An open fluidic chip preparation device and method based on air flow cutting

Abstract

The application discloses an open fluid chip preparation device and method based on airflow cutting, and belongs to the technical field of microfluidics. The device comprises an air source supply module, an airflow control module, a cutting execution module, a motion and positioning module and a terminal control module. The method comprises the following steps: placing a prepared wrinkle liquid cake on the motion and positioning module, adjusting and controlling the airflow control module so that the gas flow sprayed by the cutting execution module is suitable for the current liquid cake state; converting a planar pattern of a target fluid chip into G code and inputting the G code into a control computer; running the G code through the control computer to drive the motion and positioning module to move the cutting execution module according to a preset path, airflow cutting is performed on the wrinkle liquid cake to shape the open fluid chip. The application first uses high-speed airflow as a shaping tool, realizes the automatic and programmable preparation of the open fluid chip, is compatible with various hydrophobic particle materials, is simple to operate and has strong controllability.

Description

Technical Field

[0001] This invention belongs to the field of microfluidics technology and relates to the fabrication of open fluidic chips, specifically to an open fluidic chip fabrication device and method based on airflow cutting. Background Technology

[0002] Microscale fluidic control technology, as a crucial means of precisely managing liquid flow and reactions at a microscale, has demonstrated its significant importance in several key fields, including synthetic chemistry, life science detection, and the development of novel materials. This technology, relying on device miniaturization and functional integration, significantly accelerates reaction rates, reduces material usage, and enables more stringent control over experimental conditions. It is particularly suitable for handling extremely small or high-value samples, exhibiting unique application potential compared to large conventional experimental setups (such as beakers and reaction vessels). However, most currently widely used microfluidic devices rely on completely sealed solid-state tubing to construct their flow paths. While this design ensures structural stability and prevents leakage, it also severs the immediate communication between the internal fluid environment of the chip and the external environment. The direct consequence is that operators cannot flexibly inject new substances or extract intermediate products into desired areas during experiments, nor can they effectively monitor and control ongoing reactions in real time. This inherent interaction deficiency in such closed systems greatly restricts the widespread adoption of this technology in operations requiring real-time process feedback, dynamic parameter correction, or continuous sampling from different sites.

[0003] To overcome the operational limitations imposed by the aforementioned closed systems, microfluidics with open interfaces have gradually gained attention. These systems allow users to directly contact exposed fluid interfaces, enabling on-demand sample introduction, immediate extraction of intermediate products, and in-situ monitoring and intervention of the reaction process. This significantly enhances the flexibility and controllability of experimental procedures and expands the application prospects of the technology in dynamic, multi-step, and complex experiments. However, despite the clear advantages of the open design concept, the fabrication and functional realization of actual devices still face significant technical bottlenecks. First, to maintain the morphological stability of open channels in air, existing methods often rely on immersing the entire system in immiscible supporting fluids (such as oil phases), which essentially weakens the original intent and convenience of "open" operation. Second, for open fluidic chips that can exist stably in air and are based on hydrophobic particle encapsulation, their construction process often relies on manual operation or complex multi-step processes, making it difficult to achieve high-throughput, high-consistency automated fabrication, and imposing strict limitations on the types of particulate materials constituting the channel walls. Furthermore, existing automated fabrication technologies involve contact processing or thermal processes, which may affect sensitive materials. Therefore, developing a non-immersion, non-contact, automated, and compatible open microfluidic chip fabrication method that allows for cold processing has become a key requirement for driving the development of this field. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide an open fluid chip fabrication apparatus and method based on airflow cutting, thereby solving the technical problems in existing open microfluidic chip fabrication that rely on immiscible liquids to support the shape of the fluid chip, are manually operated, difficult to automate, have poor material compatibility, and are subject to contact or thermal effects.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: An open fluid chip fabrication device based on airflow cutting includes: an air supply module, an airflow control module, a cutting execution module, a motion and positioning module, and a terminal control module; the air outlet of the air supply module is connected to the air inlet of the airflow control module, the air outlet of the airflow control module is connected to the air inlet of the cutting execution module, and the cutting execution module is integrated on the motion and positioning module via an aluminum profile; the terminal control module is used to control the cutting execution module.

[0006] Specifically, the gas supply module includes an air drying filter canister and a gas flow pump; the air drying filter canister is connected to the inlet of the gas flow pump via a hose, and the outlet of the gas flow pump is connected to the main airflow control valve of the airflow control module via a hose.

