A non-invasive on-chip droplet segmentation magnetron chip

Abstract

This invention provides a non-invasive on-chip droplet segmentation magnetron splicing chip, relating to the field of microfluidic chips. The non-invasive on-chip droplet segmentation magnetron splicing chip provided by this invention includes a top chip, a permanent magnet layer, and a bottom chip sequentially packaged. The top of the top chip is provided with a clamp-shaped liquid separation opening. The clamp-shaped liquid separation opening includes a main channel and multiple clamp-shaped flow channels. Each clamp-shaped flow channel is located on the same side of the main channel and is sequentially arranged along the extension direction of the main channel. The clamp-shaped flow channels include a horizontal flow channel and an oblique flow channel connected in sequence. The extension direction of the horizontal flow channel is consistent with the extension direction of the main channel, while the extension direction of the oblique flow channel deviates outward from the extension direction of the main channel. This invention eliminates the need for magnetic additives. Using oil-based ferrofluid to transport sample droplets and performing liquid separation through clamp-shaped flow channels not only simplifies the preparation process but also eliminates the need to magnetize the sample, preventing contamination of the sample droplets.

Description

Technical Field

[0001] This invention relates to the field of microfluidic chips, and in particular to a non-invasive on-chip droplet segmentation magnetocontrol chip. Background Technology

[0002] Microfluidic chips are integrated chip platforms used to manipulate, analyze, and process tiny fluid samples. Their greatest advantage is the ability to precisely control liquid flow at the micrometer scale, enabling small-volume mixing, reactions, and separation. They are currently widely used in drug toxicity analysis, water quality testing, and food safety monitoring, offering advantages such as small reaction volumes, low reagent requirements, automation, and fast reaction speeds. Driving droplets using magnetic forces is a very common droplet-driving method. This typically involves adding nano-magnetic particles within the sample droplet to respond to permanent magnets or electromagnets beneath the chip structure, achieving droplet movement, splitting, and fusion. This has significant implications for biological experiments and drug research.

[0003] However, traditional invasive magnetically controlled chips require the addition of extra magnetic particles inside the sample droplet, which can contaminate the droplet to some extent and may alter the properties of certain droplets or reagents, reducing the reliability of experimental results. Furthermore, the necessary internal addition of extra materials for invasive magnetic actuation limits the types of samples that can be actuated.

[0004] The "non-invasive" magnetron chip, as a novel type of magnetically driven microfluidic chip, eliminates the need to add additional magnetic particles inside the droplet sample, thus avoiding contamination of the sample droplet and simplifying the experimental procedure.

[0005] Currently available "non-invasive" magnetic actuation methods include ferrofluid encapsulation, charge response, and deformable magnet grippers. For charge response, the sample needs to carry a certain amount of charge and dielectric constant to respond to the controllable electrode above. The fabrication of the electrode is a challenge, and it is impossible to manipulate solid samples. For deformable magnet grippers, magnetic actuation is very complex, and grippers with different structures need to be fabricated for samples of different sizes.

[0006] Therefore, this invention employs a ferrofluid encapsulation method. Compared to the other two methods, ferrofluid is simple to manufacture, recyclable, and highly reusable, and can be adapted to various sample types. Furthermore, this invention proposes a liquid separation structure that combines ferrofluid and permanent magnets to perform droplet segmentation, constructing a non-invasive on-chip droplet segmentation magnetic control chip. Summary of the Invention

[0007] To address the aforementioned issues, this invention provides a non-invasive on-chip droplet segmentation magnetron sputtering chip. This invention eliminates the need for magnetic additives, using oil-based ferrofluids to transport sample droplets and separate them via clamp-shaped channels. This simplifies the preparation process and eliminates the need to magnetize the sample, preventing contamination of the sample droplets.

[0008] The present invention provides a non-invasive on-chip droplet segmentation magnetron sputtering chip, comprising a top chip, a permanent magnet layer, and a bottom chip sequentially packaged. The permanent magnet layer is a permanent magnet, and the bottom chip is a permanent magnet drive unit. The permanent magnet is connected to the drive shaft of the permanent magnet drive unit. The top of the top chip is provided with a clamp-shaped liquid-separating groove for loading oil-based ferrofluid and sample droplets. The clamp-shaped liquid-separating groove includes a main channel and multiple clamp-shaped channels. Each clamp-shaped channel is located on the same side of the main channel and is arranged sequentially along the extension direction of the main channel. Each clamp-shaped channel is connected to the main channel. The clamp-shaped channel includes a horizontal channel and an oblique channel connected sequentially. The extension direction of the horizontal channel is consistent with the extension direction of the main channel, and the extension direction of the oblique channel deviates outward from the extension direction of the main channel.

