Planar microfluidic triode and device, preparation method of planar microfluidic triode and device, and microfluidic circuit network

Abstract

The invention discloses a planar micro-fluidic triode, a planar micro-fluidic device, a preparation method of the planar micro-fluidic triode and a micro-fluidic circuit network. The planar micro-fluidic triode comprises a source electrode, a drain electrode and a grid electrode, the source electrode, the drain electrode and the grid electrode form a single-layer structure; a channel is arranged between the source electrode and the drain electrode; the grid electrode comprises a deformable thin film structure, the deformable thin film structure is located on one side of the channel, and the deformable thin film structure is used for adjusting a gap of the channel when the deformable thin film structure is subjected to liquid pressure so as to control the flow of fluid flowing through the channel. According to the planar microfluidic triode, the source electrode, the drain electrode and the grid electrode are located on the same plane, the structure is simplified, fluid control can be achieved through the deformable film structure that the adjustable pressure source applies pressure to the grid electrode, and compared with a multi-layer design scheme, better portability and integration degree can be achieved.

Description

Technical Field

[0001] The present invention relates to the field of microfluidic technology, and in particular to a planar microfluidic triode, a device and a preparation method thereof, and a microfluidic circuit network. Background Art

[0002] Microfluidic devices are widely used in medical diagnosis and biological sciences. By integrating complex laboratory operations onto microchips, they can efficiently process and analyze biological samples such as blood and urine. This type of technology can not only significantly speed up the reaction speed, but also has automation and portability. Common forms include lab-on-a-chip and lab-on-a-disk.

[0003] Microfluidic devices mainly rely on microchannels and microvalves to control the transmission, mixing, reaction and detection of fluids. However, existing microfluidic devices usually require external pneumatic equipment and complex external pipelines for control, which makes the system complex and bulky, and is not conducive to miniaturization and portable applications.

[0004] In order to solve these problems, existing solutions have proposed microfluidic transistors and microfluidic circuit solutions based on multi-layer control structures. However, the multi-layer processing solution is limited by the gas-controlled driving method, as well as the complexity of the structural design, high processing costs and long process.

[0005] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a planar microfluidic transistor, a device and a preparation method thereof, and a microfluidic circuit network, so as to solve the problems that the existing multilayer microfluidic transistor solution is limited by the gas-controlled driving mode, as well as the complexity of the structural design, the high processing cost and the long process.

[0007] The technical solution of the present invention is as follows:

[0008] In the first aspect, the present invention provides a planar microfluidic transistor, which includes: a source, a drain and a gate; the source, the drain and the gate form a single-layer structure; there is a channel between the source and the drain; the gate includes a deformable film structure, the deformable film structure is located on one side of the channel, and the deformable film structure is used to adjust the gap of the channel when subjected to liquid pressure to control the flow rate of the fluid flowing through the channel.

[0009] According to a further configuration of the present invention, the gate is a fan-shaped structure.

[0010] According to a further configuration of the present invention, the planar microfluidic triode is made of polydimethylsiloxane material.

[0011] According to a further configuration of the present invention, the arc of the fan-shaped structure is 1.049-1.696.

[0012] In a second aspect, the present invention further provides a planar microfluidic device, which comprises a substrate layer and the planar microfluidic triode as described above, wherein the planar microfluidic triode is bonded to the substrate layer.

[0013] According to a further configuration of the present invention, the planar microfluidic device further comprises a micropump assembly, wherein the micropump assembly is connected to the planar microfluidic transistor and is used to provide liquid pressure for the deformable film structure.

[0014] In a third aspect, the present invention provides a planar microfluidic circuit network, comprising a plurality of microfluidic devices as described above, wherein the microfluidic devices are integrated on the same plane, and the planar microfluidic transistors are connected in series or in parallel.

