A three-dimensional microfluidic system based on magnetically controlled droplet bouncing

Abstract

The present invention relates to the field of microfluidic technology, and specifically discloses a three-dimensional microfluidic system based on magnetically controlled droplet bouncing, which includes a superhydrophobic layer, a carrier, and a control device; the superhydrophobic layer has grooves; the carrier is used to be added to the droplet to be bounced to form a combination; the control device is used to attract the carrier so that the droplet overcomes the limitation of the superhydrophobic layer and enters the grooves to form a state to be bounced; the diameter of the carrier is smaller than the diameter of the grooves, and the volume of the combination is larger than the volume of the grooves, so that when in the state to be bounced, the combination can deform in the grooves to generate excess surface energy; when the control device no longer attracts the carrier, the combination jumps out along the direction perpendicular to the bottom of the grooves; the three-dimensional microfluidic system based on magnetically controlled droplet bouncing can simply realize operations such as spanning and transfer, thereby expanding the application surface of micro-droplet manipulation, improving the means of droplet transport, and enabling droplet transport to be applied in larger and more fields.

Description

Technical Field

[0001] The present invention relates to the field of microfluidic technology, and particularly to a three-dimensional microfluidic system based on magnetically controlled droplet bouncing. Background Art

[0002] The phenomenon of droplet transport is very common in nature and is also very important for our lives. Especially in the biological field, biological detection and microreactors are highly dependent on the manipulation of tiny droplets, that is, microfluidic systems. Existing open-surface droplet manipulation methods can only manipulate droplets in one-dimensional channels or on two-dimensional surfaces, and three-dimensional microfluidic systems are currently very rare. When droplets need to be manipulated three-dimensionally, for example, when a droplet moves to a structure with large undulations on the surface, this structure will limit the movement of the droplet; or when there is a need for the droplet to transfer to another surface, most transport methods cannot be achieved or the device is relatively complex. Summary of the Invention

[0003] The present invention provides a three-dimensional microfluidic system based on magnetically controlled droplet bouncing to solve the above technical problems. The solution is simple and can achieve operations such as spanning and transfer, thereby expanding the application scope of micro-droplet manipulation, improving the means of droplet transport, and enabling droplet transport to be applied in larger and more fields.

[0004] To solve the above problems, the present invention adopts the following technical solutions:

[0005] A three-dimensional microfluidic system based on magnetically controlled droplet bouncing, comprising: a superhydrophobic layer, a carrier, and a control device.

[0006] The superhydrophobic layer has grooves; the carrier has hydrophilicity.

[0007] The carrier is used to be added to the droplet to be bounced to form a combination.

[0008] The control device is used to attract the carrier in the combination, so that the droplet in the combination overcomes the limitation of the superhydrophobic layer and enters the groove to form a state to be bounced.

[0009] Wherein, the diameter of the carrier is smaller than the diameter of the groove, and the volume of the combination is larger than the volume of the groove, so that in the state to be bounced, the combination can be deformed in the groove to generate excess surface energy.

[0010] Wherein, when the control device no longer attracts the carrier in the combination, the combination jumps out along the direction perpendicular to the bottom of the groove.

[0011] In the three-dimensional microfluidic system based on magnetically controlled droplet bouncing provided by at least one embodiment of the present disclosure, the control device is located below the groove.

[0012] In the three-dimensional microfluidic system based on magnetically controlled droplet bouncing provided by at least one embodiment of the present disclosure, the control device is a device capable of applying a controllable magnetic field;

[0013] The carrier is magnetic microparticles or metal microparticles that can be magnetically adsorbed.

[0014] In the three-dimensional microfluidic system based on magnetically controlled droplet bouncing provided by at least one embodiment of the present disclosure, the width of the groove is 600 μm, the depth of the groove is 700 μm, and the average diameter of the carrier is 409 μm.

[0015] In the three-dimensional microfluidic system based on magnetically controlled droplet bouncing provided by at least one embodiment of the present disclosure, the width of the groove is 600 μm, the depth of the groove is 900 μm, and the average diameter of the carrier is 409 μm.