[0009] In some feasible embodiments of the present invention, the depth of the clamp-shaped liquid separation groove is 0.3–2 mm; and / or, the straight-line distance between the bottom of the upper chip and the bottom of the clamp-shaped liquid separation groove is 0.3–1.5 mm; and / or, the length of the inclined channel is 2–8 mm; and / or, the width of the inclined channel is 0.9–3 mm; and / or, the volume of the oil-based ferrofluid is 5–15 μL; and / or, the magnetic field strength of the permanent magnet is 1800 GS–2200 GS.

[0010] In one feasible embodiment of the present invention, the number of clamp-shaped flow channels is 3 to 5.

[0011] In one feasible embodiment of the present invention, the material of the upper layer of the chip is polymethyl methacrylate.

[0012] In one feasible embodiment of the present invention, the oil-based ferromagnetic fluid is obtained by a method for preparing oil-based ferromagnetic fluid, the method comprising the following steps:

[0013] Step 1): Add mineral oil and oil-based ferrofluid;

[0014] Step 2): Mix the mineral oil and oil-based ferrofluid to obtain a homogenized oil-based ferrofluid.

[0015] In one feasible embodiment of the present invention, step 1) of the method for preparing the oil-based ferromagnetic fluid further includes:

[0016] Step 1-1) Use a pipette to draw up mineral oil and add it dropwise into a centrifuge tube:

[0017] Steps 1-2) Replace the pipette tip to draw up EMG-based oil-based ferrofluid and add it dropwise into a centrifuge tube.

[0018] In one feasible embodiment of the present invention, step 2) of the method for preparing the oil-based ferromagnetic fluid further includes:

[0019] Step 2-1) Mix the mineral oil and oil-based ferrofluid in a centrifuge tube;

[0020] Step 2-2) Place the centrifuge tube on an adjustable mixer and vibrate to mix, obtaining the mixed oil-based ferrofluid.

[0021] In one feasible embodiment of the present invention, the preparation method of the oil-based ferrofluid includes the following steps:

[0022] Step 1) Add nμL of mineral oil and mμL of oil-based ferromagnetic fluid; and the volume of the oil-based ferromagnetic fluid after mixing is n+mμL, and the concentration of the oil-based ferromagnetic fluid after mixing is n / (m+n)*100%, 4≤n+m≤12;

[0023] Step 2) Mix the mineral oil and oil-based ferrofluid for x minutes to obtain the mixed oil-based ferrofluid; 0.5 mins ≤ x ≤ 10 mins;

[0024] In addition, the components of the mixed oil-based ferrofluid, by volume, include the following:

[0025] Mineral oil: 30%–96%;

[0026] Oil-based ferrofluids: 4%–70%.

[0027] In one feasible embodiment of the present invention, a host computer is also included, which is connected to the permanent magnet drive unit via an optical fiber; the host computer includes a drive module, which is used to drive the movement of the permanent magnet drive unit.

[0028] This invention also provides a method for using a non-invasive on-chip droplet segmentation magnetron sputtering chip, comprising the following steps:

[0029] Step S1): Pour oil-based ferromagnetic fluid and sample droplets into the clamp-shaped separatory groove;

[0030] Step S2): The permanent magnet drive unit drives the permanent magnet to move from one end of the main channel to the other end and generates a magnetic potential trap. The sample droplet wrapped in oil-based ferrofluid is driven by the magnetic potential trap and moves along the clamp-shaped flow channel.

[0031] Step S3): After the sample droplet moves to the end of the horizontal flow channel, it forcibly crosses the end of the horizontal flow channel and enters the main flow channel. When it crosses the end of the horizontal flow channel, the sample droplet is split into sub-droplets, which move into the oblique flow channel.