[0015] In a fourth aspect, the present invention provides a method for preparing a microfluidic device, comprising:

[0016] A microchannel template is constructed on a silicon wafer or a glass substrate by photolithography using photoresist;

[0017] Pour liquid polydimethylsiloxane material into the microchannel template, remove air bubbles by vacuuming, and perform a curing process;

[0018] After curing, the polydimethylsiloxane material is demolded to obtain a planar microfluidic triode having a source electrode, a drain electrode and a gate channel;

[0019] The surface of the planar microfluidic triode to be bonded and the corresponding surface of the substrate layer are placed in an oxygen plasma device for treatment;

[0020] Take out the planar microfluidic triode oxygen plasma device, and then fit the area to be bonded to the base layer.

[0021] In a fifth aspect, the present invention further provides a method for preparing a microfluidic device, comprising:

[0022] Print the master mold of the microfluidic transistor by 3D printing equipment;

[0023] Surface treatment of the 3D printed master mold;

[0024] Pour liquid polydimethylsiloxane material into the microchannel template, remove air bubbles by vacuuming, and perform a curing process;

[0025] After curing, the polydimethylsiloxane material is demolded to obtain a planar microfluidic triode having a source electrode, a drain electrode and a gate channel;

[0026] The surface of the planar microfluidic triode to be bonded and the corresponding surface of the substrate layer are placed in an oxygen plasma device for treatment;

[0027] Take out the planar microfluidic triode oxygen plasma device, and then attach the area to be bonded to the substrate layer;

[0028] or,

[0029] The imprinting mold is prepared by using nanoimprinting technology;

[0030] pouring liquid polydimethylsiloxane material into the microchannel imprinting mold;

[0031] Demolding the polydimethylsiloxane material to obtain a planar microfluidic triode having a source electrode, a drain electrode and a gate channel;

[0032] The surface of the planar microfluidic triode to be bonded and the corresponding surface of the substrate layer are placed in an oxygen plasma device for treatment;

[0033] Take out the planar microfluidic triode oxygen plasma device, and then fit the area to be bonded to the base layer.

[0034] The present invention provides a planar microfluidic triode, a device, a preparation method thereof, and a microfluidic circuit network. The planar microfluidic triode includes: a source, a drain, and a gate; the source, the drain, and the gate form a single-layer structure; there is a channel between the source and the drain; the gate includes a deformable film structure, the deformable film structure is located on one side of the channel, and the deformable film structure is used to adjust the gap of the channel when subjected to liquid pressure to control the flow of the fluid flowing through the channel. The planar microfluidic triode provided by the present invention has a source, a drain, and a gate in the same plane, which simplifies the structure. The control of the fluid can be achieved by applying pressure to the deformable film structure of the gate through an adjustable pressure source. Compared with the multi-layer design, it can provide better portability and integration, and reduce processing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary personnel in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0036] Figure 1 It is a schematic diagram of the overall structure of the planar microfluidic triode in the present invention.

[0037] Figure 2It is a schematic diagram of a state in which the deformable film of the planar microfluidic triode in the present invention is not subjected to liquid pressure.

[0038] Figure 3 It is a schematic diagram of the state of the deformable film of the planar microfluidic triode in the present invention being subjected to liquid pressure.

[0039] Figure 4 It is a curve diagram of the planar microfluidic triode in the present invention working in different stages.

[0040] Figure 5 This is a performance data characterization diagram of the planar microfluidic triode in the present invention.

[0041] Figure 6 It is an equivalent component diagram of the planar microfluidic triode in the present invention.

[0042] Figure 7 It is a schematic diagram of a logic microfluidic flow path that can be constructed by the planar microfluidic triode in the present invention.

[0043] Figure 8 It is a schematic diagram of the structure of the microfluidic device in the present invention.

[0044] Fig. 9 It is a circuit schematic diagram of combining a planar microfluidic triode network (active) with a burst valve-based microfluidic logic control network (passive) in one embodiment of the present invention.

[0045] Fig.10 It is a schematic diagram of the process of preparing a planar microfluidic triode by soft lithography in one embodiment of the present invention.

[0046] Fig.11 It is a schematic diagram of preparing a planar microfluidic triode by soft lithography in one embodiment of the present invention.

[0047] Fig.12 It is a schematic diagram of the process of preparing a planar microfluidic triode by 3D printing in one embodiment of the present invention.

