A high-viscosity microdroplet generating device and method based on a three-dimensional microchannel structure

Abstract

The disclosure provides a kind of high viscosity microdroplet generation device and method based on three-dimensional microchannel structure, which is T-shaped, including first straight channel, vertical channel, second straight channel and third straight channel in turn;A group of boss structures are symmetrically provided inside the second straight channel near the two sides of the inner wall of the main channel, and the outer end face of the microtube can abut with the outer end face of the boss structure after extending into the vertical channel, so that high viscosity microdroplet generation channel is formed between the two boss structures;The connecting part of high viscosity microdroplet generation channel and third straight channel also forms a tapered channel, and high viscosity microdroplets are stably output from the third straight channel through the tapered channel;The present application designs a new tip mode, realizes the high monodispersity and uniformity of high viscosity microdroplets, size controllable, improves the stability of high viscosity microdroplet generation, and can be repeatedly used based on the detachable design of three-dimensional microchannel structure, which expands the application range of the technology.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of microfluidics, and in particular to a high-viscosity microdroplet generation device and method based on a three-dimensional microchannel structure. BACKGROUND

[0002] Microdroplets generally have a size of 100 μm or less, and are widely used in drug research and development, material synthesis, chemical reactions, and many other fields. A controllable microdroplet generation method with high monodispersity is particularly important. Droplet microfluidic technology is widely used because it can controllably generate microdroplets with uniform sizes.

[0003] In recent years, microscale manipulation of functional polymer solutions and biological hydrogels and other high-viscosity fluids has become a focus of the industry, but there are few reports on stable and controllable methods for generating high-viscosity microdroplets. Currently, there are still the following problems in the generation of high-viscosity microdroplets: 1. Traditional jetting mode usually uses the structure of a microsyringe pump and a nozzle to control the ejection amount of the liquid and the flow of the high-viscosity liquid. During the ejection of the high-viscosity fluid, various phenomena such as stretching, breaking, and atomization occur. Through careful observation and analysis of the ejection process, it is found that the viscosity of the liquid and the ejection pressure have a significant impact on the ejection form of the liquid. When the viscosity of the dispersed phase is higher than 100 mPa-s, the ejected droplets are more likely to deform and break, resulting in an increase in the non-uniformity of the droplet size. This technology is difficult to stably generate high-viscosity microdroplets with controllable and uniform sizes; 2. High-viscosity droplets can also be prepared by diluting high-viscosity solutions or directly using the reaction between two components, for example, a mixed solution of high-viscosity sodium alginate and calcium chloride as the dispersed phase is introduced into a microfluidic chip. However, it is difficult to cut the mixed solution to form droplets, and the stability is poor. At the same time, this method changes the properties of the fluid, which in turn affects the function of the droplets; 3. Droplet reverse phase technology effectively improves the uniformity of the droplets, but the size of the droplets is difficult to accurately control, and the regional modification of the microchannel increases the difficulty of device processing, making it difficult to be used as a high-viscosity droplet generation device for mass production; 4. Using external surface acoustic waves as an external force field, combined with a microfluidic droplet generation chip, can induce the uniform and stable generation of high-viscosity droplets. Since the device for generating surface acoustic waves is composed of a piezoelectric substrate and an interdigital transducer processed on the upper surface, in order to effectively combine the surface acoustic wave with the microfluid, the microfluidic chip is usually directly bonded to the upper part of the piezoelectric substrate, increasing the complexity of the system. Moreover, this bonding is irreversible. When the microfluidic chip is blocked, damaged, or has other problems, the piezoelectric substrate cannot be recycled and can only be scrapped together with the chip, reducing the reuse rate of the device. The high-viscosity generation device produced by this method greatly increases the processing cost. Therefore, there is an urgent need for a high-viscosity microdroplet generation device and method based on a three-dimensional microchannel structure to solve the above problems. SUMMARY

[0004] The present application aims at the problems of uncontrollable size, low stability and poor uniformity of high-viscosity microdroplets generated by the above high-viscosity droplet generation technology, and designs a full-type high-viscosity microdroplet generation device and method based on a three-dimensional microchannel structure, so as to realize controllable and stable generation of high-viscosity microdroplets without increasing the complexity of the device / microfluidic chip and changing the fluid flow rate and properties. The present application has the advantages of simple structure, simple preparation process, convenient chip assembly and post-maintenance, good uniformity and high monodispersity of generated high-viscosity microdroplets, and can stably generate high-viscosity microdroplets with relatively small size, which has extremely high commercial application value.