[0032] The non-invasive on-chip droplet segmentation magnetron sputtering chip provided by this invention has the following beneficial effects:

[0033] 1) This invention does not require the addition of magnetic additives. Using oil-based ferrofluid to transport sample droplets and separating them through clamp-shaped channels not only simplifies the preparation process but also eliminates the need to magnetize the sample, thus preventing contamination of the sample droplets.

[0034] 2) The present invention has a high degree of automation. It uses a drive module to control the permanent magnet displacement stage and drive the permanent magnet. The oil-based ferrofluid drives the sample droplets by responding to the magnetic field force generated by the permanent magnet, and the liquid separation operation is completed in a fully automated manner.

[0035] 3) The present invention is highly flexible, and the liquid separation structure and subsequent reaction system can be integrated on the chip to realize functions such as drug sensitivity detection and drug screening.

[0036] 4) This invention has the potential to drive solid samples. Since no magnetic additives are needed, instead, oil-based ferrofluid is used for encapsulation and driving. This "non-invasive" driving method allows for more potential possibilities for the types of samples to be driven, and may even drive solid samples.

[0037] 5) The “non-invasive” magnetically controlled droplet segmentation chip adopted in this invention can realize fully automatic movement and segmentation of the target solution, with high dilution accuracy and no potential cross-contamination during the reaction process. It can be applied to drug screening, cell analysis and other scenarios, with a wide range of applications. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0039] Figure 2 This is a side view of the overall structure of the present invention.

[0040] Figure 3 This is a schematic diagram of the clamp-shaped liquid separation groove in this invention.

[0041] Figure 4 This is a front view of the clamp-shaped liquid separation groove in this invention.

[0042] Figure 5 This is the preparation process of the oil-based ferrofluid in this invention.

[0043] Figure 6 This is a schematic diagram of the oil-based ferrofluid driving the movement of sample droplets and being separated by a clamp-shaped flow channel in this invention.

[0044] Reference numerals

[0045] Upper-layer chip 1

[0046] Permanent magnet layer 2

[0047] Lower-level chip 3

[0048] Clamp-shaped separator 4

[0049] Mainstream Road 41

[0050] Pincer-shaped flow channel 42

[0051] Horizontal flow channel 42.1

[0052] 42.2 oblique flow channel Detailed Implementation

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. In the description of the present invention, it should be noted that the terms "left side", "right side", "upper side", "lower side", "above", "below", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying 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, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0054] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0055] Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0056] Before detailing the embodiments of the present invention, let's first describe oil-based ferrofluids: Oil-based ferrofluids are stable colloidal dispersion systems composed of magnetic nanoparticles (usually iron oxide) dispersed in an oily carrier liquid (such as silicone oil, kerosene, etc.). When an external magnetic field is applied, the nanoparticles in the ferrofluid align along the direction of the magnetic field, causing the fluid to exhibit macroscopic magnetism. The use of oil-based ferrofluids to drive aqueous droplets is mainly based on the following principles:

[0057] Magnetic gradient force: In a non-uniform magnetic field, ferrofluids experience a magnetic gradient force, which points in the direction of increasing magnetic field strength. The magnitude of this force depends on factors such as magnetic field strength, magnetic field gradient, and the magnetic susceptibility of the ferrofluid. By designing a specific magnetic field distribution, precise manipulation of ferrofluids can be achieved, thereby driving water droplets in contact with them.

[0058] Interfacial tension and the Marangoni effect: Interfacial tension exists between aqueous droplets and oil-based ferrofluids. When a magnetic field is applied to a ferrofluid, it may cause a change in the surface tension gradient within the ferrofluid or at the interface, thus triggering the Marangoni effect. The Marangoni effect refers to the fluid flow phenomenon caused by the surface tension gradient. This flow can effectively drive the movement of aqueous droplets. For example, a magnetic field may cause a local temperature increase in the ferrofluid, thereby reducing its surface tension and generating a Marangoni flow that drives the droplets.