[0048] Fig.13 It is a schematic diagram of the process of preparing a planar microfluidic triode by nanoimprinting in one embodiment of the present invention.

[0049] The symbols in the accompanying drawings are: 100, planar microfluidic triode; 110, source; 120, drain; 130, gate; 131, deformable film structure; 140, channel; 200, base layer. DETAILED DESCRIPTION

[0050] The present invention provides a planar microfluidic triode, a device and a method for preparing the same, and a microfluidic circuit network. To make the purpose, technical solution, and effect of the present invention clearer and more specific, the present invention is further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0051] In the embodiments and the scope of the patent application, unless the text specifically defines the article, "a", "an", "the" and "the" may also include plural forms. If there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0052] It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when an element is said to be "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there can also be intermediate elements. In addition, the "connection" or "coupling" used herein can include wireless connection or wireless coupling. The term "and / or" used herein includes all or any unit and all combinations of one or more associated listed items.

[0053] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined as herein.

[0054] In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0055] The inventors have found that microfluidic devices mainly rely on microchannels and microvalves to control the transmission, mixing, reaction and detection of fluids. However, existing microfluidic devices usually require external pneumatic equipment and complex external pipelines for control, which makes the system complex and bulky, and is not conducive to miniaturization and portable applications. In order to solve these problems and reduce dependence on external control devices, existing solutions have proposed gas-controlled driven microfluidic transistors and microfluidic circuit solutions based on multi-layer control structures. However, the multi-layer processing solution is limited by the gas-controlled drive method, structural design complexity, processing cost and process.

[0056] In view of the above technical problems, the present invention provides a planar microfluidic transistor, which controls the fluid flow between the source, drain and gate through a liquid pressure signal to achieve fluid amplification and switching functions. This planar design not only simplifies the system structure, but also enables the microfluidic transistor to achieve efficient fluid control at a lower working pressure, can be further integrated with a portable micropump, and has subsequent expansion capabilities, which is suitable for more complex and highly integrated microfluidic systems.

[0057] Please also see Figures 1 to 7 The present invention provides a preferred embodiment of a planar microfluidic triode.

[0058] In some embodiments, Figures 1 to 3 As shown, the present invention provides a planar microfluidic triode 100, which includes: a source 110, a drain 120 and a gate 130; the source 110, the drain 120 and the gate 130 form a single-layer structure; there is a channel 140 between the source 110 and the drain 120; the gate 130 includes a deformable film structure 131, and the deformable film structure 131 is located on one side of the channel 140, and the deformable film structure 131 is used to adjust the gap of the channel 140 when subjected to liquid pressure to control the flow rate of the fluid flowing through the channel 140.

[0059] Specifically, the structure of the planar microfluidic transistor 100 is similar to an electronic field effect transistor (FET), such as Figure 6As shown, there is a drain 120, a source 110 and a gate 130, wherein the gate 130 has a deformable film structure 131. When the fluid is under pressure, it can flow from the source 110 to the drain 120 through the channel 140. The deformable film structure 131 can be deformed when subjected to liquid pressure, so that the gap of the channel 140 can be changed to achieve the regulation of the fluid flow, that is, the amplification and switching functions of the fluid can be achieved. In other words, the pressure of the gate 130 controls the deformation of the deformable film structure 131, thereby affecting the on-off of the fluid between the source 110 and the drain 120. When the gate 130 applies pressure, the deformable film structure 131 is deformed, the channel is closed, and the fluid flow is blocked; when the pressure of the gate 130 is reduced, the deformable film structure 131 returns to its original state, the channel is opened, and the fluid flows again. In this way, the working range of the planar microfluidic triode 100 depends on the liquid pressure range applied to the gate 130.