[0005] To solve the above problems, the present application provides the following technical scheme: the first aspect of the present application provides a high-viscosity microdroplet generation device based on a three-dimensional microchannel structure, which comprises a microtube and a microfluidic chip. The three-dimensional microchannel structure arranged inside the microfluidic chip is in a T-shaped structure, which comprises a continuous phase module, a first straight channel of the T-shaped structure formed inside the continuous phase module for inputting a continuous phase solution; a dispersed phase module, a vertical channel of the T-shaped structure formed inside the dispersed phase module for inserting the microtube, and a high-viscosity dispersed phase solution being input through the microtube; a high-viscosity microdroplet module, a second straight channel of the T-shaped structure formed inside the high-viscosity microdroplet module for generating high-viscosity microdroplets; and an outlet module, a third straight channel of the T-shaped structure formed inside the outlet module for outputting the high-viscosity microdroplets; wherein the first straight channel, the second straight channel and the third straight channel are sequentially connected and communicated to form a main channel of the microfluidic chip, and the center axes of the channels coincide; a group of boss structures are symmetrically arranged inside the second straight channel close to the inner walls of the main channel, the outer end surface of the microtube can abut against the outer end surface of the boss structure after the microtube is inserted into the vertical channel, so that a high-viscosity microdroplet generation channel is formed between the two boss structures, and the high-viscosity microdroplet generation channel is in a right prism shape; a tapered channel for stably conveying the high-viscosity microdroplets is further formed at the connection between the high-viscosity microdroplet generation channel and the third straight channel, and the high-viscosity microdroplets are output from the third straight channel through the tapered channel.

[0006] Further, the high-viscosity dispersed phase solution refers to a fluid with a minimum viscosity not less than 100 mPa-s.

[0007] Further, the channel horizontal width at the connection between the high-viscosity microdroplet generation channel and the third straight channel is equal, the cross-sectional dimensions of the oppositely arranged high-viscosity microdroplet generation channel and tapered channel gradually increase along the opposite direction of the connection, the longitudinal inner diameter of the tapered channel changes in a gradient-like manner, and finally the outer cross sections of the high-viscosity microdroplet generation channel and the tapered channel are sealingly connected with the inner side wall of the main channel.

[0008] Further, the vertical channel penetrates outside the second straight channel and does not penetrate completely, thereby a set of limiting structures are symmetrically formed on both sides of the main channel, and a distance is kept between the outer end face of the limiting structure and the outer end face of the main channel.

[0009] Further, the first straight channel, the vertical channel, the high-viscosity microdroplet generating channel, the tapered channel and the third straight channel are integrally formed by a stereolithography method of the 3D printing technology, and the preparation material is photosensitive resin.

[0010] Further, the longitudinal inner diameter of the first straight channel is greater than the longitudinal inner diameter of the tapered channel, the longitudinal inner diameter of the tapered channel is greater than the longitudinal inner diameter of the high-viscosity microdroplet generating channel, and the longitudinal inner diameters of the first straight channel and the third straight channel are equal.

[0011] Further, the cross sections of the first straight channel, the vertical channel and the third straight channel are circular or rectangular, the inner diameters of the first straight channel and the third straight channel are between 300 μm and 800 μm, the inner diameter of the vertical channel is between 800 μm and 1600 μm, the height of the boss structure is between 50 μm and 300 μm, the inner diameter of the microtube is between 50 μm and 800 μm, and the outer diameter of the microtube is between 300 μm and 1600 μm.

[0012] Further, the microtube is detachably connected with the vertical channel.

[0013] The second aspect of the present disclosure provides a method for generating high-viscosity microdroplets based on a three-dimensional microchannel structure, which comprises: inserting a microtube into the bottom of a vertical channel, inputting a continuous phase solution into a first straight channel, and inputting a high-viscosity dispersed phase solution into a microtube inner diameter port in the vertical channel; when the continuous phase solution flows through the high-viscosity microdroplet generating channel, the continuous phase solution partially backflows into the microtube inner diameter port at a junction, causing the high-viscosity dispersed phase solution to incompletely wet the port, so that the high-viscosity dispersed phase solution at the junction is extruded, thereby generating high-viscosity microdroplets smaller than the area of the junction;

[0014] The high-viscosity microdroplets are stably output from the third straight channel through the tapered channel.

[0015] The size of the generated high-viscosity microdroplets can be further controlled by changing the size of the microtube or adjusting the gap distance of the microtube inserted into the vertical channel.

