A method for generating vacuum and continuous liquid phase filling inside a microfluidic chip using a pipette tip

Abstract

The present invention discloses a method for generating vacuum and continuously filling liquid phase inside a microfluidic chip by using a pipette tip. The microfluidic chip is subjected to vacuum treatment by the pipette tip, and then the same or a similar pipette tip is used to aspirate various required reagents or liquid phases to fill the inside of the microfluidic chip chamber, so that the inside of the microfluidic chip chamber can be filled with different liquid phases in sequence, realizing rapid vacuum generation inside the microfluidic chip and simple and rapid filling of the continuous liquid phase.

Description

Technical Field

[0001] The present invention relates to a method for generating vacuum and continuous liquid-phase filling inside a microfluidic chip using a pipette tip, and belongs to the technical field of microfluidic chips. Background Art

[0002] Microfluidic chips are a hot area in the development of current Miniaturized Total Analysis Systems. With the chip as the operating platform, based on analytical chemistry, relying on microelectromechanical processing technology, featuring a microchannel network, and with life science as the current main application object, it is one of the rapidly developing frontier technologies and has been widely used in biochemical analysis and detection. Its goal is to integrate the functions of an entire laboratory, including sampling, dilution, reagent addition, reaction, separation, detection, etc., on a microchip and can be used multiple times.

[0003] Microfluidic chips are the main platforms for realizing microfluidic technology. The device feature is mainly that its effective structure for accommodating fluids (channels, reaction chambers, and some other functional components) is at the micron scale in at least one dimension. Due to the micron-scale structure, fluids exhibit and generate special properties different from those at the macroscopic scale inside. Therefore, unique analytical properties have been developed. Microfluidic chips have the characteristics of controllable liquid flow, extremely low consumption of samples and reagents, and a ten-fold or even hundreds-fold increase in analysis speed. It can analyze hundreds of samples simultaneously in a few minutes or even shorter, and can preprocess samples and analyze the entire process online.

[0004] Fluid injection of microfluidic chips is a key technology in microfluidic chips. Different microfluidic chip fluid driving technologies have been developed for different application scenarios, including pressure driving, electroosmotic flow driving, interfacial tension driving, and braking deformation driving, etc. Among them, pressure driving is the most common driving technology for microfluidic chips. Pressure driving usually has positive pressure driving and negative pressure driving modes. Positive pressure driving is simple and convenient, but the gas in the chip will lead to insufficient flow stability and problems such as bubble blockage. Negative pressure driving is easier to control the filling of the microfluidic chip chamber and has higher stability. The conventional negative pressure treatment method for microfluidic chips is to place the entire chip into a vacuum chamber, and then evacuate and degas the vacuum chamber through a vacuum pump to perform negative pressure treatment on the microfluidic chip. The entire treatment process is relatively complex, and it is not convenient to directly add samples into the microfluidic chip after negative pressure treatment. Summary of the Invention

[0005] In view of this, the present invention provides a method for generating vacuum and continuous liquid-phase filling inside a microfluidic chip using a pipette tip to solve the above problems existing in the prior art.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for generating vacuum and continuous liquid-phase filling inside a microfluidic chip using a pipette tip, the steps are as follows:

[0008] (1), Use a first pipette tip to connect a power source to a pore of the microfluidic chip chamber, close other pores of the microfluidic chip chamber, and use the power source to provide negative pressure to exhaust the air inside the microfluidic chip chamber, so that the inside of the chip chamber reaches or approaches a vacuum state;

[0009] (2), Close the pore connected to the first pipette tip of the microfluidic chip and separate the first pipette tip from the pore of the microfluidic chip, and use the power source to provide negative pressure to make the first pipette tip suck the first liquid phase;

[0010] (3), Open the pore connected to the first pipette tip of the microfluidic chip, reconnect the first pipette tip to the pore of the microfluidic chip chamber, and use the power source to provide positive pressure or utilize the negative pressure inside the chip to make the first liquid phase enter the chamber of the microfluidic chip;

[0011] (4), Discard the first pipette tip, then connect the second pipette tip to the power source, and use the power source to provide negative pressure to suck the second liquid phase;

[0012] (5), Connect the second pipette tip sucking the second liquid phase to a pore of the microfluidic chip chamber, open this pore and another pore, and use the power source to provide positive pressure to make the second liquid phase enter the chamber of the microfluidic chip.