[0007] Specifically, the airflow control module includes an airflow control main valve, a three-way air pipe interface, an airflow pressure regulating valve, an exhaust valve, a gas flow meter, and a normally closed solenoid valve; the first port of the three-way air pipe interface is connected to the airflow control main valve via an air pipe, the second port is connected to the air inlet of the airflow pressure regulating valve via an air pipe, and the third port is connected to the exhaust valve via an air pipe; the outlet of the airflow pressure regulating valve is connected in sequence via an air pipe to the gas flow meter, the normally closed solenoid valve, and the gas buffer pipe of the cutting execution module.

[0008] Specifically, the cutting execution module includes a gas buffer tube and a needle; the gas buffer tube and the needle are fixedly and sealed together.

[0009] Specifically, the motion and positioning module is an X / Y / Z three-axis gantry slide moving module; the module includes a Y-axis translation rail arranged along the longitudinal direction, an X-axis translation rail movably mounted on the Y-axis translation rail, the X-axis translation rail being arranged along the transverse direction; a Z-axis lifting rail movably mounted on the X-axis translation rail, the Z-axis lifting rail being arranged along the vertical direction, and a gas buffer tube movably mounted on the Z-axis lifting rail.

[0010] Specifically, the terminal control module includes a signal control generator and a terminal computer; the instruction receiving interface of the signal control generator is connected to the terminal computer, and its three signal output interfaces are respectively connected to the motion and positioning module, the normally closed solenoid valve, and the gas flow pump.

[0011] Specifically, the outer diameter of the air outlet of the needle is 0.23–1.2 mm.

[0012] This invention also protects an open fluidic chip fabrication method based on airflow cutting, which is implemented using the apparatus described above; specifically, it includes the following steps: Step 1: Utilize the siphon effect to prepare a wrinkled liquid cake in a blocked state, with its surface coated with hydrophobic particles: Alkylated silica hydrophobic particles are evenly spread to form a hydrophobic particle bed; the target liquid is dropped onto the surface of the hydrophobic particle bed and gently shaken to make the hydrophobic particles evenly coat the liquid, forming a smooth liquid cake with a hydrophobic particle shell on the surface and a liquid core inside; then, a portion of the liquid inside the smooth liquid cake is extracted using the siphon effect to obtain a wrinkled liquid cake in an interface blockage state.

[0013] Step 2: Adjust the airflow to suit the current state of the liquid cake: Using the terminal computer to control the cutting execution module, move the needle above the edge of the wrinkled liquid cake; with the main airflow control valve and the normally closed solenoid valve closed, open the exhaust valve to vent the residual gas in the pipeline; then close the exhaust valve and open the main airflow control valve, and send a command to the signal control generator via the terminal computer to turn on the power to supply power to the gas flow pump and the normally closed solenoid valve; slowly adjust the flow control knob of the airflow pressure regulating valve, observe the gas flow meter reading, and gradually increase the gas flow rate in the pipeline from 0 mL / min until the surface of the liquid cake is slightly perforated by the airflow, and record the flow rate at this time; then keep the airflow pressure regulating valve knob in the same position and close the gas flow pump and the normally closed solenoid valve.

[0014] Step 3: Input the planar diagram of the fluidic chip to be prepared and convert it into G-code: Use vector graphics drawing software to draw the preset pattern, then use commercial software to convert it into G-code format, adjust the G-code, and then input it into the terminal computer.

[0015] Step 4: Perform airflow cutting and shaping. The wrinkled liquid cake obtained in step one is placed on the stage of the motion and positioning module. The G code entered in step three is run through the terminal computer; the cutting execution module automatically moves to the starting point according to the program settings, turns on the airflow and moves along the preset path to cut the liquid cake; after the cutting is completed, microchannels with the same shape as the preset pattern drawn in step three can be obtained on the surface of the liquid cake, and the open fluid chip is successfully produced.

[0016] The present invention also has the following technical features: Specifically, in step one, the device used to extract the liquid inside the smooth liquid cake is a siphon effect liquid extraction device. The device includes a pipette with one end of a silicone tube connected to its tail and the other end of the silicone tube connected to a bulb syringe. The silicone tube is fixed on the lifting bracket.