[0016] The present disclosure has at least the following beneficial effects over the prior art:

[0017] (1) The high-viscosity microdroplet generation device provided by the disclosure comprises a three-dimensional microchannel structure. Compared with a traditional microfluidic device which is complex and expensive to prepare, the device uses a 3D printed microfluidic chip and a commercial pipe material to form a detachable three-dimensional microchannel structure. The device is simple to prepare, low in cost and easy to operate;

[0018] (2) The traditional microfluidic device is an integrated device, which cannot be disassembled and replaced when problems such as channel congestion occur. The three-dimensional microchannel structure provided by the disclosure is based on a detachable design, which realizes the quick plugging and flexible disassembly of the micro-pipe and the vertical channel, facilitates the disassembly and cleaning, and the replacement of parts. The micro-pipe can be disassembled to solve the chip failure, so that the device can be repeatedly used, facilitating assembly, use and later maintenance. The commercial micro-pipe and chip module can realize the rapid manufacturing of the high-viscosity droplet microfluidic device, and the overall cost is reduced.

[0019] (3) Compared with the two-dimensional microchannel structure of the traditional microfluidic device, the disclosure provides a new three-dimensional microchannel structure. Under the joint action of the high-viscosity microdroplet generation channel and the tapered channel, the high-viscosity dispersed phase solution can be stably stayed in the intersection at a smaller area, thereby greatly reducing the size of the high-viscosity microdroplet generation, and the high-viscosity microdroplet is more stably output. The size of the generated high-viscosity microdroplet can be further controlled by changing the size of the micro-pipe or adjusting the gap distance of the micro-pipe inserted into the vertical channel, which greatly widens the generation range of the high-viscosity microdroplet. Without increasing the complexity of the device / microfluidic chip and without changing the fluid flow rate and properties, the size of the high-viscosity microdroplet can be controlled and stably generated, which has a very high commercial application value.

[0020] (4) Based on the device, the high-viscosity microdroplet generation method provided by the disclosure effectively suppresses the generation of the jetting mode, generates a new tip mode, realizes the high monodispersity and uniformity of the high-viscosity microdroplet, controls the size, improves the stability of the high-viscosity microdroplet generation, and expands the application range of the technology. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more completely understand the disclosure and its advantages, reference will now be made to the following description taken together with the accompanying drawings, in which:

[0022] Figure 1 A top view of a three-dimensional microchannel structure according to an embodiment of the disclosure is schematically shown;

[0023] Figure 2 A cross-sectional view of a three-dimensional microchannel structure according to an embodiment of the disclosure is schematically shown;

[0024] Figure 3 A three-dimensional schematic view of a three-dimensional microchannel structure according to an embodiment of the disclosure is schematically shown;

[0025] Figure 4 A flow chart of a method for generating high viscous microdroplets based on a three-dimensional microchannel structure according to an embodiment of the present disclosure is schematically shown;

[0026] Figure 5 An optical microscope photo of generating high viscous microdroplets by a structure of a 3D printed microchannel according to an embodiment of the present disclosure is schematically shown;

[0027] Figure 6 A contrast schematic diagram of three different modes of droplets is schematically shown.

[0028] The reference signs in the drawings are: 100, three-dimensional microchannel structure; 10, continuous phase module; 101, first straight channel; 102, continuous phase solution; 20, dispersed phase module; 201, vertical channel; 202, microtube; 203, intersection; 204, high viscous dispersed phase solution; 205, limiting structure; 30, high viscous microdroplet module; 301, second straight channel; 302, boss structure; 303, high viscous microdroplet generating channel; 304, high viscous microdroplet; 40, outlet module; 401, third straight channel; 402, tapered channel; 50, high viscous dispersed phase solution outlet. DETAILED DESCRIPTION

[0029] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be understood, however, that the description is merely exemplary and is not intended to limit the scope of the present disclosure. In the following detailed description of the embodiments, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the present disclosure. However, it would be apparent to those skilled in the art that the embodiments can be practiced without these specific details. In other instances, well-known structures and techniques have been not described in detail in order to avoid obscuring aspects of the present disclosure.

[0030] The terms used herein are merely used to describe specific embodiments and are not intended to limit the present disclosure. The terms "include", "comprise" and the like used herein indicate the presence of the described features, steps, operations and / or components, but do not exclude the presence or addition of one or more other features, steps, operations or components.

[0031] All terms used herein, including technical and scientific terms, have the meanings commonly understood by one of ordinary skill in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having meanings consistent with the context of the specification, and should not be interpreted in an idealized or overly formal manner.

[0032] Reference should be made to Figures 1-6The application provides a high-viscosity microdroplet generating device and method based on a three-dimensional microchannel structure, generates a new tip mode, realizes high monodispersity and uniformity of high-viscosity microdroplets 304, is size-controllable, improves stability of high-viscosity microdroplet 304 generation, is based on a detachable design through the three-dimensional microchannel structure, is reusable, is simple in preparation, low in cost and easy to operate, and expands the application range of the technology.

