A multi-channel centrifugal microfluidic reactor with controllable diameter and multi-layer coating

Abstract

This invention belongs to the field of microfluidics technology, specifically relating to a multi-channel centrifugal microfluidic reactor with controllable diameter and multi-layer coating. It includes a body, a centrifugal microfluidic unit, and a liquid accumulation unit. The multi-layer coated droplet initial formation unit within the centrifugal microfluidic unit includes a driven shaft. The output end of a rotation drive unit is connected to the driven shaft, driving it to rotate. A cylindrical liquid injection chamber is centrally located inside the driven shaft, surrounded by multiple annular liquid injection chambers. Microfluidic connectors, the same number as the vertical channels, are connected below the driven shaft. These connectors communicate with both horizontal and vertical channels, and each connector contains a liquid confluence point. A needle is connected below each connector. The liquid accumulation unit includes a liquid accumulation cup. This invention features high throughput, low coefficient of variation, precise controllable liquid capsule size, and the ability to achieve multi-layer coating.

Description

Technical Field

[0001] This invention belongs to the field of microfluidics technology, specifically relating to a multi-channel centrifugal microfluidic reactor with controllable diameter and multi-layer coating, which is suitable for applications requiring high-throughput and high-precision fluid manipulation, such as pharmaceutical engineering, biomedical testing, food, and environmental applications. Background Technology

[0002] Microfluidics, a significant breakthrough in modern analytical science and biomedical engineering, is a key technology for building "lab-on-a-chip" systems and realizing "micro total analysis systems." Its core advantage lies in the precise manipulation of fluids from nanoliters to picoliters through micrometer-scale fluid channels, thereby enabling miniaturized, automated, integrated, and high-throughput operation of complex biological and chemical processes.

[0003] Droplet microfluidics, as an important branch, is a technological platform that enables two-phase or multi-phase immiscible fluids to interact within microscale channels, generating and precisely manipulating discrete droplets. Its core characteristic is the transformation of macroscopic fluid manipulation into precise control of monodisperse droplet units. It offers advantages such as low reagent consumption, fast reaction rates, high throughput, and independent control over the volume and composition of droplets (capsules). It is widely used in materials synthesis (such as the synthesis of microcapsules, microparticles, and microfibers), chemical and biochemical microreactors, drug development, clinical chemistry, immunodiagnostics, protein analysis, cell processing, molecular diagnostics, and environmental, biological, and food testing fields.

[0004] Currently, droplet microfluidics primarily achieves precise control over droplet (capsule) generation through two methods: manipulating microchannel geometry and external energy. Microchannel geometries encompass various types, such as "T-junctions," "coaxial flow," "flow focusing," and "stepped emulsification." By adjusting these structures and combining them with the fluid's inherent physical properties (viscosity ratio, interfacial tension, wettability, density difference, and velocity ratio), precise control of droplet (capsule) size can be achieved, adapting them to multiphase systems and generating multiple emulsions (W / O / W, O / W / O) or complex structures. External energy inputs mainly include, but are not limited to, electric fields, magnetic fields, and centrifugal forces. This energy directly acts on the fluid interface, altering its physical properties (such as interfacial tension and contact angle) or mechanical state (distribution), thereby effectively controlling the droplet (capsule) generation process. Thanks to the flexibility and proactivity of this method, the generated droplets (capsules) exhibit a low coefficient of variation (CV). In practical applications, both methods are typically combined to achieve better results.