[0017] Specifically, in step one, the process of extracting a portion of the liquid from the inside of the smooth liquid cake using the siphon effect is as follows: Transfer the smooth liquid cake to the siphon effect extraction device; adjust the lifting support so that the tip of the pipette is 0.8–1.2 mm away from the bottom of the smooth liquid cake; gently draw air from the end of the silicone tubing using a bulb syringe, pulling the liquid inside the liquid cake over the highest point of the silicone tubing to form a siphon; remove the bulb syringe after the liquid begins to flow out naturally; as the liquid is continuously discharged, the thickness of the liquid cake gradually decreases, and after 3–8 minutes, the liquid cake detaches from the pipette, the siphon automatically stops, and a wrinkled liquid cake in a state of interface blockage is obtained.

[0018] Specifically, in step one, the hydrophobic particles are selected from one or more of alkylated silica particles, polytetrafluoroethylene particles, silica, polyvinylidene fluoride, phytolith powder and glass sand, with a particle size of 20 nm to 100 μm.

[0019] Specifically, in step one, the target liquid is water or any solution, such as deionized water, an aqueous solution containing fluorescent dye, a thermosensitive hydrogel solution, or cell culture medium. More specifically, the thermosensitive hydrogel solution is a 10 wt% solution of methacrylic anhydride-modified gelatin.

[0020] Specifically, in step two, the distance between the air outlet of the needle and the surface of the wrinkled liquid cake is 0.4 to 0.6 mm.

[0021] Specifically, in step two, when the surface of the wrinkled liquid cake is slightly perforated by the airflow, the gas flow rate is 30-80 mL / min, which is determined according to the type of target liquid.

[0022] Specifically, in step four, the G-code used for cutting to form microchannels executes the following logic: (a) Keep the Z-axis height of the motion and positioning module unchanged, and move the cutting execution module to the starting point of the preset cutting path.

[0023] (b) Open the gas flow pump, the main gas flow control valve and the normally closed solenoid valve, and pause for 1 to 3 seconds.

[0024] (c) Keep the Z-axis height of the motion and positioning module constant, and control the cutting execution module to translate along the path of the preset pattern.

[0025] (d) Close the gas flow pump, the main gas flow control valve and the normally closed solenoid valve.

[0026] (e) If the preset pattern contains multiple paths, repeat steps (a) to (c) when cutting each path.

[0027] (f) After completing the cutting of the last preset path, raise the cutting execution module and stop the cutting action.

[0028] Specifically, in step four, the cutting speed of the cutting execution module (i.e., its moving speed along a certain direction) is controlled to be 3-5 mm / s.

[0029] Specifically, in step four, according to shape, the microchannels include straight microchannels, Y-shaped microchannels, and triangular microchannels.

[0030] Specifically, in step four, the length of the linear microchannel is 15–25 mm and the depth is 0.5–1.5 mm; when cutting to form the linear microchannel, the cutting execution module is controlled to move linearly along the positive X-axis, and the moving distance is equal to the length of the linear microchannel.

[0031] Specifically, in step four, the main channel of the Y-shaped microchannel is 10-20 mm long, the branch channels are 5-15 mm long, and the branch angle is 30-75°. When cutting to form the Y-shaped microchannel, the main channel is cut first, and then the two branch channels are cut in sequence. The cutting execution module is controlled to move linearly along the direction of the main channel or the branch channel, and the moving distance is equal to the length of the main channel or the branch channel.

[0032] Specifically, in step four, the three sides of the triangular microchannel are 6 to 10 mm. When cutting to form the triangular microchannel, the three sides are cut sequentially, and the cutting execution module is controlled to move linearly along the direction of the triangle side length, with the moving distance equal to the length of the triangle side length.

[0033] Compared with the prior art, the present invention has the following technical effects: (I) The preparation method of this invention is the first to use high-speed airflow as a shaping tool, and achieves the construction of open fluid channels by precisely cutting the liquid cake in the interface blockage state. This method completely eliminates the dependence on the immiscible liquid support environment in traditional methods, and the preparation process can be completed in an air environment, which greatly improves the ease of operation and environmental adaptability of the chip in practical applications.

[0034] (II) This invention automates and programmes the fabrication process of open-loop fluidic chips. By integrating the airflow cutting execution module into a three-axis precision motion platform and combining it with vector graphics to G-code conversion path control, the liquid cake can be precisely cut according to a preset program, thereby constructing a fluid channel network with complex geometries. Compared to existing fabrication methods that rely on manual operation or multi-step processes, this invention significantly improves the throughput, repeatability, and structural complexity of chip fabrication, providing a feasible technical path for the transformation of open-loop microfluidic chips from laboratory prototypes to large-scale applications.