[0016] In the three-dimensional microfluidic system based on magnetically controlled droplet bouncing provided by at least one embodiment of the present disclosure, the width of the groove is 600 μm, the depth of the groove is 1000 μm, and the average diameter of the carrier is 409 μm.

[0017] In the three-dimensional microfluidic system based on magnetically controlled droplet bouncing provided by at least one embodiment of the present disclosure, the volume of the droplet is 0.3 - 3.0 μL.

[0018] In the three-dimensional microfluidic system based on magnetically controlled droplet bouncing provided by at least one embodiment of the present disclosure, in the state to be bounced, the central points of the carrier, the droplet, and the control device are all located on the same straight line perpendicular to the bottom of the groove.

[0019] The beneficial effects of the present invention are as follows:

[0020] 1. It can achieve the control of single-droplet bouncing. This manipulation of droplet bouncing behavior has a supplementary effect in the field of micro-droplet manipulation and can achieve out-of-plane manipulation of droplets, such as transferring substrates and crossing steps.

[0021] 2. The solution is simple. The sample to be prepared only requires a superhydrophobic surface with a specific groove structure, and then the droplet can be controlled by magnetic microparticles and a magnetic field, which has simplicity and easy operability.

[0022] 3. By using magnetic microparticles and a magnetic field, the droplet bouncing becomes controllable and can be used for droplet transportation. Description of the Drawings

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the attached drawings required for the description of the embodiments. Obviously, the attached drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other attached drawings can be obtained based on these attached drawings.

[0024] Figure 1 It is a schematic diagram of the droplet bouncing process of a three-dimensional microfluidic system based on magnetically controlled droplet bouncing according to the present invention.

[0025] Figure 2 It is a graph of the bouncing height of water droplets with different volumes in Experimental Example 1.

[0026] In the figure:

[0027] 10. Superhydrophobic layer; 11. Groove;

[0028] 20. Carrier;

[0029] 30. Control device;

[0030] 40. Droplet. Specific embodiments

[0031] The following will clearly and completely describe the technical solutions in the embodiments in conjunction with the attached drawings in the embodiments. Obviously, the described embodiments are only some embodiments, rather than all embodiments.

[0032] As Figure 1 shown, a three-dimensional microfluidic system based on magnetically controlled droplet bouncing includes: a superhydrophobic layer 10, a carrier 20, and a control device 30.

[0033] The superhydrophobic layer 10 has grooves 11, and the carrier 20 has hydrophilicity.

[0034] The carrier 20 is used to be added to the droplet 40 to be bounced to form a combination.

[0035] The control device 30 is used to attract the carrier 20 in the combination, so that the droplet 40 in the combination can overcome the limitation of the superhydrophobic layer 10 and enter the groove 11, and then form a state to be bounced.

[0036] The diameter of the carrier 20 is smaller than the diameter of the groove 11, and the volume of the combination is larger than the volume of the groove 11, so that when in the state to be bounced, the combination can be deformed in the groove 11, thereby generating excess surface energy.

[0037] When the control device 30 no longer attracts the carrier 20, the combination jumps out along the direction perpendicular to the bottom of the groove 11.

[0038] In this embodiment, the control device 30 is located below the groove 11.

[0039] In this embodiment, in the waiting-to-bounce state, the center points of the carrier 20, the droplet, and the control device 30 are all located on the same straight line perpendicular to the bottom of the groove 11.

[0040] Exemplarily, the control device 30 is a device capable of applying a controllable magnetic field; the carrier 20 is a magnetic particle or a metal particle that can be magnetically adsorbed.

[0041] In some embodiments, the width of the groove 11 is 600 μm, the depth of the groove 11 is 700 μm, the average diameter of the carrier 20 is 409 μm, and the volume of the droplet 40 is 0.3 μL.

[0042] In some embodiments, the width of the groove 11 is 600 μm, the depth of the groove 11 is 900 μm, the average diameter of the carrier 20 is 409 μm, and the volume of the droplet 40 is 3.0 μL.

[0043] In some embodiments, the width of the groove 11 is 600 μm, the depth of the groove 11 is 1000 μm, the average diameter of the carrier 20 is 409 μm, and the volume of the droplet 40 is 2 μL.

