A microfluidic on-chip peristaltic micropump

Abstract

This invention discloses an on-chip peristaltic micropump for microfluidics, comprising a micropump chip system and a drive system. The micropump chip system includes a thin-film channel layer, an elastic thin-film layer, and a base plate arranged sequentially. A pumping module and a fluid control module are disposed on the thin-film channel layer. The pumping module includes an inlet, an annular flow channel, an output buffer, a pump outlet channel, and an outlet, all connected sequentially. The fluid control module includes a one-way valve disposed between the output buffer and the pump outlet channel, and a gas accumulator assembly connected to the pump outlet channel. The one-way valve includes a fluid channel composed of an upper valve chamber and a lower valve chamber. The elastic thin-film layer passes between the upper and lower valve chambers and has an inner valve hole. The upper valve chamber also has a protruding boss that extends into the fluid channel and fits against the plane of the elastic thin-film layer. This micropump possesses compact, reliable, stable, and precise fluid control and regulation capabilities, and has significant application value in the field of microfluidics.

Description

Technical Field

[0001] This invention relates to a microfluidic on-chip peristaltic micropump, belonging to the field of microfluidic chip technology. Background Technology

[0002] In the field of microfluidics, the precise transport and control of sample reagents is crucial. In existing microfluidic systems, external pumps (valves) are the traditional power source driving microfluidic chips, commonly including syringe pumps and peristaltic pumps. However, external pumps are too complex and hinder integration into microfluidic chips. Micropumps, as a new power source, are widely used due to the high integration of microfluidic chips. As a primary driving unit in the microfluidics field, micropumps can be used to control fluid detection, pumping, mixing, and the transport of small volumes of liquid. Furthermore, micropumps offer advantages such as small overall device size, good biocompatibility, lower cost in fluid pumping, and no cross-contamination.

[0003] Peristaltic micropumps, as a branch of micropump systems, are a concentrated manifestation of biological transport mechanisms. Peristalsis, as an essential transport mechanism within organisms, enables functions such as digestive tract movement and the circulatory system. This highly elegant transport mechanism has inspired researchers in the field of peristaltic micropump microfluidic devices. Peristaltic micropumps can be categorized into mechanical and non-mechanical micropumps based on their working principle. Mechanical micropumps typically use continuous rotors or integrated actuators to deform the pump cavity boundaries, thereby transporting fluid within the pump cavity. Mechanical micropumps are broadly classified according to the type of actuator, including electric motors, piezoelectric, electrostatic, electromagnetic, and pneumatic types. Non-mechanical micropumps primarily rely on the physicochemical properties of the fluid itself, converting non-mechanical energy into the fluid's kinetic energy to achieve fluid transport. Common non-mechanical micropumps include electroosmotic, surface tension, and thermally driven types. Because non-mechanical micropumps rely heavily on the fluid's inherent properties, their application scenarios are limited, making integration difficult.

[0004] In the field of microfluidics, mechanical micropumps primarily achieve fluid pumping by using actuators driven by drivers to power microfluidic chip structures. Therefore, microfluidic chips play a crucial role in the stability of the pumped fluid. However, conventional micropump chips only perform simple fluid pumping and cannot output stable flow rates without pulsation fluctuations. Thus, micropumps, as the main driving unit, are usually integrated with other fluid manipulation methods, such as accumulators and microvalves. Accumulators can absorb and store flow pulses, thereby outputting a more stable flow rate. Furthermore, microvalves are mainly used for fluid motion control and have fluid driving capabilities. Current technologies primarily focus on the research of these individual functions, and in-depth research has not yet been conducted on micropump systems that combine the driving capabilities of micropumps, the ability of accumulators to eliminate flow pulses, and the motion control capabilities of microvalves.

[0005] Existing research suggests that for certain specialized applications, multiple devices are required to achieve stable fluid pumping. However, this involves considerations such as compatibility between different devices, the bulkiness of multiple devices requiring specific experimental space, and the potential for secondary contamination of sample solutions, impacting experimental results. Therefore, a micropump system integrating multiple device functions is needed. This system would combine the driving power of a micropump, the ability of an accumulator to eliminate flow pulses, and the motion control function of a microvalve to achieve stable fluid pumping. Integrated micropump systems offer advantages such as small overall size, good biocompatibility, lower cost in fluid pumping, and no cross-contamination. However, due to the multi-layered structure of the micropump chip system, achieving tight bonding of these layers is challenging, leading to bonding failures, detachment, and difficulties in positioning specific structures. Existing bonding techniques can improve bonding through deionization machines. Furthermore, because the microstructure is primarily microscopic, achieving the same level of alignment as conventional machining processes, such as drilling holes in one-way valves, can be addressed by modifying the manufacturing process to partially bond the components and then manually align them during drilling. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a microfluidic on-chip peristaltic micropump that can precisely control fluid flow and effectively avoid the influence of backflow and pulsating flow on the output flow rate.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] This invention provides a microfluidic on-chip peristaltic micropump, including a micropump chip system and a driving system;

[0009] The micropump chip system includes a thin film channel layer, an elastic thin film layer, and a substrate arranged sequentially.