[0033] As Figure 1 A top view of a three-dimensional microchannel structure 100 according to an embodiment of the present disclosure is schematically shown; and as Figure 2 A cross-sectional view of the three-dimensional microchannel structure 100 according to an embodiment of the present disclosure is schematically shown.

[0034] As Figure 1 The three-dimensional microchannel structure 100 is in a T-shaped structure, and specifically comprises:

[0035] A continuous phase module 10, which is internally formed with a first straight channel 101 of the T-shaped structure, is used for input of a continuous phase solution 102;

[0036] A dispersed phase module 20, which is internally formed with a vertical channel 201 of the T-shaped structure, is used for extension of a microtube 202, and a high-viscosity dispersed phase solution 204 is input through the microtube 202;

[0037] Specifically, the vertical channel 201 penetrates the outside of the second straight channel 301 and does not penetrate completely, thereby a set of limiting structures 205 are symmetrically formed on both sides of the main channel, and the outer end surface of the limiting structure 205 keeps a certain distance from the outer end surface of the main channel; the vertical channel 201 with a certain thickness is formed in the microfluidic chip, the high-viscosity microdroplet generating channel 303 can be located above or below the vertical channel 201, and is in communication with the high-viscosity dispersed phase outlet 50 to form a junction 203, at which part of the continuous phase solution 102 flows back into the inner diameter of the microtube 202, causing the high-viscosity dispersed phase solution 204 to not completely wet the tube opening, so that the high-viscosity dispersed phase solution 204 at the junction 203 is extruded to form a high-viscosity microdroplet 304; the size of the generated high-viscosity microdroplet is controlled by adjusting the gap distance between the microtube 202 inserted into the vertical channel 201 and the limiting structure 205, when the microtube 202 contacts the outer end surface of the limiting structure 205, the distance gap between the outer end surface of the microtube 202 and the inner end surface of the second straight channel 301 is the smallest, that is, the high-viscosity microdroplet generating channel 303 reaches the most narrow state, under the premise of not replacing the microtube 202, when the continuous phase solution 102 flows through the high-viscosity microdroplet generating channel 303 in the most narrow state, the generated high-viscosity microdroplet 304 is the smallest, when the microtube 202 is inserted to the same height as the connecting tapered channel 402, the distance gap between the outer end surface of the microtube 202 and the inner end surface of the second straight channel 301 is the largest, that is, the high-viscosity microdroplet generating channel 303 reaches the most wide state, when the continuous phase solution 102 flows through the high-viscosity microdroplet generating channel 303 in the most wide state, the generated high-viscosity microdroplet 304 is the largest; therefore, the purpose of designing the limiting structure 205 is to better regulate and control the size of the generated high-viscosity microdroplet 304 without replacing the size of the microtube 202, to meet different actual application requirements.

[0038] The high-viscosity microdroplet module 30, as shown in Figure 3 , has the second straight channel 301 with the T-shaped structure formed inside, for generating high-viscosity microdroplets.

[0039] Specifically, as shown in Figure 3As shown, a set of protrusion structures 302 are symmetrically arranged inside the second straight channel 301 near the inner walls on both sides of the main channel. After the microtube 202 extends into the vertical channel 201, its outer end face can abut against the outer end face of the protrusion structure 302, so that a high-viscosity microdroplet generation channel 303 is formed between the two protrusion structures 302. The high-viscosity microdroplet generation channel 303 is in the shape of a regular frustum. Specifically, the cross-sectional size of the high-viscosity microdroplet generation channel 303 gradually decreases from upstream to downstream. The high-viscosity microdroplet generation channel 303 is used to transport the continuous phase solution 102, and makes the continuous phase solution 102 generate more shear force in the high-viscosity microdroplet generation channel 303, thereby changing the state of the continuous phase solution 102. The vertical channel 201 is used to input a high-viscosity dispersed phase solution 204, which refers to a high-viscosity fluid with a minimum viscosity of not less than 100 mPa-s.