[0059] This invention provides a non-invasive on-chip droplet segmentation magnetron chip, see reference. Figure 1 and Figure 2 The magnetically controlled chip includes an upper chip 1, a permanent magnet layer 2, and a lower chip 3, sequentially packaged. The permanent magnet layer 2 is a permanent magnet, and the lower chip 3 is a permanent magnet drive. The permanent magnet is connected to the drive shaft of the permanent magnet drive. Typically, the permanent magnet is close to the bottom of the upper chip 1. The permanent magnet drive can be a dual-axis displacement stage, which allows the permanent magnet to move along the length and width of the upper chip 1. The model of the permanent magnet drive can be the Dediwei DXH4-50L-XY high-precision electric dual-axis displacement stage. As a supplementary note, the material of the upper layer of the chip is PMMA (polymethyl methacrylate). (Continue reading...) Figure 3 The top of the upper chip 1 is provided with a clamp-shaped liquid distribution groove 4, which is used to load oil-based ferromagnetic fluid and sample droplets. The clamp-shaped liquid distribution groove 4 includes a main channel 41 and multiple clamp-shaped flow channels 42. The main channel 41 is typically rectangular in shape, with a length of 0.9–1.8 mm and a width of 2–4 mm. All clamp-shaped flow channels 42 are located on the same side of the main channel 41 and are arranged sequentially along the extension direction of the main channel 41. Each clamp-shaped flow channel 42 is connected to the main channel 41. (Continue reading) Figure 3The clamp-shaped flow channel 42 includes a horizontal flow channel 42.1 and an oblique flow channel 42.2 connected in sequence. The extension direction of the horizontal flow channel 42.1 is consistent with the extension direction of the main flow channel 41, while the extension direction of the oblique flow channel 42.2 deviates outward from the extension direction of the main flow channel 41. In a specific embodiment, the number of clamp-shaped flow channels 42 is 3 to 5, preferably 3.

[0060] In the non-invasive on-chip droplet segmentation magnetron sputtering chip provided in this embodiment of the invention, the depth of the clamp-shaped liquid-splitting groove 4 is 0.3–2 mm; and / or, the straight-line distance between the bottom of the upper chip 1 and the bottom of the clamp-shaped liquid-splitting groove 4 is 0.3–1.5 mm; and / or, the length of the inclined channel 42.2 is 2–8 mm; and / or, the width of the inclined channel 42.2 is 0.9–3 mm; and / or, the volume of the oil-based ferrofluid is 5–15 μL; and / or, the magnetic field strength of the permanent magnet is 1800 GS–2200 GS.

[0061] The non-invasive on-chip droplet segmentation magnetocontrol chip provided in this embodiment of the invention also includes a host computer, which is connected to the permanent magnet drive unit via an optical fiber. The host computer includes a drive module, which is used to drive the movement of the permanent magnet drive unit. For illustrative purposes, the drive module can be programmed using a Raspberry Pi; the specific control program is a common practice in the art and will not be described in detail here.

[0062] This invention also provides a method for using a non-invasive on-chip droplet segmentation magnetron sputtering chip, comprising the following steps:

[0063] Step S1): Pour oil-based ferromagnetic fluid and sample droplets into the clamp-shaped separatory groove 4; for illustration, the sample droplets are usually aqueous sample droplets;

[0064] Step S2): The permanent magnet drive unit moves the permanent magnet from one end of the main flow channel 41 to the other end, generating a magnetic potential trap. The sample droplet, encapsulated by the oil-based ferrofluid, is driven by the magnetic potential trap and moves along the clamp-shaped flow channel 42. The trajectory of the sample droplet can be found in [reference needed]. Figure 1 The key point is that the sample droplets must always move in close contact with the side wall of the clamp-shaped liquid separation groove 4.

[0065] Step S3): After the sample droplet moves to the end of the horizontal flow channel 42.1, it forcibly crosses the end of the horizontal flow channel 42.1 and enters the main flow channel 41. When crossing the end of the horizontal flow channel 42.1, the sample droplet is split into sub-droplets, which move into the oblique flow channel 42.2. For illustration, the volume of the split sub-droplets is related to the size of the clamp-shaped flow channel 42, which can be found in Example 3.

[0066] Example 1

[0067] In the non-invasive on-chip droplet segmentation magnetron sputtering chip provided in this embodiment of the invention, the oil-based ferrofluid is obtained by a method for preparing oil-based ferrofluids, see reference. Figure 5 The preparation method of the oil-based ferrofluid includes the following steps:

[0068] Step 1): Add mineral oil and oil-based ferrofluid;

[0069] Alternatively, step 1) may also include:

[0070] Step 1-1) Use a pipette to draw up mineral oil and add it dropwise into a centrifuge tube:

[0071] Steps 1-2) Replace the pipette tip to draw up EMG-based oil-based ferrofluid and add it dropwise into a centrifuge tube.