[0035] (III) The cutting medium used in this invention is a high-speed airflow at room temperature, which is a typical cold processing and non-contact processing method. This process does not involve heating, light exposure, or chemical reactions, and has no special restrictions on the hydrophobic particulate materials constituting the fluid channel walls. It is compatible with a variety of common hydrophobic materials such as silica, polystyrene, and polytetrafluoroethylene. This characteristic greatly expands the material selection range of open fluidic chips and provides flexibility for targeted selection of chip materials for different application scenarios (such as biocompatibility requirements, organic solvent tolerance requirements, etc.).

[0036] (IV) The device of this invention has a simple structure, with highly integrated and easily disassembled functional modules. Airflow parameters (such as flow rate and stability) and motion parameters (such as path and speed) can be independently controlled, and the operation process is concise and clear. The operator only needs to import the target chip pattern through the control computer, and the system can automatically complete the entire process from airflow parameter matching to cutting and shaping, significantly reducing the dependence on the operator's manual skills and providing a systematic solution for the preparation of human-computer interactive open microfluidic chips. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of a siphon pumping device.

[0038] Figure 2 This is a schematic diagram of an apparatus for fabricating open fluidic chips using airflow cutting. In the diagram, the green pipe is a silicone tube, the blue pipe is a PU tube, and the red line is a voltage and signal connection line.

[0039] Figure 3 A physical image of the apparatus used for fabricating open fluidic chips via airflow cutting.

[0040] Figure 4 A physical image of the gas supply module device.

[0041] Figure 5 This is a physical image of the airflow control module.

[0042] Figure 6 This is a physical image of the cutting execution module device.

[0043] Figure 7 This is a physical image of the motion and positioning module device.

[0044] Figure 8 Logic diagram of the code running for the motion and positioning module.

[0045] Figure 9 A real-world image showing the process of fabricating a three-sphere open-loop fluidic chip using airflow cutting.

[0046] Figure 10 An open fluid chip sample prepared by airflow cutting is shown.

[0047] The labels in the diagram represent the following: 1-Air drying filter canister, 2-Gas flow pump, 3-Airflow control main valve, 4-Three-way air pipe interface, 5-Airflow pressure regulator, 6-Exhaust valve, 7-Gas flow meter, 8-Normally closed solenoid valve, 9-Gas buffer tube, 10-Needle, 11-Y-axis translation rail, 12-X-axis translation rail, 13-Z-axis lifting rail, 14-Signal control generator, 15-Terminal computer, 16-Hose, 17-Air pipe.

[0048] The specific content of the present invention will be further explained in detail below with reference to the embodiments. Detailed Implementation

[0049] It should be noted that, unless otherwise specified, all components in this invention are components known in the art.

[0050] Following the above technical solutions, specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0051] Example 1 This embodiment provides an open fluidic chip fabrication apparatus based on airflow cutting, such as... Figure 1 As shown, the device includes an air supply module, an airflow control module, a cutting execution module, a motion and positioning module, and a terminal control module. The air outlet of the air supply module is connected to the air inlet of the airflow control module, and the air outlet of the airflow control module is connected to the air inlet of the cutting execution module. The cutting execution module is integrated into the motion and positioning module via an aluminum profile. The terminal control module is used to control the cutting execution module.

[0052] As a specific embodiment, the gas supply module includes an air drying filter canister (1) and a gas flow pump (2); the air drying filter canister (1) is connected to the inlet of the gas flow pump (2) via a hose (16), and the outlet of the gas flow pump (2) is connected to the airflow control main valve (3) of the airflow control module via a hose (16). In this embodiment, the air drying filter canister (1) is used to provide a dry and clean gas source.

[0053] As a specific solution in this embodiment, the gas flow pump (2) is a plug-in micro gas flow pump known in the prior art, with an output flow range of 20 to 2000 mL / min.

[0054] As a specific solution in this embodiment, the flexible tube (16) is made of silicone, with an inner diameter of 5 mm and an outer diameter of 8 mm.