[0010] The thin film channel layer is provided with a pumping module and a fluid control module. The pumping module includes an inlet, an annular flow channel, an output buffer tank, a pumping out flow channel, and an outlet connected in sequence.

[0011] The fluid control module includes a one-way valve disposed between the output buffer tank and the pump outlet channel, and a gas accumulator group connected to the pump outlet channel; the one-way valve includes a fluid channel composed of an upper valve chamber and a lower valve chamber, the upper valve chamber being disposed in a thin film channel layer, and the lower valve chamber being disposed on a base plate.

[0012] The elastic film layer passes between the upper and lower valve chambers, and the elastic film layer between the upper and lower valve chambers is provided with an inner valve hole; the upper valve chamber is provided with a boss protruding into the fluid channel, and the elastic film layer is in contact with the plane of the boss.

[0013] The bearing positioning shaft in the drive system is set on the annular flow channel.

[0014] Furthermore, the thin-film channel layer is a single-channel thin-film layer or a dual-channel thin-film layer; the single-channel thin-film layer is provided with a pumping module and a fluid control module, and the dual-channel thin-film layer is provided with two pumping modules and two fluid control modules; the output end of the output buffer pool and / or the pump outlet channel are connected to a gas accumulator group.

[0015] Furthermore, the deformation displacement of the elastic film layer is greater than 5 times the film thickness of the elastic film layer, and the fluid pressure exerted on the elastic film layer is in the range of 5-100 kPa.

[0016] Furthermore, the cross-section of the annular flow channel is arc-shaped.

[0017] Furthermore, the cross-sectional shape of the pump outlet channel is rectangular, and at least two gas accumulator groups are connected in parallel at opposite corners of the rectangle to achieve stable pumping of fluid.

[0018] Furthermore, the gas accumulator assembly includes a curved gas chamber with one end connected to the pump outlet channel, and a circular gas chamber connected to the other end of the curved gas chamber.

[0019] Furthermore, the base plate is made of plexiglass, glass, or printed circuit board material.

[0020] Furthermore, the drive system includes a stepper motor, and the bearing positioning shaft is connected to the stepper motor via a coupling.

[0021] Furthermore, the bearing positioning shaft includes an interference fit shaft and a roller bearing. The shaft is connected to a stepper motor via a coupling. The roller bearing is in close contact with the annular flow channel, rotating and compressing the annular flow channel to pump fluid.

[0022] Furthermore, the drive system is also equipped with a Z-axis slide rail, which is connected to a stepper motor. The up and down movement of the Z-axis slide rail drives the up and down adjustment of the motor.

[0023] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0024] The micropump chip system of the present invention is designed with a pumping module and a fluid control module. The motor of the drive system drives the roller bearing to squeeze the annular flow channel of the pumping module. The pumped fluid is based on the suppression of backflow by a one-way valve, and the gas accumulator group can adjust, replenish and store the impact energy under the impact of fluid flow pulse, thereby achieving precise flow control.

[0025] The annular flow channel of this invention has an arc-shaped cross-section, which allows the roller bearing to fully compress the flow channel to achieve an excellent pumping effect.

[0026] The microfluidic on-chip peristaltic micropump proposed in this invention integrates the functions of a micro-peristaltic pump and a flow regulating microvalve, and has the advantages of precise microfluidic drive and control. It has good application prospects in applications such as low-cost, portable microfluidic chip laboratories and point-of-care testing instruments. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of the on-chip peristaltic micropump provided in an embodiment of the present invention;

[0028] Figure 2 This is an exploded view of the micropump chip system provided in an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of the flow channel structure of the thin film single-channel layer provided in an embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram of the flow channel structure of the thin film dual-channel layer provided in an embodiment of the present invention;

[0031] Figure 5 This is a cross-sectional structural diagram of the one-way valve provided in an embodiment of the present invention;