[0072] Step 2): Mix the mineral oil and oil-based ferrofluid to obtain a homogenized oil-based ferrofluid.

[0073] Alternatively, step 2) may also include:

[0074] Step 2-1) Mix the mineral oil and oil-based ferrofluid in a centrifuge tube;

[0075] Step 2-2) Place the centrifuge tube on an adjustable mixer and vibrate to mix, obtaining the mixed oil-based ferrofluid.

[0076] In the preparation method of oil-based ferromagnetic fluid provided in this embodiment of the invention, step 1) can be: adding n μL of mineral oil and m μL of oil-based ferromagnetic fluid; and the volume of the mixed oil-based ferromagnetic fluid is n + m μL, the concentration of the mixed oil-based ferromagnetic fluid is n / (m + n)*100%, and 4 ≤ n + m ≤ 12.

[0077] In addition, the components of the mixed oil-based ferrofluid, by volume, include the following:

[0078] Mineral oil: 30%–96%;

[0079] Oil-based ferrofluids: 4%–70%.

[0080] Example 3

[0081] In this embodiment, the sample droplet is a phosphate buffer solution, and there are three clamp-shaped flow channels 42. By inputting a command to the biaxial displacement stage, it manipulates the permanent magnet to form a magnetic potential trap on the surface of the oil-based ferrofluid, driving the sample droplet to continuously separate through the three clamp-shaped flow channels 42 of the same size. The initial volume of the droplet sample is 20 μL, and the volume of the oil-based ferrofluid in the clamp-shaped separation groove 4 is 80 μL.

[0082] The parameters of each feature in the clamp-shaped flow channel 42 are detailed in Table 1 and... Figure 4 The parameters of various characteristics of oil-based ferrofluids are detailed in Table 2.

[0083] Table 1

[0084]

[0085] Table 2

[0086]

[0087]

[0088] The process of separating a sample droplet into sub-droplets is described below, and the process diagram is shown below. Figure 6 As shown:

[0089] 1) Initial state: The sample droplets to be separated are placed at the leftmost end of the clamp-shaped separation groove 4.

[0090] 2) The dual-axis displacement stage controls the permanent magnet to move laterally, generating a magnetic potential trap. The sample droplet, which is wrapped in oil-based ferrofluid, is driven by the magnetic potential trap and moves toward the right end of the clamp-shaped liquid separation groove 4. When it passes through the first clamp-shaped flow channel 42, the first sub-droplet is separated.

[0091] 3) The dual-axis displacement stage controls the permanent magnet to continue to move laterally, generating a magnetic potential trap. The sample droplet wrapped by the oil-based ferrofluid is driven by the magnetic potential trap and moves towards the right end of the clamp-shaped liquid separation groove 4. When passing through the second clamp-shaped flow channel 42, the second sub-droplet is separated.

[0092] 4) The dual-axis displacement stage controls the permanent magnet to continue to move laterally, generating a magnetic potential trap. The sample droplet wrapped by the oil-based ferrofluid is driven by the magnetic potential trap and moves towards the right end of the clamp-shaped liquid separation groove 4. When it passes through the third clamp-shaped flow channel 42, the third sub-droplet is separated, realizing three consecutive liquid separation operations.

[0093] Example 4

[0094] In this embodiment, the sample droplet is a phosphate buffer solution, and there are three clamp-shaped channels 42. By inputting a command to the biaxial displacement stage, it manipulates the permanent magnet to form a magnetic potential trap on the surface of the oil-based ferrofluid, driving the sample droplet to continuously separate through the three clamp-shaped channels 42 of the same size. The initial volume of the droplet sample is 30 μL, and the volume of the oil-based ferrofluid in the clamp-shaped separation groove 4 is 10 μL.

[0095] The parameters of each feature in the clamp-shaped flow channel 42 are detailed in Table 3 and... Figure 4 The parameters of various characteristics of oil-based ferrofluids can be found in Table 4.

[0096] Table 3

[0097]

[0098] Table 4

[0099]

[0100] The process of separating a sample droplet into sub-droplets is described below, and the process diagram is shown below. Figure 6 As shown:

[0101] 1) Initial state: The sample droplets to be separated are placed at the leftmost end of the clamp-shaped separation groove 4.