[0055] As a specific embodiment, the airflow control module includes an airflow control main valve (3), a three-way air pipe interface (4), an airflow pressure regulating valve (5), an exhaust valve (6), a gas flow meter (7), and a normally closed solenoid valve (8). The first interface of the three-way air pipe interface (4) is connected to the airflow control main valve (3) through an air pipe (17), the second interface is connected to the air inlet of the airflow pressure regulating valve (5) through an air pipe (17), and the third interface is connected to the exhaust valve (6) through an air pipe (17). The outlet of the airflow pressure regulating valve (5) is connected to the gas flow meter (7), the normally closed solenoid valve (8), and the gas buffer pipe (9) of the cutting execution module in sequence through an air pipe (17).

[0056] As a specific embodiment, the airflow control main valve (3) and the exhaust valve (6) are both mechanically balanced shut-off valves known in the prior art.

[0057] As a specific embodiment, the trachea (17) is made of polyurethane, with an outer diameter of 8 mm and an inner diameter of 5 mm.

[0058] As a specific embodiment, the pressure limit of the airflow pressure regulating valve (5) is 0.6 MPa, and the flow rate adjustment range is 0 to 200 mL / min.

[0059] As a specific solution in this embodiment, the gas flow meter (7) is a digital display high-precision thermal gas mass flow meter with a pressure limit of 1 MPa, a measurement range of 0 to 500 mL / min, and a measurement accuracy of ±10 mL / min.

[0060] As a specific solution in this embodiment, the pressure limit of the normally closed solenoid valve (8) is 1 MPa, and it is connected to an external 24 V DC power supply when working.

[0061] As a specific solution in this embodiment, the cutting execution module includes a gas buffer tube (9) and a needle (10); the gas buffer tube (9) and the needle (10) are connected by a threaded structure to ensure airtightness.

[0062] As a specific embodiment, the needle (10) is 2 cm long and the outer diameter of the air outlet is 0.23 to 1.2 mm.

[0063] As a specific solution of this embodiment, the motion and positioning module is an X / Y / Z three-axis gantry slide moving module. The module includes a Y-axis translation rail (11) arranged along the longitudinal direction, an X-axis translation rail (12) movably mounted on the Y-axis translation rail (11), the X-axis translation rail (12) being arranged along the transverse direction; a Z-axis lifting rail (13) movably mounted on the X-axis translation rail (12), the Z-axis lifting rail (13) being arranged along the vertical direction, and a gas buffer tube (9) movably mounted on the Z-axis lifting rail (13).

[0064] As a specific embodiment, the effective travel of the motion and positioning module in the X, Y, and Z directions is 285 mm, 414 mm, and 92 mm, respectively.

[0065] As a specific solution in this embodiment, the terminal control module includes a signal control generator (14) and a terminal computer (15); the instruction receiving interface of the signal control generator (14) is connected to the terminal computer (15), and its three motion signal output interfaces are respectively connected to the motion and positioning module, the normally closed solenoid valve (8) and the gas flow pump (2) to realize the control function of the motion and positioning module, and to supply power to the normally closed solenoid valve (8) and the gas flow pump (2).

[0066] Example 2: This embodiment presents an open fluidic chip fabrication method based on airflow cutting, implemented using the apparatus of Embodiment 1. The method specifically includes the following steps: Step 1: Utilize the siphon effect to prepare a wrinkled liquid cake in a blocked state, with its surface coated with hydrophobic particles: Weigh 20 g of alkylated silica hydrophobic particles (approximately 100 nm in diameter) and evenly spread them in a petri dish to form a hydrophobic particle bed approximately 5 mm thick. Use a pipette to add 10 mL of deionized water droplets to the surface of the hydrophobic particle bed. Gently shake the petri dish manually to ensure the hydrophobic particles evenly coat the liquid, forming a smooth liquid cake with a hydrophobic particle shell and a liquid core. Then, transfer the smooth liquid cake to a siphon effect aspiration device. This device consists of a 2 mL pipette with a 0.5 mm inner diameter silicone tubing attached to its end, and the entire tubing is fixed to a lifting support. Adjust the lifting support so that the pipette tip is approximately 1 mm from the bottom of the smooth liquid cake. Gently draw air through the silicone tubing using a bulb syringe, pulling the liquid inside the cake over the highest point of the tubing to create a siphon. Once the liquid begins to flow out naturally, remove the bulb syringe. As the liquid is continuously drained, the thickness of the liquid cake gradually decreases. After about 5 minutes, the liquid cake detaches from the pipette, the siphon stops automatically, and a wrinkled liquid cake in a state of interface blockage is obtained.