[0013] On the basis of the above technical solutions, the present invention can also be improved as follows:

[0014] Further, the microfluidic chip has at least one connected chamber, and the chamber has at least 2 pores and is connected to the outside atmosphere through the pores.

[0015] Further, the pores are hermetically connected to the first pipette tip and the second pipette tip.

[0016] Further, the opening and closing of the pores are controlled by microvalves.

[0017] Further, the first liquid phase and the second liquid phase are immiscible.

[0018] Further, the volumes of the first liquid phase and the second liquid are both not less than the volume of the microfluidic chip chamber.

[0019] The present invention also provides another method for generating vacuum and continuous liquid-phase filling inside a microfluidic chip using a pipette tip, the steps are as follows:

[0020] (1) Use the first pipette tip to connect one air hole of the power source and the microfluidic chip chamber, close the other air holes of the microfluidic chip chamber, and use the power source to provide negative pressure to exhaust the air in the microfluidic chip chamber, so that the inside of the chip chamber reaches or approaches a vacuum state;

[0021] (2) Close the air hole where the microfluidic chip is connected to the first pipette tip and separate the first pipette tip from the air hole of the microfluidic chip. Use the power source to provide negative pressure to make the first pipette tip suck the first liquid phase; then continuously suck the second liquid phase that is immiscible with the first liquid phase;

[0022] (3) Open the air hole where the microfluidic chip is connected to the first pipette tip, reconnect the first pipette tip and the air hole of the microfluidic chip chamber. Under the negative pressure of the microfluidic chip, make the second liquid phase enter the microfluidic chip chamber, and then use the power source to provide positive pressure to make the first liquid phase enter the microfluidic chip chamber.

[0023] The beneficial effects of the present invention are as follows: Using the most common pipette tip to perform vacuum treatment on the microfluidic chip has higher efficiency than the existing method of using a vacuum chamber to perform vacuum treatment on the chip, and is easier to control and automate; at the same time, this pipette tip is also used to fill the liquid phase inside the chip, ensuring that other systems will not be contaminated by the reagent. Description of the Drawings

[0024] Figure 1 It is the state of the first pipette tip in Example 1 of the present invention when evacuating the microfluidic chip;

[0025] Figure 2 It is the state of the first pipette tip in Example 1 of the present invention when sucking the first reagent;

[0026] Figure 3 It is the state of the first pipette tip in Example 1 of the present invention when injecting the first liquid phase into the microfluidic chip chamber;

[0027] Figure 4 It is the state of the second pipette tip in Example 1 of the present invention when sucking the second liquid phase;

[0028] Figure 5 It is the state of the second pipette tip in Example 1 of the present invention when injecting the second liquid phase into the microfluidic chip chamber;

[0029] Figure 6 It is the state of the first pipette tip in Example 2 of the present invention when sucking the first liquid phase and then sucking the second liquid phase;

[0030] Figure 7 It is the state of the first pipette tip in Example 2 of the present invention when injecting the second liquid phase and the first liquid phase into the microfluidic chip chamber. Detailed implementation mode

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with 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 belong to the scope of protection of the present invention. It should be specifically noted that the number of air holes in the microfluidic chamber may not only be two, but also one or more. The number of pipette tips used during the vacuum pumping and sample injection processes of the entire microfluidic chip may not only be one or two, but also more pipette tips can be used to achieve the same effect.

[0032] Embodiment 1

[0033] As Figures 1-5 , in a microfluidic chip sample injection, first connect the power source to the tail of the first pipette tip, and then insert the tip of the first pipette tip into the first air hole of the microfluidic chip. At this time, the first air hole is in an open state, and the microfluidic chip chamber is connected to the power source through the pipette tip. Use the microvalve to close the second air hole or more other air holes of the microfluidic chip. At this time, the microfluidic chip chamber forms a sealed space, and then the power source turns on the negative pressure mode to pump out the air in the microfluidic chip chamber, making the inside of the microfluidic chip in a vacuum state. Using the pipette tip to directly vacuum-treat the microfluidic chip chamber reduces the operation complexity of the conventional vacuum treatment of the chip in the sealed chamber. The pipette tip after vacuum-treating the microfluidic chip can also be used to suck and inject the liquid phase into the microfluidic chip chamber, which not only improves the utilization efficiency of the pipette tip but also reduces the reagent contamination of other systems.

