Bidirectional microfluidic pump chip based on fully enclosed microbubble structure and manufacturing method

Abstract

The application discloses a bidirectional micro-fluid pump chip based on a fully-closed micro-bubble structure and a manufacturing method. The micro-fluid pump chip comprises a ring-shaped flow channel, the ring-shaped flow channel comprises a first flow channel and a second flow channel which extend in a meandering manner, two side banks of the first flow channel are provided with a first resonance cavity, and two side banks of the second flow channel are provided with a second resonance cavity. Since the first resonance cavity and the second resonance cavity have different characteristic frequencies, the pumping of the fluid can be realized through selective excitation of different frequency ultrasonic waves, so that the fluid in the first flow channel and the second flow channel is driven to flow in different directions. The manufacturing method comprises photoetching, reverse molding and bonding processes. The application can realize the control of the flow direction of the liquid by changing the ultrasonic frequency, and realizes the bidirectional pumping of the liquid.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of microfluidic technology, and particularly relates to a bidirectional microfluidic pump chip based on a fully-closed microbubble structure and a manufacturing method. BACKGROUND

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

[0003] In microfluidic technology, the driving of liquid is one of the core contents, and the precise control of the movement of liquid is the main reason for the high precision of microfluidic technology, and how to effectively and quickly drive the liquid is the key technology of microfluidic technology. The current main driving methods of microfluidic technology are: external pump, magnetic field, electric field, ultrasonic driving, etc. The existing driving methods have some problems, such as: using external pump requires the pump to have very high precision and response speed and large size, which weakens the advantage of small size of microfluidic technology; magnetic field, electric field control requires complex structure design, and the microstructure is controlled by the magnetic field and electric field to drive the fluid; the ultrasonic driving method mainly drives 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 driving direction of the acoustic streaming effect on the liquid is fixed and lacks a certain flexibility. SUMMARY

[0004] The present application aims to overcome the shortcomings of the prior art, and provides a bidirectional microfluidic pump chip based on a fully-closed microbubble structure and a manufacturing method, which solves the problems in the background art.

[0005] One of the technical solutions adopted by the present application to solve its technical problems is to provide a bidirectional microfluidic pump chip based on a fully-closed microbubble structure, which comprises a ring-shaped flow channel, the ring-shaped flow channel comprises a first flow channel and a second flow channel extending in a meandering manner, first resonance cavities are arranged on the two sides of the first flow channel, second resonance cavities are arranged on the two sides of the second flow channel, the first resonance cavities and the second resonance cavities realize the pumping of fluid by selective excitation of different frequency ultrasonic waves, thereby driving the fluid in the first flow channel and the second flow channel to flow in different directions.

[0006] In a preferred embodiment of the present application, a plurality of first resonance cavities are arranged at equal distances on the two sides of the first flow channel, and a plurality of second resonance cavities are arranged at equal distances on the two sides of the second flow channel.

[0007] In a preferred embodiment of the present application, the first resonance cavities and the second resonance cavities are cylindrical, and the radius of the second resonance cavities is greater than that of the first resonance cavities.

[0008] In a preferred embodiment of the present application, the projection of the convex bank of the first flow channel and the second flow channel is composed of a circular arc thin wall and a slope.

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

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

[0011] In a preferred embodiment of the present application, the thickness of the thin wall structure is not greater than 3 microns.

[0012] In a preferred embodiment of the present application, the circular arc thin wall formed by the first resonant cavity has a larger sector angle than the circular arc thin wall formed by the second resonant cavity.

[0013] In a preferred embodiment of the present application, the chip comprises a main body and a packaging substrate, the annular flow channel, the first resonant cavity and the second resonant cavity are arranged in the main body, and the main body is bonded with the packaging substrate.

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

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

[0016] 1) A mold is made through a photolithography process;

[0017] 2) The elastic polymer with removed bubbles is inverted-molded;

[0018] 3) The molded main body is packaged through a bonding process.

[0019] Compared with the background art, the present technical solution has the following advantages:

[0020] 1. The present application integrates the resonant cavity as a driving device in the chip, which is fully-closed and small in size, and ensures the long-term stability of the chip.

[0021] 2. The present application arranges resonant cavities of different sizes beside different flow channels, actively controls by changing the ultrasonic frequency, simply realizes the bidirectional flow of liquid, and improves the flexibility of the acoustic streaming effect driving.

[0022] 3. The manufacturing method is simple, can accurately construct flow channels and cavities, flexibly set size, shape and position, ensure that the liquid is in the microfluidic level, meet the characteristics that the cavity position does not block the microfluidic channel and the characteristic frequency of the cavities on both sides of different flow channels is different. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The exploded structure schematic diagram of the bidirectional microfluidic pump chip is shown in the embodiment;

[0024] Figure 2 The overall schematic diagram of the bidirectional microfluidic pump chip is shown in the embodiment;

[0025] Figure 3 The structure schematic diagram of the bidirectional microfluidic pump chip and the enlarged view of part of the structure are shown in the embodiment;

[0026] Figure 4 The manufacturing process flow schematic diagram of the bidirectional microfluidic pump chip is shown in the embodiment;

[0027] Figure 5 The mold schematic diagram of the bidirectional microfluidic pump chip is shown in the embodiment;

[0028] Figure 6 The schematic diagram of different liquid flow directions under different ultrasonic frequencies is shown in the embodiment. DETAILED DESCRIPTION

[0029] It should be noted that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only for description purposes and cannot be understood as indicating or implying relative importance.