[0067] Step 2: Adjust the airflow to suit the current state of the liquid cake: Using the terminal computer (15) to control the cutting execution module, the needle (10) with an outer diameter of 0.23 mm is moved above the edge of the wrinkled liquid cake, and the distance between the needle outlet and the liquid cake surface is controlled to be about 0.5 mm. With the airflow control main valve (3) and the normally closed solenoid valve (8) closed, the exhaust valve (6) is opened to empty the residual gas in the pipeline; then the exhaust valve (6) is closed and the airflow control main valve (3) is opened. The terminal computer (15) sends a command to the signal control generator (14) to turn on the power to supply power to the gas flow pump (2) and the normally closed solenoid valve (8); the flow control knob of the airflow pressure regulating valve (5) is slowly adjusted, and the reading of the gas flow meter (7) is observed to gradually increase the gas flow rate in the pipeline from 0 mL / min until the liquid cake surface is slightly perforated by the airflow. The flow rate at this time is recorded as 40 mL / min. Then, the position of the airflow pressure regulating valve (5) knob is kept unchanged, and the gas flow pump (2) and the normally closed solenoid valve (8) are closed.

[0068] Step 3: Input the planar diagram of the fluidic chip to be prepared and convert it into G-code: Use vector graphics drawing software (such as AutoCAD, CorelDRAW) to draw a straight line with a length of 20 mm as a simple channel pattern for the target fluid chip. Use commercial software (such as ArtCAM) to convert the vector image into G-code and manually adjust the G-code to conform to the following operating logic: ① Keep the Z-axis height unchanged and move the cutting execution module to the starting point of the preset cutting path (one end of the straight line); ② Open the gas flow pump (2), the airflow control main valve (3) and the normally closed solenoid valve (8), and pause for 2 seconds; ③ Keep the Z-axis height unchanged and control the cutting execution module to move 20 mm in a straight line along the positive X-axis at a speed of 5 mm / s; ④ After the cutting is completed, close the gas flow pump (2), the airflow control main valve (3) and the normally closed solenoid valve (8), and raise the cutting execution module by 10 mm; input the adjusted G-code into the terminal computer (15).

[0069] Step 4: Perform airflow cutting and shaping. The wrinkled liquid cake obtained in step one is placed on the stage of the motion and positioning module. The G code entered in step three is run through the terminal computer (15). The cutting execution module automatically moves to the starting point according to the program settings, turns on the airflow and moves along the preset path to cut the liquid cake. After the cutting is completed, a microchannel with a depth of about 1 mm formed by airflow etching can be obtained on the surface of the liquid cake, and the open fluid chip is successfully prepared.

[0070] Example 3: This embodiment presents an open-loop fluidic chip fabrication method based on airflow cutting, which is implemented using the apparatus of Embodiment 1. This method is essentially the same as steps one, two, and four of Embodiment 2, except for step three.

[0071] In this embodiment, step three is as follows: A "Y"-shaped branch channel pattern is drawn using vector graphics software. The main channel is 15 mm long, the branch channels are 10 mm long, and the branch angle is 60°. The vector image is converted into G-code, and the G-code execution logic is adjusted so that it can cut three paths sequentially: first, the main channel is cut, and then the two branch channels are cut sequentially. The operation sequence of "move to the starting point - turn on the airflow and pause - move along the path - turn off the airflow" is repeated between each pair of paths. During the cutting, the airflow rate is adjusted to 50 mL / min, and the cutting speed is maintained at 5 mm / s. After cutting, an open fluid channel with a branch structure consistent with the preset "Y"-shaped pattern is successfully prepared on the surface of the wrinkled liquid cake.

[0072] Example 4: This embodiment presents an open-loop fluidic chip fabrication method based on airflow cutting, implemented using the apparatus of Embodiment 1. The steps of this method are essentially the same as those of Embodiment 2, the difference being the hydrophobic particulate material used in step one and the airflow parameters in step two.

[0073] In this embodiment, step one is as follows: Weigh 20 g of hydrophobic polytetrafluoroethylene particles (particle size approximately 1 μm) and evenly spread them in a petri dish to form a hydrophobic particle bed. Add 5 mL of an aqueous solution containing green fluorescent dye to the particle bed, and prepare a wrinkled liquid cake through shaking and siphon effect.

[0074] In step two, when adjusting the airflow, it was observed that the required airflow rate to blow open the surface of the liquid cake was 80 mL / min due to the different particulate materials. Therefore, the flow rate of the airflow regulating valve (5) was set to 80 mL / min.