[0102] 2) The dual-axis displacement stage controls the permanent magnet to move laterally, generating a magnetic potential trap. The sample droplet, which is wrapped in oil-based ferrofluid, is driven by the magnetic potential trap and moves toward the right end of the clamp-shaped liquid separation groove 4. When it passes through the first clamp-shaped flow channel 42, the first sub-droplet is separated.

[0103] 3) The dual-axis displacement stage controls the permanent magnet to continue to move laterally, generating a magnetic potential trap. The sample droplet wrapped by the oil-based ferrofluid is driven by the magnetic potential trap and moves towards the right end of the clamp-shaped liquid separation groove 4. When passing through the second clamp-shaped flow channel 42, the second sub-droplet is separated.

[0104] 4) The dual-axis displacement stage controls the permanent magnet to continue to move laterally, generating a magnetic potential trap. The sample droplet wrapped by the oil-based ferrofluid is driven by the magnetic potential trap and moves towards the right end of the clamp-shaped liquid separation groove 4. When it passes through the third clamp-shaped flow channel 42, the third sub-droplet is separated, realizing three consecutive liquid separation operations.

[0105] Example 5

[0106] In this embodiment, the sample droplet is a phosphate buffer solution, and there are three clamp-shaped flow channels 42. By inputting a command to the biaxial displacement stage, it manipulates the permanent magnet to form a magnetic potential trap on the surface of the oil-based ferrofluid, driving the sample droplet to continuously separate through the three clamp-shaped flow channels 42 of the same size. The initial volume of the droplet sample is 20 μL, and the volume of the oil-based ferrofluid in the clamp-shaped separation groove 4 is 8 μL.

[0107] The parameters of various features in the clamp-shaped flow channel 42 are detailed in Table 5 and... Figure 4 The parameters of various characteristics of oil-based ferrofluids are detailed in Table 6.

[0108] Table 5

[0109]

[0110]

[0111] Table 6

[0112]

[0113] The process of separating a sample droplet into sub-droplets is described below, and the process diagram is shown below. Figure 6 As shown:

[0114] 1) Initial state: The sample droplets to be separated are placed at the leftmost end of the clamp-shaped separation groove 4.

[0115] 2) The dual-axis displacement stage controls the permanent magnet to move laterally, generating a magnetic potential trap. The sample droplet, which is wrapped in oil-based ferrofluid, is driven by the magnetic potential trap and moves toward the right end of the clamp-shaped liquid separation groove 4. When it passes through the first clamp-shaped flow channel 42, the first sub-droplet is separated.

[0116] 3) The dual-axis displacement stage controls the permanent magnet to continue to move laterally, generating a magnetic potential trap. The sample droplet wrapped by the oil-based ferrofluid is driven by the magnetic potential trap and moves towards the right end of the clamp-shaped liquid separation groove 4. When passing through the second clamp-shaped flow channel 42, the second sub-droplet is separated.

[0117] 4) The dual-axis displacement stage controls the permanent magnet to continue to move laterally, generating a magnetic potential trap. The sample droplet wrapped by the oil-based ferrofluid is driven by the magnetic potential trap and moves towards the right end of the clamp-shaped liquid separation groove 4. When it passes through the third clamp-shaped flow channel 42, the third sub-droplet is separated, realizing three consecutive liquid separation operations.

[0118] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A non-invasive on-chip droplet segmentation magnetron sputtering chip, characterized in that: The magnetic control chip includes an upper chip (1), a permanent magnet layer (2), and a lower chip (3) that are sequentially packaged; the permanent magnet layer (2) is a permanent magnet, the lower chip (3) is a permanent magnet drive, and the permanent magnet is connected to the drive shaft of the permanent magnet drive. The top of the upper chip (1) is provided with a clamp-shaped liquid dispensing groove (4), which is used to load oil-based ferromagnetic fluid and sample droplets; the clamp-shaped liquid dispensing groove (4) includes a main channel (41) and multiple clamp-shaped flow channels (42); each clamp-shaped flow channel (42) is located on the same side of the main channel (41) and is arranged sequentially along the extension direction of the main channel (41); each clamp-shaped flow channel (42) is connected to the main channel (41); The clamp-shaped flow channel (42) includes a horizontal flow channel (42.1) and an oblique flow channel (42.2) connected in sequence; the extension direction of the horizontal flow channel (42.1) is consistent with the extension direction of the main flow channel (41), and the extension direction of the oblique flow channel (42.2) deviates outward from the extension direction of the main flow channel (41).