[0030] EMBODIMENT

[0031] The bidirectional microfluidic pump chip based on the fully enclosed microbubble structure in the embodiment comprises a ring-shaped flow channel, the ring-shaped flow channel comprises a first flow channel and a second flow channel extending in a meandering manner, a plurality of first resonance cavities are equidistantly arranged on the two sides of the first flow channel, a plurality of second resonance cavities are equidistantly arranged on the two sides of the second flow channel, and the first resonance cavities and the second resonance cavities have different characteristic frequencies.

[0032] As a bidirectional microfluidic device, it further comprises an ultrasonic driving device. When excited by ultrasonic waves, the first resonant cavity and the second resonant cavity realize pumping of the fluid by selective excitation of ultrasonic waves of different frequencies, so as to drive the fluid in the first flow channel and the second flow channel to flow in different directions, realizing bidirectional pumping.

[0033] As Figure 3 , in the embodiment, the first flow channel and the second flow channel are respectively arranged above and below the annular flow channel with a length of 100 μm and a width of 100 μm. The resonant cavity arrays with the same size are arranged in the same flow channel, and the resonant cavity arrays with different diameters are arranged in different flow channels. The first resonant cavity and the second resonant cavity are cylindrical, and the diameter d2 of the second resonant cavity is greater than the diameter d1 of the first resonant cavity. The lower right corner shows a schematic diagram of the flow state of the liquid under the action of the cavities under the ultrasonic waves.

[0034] The projection of the convex bank of the first flow channel and the second flow channel is composed of an arc thin wall and a slope. The tangent line of the starting point of the arc of the first flow channel and the second flow channel forms an acute angle with the inner wall of the flow channel, and the connecting line of the terminal 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 an arc thin wall with a thickness w of 3 μm between the flow channel. The arc thin wall formed by the first resonant cavity has a larger sector angle than the arc thin wall formed by the second resonant cavity.

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

[0036] As Figure 1 and 2 , the annular flow channel, the first resonant cavity and the second resonant 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. As Figure 4 , the specific manufacturing method comprises the following steps:

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

[0038] 2) Mix the polydimethylsiloxane (PDMS) prepolymer and the crosslinking agent to obtain the elastic polymer 7; wherein the elastic polymer 7 needs to be able to fully fill the gap of the mold 5; it is necessary to ensure that the elastic polymer 7 and the substrate 8 can be effectively attached to ensure that the liquid does not leak;

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

[0040] 4) The container with the mold and the PDMS solution 6 obtained in steps 1) to 3) is subjected to a suction process to remove air bubbles;

[0041] 5) The PDMS solution 6 obtained in step 4) is subjected to a baking process on a hot plate together with the container and the mold. The baking process is performed at 60°C for 1 h and then at 80°C for 1 h.

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

[0043] 7) The cut PDMS elastic polymer 7 is connected to another substrate 8 by a bonding process.

[0044] The above examples are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A bidirectional microfluidic pump chip based on a fully enclosed microbubble structure, characterized by: The device comprises an annular flow channel, the annular flow channel comprising a first flow channel and a second flow channel extending in a winding manner, a first resonant cavity being provided on both sides of the convex banks of the first flow channel, and a second resonant cavity being provided on both sides of the convex banks of the second flow channel, wherein 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; The first resonant cavity and the second resonant cavity are cylindrical, and the radius of the second resonant cavity is larger than that of the first resonant cavity; The projections of the convex banks of the first flow channel and the second flow channel are composed of a circular arc and a slope; 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; The first resonance cavity and the second resonance cavity are arranged in the arc and form an arc thin wall with the flow channel.

2. A bidirectional microfluidic pump chip based on a fully enclosed microbubble structure according to claim 1, characterized in that: The thickness of the arc thin-wall structure is no more than 3 microns.

3. A bidirectional microfluidic pump chip based on a fully enclosed microbubble structure according to claim 1, characterized in that: The arc-shaped thin wall formed by the first resonant cavity has a larger fan-shaped angle than the arc-shaped thin wall formed by the second resonant cavity.

4. 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.

5. The 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 provided on both sides of the first flow channel, and a plurality of second resonance cavities are equidistantly provided on both sides of the second flow channel.

6. The method for manufacturing a bidirectional microfluidic pump chip based on a fully enclosed microbubble structure according to any one of claims 1 to 5, characterized in that: The steps include: 1) Making a mold by photolithography; 2) performing reverse molding on the elastic polymer from which bubbles have been removed; 3) Encapsulate the formed body through a bonding process.

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