[0005] The technology of using centrifugal force to drive fluid flow is called centrifugal microfluidics. This technology boasts several significant advantages: First, its pump-free design simplifies the system structure and reduces complexity; second, precise control of droplet (capsule) size can be achieved by adjusting the rotational speed; and finally, the centrifugal field effectively eliminates bubble interference within microchannels and reduces dead volume, thereby improving system stability and detection accuracy. With these advantages, centrifugal microfluidics shows broad application prospects in multiple fields, especially in applications requiring precise control of droplet (capsule) size, monodispersity, and high throughput, such as the preparation of emulsions, suspensions, and microcapsules. Currently, this technology is widely used in materials synthesis, drug development, clinical chemistry, immunodiagnostics, protein analysis, cell processing, molecular diagnostics, and environmental, biological, and food testing. The typical implementation of traditional centrifugal microfluidic systems is the "lab-on-disk," which integrates various microchannel structures onto a circular turntable similar to an optical disc using micro-nano fabrication processes such as photolithography or thermoforming. This forms a single-layer or multi-layer disc-shaped chip, which is then driven by centrifugal force to generate microdroplets (capsules) of the desired morphology. This structure played a crucial role in the early development of centrifugal microfluidic technology, becoming the mainstream choice for centrifugal systems due to its ease of rotational driving and integrated operation. However, the disc-shaped chip structure has several limitations in practical applications and engineering transformation. First, the channel design inside the chip is extremely complex, placing extremely high demands on the precision and consistency of micro-nano fabrication processes, resulting in high manufacturing costs. Second, its ability to integrate and expand multifunctional modules is limited, inevitably facing the challenge of performance trade-offs while pursuing high-throughput and highly monodisperse droplet (capsule) generation. In addition, the disc structure is highly dependent on custom chips, which not only hinders rapid system iteration and flexible deployment but also limits its large-scale promotion in the productization process. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a multi-channel centrifugal microfluidic reactor with controllable diameter and multi-layer coating, namely a chipless centrifugal multi-channel microfluidic reaction system. Based on four core concepts—centrifugal force driving mechanism, combination of 3D-printed microchannels and chipless structure design, open platform architecture, and external modular expansion—it effectively solves the core pain points of traditional technologies, such as complex processes, rigid structures, slow iteration, and poor flexibility.

[0007] This invention is implemented as follows: A multi-channel centrifugal microfluidic reactor with controllable diameter and multi-layer coating is provided, comprising a body, a centrifugal microfluidic unit, and a liquid accumulation unit. The centrifugal microfluidic unit is vertically movable on the body and includes an upper support, a lower support, a rotation drive unit, and a multi-layer coated droplet preliminary formation unit. The inverted U-shaped upper and lower support are fixedly connected. The output end of the rotation drive unit passes through the upper support. The multi-layer coated droplet preliminary formation unit includes a driven shaft, which is rotatably connected to the upper and lower support. The output end of the rotation drive unit is connected to... The driven shaft is connected and drives its rotation. A cylindrical liquid injection chamber is located in the center of the driven shaft. Multiple horizontal channels are connected to the lower end of the cylindrical liquid injection chamber. Multiple annular liquid injection chambers are located around the cylindrical liquid injection chamber. Multiple vertical channels are located at the lower end of the annular liquid injection chambers. Microfluidic connectors with the same number of vertical channels are connected below the driven shaft. The microfluidic connectors are connected to the horizontal and vertical channels respectively, and liquid confluence points are provided inside the microfluidic connectors. A needle is connected below each microfluidic connector. The liquid accumulation unit includes a liquid accumulation cup, which is located on the body directly below the driven shaft.

[0008] Preferably, the machine body includes a profile frame, a linear guide rail is provided on the vertical profile of the profile frame, a slider is provided on the linear guide rail, one end of the upper support seat and the lower support seat is fixedly connected to the slider, and a linear guide clamp is provided on the linear guide rail below the slider.

[0009] Preferably, the rotation drive unit includes a motor, a coupling, a driving synchronous pulley, and a synchronous belt. A motor mount is provided on the upper support, the motor is mounted on the motor mount, the output end of the motor is connected to the coupling, the coupling passes through the upper support and is connected to the driving synchronous pulley, and the synchronous belt is sleeved on the driving synchronous pulley and the driven synchronous pulley on the driven shaft.

[0010] Further preferably, a timing belt tensioning unit is provided on the upper support seat. The timing belt tensioning unit includes a tensioning block, an idler shaft, and an idler wheel. The tensioning block is installed on the upper surface of the upper support seat and connected to the idler shaft. The lower end of the idler shaft is rotatably connected to the idler wheel, and the idler wheel is in contact with the timing belt.

[0011] Preferably, an indexing plate is provided on the outer side of the portion of the driven shaft above the upper support, the indexing plate has an array of strip holes, and a photoelectric encoder sensor is provided on the upper support, with the indexing plate within the sensing range of the photoelectric encoder sensor.