[0044] The principle of the three-dimensional microfluidic system based on magnetically controlled droplet bouncing is as follows:

[0045] The diameter of the carrier 20 is smaller than the diameter of the groove 11, so the carrier 20 can move within the groove 11. Since the superhydrophobic layer 10 has superhydrophobicity and the carrier 20 has hydrophilicity; when the control device 30 is used to generate a magnetic field to attract the carrier 20 to the bottom of the groove 11, the droplet is deformed by the force. Therefore, the position of the carrier 20 in the groove 11 can be controlled by the magnetic field to change the shape of the droplet, so that the droplet 40 in the combination can overcome the limitation of the superhydrophobic layer 10.

[0046] The volume of the combination is larger than the volume of the groove 11. When the combination enters the groove, the droplet is deformed, thereby generating excess surface energy. Analyzed from the perspective of energy, the energy required for jumping is all provided by this excess surface energy. Under the action of the magnetic field, the combination is first attracted by the magnetic force into the groove, and then maintains a steady state. At this time, the deformation of the droplet generates excess surface energy; when the magnetic field disappears, the magnetic force disappears accordingly, and the magnetic particles are pulled upward by the capillary force they receive. At this time, due to the different curvature radii of the upper and lower parts of the droplet, there is a Laplace pressure difference inside, which causes the lower fluid to flow upward, and the droplet will also move upward. Therefore, the entire combination will jump out of the groove along the direction perpendicular to the bottom of the groove.

[0047] The three-dimensional microfluidic system based on magnetically controlled droplet bouncing in the embodiment will be further described below according to experiments.

[0048] Experimental Example 1:

[0049] 1) Prepare a superhydrophobic sample with a rectangular groove 600 μm wide and 700 μm deep as the experimental substrate. Place the substrate on the placement table, and use a pipette to aspirate 0.3 μL of the droplet and place it on the rectangular groove;

[0050] 2) Use tweezers to pick up the magnetic particles and then place them into the droplet in step 1); the magnetic particles are iron balls with an average diameter of 409 μm;

[0051] 3) Place an electromagnet on the lower surface of the placement table, and adjust the position of the substrate so that the centers of the magnetic particles, the droplet, and the electromagnet are on the same vertical line;

[0052] 4) Modulate the period of the electromagnet to 1 Hz, where the high level of the input voltage is 22.5 V and the low level is 0 V;

[0053] 5) After preparing the above steps, the experiment can be started. Start the electromagnet, and the magnetic particles enter the groove under the action of the magnetic force, and the droplet deforms under the action of capillary action; when the electromagnet is turned off, the magnetic field disappears and the droplet bounces.

[0054] 6) Use a camera to record the bouncing process, analyze the collected droplet bouncing process, obtain the position information of the droplet and calculate it to obtain the droplet bouncing height data;

[0055] 7) Remove the droplet on the superhydrophobic sample, take out the magnetic particles, and blow the substrate clean with an ear bulb;

[0056] 8) Repeat steps 1) and 6), and gradually increase the water droplet volume from 0.3 μL to 3.0 μL for multiple tests, and summarize the results.

[0057] Among them, the data summary results are shown in the following table:

[0058] Table of Bouncing Heights of Different Water Droplet Volumes

[0059]

[0060] It can be seen from Figure 2 that as the droplet volume gradually increases, the bouncing height of the droplet first increases and then decreases, proving that on the superhydrophobic sample with a rectangular groove 600 μm wide and 700 μm deep, the droplet bouncing can be realized and its triggering control can be carried out by using this method.