2. The non-invasive on-chip droplet segmentation magnetron chip according to claim 1, characterized in that: The depth of the clamp-shaped liquid separation groove (4) is 0.3 to 2 mm; and / or, the straight-line distance between the bottom of the upper chip (1) and the bottom of the clamp-shaped liquid separation groove (4) is 0.3 to 1.5 mm; and / or, the length of the inclined channel (42.2) is 2 to 8 mm; and / or, the width of the inclined channel (42.2) is 0.9 to 3 mm; and / or, the volume of the oil-based ferrofluid is 5 to 15 μL; and / or, the magnetic field strength of the permanent magnet is 1800 GS to 2200 GS.

3. The non-invasive on-chip droplet segmentation magnetron chip according to claim 1, characterized in that: The number of the clamp-shaped flow channels (42) is 3 to 5.

4. The non-invasive on-chip droplet segmentation magnetron chip according to claim 1, characterized in that: The material of the upper chip (1) is polymethyl methacrylate.

5. The non-invasive on-chip droplet segmentation magnetron chip according to claim 1, characterized in that, The oil-based ferromagnetic fluid is obtained by a method for preparing oil-based ferromagnetic fluids, which includes the following steps: Step 1): Add mineral oil and oil-based ferrofluid; Step 2): Mix the mineral oil and oil-based ferrofluid to obtain a homogenized oil-based ferrofluid.

6. The non-invasive on-chip droplet segmentation magnetron chip according to claim 5, characterized in that, Step 1) also includes: Step 1-1) Use a pipette to draw up mineral oil and add it dropwise into a centrifuge tube: Steps 1-2) Replace the pipette tip to draw up EMG-based oil-based ferrofluid and add it dropwise into a centrifuge tube.

7. The non-invasive on-chip droplet segmentation magnetron chip according to claim 5, characterized in that, Step 2) also includes: Step 2-1) Mix the mineral oil and oil-based ferrofluid in a centrifuge tube; Step 2-2) Place the centrifuge tube on an adjustable mixer and vibrate to mix, obtaining the mixed oil-based ferrofluid.

8. The non-invasive on-chip droplet segmentation magnetron chip according to any one of claims 5 to 7, characterized in that, The preparation method of the oil-based ferrofluid includes the following steps: Step 1) Add n μL of mineral oil and m μL of oil-based ferromagnetic fluid; and the volume of the oil-based ferromagnetic fluid after mixing is n+mμL, and the concentration of the oil-based ferromagnetic fluid after mixing is n / (m+n)*100%, 4≤n+m≤12; Step 2) Mix the mineral oil and oil-based ferrofluid for x minutes to obtain the mixed oil-based ferrofluid; 0.5 mins ≤ x ≤ 10 mins; In addition, the components of the mixed oil-based ferrofluid, by volume, include the following: Mineral oil: 30%–96%; Oil-based ferrofluids: 4%–70%.

9. The non-invasive on-chip droplet segmentation magnetron chip according to claim 1, characterized in that: It also includes a host computer, which is connected to the permanent magnet drive unit via optical fiber; the host computer contains a drive module, which is used to drive the movement of the permanent magnet drive unit.

10. The method of using the non-invasive on-chip droplet segmentation magnetron sputtering chip as described in any one of claims 1 to 9, characterized in that, It includes the following steps: Step S1): Pour oil-based ferromagnetic fluid and sample droplets into the clamp-shaped separatory groove (4); Step S2): The permanent magnet drive unit drives the permanent magnet to move from one end of the main channel (41) to the other end and generates a magnetic potential trap. The sample droplet wrapped in oil-based ferrofluid is driven by the magnetic potential trap and moves along the clamp-shaped flow channel (42). Step S3): After the sample droplet moves to the end of the horizontal channel (42.1), it forcibly crosses the end of the horizontal channel (42.1) and enters the main channel (41). When it crosses the end of the horizontal channel (42.1), the sample droplet is divided into sub-droplets, which move to the oblique channel (42.2).

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