[0060] Among them, the deformation principle of the film is: the core working principle of the microfluidic planar triode involves controlling the fluid flow between the source, drain and gate through pneumatic pressure (controlling the liquid pressure through air pressure). The applied pressure of the gate causes the deformation of the vertical film, thereby regulating the opening and closing state of the fluid channel. The deformation of the film can be described according to the film deformation theory, and the calculation formula of the deformation amount is:

[0061]

[0062] Where: ΔP represents the applied pressure difference, r is the radius of the film, v is the Poisson's ratio of the film, E is the elastic modulus of the film material, and t is the thickness of the film. By applying different pressures, the deformation of the film can effectively control the channel size and closure of the fluid between the source and drain, thereby realizing the switching function of the fluid. This film structure design not only simplifies the physical structure of the system, but also can achieve precise fluid control at lower working pressures.

[0063] Shapiro Number (S number) analysis: When analyzing fluid dynamics in pneumatic channels, Shapiro number is used to measure the ratio of characteristic fluid velocity to pipe wave velocity, especially the velocity restriction effect in flexible structures such as film-deformed pipes. The calculation formula of Shapiro number is:

[0064]

[0065] Q is the flow rate, A is the cross-sectional area of ​​the fluid channel, E (Young's modulus) and T (film thickness) are the parameters of the film, which are used to describe its structural characteristics, ρ is the fluid density, and H is the geometric height of the channel. When S>1, it indicates that the flow rate limitation effect caused by the cavity deformation is enhanced, and the dynamic deformation of the film further regulates the fluid flow rate. In the planar microfluidic transistor, the deformation of the deformable film structure not only regulates the switch of the fluid channel, but also affects the flow rate, so that the device can accurately control the movement of the fluid under different pressure conditions. Combining the analysis of film deformation theory and Shapiro number, the planar microfluidic transistor realizes efficient fluid regulation function through flexible control of pressure.

[0066] like Figure 4 As shown, Figure 4 Represents the flow trend of drain flow before and after the gate pressure is at the pinch-off point pressure. Figure 5 a represents the relationship between source pressure and drain flow. Figure 5 In the figure b, it represents the relationship between the gate pressure and the drain flow. When the source pressure component increases, the flow between the source and the drain gradually approaches saturation. When the gate pressure gradually increases, the flow between the source and the drain gradually decreases. It can be seen that the flow of the fluid in the channel of the planar microfluidic triode can be controlled by controlling the liquid pressure of the gate.

[0067] It can be seen that the planar microfluidic triode provided by the present invention has a source, a drain and a gate in the same plane, which simplifies the structure, and can control the fluid by applying pressure to the deformable film structure of the gate through an adjustable pressure source. By combining this planar microfluidic triode into a logical flow path, it can provide precise control for complex liquid processing, improve portability and integration, and reduce processing costs. It is particularly suitable for those application scenarios that require lightness and speed, such as biomedical analysis, portable chemical detection and other fields.

[0068] For example, Figure 6 This is the equivalent circuit diagram of the planar microfluidic transistor. Based on the basic component structure of the planar microfluidic transistor, more complex fluid logic circuits can be constructed. These logic circuits can realize logic functions similar to electronic circuits, such as Figure 7 As shown, for example, Figure 7 The inverter in a, Figure 7 The AND-OR-N logic gate in b, Figure 7 The fluid controller in c and Figure 7The oscillator in d. Among them, the principle of realizing the inverter is: by connecting two microfluidic triodes in series, a fluid inverter can be constructed. The input of the inverter is a pneumatic pressure signal. When the input signal is "high" (i.e., high pressure), the output channel is in a closed state; when the input signal is "low", the output channel is opened to achieve reverse output. The principle of realizing the AND / OR / NOT logic gate is: through the combination of multiple microfluidic triodes, the logical operations of AND gate, OR gate and NOT gate can be realized. For the AND gate, the gates of multiple triodes are controlled at the same time, and the output channel is opened only when all input signals are "high"; for the OR gate, as long as any one input signal is "high", the output will be opened. The NOT gate is realized by an inverter. The principle of realizing the fluid controller is: the fluid controller is composed of a microfluidic triode and a flow resistor, which can achieve a relatively stable output flow rate when the input pressure fluctuates to a certain extent. The fluid controller has important applications in biomedicine and chemical synthesis. By adjusting the pneumatic pressure, complex fluid processing operations such as automated mixing, separation and reaction can be achieved. The principle of realizing the oscillator is: by constructing multiple microfluidic transistors into a feedback loop, a periodic fluid oscillation signal can be generated.