[0040] And, the outlet module 40, which has a third straight channel 401 forming the T-shaped structure inside, is used to output high-viscosity microdroplets 304;

[0041] Specifically, such as Figures 1-3 As shown, a conical channel 402 for stably conveying high-viscosity microdroplets is also formed at the connection between the high-viscosity microdroplet generating channel 303 and the third straight channel 401. The high-viscosity microdroplets 304 are output from the third straight channel 401 through the conical channel 402. The horizontal width of the channels at this connection is equal, and the cross-sectional dimensions of the high-viscosity microdroplet generating channel 303 and the conical channel 402 gradually increase in opposite directions along the connection. The longitudinal inner diameter of the conical channel 402 exhibits a gradient-like change, and ultimately, the outer cross-sections of both the high-viscosity microdroplet generating channel 303 and the conical channel 402 are sealed to the inner wall of the main channel. Figure 1 As shown, the transverse inner diameter at the connection between the conical channel 402 and the high-viscosity microdroplet generation channel 303 is... w 1. Equal, such as Figure 1 As shown, from left to right, the lateral inner diameter of the high-viscosity microdroplet generation channel 303 gradually decreases, while the lateral inner diameter of the conical channel 402 gradually increases, and the maximum lateral inner diameter of the high-viscosity microdroplet generation channel 303 is equal to the maximum lateral inner diameter of the conical channel 402.

[0042] Among them, the Figures 1-2 As shown, the first straight channel 101, the second straight channel 301 and the third straight channel 401 are connected and interconnected in sequence to form the main channel of the microfluidic chip, and the central axes of each channel coincide.

[0043] Specifically, such as Figure 3As shown, the tapered channel 402 is arranged inside the third straight channel 401, the upstream end of which is communicated with the high-viscosity micro-droplet generating channel 303, and the other end of which is integrally formed with the two inner side walls of the main channel and communicated with the two inner side walls. It should be noted that the first straight channel 101, the vertical channel 201, the high-viscosity micro-droplet generating channel 303, the tapered channel 402, and the third straight channel 401 are integrally formed by the stereolithography method of the 3D printing technology, and the preparation material is preferably photosensitive resin.

[0044] Specifically, as shown in Figure 2 , the transverse inner diameter w 2 of the first straight channel 101 is equal to the transverse inner diameter w 3 of the third straight channel 401. The embodiments of the present disclosure do not limit the transverse length of the first straight channel 101 and the transverse length of the third straight channel 401, which are set according to actual application requirements.

[0045] In the embodiments of the present disclosure, the longitudinal inner diameters of the first straight channel 101, the high-viscosity micro-droplet generating channel 303, and the tapered channel 402 are different, the longitudinal inner diameters of the first straight channel 101 and the third straight channel 401 are the same, and the longitudinal inner diameter of the tapered channel 402 inside the third straight channel 401 changes in a gradient manner.

[0046] Specifically, as shown in Figures 1-2 , due to the embedded arrangement of the micro-pipe 202 and the high-viscosity micro-droplet generating channel 303, the longitudinal inner diameter h 1 of the first straight channel 101 is greater than the longitudinal inner diameter h 3 of the tapered channel 402, the longitudinal inner diameter h 3 of the tapered channel 402 is greater than the longitudinal inner diameter h 2 of the high-viscosity micro-droplet generating channel 303, and the transverse inner diameter of the high-viscosity micro-droplet generating channel 303 decreases in sequence, so that more shear force can be generated when the continuous phase solution 102 passes through the high-viscosity micro-droplet generating channel 303, thereby more easily changing the state of the continuous phase solution 102, so that the continuous phase solution 102 can stably stay at the intersection 203 in a small area, and then part of the continuous phase solution 102 partially flows back into the inner diameter of the micro-pipe 202 at the intersection 203, causing the high-viscosity dispersed phase solution 204 to not completely wet the pipe opening, so as to extrude the high-viscosity dispersed phase solution 204 at the intersection 203, to achieve the effect of extruding the high-viscosity dispersed phase solution 204, thereby generating a high-viscosity micro-droplet 304 smaller than the intersection 203.

[0047] Specifically, as shown in Figure 1 and 3 , the longitudinal inner diameter h3is a gradient change. It can be understood that, since the lateral inner diameter of the tapered channel 402 gradually increases, and the longitudinal inner diameter h 3also gradually increases, and the longitudinal inner diameter of the tapered channel 402 at the connection is greater than the longitudinal inner diameter of the high-viscosity microdroplet generation channel 303, which is designed for the purpose of making the generated high-viscosity microdroplet 304 more stable in the inclined tapered channel 402, and the second is to make the gap distance adjustment maximum without the high-viscosity microdroplet 304 flowing out of the gap between the tapered channel 402 and the third straight channel 401 when the microtube 202 is inserted into the vertical channel 201 and the gap distance of the limiting structure 205, ensuring the sealed flow performance of the three-dimensional microchannel structure 100.

