic diagram of the structure of a bidirectional microfluidic pump chip according to an embodiment and an enlarged diagram of a part of the structure thereof;

[0026] Figure 4 Schematic diagram of the manufacturing process of a bidirectional microfluidic pump chip according to an embodiment;

[0027] Figure 5 Schematic diagram of a mold of a bidirectional microfluidic pump chip of an embodiment;

[0028] Figure 6 Schematic diagram of different liquid flow directions under different ultrasonic frequencies. DETAILED DESCRIPTION

[0029] It should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0030] Example

[0031] The present embodiment provides a bidirectional microfluidic pump chip based on a fully enclosed microbubble structure, including an annular flow channel, wherein the annular flow channel includes a first flow channel and a second flow channel extending in a winding manner, a plurality of first resonant cavities are equidistantly provided on both sides of the convex banks of the first flow channel, a plurality of second resonant cavities are equidistantly provided on both sides of the convex banks of the second flow channel, and the first resonant cavity and the second resonant cavity have different characteristic frequencies.

[0032] As a bidirectional microfluidic device, it also includes an ultrasonic drive device. When excited by ultrasound, the first resonant cavity and the second resonant cavity achieve fluid pumping through selective excitation of ultrasound of different frequencies, thereby driving the fluids in the first flow channel and the second flow channel to flow in different directions, achieving bidirectional pumping.

[0033] like Figure 3 In this embodiment, the cross section is a circular flow channel with a length and width of 100 μm, and the upper and lower parts are the first flow channel and the second flow channel respectively. The same flow channel is distributed with a resonance cavity array of the same size, and the resonance cavity arrays distributed with different flow channels have different diameters. The first resonance cavity and the second resonance cavity are cylindrical, and the diameter d of the second resonance cavity is 2 Greater than the first resonance cavity d 1 The lower right corner shows a schematic diagram of the flow state of liquid in the cavity under the action of ultrasound.

[0034] The projection of the convex bank of the first flow channel and the second flow channel consists of a thin arc wall and a slope. The tangent of the arc of the first flow channel and the second flow channel at the starting point forms an acute angle with the inner wall of the flow channel, and the line connecting the end point of the arc and the inner wall of the flow channel forms the slope. The first resonant cavity and the second resonant cavity are arranged in the arc and form a thin arc wall with a thickness w of 3μm between the flow channels. The thin arc wall formed by the first resonant cavity has a larger fan angle than the thin arc wall formed by the second resonant cavity.

[0035] like Figure 6 , a schematic diagram of different liquid flow directions under the influence of ultrasonic waves of different frequencies emitted by the ultrasonic probe 8; arrows of the same color indicate the direction of movement of the liquid in the flow channel under the influence of ultrasonic waves of the same color.

[0036] like Figure 1 and 2 In this embodiment, the annular flow channel, the first resonance cavity and the second resonance cavity are arranged in the main body, and then the main body and the packaging substrate are bonded to realize a fully enclosed microbubble structure. Figure 4 The specific manufacturing method comprises the following steps:

[0037] 1) Place the mold 5 at the bottom of the container; Figure 5 , the mold 5 is made by photolithography;

[0038] 2) Mixing polydimethylsiloxane (PDMS) prepolymer with a cross-linking agent to obtain an elastic polymer 7; wherein the elastic polymer 7 must be able to fully fill the gap of the mold 5; and the elastic polymer 7 and the substrate 8 must be effectively bonded to ensure that there is no leakage of the liquid;

[0039] 3) introducing the mixed solution 6 obtained in step 2) into the container of step 1, with the liquid level exceeding the upper surface of the mold 5;

[0040] 4) removing bubbles from the container with the mold and the PDMS solution 6 obtained from step 1) to step 3) by suction;

[0041] 5) The PDMS solution 6 obtained in step 4) with the bubbles removed is placed on a hot plate together with the container and the mold for baking at 60° C. for 1 hour and then at 80° C. for 1 hour.

[0042] 6) After baking, the PDMS elastic polymer 7 is peeled off from the mold, and the excess blank part is removed with a blade;

[0043] 7) Connecting the cut PDMS elastic polymer 7 to another substrate 8 through a bonding process.

[0044] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A bidirectional microfluidic pump chip based on a fully enclosed microbubble structure, characterized in that: The invention comprises an annular flow channel, wherein the annular flow channel comprises a first flow channel and a second flow channel extending in a winding manner, wherein first resonance cavities are provided on convex banks on both sides of the first flow channel, and second resonance cavities are provided on convex banks on both sides of the second flow channel, and the first resonance cavity and the second resonance cavity realize fluid pumping through selective excitation of ultrasound of different frequencies, thereby driving the fluids in the first flow channel and the second flow channel to flow in different directions.

2. A bidirectional microfluidic pump chip based on a fully enclosed microbubble structure according to claim 1, characterized in that: The first resonant cavity and the second resonant cavity are cylinders, and the radius of the second resonant cavity is greater than that of the first resonant cavity.

3. A bidirectional microfluidic pump chip based on a fully enclosed microbubble structure according to claim 2, characterized in that: The projections of the convex banks of the first flow channel and the second flow channel are composed of a section of circular arc thin wall and a slope.

4. A bidirectional microfluidic pump chip based on a fully enclosed microbubble structure according to claim 3, characterized in that: The tangent lines of the arcs of the first flow channel and the second flow channel at the starting points form an acute angle with the inner wall of the flow channel, and the line connecting the end point of the arc and the inner wall of the flow channel forms the slope.

5. A bidirectional microfluidic pump chip based on a fully enclosed microbubble structure according to claim 4, characterized in that: The first resonance cavity and the second resonance cavity are arranged in the arc and form an arc thin wall with the flow channel.

6. A bidirectional microfluidic pump chip based on a fully enclosed microbubble structure according to claim 5, characterized in that: The thickness of the thin-walled structure is no more than 3 microns.

7. A bidirectional microfluidic pump chip based on a fully enclosed microbubble structure according to claim 5, characterized in that: The arc thin wall formed by the first resonance cavity has a larger fan angle than the arc thin wall formed by the second resonance cavity.

8. A bidirectional microfluidic pump chip based on a fully enclosed microbubble structure according to claim 1, characterized in that: The invention comprises a main body and a packaging substrate. The annular flow channel, the first resonance cavity and the second resonance cavity are arranged in the main body. The main body is bonded to the packaging substrate.

9. A bidirectional microfluidic pump chip based on a fully enclosed microbubble structure according to claim 1, characterized in that: A plurality of first resonance cavities are equidistantly disposed on both sides of the first flow channel, and a plurality of second resonance cavities are equidistantly disposed on both sides of the second flow channel.

10. A method for manufacturing a bidirectional microfluidic pump chip based on a fully enclosed microbubble structure according to any one of claims 1 to 9, characterized in that: The steps include: 1) Making a mold by photolithography; 2) performing reverse molding of the elastic polymer from which bubbles have been removed; 3) Encapsulate the formed body through a bonding process.

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