[0032] Figure 6 This is a schematic diagram of the opening (upper) and shut-off (lower) operation of the one-way valve provided in this embodiment of the invention;

[0033] Figure 7 This is a schematic diagram of the overall structure of two types of bearing shafts provided in the embodiments of the present invention;

[0034] Figure 8 This is a schematic diagram of the working principle structure of the on-chip peristaltic micropump provided in an embodiment of the present invention;

[0035] Figure 9 It is a schematic diagram of the cross-section of the roller without extruded annular flow channel and extruded annular flow channel;

[0036] In the diagram: 1. Z-axis slide rail, 2. Stepper motor, 3. Coupling, 4. Bearing positioning shaft, 41. Shaft, 42. Roller bearing, 5. Micropump chip system, 51. Thin film channel layer, 511. Pump outlet channel, 512. Gas accumulator group, 513. Check valve, 514. Output buffer tank, 515. Liquid inlet, 516. Liquid outlet, 517. Annular channel, 513. Check valve, 5131. Check valve inlet, 5132. Upper valve chamber, 5133. Boss, 5134. Check valve outlet, 52. Elastic thin film layer, 521. Valve inner hole, 53. Base plate, 531. Lower valve chamber. Detailed Implementation

[0037] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0038] like Figure 1-6 As shown, the microfluidic on-chip peristaltic micropump provided by the present invention is an on-chip peristaltic micropump with precisely adjustable flow rate, including a drive system and a micropump chip system 5. The micropump chip system 5 includes a thin film channel layer 51, an elastic thin film layer 52, and a base plate 53, wherein the elastic thin film layer 52 is an elastic material that can recover its original shape after being squeezed under fluid pressure, and the thin film channel layer 51 includes a pumping module and a fluid control module.

[0039] The pumping module includes an inlet 515, an outlet 516, an annular flow channel 517, a pump outlet flow channel 511, and an output buffer tank 514. The inlet 515, outlet 516, and output buffer tank 514 are all circular buffer tanks. The sample liquid enters the annular flow channel 517 through the inlet 515. The annular flow channel 517 consists of a semi-circular channel with a semi-circular arc shape in cross-section. It connects to the pump outlet flow channel 511 through the output buffer tank 514. The pump outlet flow channel 511 has a rectangular cross-section. Finally, the sample liquid is pumped once through the outlet 516.

[0040] It is feasible to install a fluid control module on the pumping channel 511 to control the flow rate of the pumped fluid. The fluid control module includes a one-way valve 513 and a gas accumulator group 512. The one-way valve 513 can effectively suppress fluid backflow and play the role of interception and conduction.

[0041] At the rectangular diagonal of the pump outlet channel 511, a gas accumulator group 512 is connected in parallel to achieve stable fluid pumping. The gas accumulator group 512 includes a circular gas chamber and a curved gas chamber, which together form a closed gas chamber connected to the pump outlet channel 511 to regulate the pulse flow of the sample liquid passing through the pump outlet channel 511, effectively reducing sample liquid fluctuations and stabilizing the pumping flow rate.

[0042] The one-way valve 513 includes a one-way valve inlet 5131, an upper valve chamber 5132, a boss 5133, a one-way valve outlet 5134, a one-way valve inner hole 521 on the elastic diaphragm layer 52, and a lower valve chamber 531 on the base plate 53. The upper valve chamber 5132 and the lower valve chamber 531 together form the fluid passage of the one-way valve; the inlet 5131 is connected to the output buffer tank 514, and the one-way valve outlet 5134 leads to the gas accumulator group 512 and the pump outlet channel 511.

[0043] In order to achieve the one-way conduction function of the one-way valve 513, an elastic film layer 52 is provided between the upper valve chamber 5132 and the lower valve chamber 531 of the one-way valve. The elastic film layer 52 is a thin film, and the elastic film layer 52 is provided with a valve inner hole 521 for the fluid switch of one-way conduction.

[0044] In order to facilitate the function of the elastic diaphragm 52 in intercepting or conducting flow, a boss 5133 is provided on the inner wall of the upper half valve cavity 5132 of the fluid channel, and the boss 5133 protrudes into the fluid channel of the one-way valve.

[0045] One end of the elastic diaphragm 52 is fixedly connected to the inner wall of the upper half of the valve cavity in the fluid channel, and the other end is attached to the boss 5133. When the fluid flows from the inlet 5131 of the one-way valve to the outlet 5134 of the one-way valve, the elastic diaphragm 52 disengages from the boss 5133, and the fluid is allowed to flow. When the fluid flows from the outlet 5134 of the one-way valve to the inlet 5131 of the one-way valve, the elastic diaphragm 52 is attached to the boss 5133, which cuts off the flow and prevents the fluid from flowing, thereby suppressing backflow.