[0034] Then, close the first microvalve to keep the vacuum in the microfluidic chip chamber, and the first pipette tip is removed from the first air hole of the microfluidic chip.

[0035] The first pipette tip connected to the power source is inserted into the first liquid phase, and under the action of negative pressure, the first liquid phase is sucked into the first pipette tip.

[0036] Then, insert the first pipette tip after sucking the first liquid phase into the first air hole of the microfluidic chip and open the first microvalve. At this time, the first liquid phase in the first pipette tip will quickly enter the microfluidic chip chamber under the drive of the negative pressure in the microfluidic chip until the entire microfluidic chip chamber is filled with the first liquid phase; in addition, a positive pressure can also be applied to the first liquid phase through the power source to accelerate the speed of the first liquid phase entering the microfluidic chip chamber.

[0037] Then, withdraw the first pipette tip from the first air hole and disconnect it from the power source. Next, connect the tail of the second pipette tip to the power source, insert the tip into the second liquid phase, and under the action of the negative pressure of the power source, aspirate the second liquid phase. Then, insert the second pipette tip after aspirating the second liquid phase into the first air hole, open the second micro-valve, and under the driving of the positive pressure of the power source, the second liquid phase enters the microfluidic chip chamber, which will push the first liquid phase on the main flow channel in the microfluidic chip out of the second air hole, and the main flow channel is filled with the second liquid phase. For some micro-chambers in the microfluidic chip chamber, due to the "dead-end" structure, the first liquid phase inside cannot be pushed out by the second liquid phase and remains in the microfluidic chip, being segmented and sealed inside the microfluidic chip by the second liquid phase.

[0038] In particular, when the first liquid phase is an aqueous phase and the second liquid phase is an oil-phase reagent immiscible with water, micro-droplets of the first liquid phase separated by the second liquid phase and the micro-chambers of the chip will be formed within the "dead-end" structure in the chip.

[0039] Example 2

[0040] Such as Figure 6 、 7 , in a microfluidic chip injection, first connect the power source to the tail of the first pipette tip, then insert the tip of the first pipette tip into the first air hole of the microfluidic chip. At this time, the first air hole is in an open state, and the microfluidic chip chamber is connected to the power source through the pipette tip. Use the micro-valve to close the second air hole or more other air holes of the microfluidic chip. At this time, the microfluidic chip chamber forms a closed space. Then, the power source turns on the negative pressure mode to pump out the air in the microfluidic chip chamber, making the inside of the microfluidic chip in a vacuum state.

[0041] Then, close the first micro-valve to maintain the vacuum in the microfluidic chip chamber, and withdraw the first pipette tip from the first air hole of the microfluidic chip.

[0042] Insert the first pipette tip connected to the power source into the first liquid phase, and under the action of negative pressure, aspirate the first liquid phase into the first pipette tip. Then, insert it into the second liquid phase, and under the action of negative pressure, continue to aspirate the second liquid phase into the first pipette tip. The second liquid phase and the first liquid phase are immiscible, and the specific gravity of the first liquid phase is lower than that of the second liquid phase. Through this mode, only one pipette tip is needed to complete the vacuum treatment of the microfluidic chip and sequentially add different continuous phases into the microfluidic chip chamber.

[0043] Then, insert the first pipette tip after aspirating the first liquid phase and the second liquid phase into the first air hole of the microfluidic chip, and open the first micro-valve. At this time, under the drive of the negative pressure in the microfluidic chip, the second liquid phase in the first pipette tip will quickly enter the chamber of the microfluidic chip until the entire chamber of the microfluidic chip is filled with the second liquid phase. Open the second micro-valve. Driven by the positive pressure of the power source, the first liquid phase enters the chamber of the microfluidic chip, and will push the second liquid phase on the main flow channel in the microfluidic chip out of the second air hole. The main flow channel is then filled with the first liquid phase. For some micro-chambers in the chamber of the microfluidic chip, due to the "dead end" structure, the second liquid phase inside cannot be pushed out by the first liquid phase and remains in the microfluidic chip, being divided and sealed inside the microfluidic chip by the first liquid phase.