[0069] Take the application of oscillators based on planar microfluidic triodes in automated cell culture as an example: some cell types (such as cardiomyocytes and endothelial cells) require a dynamic pressure change environment in in vitro culture to simulate their in vivo growth conditions. However, traditional culture methods are difficult to provide such a periodically changing environment. The oscillator composed of planar microfluidic triodes can generate fluid oscillations of a specific waveform, produce a periodically changing flow rate environment, and provide cells with a periodic variable pressure environment. This dynamic pressure simulation can effectively promote cell growth and functionalization. In the specific implementation, the oscillator forms a feedback loop through multiple triodes to generate a stable oscillation waveform. Integrating this oscillator into a cell culture system can provide cells with a dynamic variable pressure environment, which is suitable for automated cell culture, especially cells that are sensitive to dynamic pressure, such as cardiomyocytes, endothelial cells, etc. In this way, researchers can control the frequency and amplitude of the oscillation, thereby providing customized culture conditions for different types of cells, improving culture efficiency and reducing human interference.

[0070] In some embodiments, the planar microfluidic transistor 100 is made of polydimethylsiloxane (PDMS) material.

[0071] Specifically, the planar microfluidic transistor 100 can be integrally formed using PDMS material, so that the deformable film structure 131 is a PDMS film, which is elastic and can be deformed when subjected to liquid pressure to reduce the size of the channel 140. When the liquid pressure disappears, the PDMS film can return to its initial state to achieve the opening and closing of the channel 140.

[0072] The thickness and elastic modulus of the deformable film structure 131 have an impact on the deformation ability. The thinner the film is, the shorter the deformation response time is, and the thicker the film is, the longer the film deformation response time is. At the same time, the film deformation is relatively stable, which is suitable for high-precision fluid control.

[0073] In some embodiments, the width H (i.e., thickness) of the deformable film structure 131 is 10-20 mm, such as 10 mm, 15 mm, and 20 mm, the height W2 is 100-300 mm, such as 100 mm, 200 mm, and 300 mm, and the length L is 300-800 mm, such as 300 mm, 500 mm, and 800 mm. In one implementation, the deformable film structure 131 may be a PDMS film having a thickness of 10 mm, a height of 100 mm, and a length of 300 mm.

[0074] Furthermore, if Figures 1 to 3 As shown, the gate 130 is a fan-shaped structure. Specifically, the inside of the gate 130 is a fan-shaped structure to achieve more stable interlayer bonding. Because the planar microfluidic triode 100 adopts an integrated planar design as a whole, the gate 130 can effectively control the flow between the source 110 and the drain 120 under a liquid pressure of 30-60kPa. In some embodiments, the curvature of the fan-shaped structure is 1.049-1.696, for example, it can be 1.049, 1.530, 1.696, etc. The size of the planar microfluidic triode 100 (that is, the size of the deformable film structure 131 and the width W1 of the channel 140) and the material have an impact on the response speed, sensitivity and overall performance (including transconductance, impedance, gain, switching ratio, etc.) of the planar microfluidic triode 100. By adjusting the geometric structure of the intermediate channel, the switching control of the fluid can be achieved under a small deformation, thereby accelerating the arrival of the saturation state. The geometry of the microfluidic channel is optimized so that the membrane deformation caused by the gate 130 pressure can more accurately match the change in the flow channel, thereby improving the accuracy and reaction speed of the fluid switch. In addition, the planar design has the ability to be subsequently expanded and can be integrated into more complex microfluidic circuits, such as integrating more functional modules by superimposing multiple layers of fluid channels.

[0075] In some embodiments, Figure 8As shown, the present invention also provides a planar microfluidic device, which includes a substrate layer 200 and the planar microfluidic triode 100 as described above, and the planar microfluidic triode 100 is bonded to the substrate layer 200. In this embodiment, the planar microfluidic triode 100 and the substrate layer 200 are bonded together by bonding, and the planar microfluidic triode 100 can be obtained after being sealed by the substrate layer 200.