[0046] In this invention, the elastic diaphragm 52 is a highly elastic thin film and is attached to the plane of the protrusion 5133. It can achieve a deformation displacement of not less than 5 times its own thickness under fluid pressure below 30 kPa.

[0047] This invention designs two types of thin-film channel layers 52, one of which is Figure 3 The thin-film single-channel layer shown includes a single pump module and a single fluid control module to achieve precise and stable sample liquid inlet and outlet via a single inlet. Another type is... Figure 4 The illustrated dual-channel thin-film layer includes a dual-pump module and a dual-fluid control module to achieve precise and stable sample liquid inflow through dual inlets and dual outlets, essentially integrating two single-channel thin-film chips. Because the width of the roller on the bearing positioning shaft 4 is approximately five times the width of the annular channel 517, the bearing positioning shaft 4 can simultaneously compress multiple annular channels. Both channels contain pumping and fluid control modules, and the channels are independent and do not interfere with each other, preventing secondary contamination of the sample liquid between the two channels and achieving stable dual-inflow and dual-outflow of the sample liquid.

[0048] The drive system includes a Z-axis slide rail 1, a stepper motor 2, a coupling 3, and a bearing positioning shaft 4, wherein the bearing positioning shaft 4 includes a shaft 41 and a roller bearing 42; the present invention provides two types of bearing positioning shafts 4, such as... Figure 7 As shown, where Figure 7 The left image shows a two-phase bearing positioning shaft with two roller bearings, while the right image shows a three-phase bearing positioning shaft with three roller bearings. The shaft is driven by a stepper motor connected to a coupling.

[0049] The roller bearing 42 and the shaft 41 of the two bearing positioning shafts 4 provided in this invention are connected by an interference fit.

[0050] The coupling 3 provided in this invention is mainly used to connect the bearing shaft and the motor shaft to achieve power transmission.

[0051] The stepper motor in this invention adopts the PID algorithm speed closed-loop control theory. The stepper motor is driven by the control board through simulated control signals to achieve arbitrary speed. The speed of the motor is adjusted to adjust the frequency of the roller extrusion pump flow channel, thereby achieving adjustable flow rate.

[0052] The Z-axis displacement platform provided in this invention can achieve vertical lifting and lowering of the stepper motor through manual fine-tuning, such as... Figure 9 The diagram shown illustrates the effect of roller extrusion annular flow channel. The flow rate is adjustable by changing the cross-sectional area of ​​the extrusion annular flow channel by moving the rollers up and down through a Z-axis displacement platform.

[0053] The annular flow channel 514 in this invention includes an arc flow channel composed of small circular arcs in cross-section, which is the main pumping channel.

[0054] In the gas accumulator group 515 of the present invention, the gas cavity and the curved flow channel are directly bonded to the bottom plate 53 to form a gas cavity, and a gas-liquid boundary is formed at the connection between the pump outlet flow channel 516 and the curved flow channel.

[0055] The micropump of this invention is fabricated using soft photolithography, a technique commonly used in microfluidics laboratories, and is made of polydimethylsiloxane. Specifically, the polydimethylsiloxane in the elastic diaphragm 52 is in a prepolymer to crosslinked form mass ratio of 20:1, ensuring high elasticity. In other components of the micropump, the polydimethylsiloxane is in a prepolymer to crosslinked form mass ratio of 10:1, further ensuring good mechanical properties for each component.

[0056] like Figure 8 The image shows the working state of the micro-pump fluid delivery. Figure 9 This is a schematic diagram of the cross-sections of the roller without an extruded annular flow channel and with an extruded annular flow channel, wherein, Figure 9 The left image is a cross-sectional view of the roller without compressing the annular flow channel; the right image is a cross-sectional view of the roller with compressed annular flow channel. The specific working process of the microfluidic on-chip peristaltic micropump provided by this invention is as follows:

[0057] The Z-axis slide rail 1 is adjusted so that the roller bearing 42 on the bearing positioning shaft 4 is tightly attached to the annular flow channel 514. The bearing positioning shaft 4 is driven to rotate clockwise by the stepper motor coupling. The sample liquid is input from the inlet and pumped by the roller bearing 42 squeezing the annular flow channel 514. After one cycle, the sample liquid reaches the pump outlet flow channel 516 and enters the lower half valve chamber 531 from the inlet of the one-way valve 5131. After reaching the cumulative flow, the elastic diaphragm 52 disengages from the boss 5133 under the action of liquid pressure, and the fluid flows out from the outlet of the one-way valve 513. At the same time, when reverse backflow occurs, that is, when the fluid flows from the outlet 5134 of the one-way valve to the inlet 5131 of the one-way valve, the elastic diaphragm 52 adheres to the boss 5133 to achieve interception and suppress backflow.