[0044] In particular, when the second liquid phase is an aqueous phase and the first liquid phase is an oil-phase reagent immiscible with water, second liquid phase micro-droplets separated by the first liquid phase and the micro-chambers of the chip will be formed in the "dead end" structure inside the chip.

Claims

1. A method for generating a vacuum and continuously filling a liquid phase inside a microfluidic chip using a pipette tip, characterized in that, The steps are as follows: (1) Connect a power source to one air hole of the microfluidic chip chamber using a first pipette tip, close the other air holes of the microfluidic chip chamber, and use the power source to provide negative pressure to exhaust the air in the microfluidic chip chamber, so that the chip chamber reaches or approaches a vacuum state; (2) Close the air hole connected to the first pipette tip of the microfluidic chip and separate the first pipette tip from the air hole of the microfluidic chip, and use the power source to provide negative pressure to make the first pipette tip suck the first liquid phase; (3) Open the air hole connected to the first pipette tip of the microfluidic chip, reconnect the first pipette tip and the air hole of the microfluidic chip chamber, and use the power source to provide positive pressure or utilize the negative pressure in the chip to make the first liquid phase enter the chamber of the microfluidic chip; (4) Discard the first pipette tip, then connect the second pipette tip to the power source, and use the power source to provide negative pressure to suck the second liquid phase; (5) Connect the second pipette tip that has sucked the second liquid phase to one air hole of the microfluidic chip chamber, open this air hole and another air hole, and use the power source to provide positive pressure to make the second liquid phase enter the chamber of the microfluidic chip.

2. The method for generating a vacuum and continuously filling a liquid phase inside a microfluidic chip using a pipette tip according to claim 1, characterized in that, The microfluidic chip has at least one connected chamber, and the chamber has at least two air holes and is connected to the outside atmosphere through the air holes.

3. The method for generating a vacuum and continuously filling a liquid phase inside a microfluidic chip using a pipette tip according to any one of claims 1-2, characterized in that, The air holes are in sealed connection with the first pipette tip and the second pipette tip.

4. The method for generating a vacuum and continuously filling a liquid phase inside a microfluidic chip using a pipette tip according to claim 1, characterized in that, The opening and closing of the air holes are controlled by microvalves.

5. The method for generating a vacuum and continuously filling a liquid phase inside a microfluidic chip using a pipette tip according to claim 1, characterized in that, The first liquid phase and the second liquid phase are immiscible.

6. The method for generating a vacuum and continuously filling a liquid phase inside a microfluidic chip using a pipette tip according to claim 1 or 5, characterized in that, The volumes of the first liquid phase and the second liquid phase are both not less than the volume of the microfluidic chip chamber.

7. A method for generating a vacuum and continuously filling a liquid phase inside a microfluidic chip using a pipette tip, characterized in that, The steps are as follows: (1) Connect a power source to one air hole of the microfluidic chip chamber using a first pipette tip, close the other air holes of the microfluidic chip chamber, and use the power source to provide negative pressure to exhaust the air in the microfluidic chip chamber, so that the chip chamber reaches or approaches a vacuum state; (2) Close the air hole connected to the first pipette tip of the microfluidic chip and separate the first pipette tip from the air hole of the microfluidic chip, and use the power source to provide negative pressure to make the first pipette tip suck the first liquid phase; then continuously suck the second liquid phase that is immiscible with the first liquid phase; (3) Open the air hole connected to the first pipette tip of the microfluidic chip, reconnect the first pipette tip and the air hole of the microfluidic chip chamber, and under the negative pressure of the microfluidic chip, make the second liquid phase enter the chamber of the microfluidic chip, and then use the power source to provide positive pressure to make the first liquid phase enter the chamber of the microfluidic chip.

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