[0012] Preferably, a liquid injection bracket is connected to the upper support base, the liquid injection bracket extends above the driven shaft, and multiple liquid injection connectors are provided on the liquid injection bracket, with one liquid injection connector above both the cylindrical liquid injection cavity and the annular liquid injection cavity.

[0013] Preferably, the machine body is provided with an electronic control board and a touch screen, and the electronic control board is connected to the touch screen and the rotation drive unit respectively.

[0014] Compared with the prior art, the advantages of the present invention are as follows:

[0015] 1) Significant cost-effectiveness, greatly reducing manufacturing costs and achieving effective integration of 3D printed parts (microfluidic connectors);

[0016] 2) It adopts a modular design, supports flexible functional expansion, and facilitates rapid productization and mass production;

[0017] 3) Possesses excellent iteration capabilities and can quickly complete technology upgrades;

[0018] 4) Exhibits excellent performance in droplet (capsule) generation: high throughput, low coefficient of variation, precise and controllable particle size, and can achieve multiple coating functions;

[0019] 5) The overall design adopts a chipless approach, eliminating the need for microfabrication and microchannel operations during the manufacturing process. This eliminates complex and expensive processes such as photolithography, etching, and bonding, which require a cleanroom environment. As a result, costs are significantly reduced, the operation process is simplified, and portability is improved. While achieving the goal of chipless operation, the characteristics of precise microscale control are still retained. Attached Figure Description

[0020] Figure 1 This is an overall structural diagram of the centrifugal microfluidic reactor provided by the present invention;

[0021] Figure 2 This is a structural diagram of the centrifugal microfluidic unit in this invention;

[0022] Figure 3 This is a structural diagram of the liquid collection cup in this invention;

[0023] Figure 4 This is a structural diagram of the organism in this invention;

[0024] Figure 5 This is a cross-sectional view of the centrifugal microfluidic unit of the present invention;

[0025] Figure 6 This is a cross-sectional view of the horizontal channel and the location of the liquid confluence in this invention;

[0026] The components are: 1-body, 101-profile frame, 102-linear guide rail, 103-slider, 104-linear guide clamp, 105-electric control board, 106-touch screen; 2-centrifugal microfluidic unit, 201-motor, 202-motor base, 203-coupling, 204-linear guide mounting plate, 205-upper support, 206-lower support, 207-tensioning block, 208-idler shaft, 209-active synchronous pulley, 210-synchronous belt, 211-idler, 212-photoelectric encoder sensor, 213-indexing plate, 214-liquid injection connector, 215-microfluidic connector, 216-needle, 217-driven shaft, 218-cylindrical liquid injection chamber, 219-annular liquid injection chamber, 220-liquid confluence, 3-liquid collection unit, 301-base, 302-liquid collection cup. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0028] refer to Figures 1-6 This invention provides a multi-channel centrifugal microfluidic reactor with controllable diameter and multi-layer coating, comprising a body 1, a centrifugal microfluidic unit 2, and a liquid accumulation unit 3. The centrifugal microfluidic unit 2 is movably mounted on the body 1. The centrifugal microfluidic unit 2 includes an upper support 205, a lower support 206, a rotation drive unit, and a multi-layer coated droplet preliminary forming unit. The inverted U-shaped upper support 205 and lower support 206 are fixedly connected. The output end of the rotation drive unit passes through the upper support 205. The multi-layer coated droplet preliminary forming unit includes a driven shaft 217, which is rotatably connected to the upper support 205 and lower support 206. The output end of the rotation drive unit is connected to the driven shaft 217, driving the driven shaft 217 to rotate. The driven shaft 217 has a cylindrical liquid injection chamber 218 in the center. The lower end of the cylindrical liquid injection chamber 218 is connected to multiple horizontal channels. The outer periphery of the cylindrical liquid injection chamber 218 has multiple annular liquid injection chambers 219. The lower end of the annular liquid injection chambers 219 has multiple vertical channels. The same number of microfluidic connectors 215 as the vertical channels are connected below the driven shaft 217. The microfluidic connectors 215 are connected to the horizontal channels and the vertical channels respectively. A liquid confluence point 220 is provided in the microfluidic connector 215. A needle 216 is connected below each microfluidic connector 215. The liquid accumulation unit 3 includes a liquid accumulation cup 302. The liquid accumulation cup 302 is set on the body 1 directly below the driven shaft 217 via a base 301.