[0076] In some embodiments, the planar microfluidic device further includes a micropump assembly, which is connected to the planar microfluidic transistor 100 and is used to provide liquid pressure to the deformable film structure 131 .

[0077] In this embodiment, the micropump assembly can provide precise hydraulic pressure to regulate the deformation degree of the deformable film structure 131, so as to achieve precise control of the transmission and output of the fluid without relying on external traditional starting devices. In one implementation, the micropump assembly can be controlled by Bluetooth, so as to achieve remote and precise control of the flow rate of the fluid, meet the requirements of portability, and expand the application field of microfluidic devices. The specific structure of the micropump assembly of this embodiment can be found in the definition of patent CN201710923269.0, which will not be repeated here.

[0078] In some embodiments, the present invention provides a planar microfluidic circuit network, comprising a plurality of microfluidic devices as described above, wherein the microfluidic devices are integrated on the same plane, and the planar microfluidic transistors are connected in series or in parallel.

[0079] Specifically, the planar microfluidic transistor has a design of a single-layer patterned superimposed sealing layer (i.e., a substrate layer), which can realize the construction of complex microfluidic circuit networks, such as multi-channel liquid transmission, automated sample processing, and dynamic liquid distribution. By integrating multiple planar microfluidic transistors in a single planar structure, multi-stage series or parallel fluid logic operations, fluid signal processing, and dynamic adjustment of fluid transmission paths can be achieved. Furthermore, it can be combined with a portable micropump and can be widely used in biomedical analysis, such as multi-sample high-throughput detection, automated cell culture, liquid dilution, and precise control during the reaction process; in the field of chemical reactions, it can realize complex multi-step chemical synthesis and online analysis to ensure efficient and precise operation.

[0080] In some embodiments, Fig. 9As shown, the planar microfluidic transistor network (active) can also be combined with the microfluidic logic control network based on the burst valve (passive) to further enhance the control accuracy and logic function of the system, wherein the power supply represents the capillary burst valve, which has a certain fluid blocking effect and will not pass until the threshold pressure P is reached. The square represents the flow resistance, which is composed of the flow channel. The capacitor represents the cavity, which has the ability to store fluid, and the transistor corresponds to the microfluidic transistor.

[0081] In this embodiment, the burst valve controls the fluid through a preset pressure threshold, and can automatically open or close under specific conditions, combining active control schemes with passive control schemes to adapt to a wider range of application scenarios and needs. In this embodiment, the microfluidic transistor network serves as the main fluid control unit, regulating the transmission and switching state of the fluid through the gate, while the burst valve network provides an additional logic control layer. Specifically, the threshold of the burst valve can be set to different pressure values ​​to achieve logical functions such as AND, OR, and NOT. For example, microfluidic transistors can be used for basic fluid on-off control, while the burst valve can be used as a switch node for fluid signals under specific pressure conditions, thereby realizing multi-level logic operations.

[0082] The application scenarios of this solution include multi-step chemical reactions, automatic sample dilution, dynamic adjustment of fluid paths, etc. By combining the logic control of microfluidic triodes with burst valves, a more complex and automated microfluidic circuit network can be designed, which not only realizes precise fluid transmission control, but also can execute preset logic conditions within the system, further expanding the application scope of the present invention. This combination of structures also provides stronger control capabilities and application flexibility for high-throughput biological detection, on-site rapid analysis and multi-stage chemical reactions.

[0083] In some embodiments, Fig.10 As shown, the present invention provides a method for preparing a microfluidic device, which comprises the steps of:

[0084] S100, using photoresist to construct a microchannel template on a silicon wafer or a glass substrate by photolithography technology;

[0085] S200, pouring liquid polydimethylsiloxane material into the microchannel template, vacuuming to remove bubbles, and performing a curing process;

[0086] S300, after curing, demolding the polydimethylsiloxane material to obtain a planar microfluidic triode having a source electrode, a drain electrode and a gate channel;

[0087] S400, placing the surface of the planar microfluidic triode to be bonded and the corresponding surface of the substrate layer in an oxygen plasma device for treatment;

[0088] S500, taking out the planar microfluidic triode oxygen plasma device, and then laminating the area to be bonded with the base layer.