[0048] In an embodiment of the present disclosure, for the convenience of integral molding of the entire structure, the longitudinal inner diameter h 1of the first straight channel 101 is equal to the longitudinal inner diameter h 4of the third straight channel 401, that is, the size of the first straight channel 101 and the third straight channel 401 remains consistent.

[0049] In an embodiment of the present disclosure, the cross section of the first straight channel 101, the vertical channel 201 and the third straight channel 401 is circular or rectangular, the inner diameter of the first straight channel 101 and the third straight channel 401 is between 300 μm and 800 μm, the inner diameter of the vertical channel 201 is between 800 μm and 1600 μm, the height of the boss structure 302 is between 50 μm and 300 μm, the inner diameter of the microtube 202 is between 50 μm and 800 μm, and the outer diameter is between 300 μm and 1600 μm, and the specific size is set according to the actual application requirement. Specifically, as shown in the figure, based on the change of the three-dimensional microchannel structure 100, the method can generate high-viscosity microdroplets 304 of 100 μm and below in an embodiment of the present disclosure. Figure 5

[0050] According to an embodiment of the present disclosure, the microtube 202 and the vertical channel 201 are detachably connected, and through the detachable design, the fault can be solved when the channel congestion occurs in the microchannel, so that the device can be repeatedly used, and the use cost of the device is reduced.

[0051] Specifically, the three-dimensional microchannel structure 100 uses a 3D printing microfluidic chip and a commercial pipe material (microtube 202) to form a detachable three-dimensional microchannel structure 100, and the inner diameter of the commercial pipe material (microtube 202) can be selected according to the size of the prepared high-viscosity microdroplet 304. The size requirement is matched; compared with the traditional preparation of complex and expensive microfluidic structure, the structure is simple, low in cost and easy to operate. The 3D printing material can be various types of photosensitive resin, and the transparent photosensitive resin matched with the used 3D printer is preferred.​

[0052] It should be noted that the embodiments of the present disclosure do not limit the structure size of each component of the three-dimensional microchannel structure 100, for example, the opening angle of the longitudinal section of the high-viscosity microdroplet generation channel 303 and the tapered channel 402 can be between 0-90°, preferably 30-60°, etc. These are only exemplary descriptions, and the embodiments of the present disclosure do not limit this.

[0053] Another aspect of the present disclosure provides a method for generating high-viscosity microdroplets based on the three-dimensional microchannel structure 100, which is implemented by the three-dimensional microchannel structure 100 as shown in Figures 1-3 The method comprises the following steps:

[0054] S501: Insert the microtube 202 into the bottom of the vertical channel 201, input the continuous phase solution 102 into the first straight channel 101, and input the high-viscosity dispersed phase solution 204 into the inner diameter port of the microtube 202 in the vertical channel 201. The continuous phase solution 102 partially flows back into the inner diameter port of the microtube 202 at the junction 203 under the action of the high-viscosity microdroplet generation channel 303, causing the high-viscosity dispersed phase solution 204 to incompletely wet the port, so as to extrude the high-viscosity dispersed phase solution 204 at the junction 203, thereby forming a high-viscosity microdroplet 304 smaller than the area of the junction 203. It should be noted that the continuous phase solution 102 and the high-viscosity dispersed phase solution 204 are input into the microchannel at the same time or at different times by inputting the continuous phase solution 102 on one side of the first straight channel 101 and inputting the high-viscosity dispersed phase solution 204 into the microtube 202 in the vertical channel 201. Among them, when the continuous phase solution 102 passes through the high-viscosity microdroplet generation channel 303, due to the structural arrangement of the high-viscosity microdroplet generation channel 303, more shear force is generated to change the state of the continuous phase solution 102, so that the continuous phase solution 102 can stably stay in a small area at the junction 203, and then part of the continuous phase solution 102 flows back into the inner diameter port of the microtube 202 at the junction 203, causing the high-viscosity dispersed phase solution 204 to incompletely wet the port, so as to extrude the high-viscosity dispersed phase solution 204 at the junction 203, thereby generating a high-viscosity microdroplet 304 smaller than the area of the junction 203.

[0055] S502: Stably output the high-viscosity microdroplet from the third straight channel 401 through the tapered channel 402; it should be noted that the high-viscosity microdroplet 304 generated in the previous step first passes through the tapered channel 402 and is then stably output from the third straight channel 401. The stable output here can be understood as follows: when the high-viscosity microdroplet 304 first passes through the tapered channel 402, due to the improvement of the structure of the tapered channel 402, the longitudinal inner diameter and the transverse inner diameter of the tapered channel 402 increase in turn, so that the generated high-viscosity microdroplet stably flows out from the tapered channel 402 one by one, as shown in Figure 5The high-viscosity microdroplet jetting phenomenon is effectively inhibited, a new tip mode is generated, high monodispersity of the high-viscosity microdroplet is achieved, and the stability of the high-viscosity microdroplet 304 is greatly improved, thereby expanding the application range of the technology.