[0029] In this embodiment, a two-layer driven shaft 217 is adopted, namely, a cylindrical liquid injection chamber 218 and an annular liquid injection chamber 219, and four horizontal channels, four vertical channels, four microfluidic connectors 215 and four needles 216.

[0030] In the process of preparing multilayer coated droplets or capsules using the centrifugal microfluidic reactor provided in this embodiment, the outer phase liquid of the capsule is injected into the accumulation cup 302, and the position of the centrifugal microfluidic unit 2 on the body 1 is lowered until the needle 216 penetrates below the liquid surface of the accumulation cup 302. Then, liquid A and liquid B are injected into the annular liquid injection chamber 219 and the cylindrical liquid injection chamber 218. The rotation drive unit is started, and the rotation drive unit drives the driven shaft 217 to rotate. When the driven shaft 217 rotates, it drives the four microfluidic connectors 215 and the four needles 216 to rotate. During the rotation, due to the centrifugal force, liquid A and liquid B inside the driven shaft 217 are thrown out. They pass through the horizontal channel and the vertical channel respectively and enter the microfluidic connector 215, forming two layers of coated liquid capsules at the liquid confluence 220. The liquid capsules are thrown out from the four needles 216 respectively, and the two layers of coated liquid capsules enter the outer phase liquid of the accumulation cup 302 to form a three-layer coated outer phase liquid. The reaction is then completed.

[0031] If the driven shaft 217 chamber is modified to a three-layer structure, i.e., with a cylindrical liquid injection chamber 218 and two annular liquid injection chambers 219, the ejected liquid capsule will have a three-layer coating, and after entering the liquid collection cup 302, it will form a four-layer coating. Similarly, the more layers the driven shaft chamber structure has, the more coating layers will be formed.

[0032] As a specific implementation of the body 1, the body 1 includes a profile frame 101, a linear guide rail 102 is provided on the vertical profile of the profile frame 101, a slider 103 is provided on the linear guide rail 102, one end of the upper support 205 and the lower support 206 (through the linear guide mounting plate 204) is fixedly connected to the slider 103, and a linear guide clamp 104 is provided on the linear guide rail 102 below the slider 103.

[0033] When adjusting the position of the centrifugal microfluidic unit 2 on the body 1, the position of the linear guide clamp 104 is adjusted, and then the slider 103 slides on the linear guide rail 102, thereby changing the position of the centrifugal microfluidic unit 2.

[0034] As a specific implementation of the rotation drive unit, the rotation drive unit includes a motor 201, a coupling 203, a driving synchronous pulley 209, and a synchronous belt 210. A motor seat 202 is provided on the upper support 205, and the motor 201 is mounted on the motor seat 202. The output end of the motor 201 is connected to the coupling 203. The coupling 203 passes through the upper support 205 and is connected to the driving synchronous pulley 209. The synchronous belt 210 is sleeved on the driving synchronous pulley 209 and the driven synchronous pulley on the driven shaft 217.

[0035] When it is necessary to drive the driven shaft 217 to rotate, the motor 201 is started. The output shaft of the motor 201 drives the coupling 203, the driving synchronous pulley 209, and the synchronous belt 210 to rotate, thereby driving the driven synchronous pulley on the driven shaft 217 to rotate, and finally driving the driven shaft 217 to rotate.

[0036] To ensure the accuracy of the rotation speed and thus the accuracy of the particle size of the prepared liquid capsules, as an improvement to the technical solution, a synchronous belt tensioning unit is also provided on the upper support 205. The synchronous belt tensioning unit includes a tensioning block 207, an idler shaft 208, and an idler wheel 211. The tensioning block 207 is installed on the upper surface of the upper support 205 and is connected to the idler shaft 208. The lower end of the idler shaft 208 is rotatably connected to the idler wheel 211, and the idler wheel 211 is in contact with the synchronous belt 210.