[0089] In this embodiment, firstly, a photoresist (taking SU-8 photoresist as an example) is formed on a silicon wafer or a glass substrate using soft lithography technology to construct a microchannel template, which specifically includes processes such as SU-8 photoresist spin coating, L-Line light source exposure and development, as shown in FIG. Fig.11 As shown. Then, pour the liquid PDMS into the microchannel template, evacuate to remove bubbles, and then solidify. After the liquid PDMS solidifies, demold the PDMS to obtain a microfluidic triode structure with source, drain and gate channels. Then, place the surface of the planar microfluidic triode that needs to be bonded and the corresponding surface of the substrate layer in an oxygen plasma device for an appropriate period of time, take the planar microfluidic triode out of the oxygen plasma device, and finally fit the area that needs to be bonded to the substrate layer. After waiting for a certain period of time, the functional layer (planar microfluidic triode) can be bonded to the substrate layer to obtain a microfluidic device.

[0090] In some embodiments, Fig.12 As shown, the present invention also provides another method for preparing a microfluidic device, which comprises the steps of:

[0091] S100, printing a master mold of a microfluidic transistor by a 3D printing device;

[0092] S200, performing surface treatment on the 3D printed master mold;

[0093] S300, pouring liquid polydimethylsiloxane material into the microchannel template, vacuuming to remove bubbles, and performing a curing process;

[0094] S400, after curing, demolding the polydimethylsiloxane material to obtain a planar microfluidic triode having a source electrode, a drain electrode and a gate channel;

[0095] S500, placing the surface of the planar microfluidic triode to be bonded and the corresponding surface of the substrate layer in an oxygen plasma device for treatment;

[0096] S600, taking out the planar microfluidic triode oxygen plasma device, and then laminating the area to be bonded with the base layer.

[0097] In this embodiment, the master mold of the microfluidic triode is first printed by a 3D printing device, and the printing material can be selected from high-resolution resins or photosensitive materials. After the master mold is printed, the 3D printed master mold is surface treated to ensure the smoothness of the master mold surface and reduce the adhesion of PDMS during demolding. Thereafter, the liquid PDMS is poured into the microchannel template, vacuumed to remove bubbles, and cured. After curing, the PDMS is demolded to obtain a planar microfluidic triode with a source, a drain and a gate channel. After the surface of the planar microfluidic triode that needs to be bonded and the corresponding surface of the substrate layer are placed in an oxygen plasma device for a certain period of time, the planar microfluidic triode oxygen plasma device is taken out, and the area that needs to be bonded is bonded to the substrate layer. After waiting for a certain period of time, the bonding can be completed to obtain a microfluidic device.

[0098] In some embodiments, Fig.13 As shown, the present invention also provides another method for preparing a microfluidic device, which comprises the steps of:

[0099] S100, preparing an imprinting mold by using nanoimprinting technology;

[0100] S200, pouring liquid polydimethylsiloxane material into the microchannel imprinting mold;

[0101] S300, demolding the polydimethylsiloxane material to obtain a planar microfluidic triode having a source electrode, a drain electrode and a gate channel;

[0102] S400, placing the surface of the planar microfluidic triode to be bonded and the corresponding surface of the substrate layer in an oxygen plasma device for treatment;

[0103] S500, taking out the planar microfluidic triode oxygen plasma device, and then laminating the area to be bonded with the base layer.

[0104] In this embodiment, the nanoimprinting technology is first used to prepare the imprinting mold, and the liquid PDMS is poured into the microchannel imprinting mold at an appropriate temperature and pressure. After the mold is cooled, the PDMS is demolded to obtain a planar microfluidic triode with a source, a drain and a gate channel. After the surface of the planar microfluidic triode to be bonded and the corresponding surface of the substrate layer are placed in an oxygen plasma device for a certain period of time, the planar microfluidic triode oxygen plasma device is taken out, and the area to be bonded is then bonded to the substrate layer. After waiting for a certain period of time, the bonding can be completed to obtain a microfluidic device.