[0061] Experimental Example 2:

[0062] 1) Prepare a superhydrophobic sample with rectangular grooves that are 600 μm wide and 700 μm deep as the substrate for the experiment. Place the substrate on the placement table, and use a pipette to aspirate 2 μL of the droplet and place it on the rectangular grooves;

[0063] 2) Use tweezers to pick up the magnetic particles and then place them into the droplet in step 1); the magnetic particles are iron balls with an average diameter of 409 μm;

[0064] 3) Place an electromagnet on the lower surface of the placement table, and adjust the position of the substrate so that the centers of the magnetic particles, the droplet, and the electromagnet are on the same vertical line;

[0065] 4) Modulate the period of the electromagnet to 1 Hz, where the high level of the input voltage is 22.5 V and the low level is 0 V;

[0066] 5) After preparing the above steps, the experiment can be started. Start the electromagnet, the magnetic particles are attracted by the magnetic force and enter the grooves, and the droplet deforms due to capillary action; when the electromagnet is turned off, the magnetic field disappears and the droplet bounces.

[0067] 6) Use a camera to record the bouncing process, analyze the collected bouncing process of the droplet, obtain the position information of the droplet and calculate it to obtain the droplet bouncing height data.

[0068] Experimental Example 3:

[0069] 1) Prepare a superhydrophobic sample with rectangular grooves that are 600 μm wide and 1000 μm deep as the experimental substrate. Place the experimental substrate on the placement table, and use a pipette to aspirate 2 μL of the droplet and place it on the rectangular grooves;

[0070] 2) Use tweezers to pick up the magnetic particles and then place them into the droplet in step 1); the magnetic particles are iron balls with an average diameter of 409 μm;

[0071] 3) Place an electromagnet on the lower surface of the placement table, and adjust the position of the experimental substrate so that the centers of the magnetic particles, the droplet, and the electromagnet are on the same vertical line;

[0072] 4) Place another glass substrate 2.5 cm above the experimental substrate;

[0073] 5) Modulate the period of the electromagnet to 1 Hz, where the high level of the input voltage is 22.5 V and the low level is 0 V;

[0074] 6) After preparing the above steps, the experiment can be started. Start the electromagnet, the magnetic particles are attracted by the magnetic force and enter the grooves, and the droplet deforms due to capillary action; when the electromagnet is turned off, the magnetic field disappears and the droplet bounces;

[0075] 7) The droplet bounces and touches the glass substrate, staying on the upper glass substrate.

[0076] Although the embodiments of the present application have been shown and described above, the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be thought of without creative efforts should be covered within the protection scope of the present invention; unless expressly stated, any element, action, or instruction used herein should not be construed as critical or essential.

Claims

1. A three-dimensional microfluidic system based on magnetically controlled droplet bouncing, characterized in that, Comprising: A superhydrophobic layer with grooves; A carrier, which is hydrophilic and is used to be added to the droplet to be bounced to form a combination; And A control device, which is used to attract the carrier in the combination, so that the droplet in the combination overcomes the limitation of the superhydrophobic layer and enters the groove to form a state to be bounced; Wherein, the diameter of the carrier is smaller than the diameter of the groove, and the volume of the combination is larger than the volume of the groove, so that when in the state to be bounced, the combination can be deformed in the groove to generate excess surface energy; Wherein, when the control device no longer attracts the carrier in the combination, the combination jumps out along the direction perpendicular to the bottom of the groove; The control device is located below the groove; When in the state to be bounced, the central points of the carrier, the droplet and the control device are all on the same straight line perpendicular to the bottom of the groove.

2. The three-dimensional microfluidic system based on magnetically controlled droplet bouncing according to claim 1, wherein The control device is a device that can apply a controllable magnetic field; The carrier is magnetic particles or metal particles that can be magnetically adsorbed.

3. A three-dimensional microfluidic system based on magnetically controlled droplet bouncing according to claim 1, characterized in that, The width of the groove is 600μm, the depth of the groove is 700μm, and the average diameter of the carrier is 409μm.

4. A three-dimensional microfluidic system based on magnetically controlled droplet bouncing according to claim 1, wherein The width of the groove is 600μm, the depth of the groove is 900μm, and the average diameter of the carrier is 409μm.

5. A three-dimensional microfluidic system based on magnetically controlled droplet bouncing according to claim 1, characterized in that, The width of the groove is 600μm, the depth of the groove is 1000μm, and the average diameter of the carrier is 409μm.

6. A three-dimensional microfluidic system based on magnetically controlled droplet bouncing according to any one of claims 2-5, characterized in that The volume of the droplet is 0.3 - 3.0μL.

Images