[0037] The tensioning block 207 includes a fixed tensioning block and a movable tensioning block. The fixed tensioning block is fixed on the upper support base 205. The movable tensioning block has an elongated hole, and the upper support base 205 has a threaded hole. A fixing screw passes through the elongated hole on the movable tensioning block and the threaded hole on the upper support base 205, so that the movable tensioning block is variably connected to the upper support base 205. A tensioning screw is provided between the fixed tensioning block and the movable tensioning block and is connected to both of them. By turning the tensioning screw, the distance between the fixed tensioning block and the movable tensioning block is adjusted, thereby adjusting the contact tightness between the idler pulley 211 and the timing belt 210, so that the timing belt 210 is always kept in a taut state.

[0038] In order to accurately control and adjust the rotational speed of the driven shaft 217, an indexing plate 213 is provided on the outer side of the portion of the driven shaft 217 above the upper support 205. The indexing plate 213 is provided with an array of strip holes. A photoelectric encoder sensor 212 is provided on the upper support 205. The indexing plate 213 is within the sensing range of the photoelectric encoder sensor 212.

[0039] The photoelectric encoder sensor 212 calculates the rotational speed of the driven shaft 217 by sensing the number of strip holes on the indexing plate 213.

[0040] To facilitate the injection of the liquid medium forming the liquid capsule into the cylindrical liquid injection cavity 218 and the annular liquid injection cavity 219, as an improvement to the technical solution, a liquid injection bracket is connected to the upper support 205. The liquid injection bracket extends above the driven shaft 217, and multiple liquid injection connectors 214 are provided on the liquid injection bracket. A liquid injection connector 214 is provided above both the cylindrical liquid injection cavity 218 and the annular liquid injection cavity 219.

[0041] The controllable diameter of the liquid medium in the channel within this embodiment is mainly based on mechanical formulas: Where F is the magnitude of the centrifugal force (unit: Newton, N), m is the mass of the object (unit: kilogram, kg), ω is the angular velocity of the object (unit: radians per second, rad / s), and r is the distance from the object to the center of the circle, i.e., the radius of the circular motion (unit: meter, m).

[0042] The Reynolds number formula, Re = ρvL / μ, where ρ is the fluid density, v is the relative velocity of the fluid or object, L is the characteristic length, and μ is the dynamic viscosity of the fluid (in Pa·s).

[0043] Stokes' drag formula, F = 6πηrv, where η is the viscosity of the liquid, r is the characteristic dimension, and v is the relative velocity.

[0044] According to the above formula, the droplet is subjected to centrifugal force, gravity, resistance between the liquid media, and liquid surface tension during rotation. When the net force on the droplet equals the liquid surface tension, the droplet reaches the critical point of falling. The maximum centrifugal force calculated based on the rotation range used in this experiment is much smaller than the liquid surface tension, so it can be ignored. The Reynolds number is calculated by substituting the Reynolds number formula into the maximum rotation speed of the device, indicating that the fluid state is laminar. The result calculated by substituting the Stokes drag formula into the rotation range is greater than the liquid surface tension. Therefore, it can be determined that, apart from gravity, the resistance between the liquid media is the only factor determining that the droplet reaches the critical point of falling during the rotation of the device. Under the premise of ignoring centrifugal force, the liquid surface tension does not change, but the resistance between the liquid media increases, and the mass of the droplet when it falls will decrease. According to the Stokes drag formula F=6πηrv, the resistance between the liquid media is proportional to the relative velocity. Therefore, it can be concluded that the greater the angular velocity, the smaller the mass of the falling droplet.

[0045] In order to achieve automated control of this device, as an improvement to the technical solution, an electronic control board 105 and a touch screen 106 are provided on the body 1. The electronic control board 105 is connected to the touch screen 106 and the rotation drive unit respectively.

[0046] Other components that require automated control are also connected to the electronic control board 105 via signals, such as the photoelectric encoder sensor 212.