[0056] S503: The size of the generated high-viscosity microdroplet 304 can be further controlled by replacing the size of the microtube 202 or adjusting the gap distance of the microtube 202 inserted into the vertical channel 201; it should be noted that, without increasing the complexity of the device / microfluidic chip and without changing the fluid flow rate and properties, controllability and stable generation of the high-viscosity microdroplet 304 are achieved, and the size of the generated high-viscosity microdroplet 304 is greatly reduced compared with the conventional method.

[0057] In addition, the high-viscosity microdroplet 304 generated based on the high-viscosity microdroplet generation device can meet most of the current demands for high-viscosity microdroplets 304, break through the limit of the high-viscosity microdroplet 304 that can be generated by the conventional high-viscosity microdroplet generation device, and does not need to rely on external equipment, thereby greatly reducing the complexity of the device and reducing the production investment cost.

[0058] Specifically, as Figure 6 FIG. 3 shows a comparison diagram of three different modes of droplets. Figure 6 a is a conventional droplet flow mode; it should be noted that the darker circular hole shape is the output port of the high-viscosity dispersed phase solution (i.e., the high-viscosity dispersed phase solution outlet 50), and the lighter circular shape is the corresponding generated high-viscosity microdroplet 70; from Figure 6 a can be seen that the size of the high-viscosity microdroplet 304 generated in the conventional droplet flow mode is almost the same as the size of the corresponding high-viscosity dispersed phase solution outlet 50, so the size of the high-viscosity microdroplet 304 formed by breaking is large, for example, the high-viscosity microdroplet 304 generated by the conventional droplet flow mode using a tube with a tube opening of 100 μm or more is greater than 100 μm, so the conventional droplet flow mode has very limited control over the size of the high-viscosity microdroplet 304. Figure 6 b is a new tip mode generated by the method provided in the embodiments of the present disclosure, and the size of the corresponding generated high-viscosity microdroplet 304 in this mode is much smaller than the size of the corresponding high-viscosity dispersed phase solution outlet 50, the size of the high-viscosity microdroplet 304 formed by breaking is smaller, and the generation frequency is stable and does not present a stretching, breaking, and atomization state. Figure 6 c is a conventional jet mode, and the corresponding generated high-viscosity microdroplet 304 in this mode presents a long stretching state, the generated droplet size is uneven, the frequency is unstable, and the size is uncontrollable. Based on this, the high-viscosity microdroplet 304 generated by the high-viscosity microdroplet generation method provided in the embodiments of the present disclosure has a smaller droplet size and a stable generation frequency, and the size is controllable, which can better meet the application in many fields such as drug research and development, material synthesis, and chemical reaction.

[0059] While the present disclosure has been illustrated and described in detail in the drawings and foregoing description, such illustration and description is to be considered illustrative or exemplary and not restrictive; the disclosure is not limited to the disclosed embodiments.

[0060] Those skilled in the art can understand that the features recited in various embodiments and / or claims of the present disclosure can be combined in various ranges and / or combined, even if such combinations or combinations are not explicitly recited in the present disclosure. In particular, the features recited in various embodiments and / or claims of the present disclosure can be combined in various combinations and / or combined without departing from the spirit and teachings of the present disclosure. All such combinations and / or combinations fall within the scope of the present disclosure.

[0061] Although the present disclosure has been shown and described with respect to particular exemplary embodiments thereof, it should be understood by those skilled in the art that various changes in form and detail can be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims and their equivalents. Therefore, the scope of the present disclosure should not be limited to the above-described embodiments, but should be determined by the appended claims alone, and by their equivalents.