[0075] In step three, an equilateral triangle with a side length of 8 mm is drawn as the target pattern. The G-code is adjusted so that the cutting execution module moves along the triangle trajectory, and the cutting speed is set to 3 mm / s. After cutting, a triangular channel is successfully prepared on the liquid cake wrapped with polytetrafluoroethylene particles. Observation under a fluorescence microscope shows that the channel outline is clear and the fluorescent dye is well preserved, proving that the present invention has good compatibility with hydrophobic particulate materials.

[0076] Example 5: This embodiment presents an open-loop fluidic chip fabrication method based on airflow cutting, implemented using the apparatus of Embodiment 1. The steps of this method are essentially the same as those of Embodiment 2, the difference being the liquid core material used in step one and the needle specifications used in step two.

[0077] In this embodiment, step one is as follows: A temperature-sensitive hydrogel solution (a 10% (w / v) methacrylic anhydride-modified gelatin solution, kept liquid at 4°C) is used as the liquid core, and alkylated silica hydrophobic particles (approximately 20 nm in diameter) are used as the shell material. A wrinkled liquid cake is prepared by drop addition and siphon effect. The entire operation is performed on an ice pack to keep the hydrogel in a liquid state.

[0078] In step two, the needle (10) of the cutting execution module was replaced with a model with an air outlet outer diameter of 1.2 mm. When adjusting the airflow, it was observed that the airflow rate required to blow open the surface of the hydrogel cake was 30 mL / min. Therefore, the flow rate of the airflow pressure regulating valve (5) was set to 30 mL / min.

[0079] In step three, a Y-shaped fluid chip was drawn as the target pattern, and the cutting speed was set to 4 mm / s. After cutting, a Y-shaped channel was successfully prepared on the thermosensitive hydrogel cake. Subsequently, the chip was placed in an incubator at 37°C for 10 minutes, and the hydrogel inside the channel solidified, forming a self-supporting gel channel structure, proving that the present invention is also applicable to thermosensitive materials.

Claims

1. An open-loop fluidic chip fabrication apparatus based on airflow cutting, characterized in that, The device includes an air supply module, an airflow control module, a cutting execution module, a motion and positioning module, and a terminal control module. The air outlet of the air supply module is connected to the air inlet of the airflow control module, and the air outlet of the airflow control module is connected to the air inlet of the cutting execution module. The cutting execution module is integrated into the motion and positioning module. The terminal control module is used to control the cutting execution module.

2. The open fluidic chip fabrication apparatus based on airflow cutting as described in claim 1, characterized in that, The airflow control module includes an airflow control main valve (3), a three-way air pipe interface (4), an airflow pressure regulating valve (5), an exhaust valve (6), a gas flow meter (7), and a normally closed solenoid valve (8). The first interface of the three-way air pipe interface (4) is connected to the airflow control main valve (3) through an air pipe (17), the second interface is connected to the air inlet of the airflow pressure regulating valve (5) through an air pipe (17), and the third interface is connected to the exhaust valve (6) through an air pipe (17). The outlet of the airflow pressure regulating valve (5) is connected to the gas flow meter (7), the normally closed solenoid valve (8), and the gas buffer pipe (9) of the cutting execution module in sequence through an air pipe (17).

3. The open fluidic chip fabrication apparatus based on airflow cutting as described in claim 2, characterized in that, The cutting execution module includes a gas buffer tube (9) and a needle (10); the gas buffer tube (9) and the needle (10) are fixedly and sealed together.

4. The open fluidic chip fabrication apparatus based on airflow cutting as described in claim 3, characterized in that, The motion and positioning module is an X / Y / Z three-axis gantry slide table moving module.

5. The open fluidic chip fabrication apparatus based on airflow cutting as described in claim 4, characterized in that, The terminal control module includes a signal control generator (14) and a terminal computer (15); the instruction receiving interface of the signal control generator (14) is connected to the terminal computer (15), and its three motion signal output interfaces are respectively connected to the motion and positioning module, the normally closed solenoid valve (8) and the gas flow pump (2).