[0105] In summary, the planar microfluidic transistor, device, preparation method thereof, and microfluidic circuit network provided by the present invention have the following beneficial effects:

[0106] The fluid flow between the source, drain and gate is controlled by the liquid pressure signal to realize the amplification and switching functions of the fluid. This planar design not only simplifies the system structure, but also enables the microfluidic triode to achieve efficient fluid control at a lower working pressure, can be further integrated with a portable micropump, and has subsequent expansion capabilities, suitable for more complex and highly integrated microfluidic systems.

[0107] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A planar microfluidic triode, characterized in that: include: Source, drain and gate; The source, the drain and the gate form a single-layer structure; there is a channel between the source and the drain; the gate includes a deformable film structure, the deformable film structure is located on one side of the channel, and the deformable film structure is used to adjust the gap of the channel when subjected to liquid pressure to control the flow rate of the fluid flowing through the channel.

2. The planar microfluidic triode according to claim 1, characterized in that: The gate is a fan-shaped structure.

3. The planar microfluidic triode according to claim 1, characterized in that: The planar microfluidic triode is made of polydimethylsiloxane material.

4. The planar microfluidic triode according to claim 2, characterized in that: The arc of the fan-shaped structure is 1.049-1.

696.

5. The planar microfluidic triode according to claim 1, characterized in that: The planar microfluidic triode is formed in one piece.

6. A planar microfluidic device, characterized in that: It comprises a base layer and the planar microfluidic triode as claimed in any one of claims 1 to 5, wherein the planar microfluidic triode is bonded to the base layer.

7. The planar microfluidic triode according to claim 6, characterized in that: It also includes a micro pump assembly, which is connected to the planar microfluidic triode and is used to provide liquid pressure for the deformable film structure.

8. A microfluidic circuit network, comprising a plurality of microfluidic devices as claimed in claim 6 or 7, characterized in that: The microfluidic devices are integrated on the same plane, and the planar microfluidic transistors are connected in series or in parallel.

9. A method for preparing a planar microfluidic device as claimed in claim 6, characterized in that: include: A microchannel template is constructed on a silicon wafer or a glass substrate by photolithography using photoresist; Pour liquid polydimethylsiloxane material into the microchannel template, remove air bubbles by vacuuming, and perform a curing process; After curing, the polydimethylsiloxane material is demolded to obtain a planar microfluidic triode having a source electrode, a drain electrode and a gate channel; The surface of the planar microfluidic triode to be bonded and the corresponding surface of the substrate layer are placed in an oxygen plasma device for treatment; Take out the planar microfluidic triode oxygen plasma device, and then fit the area to be bonded to the base layer.

10. A method for preparing a planar microfluidic device as claimed in claim 6, characterized in that: include: Print the master mold of the microfluidic transistor by 3D printing equipment; Surface treatment of the 3D printed master mold; Pour liquid polydimethylsiloxane material into the microchannel template, remove air bubbles by vacuuming, and perform a curing process; After curing, the polydimethylsiloxane material is demolded to obtain a planar microfluidic triode having a source electrode, a drain electrode and a gate channel; The surface of the planar microfluidic triode to be bonded and the corresponding surface of the substrate layer are placed in an oxygen plasma device for treatment; Take out the planar microfluidic triode oxygen plasma device, and then attach the area to be bonded to the substrate layer; or, The imprinting mold is prepared by using nanoimprinting technology; pouring liquid polydimethylsiloxane material into the microchannel imprinting mold; Demolding the polydimethylsiloxane material to obtain a planar microfluidic triode having a source electrode, a drain electrode and a gate channel; The surface of the planar microfluidic triode to be bonded and the corresponding surface of the substrate layer are placed in an oxygen plasma device for treatment; Take out the planar microfluidic triode oxygen plasma device, and then fit the area to be bonded to the base layer.

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