Claims

1. A multi-channel centrifugal microfluidic reactor with controllable diameter and multi-layer coating, characterized in that, The system includes a body (1), a centrifugal microfluidic unit (2), and a liquid accumulation unit (3). The centrifugal microfluidic unit (2) is vertically movable on the body (1). The centrifugal microfluidic unit (2) includes an upper support (205), a lower support (206), a rotation drive unit, and a multi-layer coated droplet preliminary formation unit. The inverted U-shaped upper support (205) and lower support (206) are fixedly connected. The output end of the rotation drive unit passes through the upper support (205). The multi-layer coated droplet preliminary formation unit includes a driven shaft (217). The driven shaft (217) is rotatably connected to the upper support (205) and lower support (206). The output end of the rotation drive unit is connected to the driven shaft (217) to drive the driven shaft (217) to rotate. The driven shaft (217) contains... A cylindrical liquid injection chamber (218) is provided in the center. The lower end of the cylindrical liquid injection chamber (218) is connected to multiple horizontal channels. Multiple annular liquid injection chambers (219) are provided around the cylindrical liquid injection chamber (218). Multiple vertical channels are provided at the lower end of the annular liquid injection chambers (219). Microfluidic connectors (215) with the same number of vertical channels are connected below the driven shaft (217). The microfluidic connectors (215) are connected to the horizontal channels and the vertical channels respectively. A liquid confluence point (220) is provided in the microfluidic connector (215). A needle (216) is connected below each microfluidic connector (215). The liquid accumulation unit (3) includes a liquid accumulation cup (302). The liquid accumulation cup (302) is set on the body (1) directly below the driven shaft (217).

2. The multi-channel centrifugal microfluidic reactor with controllable diameter and multi-layer coating according to claim 1, characterized in that, The body (1) includes a profile frame (101), a linear guide rail (102) is provided on the vertical profile of the profile frame (101), a slider (103) is provided on the linear guide rail (102), one end of the upper support seat (205) and the lower support seat (206) is fixedly connected to the slider (103), and a linear guide clamp (104) is provided on the linear guide rail (102) below the slider (103).

3. The multi-channel centrifugal microfluidic reactor with controllable diameter and multi-layer coating according to claim 1, characterized in that, The rotation drive unit includes a motor (201), a coupling (203), a drive synchronous pulley (209), and a synchronous belt (210). A motor mount (202) is provided on the upper support (205). The motor (201) is mounted on the motor mount (202). The output end of the motor (201) is connected to the coupling (203). The coupling (203) passes through the upper support (205) and is connected to the drive synchronous pulley (209). The synchronous belt (210) is sleeved on the drive synchronous pulley (209) and the driven synchronous pulley on the driven shaft (217).

4. The multi-channel centrifugal microfluidic reactor with controllable diameter and multi-layer coating according to claim 3, characterized in that, A timing belt tensioning unit is also provided on the upper support base (205). The timing belt tensioning unit includes a tensioning block (207), an idler shaft (208), and an idler wheel (211). The tensioning block (207) is installed on the upper surface of the upper support base (205) and connected to the idler shaft (208). The lower end of the idler shaft (208) is rotatably connected to the idler wheel (211), and the idler wheel (211) is in contact with the timing belt (210).

5. The multi-channel centrifugal microfluidic reactor with controllable diameter and multi-layer coating according to claim 1, characterized in that, An indexing disk (213) is provided on the outer side of the portion of the driven shaft (217) that is higher than the upper support (205). The indexing disk (213) has an array of strip holes. A photoelectric encoder sensor (212) is provided on the upper support (205). The indexing disk (213) is within the sensing range of the photoelectric encoder sensor (212).

6. The multi-channel centrifugal microfluidic reactor with controllable diameter and multi-layer coating according to claim 1, characterized in that, A liquid injection bracket is connected to the upper support (205), and the liquid injection bracket extends above the driven shaft (217). Multiple liquid injection connectors (214) are provided on the liquid injection bracket, and a liquid injection connector (214) is provided above the cylindrical liquid injection cavity (218) and the annular liquid injection cavity (219).

7. The multi-channel centrifugal microfluidic reactor with controllable diameter and multi-layer coating according to claim 1, characterized in that, An electronic control board (105) and a touch screen (106) are provided on the machine body (1). The electronic control board (105) is connected to the touch screen (106) and the rotation drive unit respectively.

Images