[0058] Under continuous pumping action, the sample liquid flows to the gas-liquid interface of the gas accumulator group 512. The pulse overflow flow rate is regulated by gas compression feedback, while the downward overflow flow rate is regulated by gas expansion to achieve stable flow pumping. The pump outlet channel 511 realizes two gas accumulators connected diagonally in parallel to better achieve stable pumping of the fluid. Finally, a more accurate and stable sample liquid is obtained through the liquid outlet 512.

[0059] 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 modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A microfluidic on-chip peristaltic micropump, characterized in that, Including micropump chip systems and drive systems; The micropump chip system includes a thin film channel layer (51), an elastic thin film layer (52), and a base plate (53) arranged sequentially. The thin film channel layer (51) is provided with a pumping module and a fluid control module. The pumping module includes an inlet (515), an annular flow channel (517), an output buffer (514), a pumping flow channel (511), and an outlet (516) connected in sequence. The fluid control module includes a one-way valve (513) disposed between the output buffer pool (514) and the pump outlet channel (511), and a gas accumulator group (512) connected to the pump outlet channel (511). The pump outlet channel (511) has a rectangular cross-sectional shape, and at least two opposite corners of the rectangle are connected in parallel with the gas accumulator group (512) to achieve stable pumping of fluid. The one-way valve (513) includes a fluid channel composed of an upper valve chamber (5132) and a lower valve chamber (531). The upper valve chamber (5132) is disposed in the thin film channel layer, and the lower valve chamber (531) is disposed on the base plate (53). The elastic film layer (52) passes between the upper valve cavity (5132) and the lower valve cavity (531), wherein the elastic film layer (52) located between the upper valve cavity (5132) and the lower valve cavity (531) is provided with a valve inner hole (521); the upper valve cavity (5132) is provided with a boss (5133) protruding into the fluid channel, and the elastic film layer (52) is in plane contact with the boss (5133); The bearing positioning shaft (4) in the drive system is set on the annular flow channel (517).

2. The on-chip peristaltic micropump according to claim 1, characterized in that, The thin film channel layer (51) is a single-channel thin film layer or a dual-channel thin film layer; a pumping module and a fluid control module are provided on the single-channel thin film layer, and two pumping modules and two fluid control modules are provided on the dual-channel thin film layer; the output end of the output buffer pool (514) and / or the pump outlet channel (511) are connected to a gas accumulator group (512).

3. The on-chip peristaltic micropump according to claim 1, characterized in that, The deformation displacement of the elastic film layer (52) is greater than 5 times the thickness of the film of the elastic film layer (52), and the fluid pressure range of the elastic film layer (52) is 5-100 kPa.

4. The on-chip peristaltic micropump according to claim 1, characterized in that, The cross-section of the annular flow channel (517) is circular arc-shaped.

5. The on-chip peristaltic micropump according to claim 1, characterized in that, The gas accumulator assembly (512) includes a curved gas chamber connected at one end to a pump outlet channel (511), and a circular gas chamber connected at the other end of the curved gas chamber.

6. The on-chip peristaltic micropump according to claim 1, characterized in that, The base plate (53) is made of plexiglass, glass or printed circuit board material.

7. The on-chip peristaltic micropump according to claim 1, characterized in that, The drive system includes a stepper motor (2), and the bearing positioning shaft (4) is connected to the stepper motor (2) via a coupling (3).

8. The on-chip peristaltic micropump according to claim 7, characterized in that, The bearing positioning shaft (4) includes an interference fit shaft (41) and a roller bearing (42). The shaft (41) is connected to the stepper motor (2) through a coupling (3). The roller bearing (42) is in close contact with the annular flow channel (517) and can rotate and squeeze the annular flow channel (517) to pump fluid.

9. The on-chip peristaltic micropump according to claim 7, characterized in that, The drive system is also equipped with a Z-axis slide rail (1), which is connected to a stepper motor (2). The up and down movement of the Z-axis slide rail drives the up and down adjustment of the motor (2).

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