Claims

1. A high-viscosity microdroplet generation device based on a three-dimensional microchannel structure, characterized by, The application relates to a microfluidic chip and a microtube (202), wherein the three-dimensional microchannel structure (100) arranged inside the microfluidic chip is in a T-shaped structure, which comprises a continuous phase module (10) for forming a first straight channel (101) of the T-shaped structure and inputting a continuous phase solution (102); a dispersed phase module (20) for forming a vertical channel (201) of the T-shaped structure and inserting the microtube (202), and inputting a high-viscosity dispersed phase solution (204) through the microtube (202); a high-viscosity microdroplet module (30) for forming a second straight channel (301) of the T-shaped structure and generating a high-viscosity microdroplet (304); and an outlet module (40) for forming a third straight channel (401) of the T-shaped structure and outputting the high-viscosity microdroplet (304); wherein the first straight channel (101), the second straight channel (301) and the third straight channel (401) are sequentially connected and communicated to form a main channel of the microfluidic chip, and the central axes of the channels coincide; a group of boss structures (302) are symmetrically arranged at the positions close to the inner walls of the main channel on both sides of the second straight channel (301), the outer end surface of the microtube (202) can abut against the outer end surface of the boss structure (302) after the microtube (202) is inserted into the vertical channel (201), so that a high-viscosity microdroplet generating channel (303) is formed between the two boss structures (302), and the high-viscosity microdroplet generating channel (303) is in a positive prism shape; a tapered channel (402) for stably conveying the high-viscosity microdroplet (304) is further formed at the connection position of the high-viscosity microdroplet generating channel (303) and the third straight channel (401), and the high-viscosity microdroplet (304) is output from the third straight channel (401) through the tapered channel (402); the horizontal width of the connection position of the high-viscosity microdroplet generating channel (303) and the third straight channel (401) is equal, the cross-sectional dimensions of the oppositely arranged high-viscosity microdroplet generating channel (303) and tapered channel (402) gradually increase in the opposite direction of the connection position, and the longitudinal inner diameter of the tapered channel (402) changes in a gradient-like manner, and finally the outer cross sections of the high-viscosity microdroplet generating channel (303) and the tapered channel (402) are in sealing connection with the inner side walls of the main channel; the vertical channel (201) penetrates the outside of the second straight channel (301) and does not completely penetrate, so that a group of limiting structures (205) are symmetrically formed on both sides of the main channel, and the outer end surface of the limiting structure (205) is kept at a distance from the outer end surface of the main channel.

2. The high-viscous microdroplet generator based on three-dimensional microchannel structure according to claim 1, characterized in that, The high-viscosity dispersed phase solution (204) refers to a fluid with a minimum viscosity not less than 100 mPa-s.

3. The high-viscous microdroplet generator based on three-dimensional microchannel structure according to claim 1, characterized in that, The first straight channel (101), the vertical channel (201), the high-viscosity microdroplet generating channel (303), the tapered channel (402) and the third straight channel (401) are integrally formed by a stereolithography method of 3D printing technology, and the preparation material is photosensitive resin.

4. The high-viscous microdroplet generator based on three-dimensional microchannel structure according to claim 1, wherein, The first straight channel (101) has a longitudinal inner diameter greater than that of the tapered channel (402), which has a longitudinal inner diameter greater than that of the high-viscosity microdroplet generating channel (303), and the first straight channel (101) has the same longitudinal inner diameter as the third straight channel (401).

5. The high-viscous microdroplet generator based on three-dimensional microchannel structure according to claim 4, wherein, The first straight channel (101), the vertical channel (201) and the third straight channel (401) have circular or rectangular cross sections, the inner diameter of the first straight channel (101) and the third straight channel (401) is between 300 μm and 800 μm, the inner diameter of the vertical channel (201) is between 800 μm and 1600 μm, the height of the boss structure (302) is between 50 μm and 300 μm, the inner diameter of the microtube (202) is between 50 μm and 800 μm, and the outer diameter of the microtube (202) is between 300 μm and 1600 μm.

6. The high-viscous microdroplet generator based on three-dimensional microchannel structure according to claim 5, wherein, The microtube (202) and the vertical channel (201) are detachably connected.

7. A method for generating high viscosity microdroplets based on a three- dimensional microchannel structure according to any one of claims 1 to 6, characterized in that, The method comprises: The microtube (202) is inserted into the bottom of the vertical channel (201), the continuous phase solution (102) is input into the first straight channel (101), and the high-viscosity dispersed phase solution (204) is input into the inner diameter port of the microtube (202) in the vertical channel (201). When the continuous phase solution (102) flows through the high-viscosity microdroplet generating channel (303), the continuous phase solution (102) partially backflows into the inner diameter port of the microtube (202) at the intersection (203), causing the high-viscosity dispersed phase solution (204) to incompletely wet the port, so that the high-viscosity dispersed phase solution (204) at the intersection (203) is extruded, thereby generating high-viscosity microdroplets (304) smaller than the area of the intersection (203); the high-viscosity microdroplets (304) are stably output from the third straight channel (401) through the tapered channel (402); The size of the generated high-viscosity microdroplets (304) can be further controlled by replacing the size of the microtube (202) and adjusting the gap distance of the microtube (202) inserted into the vertical channel (201).

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