6. A method for fabricating an open-loop fluidic chip based on airflow cutting, characterized in that, This method is implemented using the apparatus described in claim 5; specifically, it includes the following steps: Step 1: Utilize the siphon effect to prepare a wrinkled liquid cake in a blocked state, with its surface coated with hydrophobic particles: Alkylated silica hydrophobic particles are evenly spread to form a hydrophobic particle bed; the target liquid is dropped onto the surface of the hydrophobic particle bed and gently shaken so that the hydrophobic particles evenly coat the liquid, forming a smooth liquid cake with a hydrophobic particle shell on the surface and a liquid core inside. Subsequently, a portion of the liquid inside the smooth liquid cake is extracted using the siphon effect, resulting in a wrinkled liquid cake in a state of interface blockage. Step 2: Adjust the airflow to suit the current state of the liquid cake: Using the terminal computer (15) to control the cutting execution module, move the needle (10) above the edge of the wrinkled liquid cake; with the airflow control main valve (3) and the normally closed solenoid valve (8) closed, open the exhaust valve (6) to empty the residual gas in the pipeline; then close the exhaust valve (6) and open the airflow control main valve (3), and send a command to the signal control generator (14) through the terminal computer (15) to turn on the power to supply power to the gas flow pump (2) and the normally closed solenoid valve (8); slowly adjust the flow control knob of the airflow pressure regulating valve (5), observe the reading of the gas flow meter (7), and gradually increase the gas flow rate in the pipeline from 0 mL / min until the surface of the liquid cake is slightly punctured by the airflow, and record the flow rate at this time; then keep the position of the airflow pressure regulating valve (5) unchanged, and close the gas flow pump (2) and the normally closed solenoid valve (8). Step 3: Input the planar diagram of the fluidic chip to be prepared and convert it into G-code: Use vector graphics drawing software to draw the preset pattern, then use commercial software to convert it into G code form, adjust the G code and input it into the terminal computer (15). Step 4: Perform airflow cutting and shaping. The wrinkled liquid cake obtained in step one is placed on the platform of the motion and positioning module. The G code entered in step three is run through the terminal computer (15); the cutting execution module moves automatically to the starting point according to the program settings, turns on the airflow and moves along the preset path to cut the liquid cake; after the cutting is completed, microchannels with the same shape as the preset pattern drawn in step three can be obtained on the surface of the liquid cake, and the open fluid chip is successfully obtained.

7. The open fluidic chip fabrication method based on airflow cutting as described in claim 6, characterized in that, In step one, the device used to extract the liquid inside the smooth liquid cake is a siphon effect liquid extraction device. The device includes a pipette, with one end of a silicone tube connected to the tail end, and the other end of the silicone tube connected to a bulb syringe; the silicone tube is fixed on the lifting bracket. In step one, the specific process of extracting a portion of the liquid from the inside of the smooth liquid cake using the siphon effect is as follows: Transfer the smooth liquid cake to the siphon effect extraction device; adjust the lifting support so that the tip of the pipette is 0.8-1.2 mm away from the bottom of the smooth liquid cake; gently draw air from the end of the silicone tube using a bulb syringe, pulling the liquid inside the liquid cake over the highest point of the silicone tube to form a siphon; remove the bulb syringe after the liquid begins to flow out naturally; as the liquid is continuously discharged, the thickness of the liquid cake gradually becomes thinner, and after 3-8 minutes, the liquid cake detaches from the pipette, the siphon automatically stops, and a wrinkled liquid cake in a state of interface blockage is obtained.

8. The open fluidic chip fabrication method based on airflow cutting as described in claim 6, characterized in that, In step two, when the surface of the wrinkled liquid cake is slightly perforated by the airflow, the gas flow rate is 30-80 mL / min.

9. The open fluidic chip fabrication method based on airflow cutting as described in claim 6, characterized in that, In step four, the G-code used for cutting to form microchannels executes the following logic: (a) Keeping the Z-axis height of the motion and positioning module constant, move the cutting execution module to the starting point of the preset cutting path; (b) Open the gas flow pump (2), the main gas flow control valve (3) and the normally closed solenoid valve (8), and pause for 1 to 3 seconds; (c) Keep the Z-axis height of the motion and positioning module constant, and control the cutting execution module to translate along the path of the preset pattern; (d) Shut down the gas flow pump (2), the main gas flow control valve (3) and the normally closed solenoid valve (8); (e) If the preset pattern contains multiple paths, repeat steps (a) to (e) when cutting each path. (f) After completing the cutting of the last preset path, raise the cutting execution module and stop the cutting action.

10. The open fluidic chip fabrication method based on airflow cutting as described in claim 9, characterized in that, In step four, the cutting speed of the cutting execution module is controlled to be 3-5 mm / s.

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