阅读说明：本技术 一种旋转式液滴生成器 (Rotary liquid drop generator ) 是由 张传闻 朱丽 王蒙 于 2021-09-21 设计创作，主要内容包括：本发明公开了一种旋转式液滴生成器,主要由步进电机、曲柄连杆结构、连有玻璃毛细管或金属针头的微流控芯片、收集器皿组成；连有玻璃毛细管或金属针头的微流控芯片固定在曲柄连杆结构上,通过步进电机的驱动使玻璃毛细管或金属针头的尖端在外相液体表面做圆周运动,通过对转速的控制来制备不同尺寸的微液滴；通过加装不同的微流控芯片生成不同组分的液滴。本发明区别于传统液滴制备的方式,无外相的流体注入,不仅可以实现油包水,水包油这类单液滴的制备,同时也可用于复杂多组分液滴的制备。(The invention discloses a rotary type liquid drop generator which mainly comprises a stepping motor, a crank connecting rod structure, a micro-fluidic chip connected with a glass capillary or a metal needle head and a collecting vessel, wherein the micro-fluidic chip is connected with the glass capillary or the metal needle head; the micro-fluidic chip connected with the glass capillary or the metal needle is fixed on the crank connecting rod structure, the tip of the glass capillary or the metal needle is driven by the stepping motor to do circular motion on the surface of the external phase liquid, and micro-droplets with different sizes are prepared by controlling the rotating speed; different micro-fluidic chips are additionally arranged to generate liquid drops with different components. The method is different from the traditional droplet preparation mode, has no external phase fluid injection, can realize the preparation of single droplets such as water-in-oil and oil-in-water, and can also be used for the preparation of complex multi-component droplets.)

1. A rotary liquid drop generator is characterized by mainly comprising two stepping motors, a crank connecting rod structure, a micro-fluidic chip connected with a glass capillary or a metal needle and a collecting vessel; the micro-fluidic chip connected with the glass capillary or the metal needle is fixed on the crank connecting rod structure, the tip of the glass capillary or the metal needle is driven by the stepping motor to do circular motion on the surface of the external phase liquid, and micro-droplets with different sizes are prepared by controlling the rotating speed; different micro-fluidic chips are additionally arranged to generate liquid drops with different components.

2. The rotary droplet generator of claim 1, wherein the crank-link structure drives the microfluidic chip to perform a uniform circular motion as a whole.

3. A rotary drop generator according to claim 1, wherein the stepper motors are two stepper motors of the same size, and the two stepper motors are connected to the two cranks respectively.

4. A rotary drop generator according to claim 3, wherein the two stepper motors are connected to a common drive control to ensure synchronism of rotation of the two motors.

5. A rotary droplet generator according to claim 1 wherein the continuous phase fluid is drawn from a glass capillary or metal needle, the external phase fluid is contained in a collection vessel, and the glass capillary or metal needle is driven by a crank and link mechanism to move circumferentially within the external phase fluid to generate droplets under the shearing action of the external phase fluid.

6. A rotary drop generator according to claim 1, wherein the microfluidic chip is made of PDMS material.

7. A rotary droplet generator according to claim 1 wherein the crank link structure is formed from an aluminium alloy material.

8. A rotary drop generator according to claim 1, wherein the tip of the glass capillary or metal needle is just immersed in the oil phase on the surface of the collection vessel.

Technical Field

The invention relates to a micro-fluidic technology, in particular to a rotary type liquid drop generator.

Background

The droplet microfluidic system is an important branch of the microfluidic chip technology in recent years, is a novel technology for controlling micro-volume liquid, is provided with two or more types of liquid which are not mutually soluble, such as water phase and oil phase, and is endowed with fluids of a dispersed phase and a continuous phase by a droplet generation means, wherein the dispersed phase is dispersed in the continuous phase in the form of droplets of micro-volume units, and is a micro-nano fluid control mode with simple structure and high flux.

The microfluidic chip is used as a platform for preparing the micro-droplets, the generated droplets are controllable in size, low in diffusivity, high in generation speed and not prone to cross contamination, and the microfluidic chip is suitable for high-throughput analysis. Droplet generation methods based on microfluidic chips can be generally classified into two types, active methods and passive methods, depending on whether they are driven by external force. The principle of the active method is that a pressure difference is generated at two ends of liquid by means of external force, and a liquid drop is formed by utilizing the shearing force and the surface tension difference of the liquid at the intersection of a micro-channel. The passive method utilizes the shearing force and interfacial tension of fluid flow, generates liquid drops through a micro-pipeline structure and adjusts the flow velocity value and proportion of a continuous phase and a disperse phase, and mainly comprises chip structure forms such as a T-shaped channel method, a flow focusing method, a coaxial focusing method and the like. The T-shaped channel chip has only two inlets and is the simplest structure in the droplet microfluidic chip. The cross structure of the flow focusing method can be regarded as the combination of two T-shaped structures, the middle channel is continuous phase fluid, and the two side channels are dispersed phase fluid. Although the active method can control a single liquid drop according to the requirement, and has great advantages in the controllability of the liquid drop, the active method has relatively complex system and higher requirements on chip processing, and increases the difficulty and cost of the experiment. The passive method system is relatively simple, is convenient to operate, is suitable for occasions where a large amount of liquid drops need to be generated simply and quickly, but has poor controllability on the liquid drops and cannot actively control the liquid drops.

When complex multicomponent microdroplets are generated, the flow rate of the external phase is often dozens of times or hundreds of times of that of the internal phase, and the external phase can generate proper droplet size only under the fixed flow rate. This also causes a large loss of continuous phase fluid.

Disclosure of Invention

The invention aims to provide a low-cost, quick and stable rotary type liquid drop generating device.

The technical solution for realizing the purpose of the invention is as follows: a rotary liquid drop generator mainly comprises a stepping motor, a crank connecting rod structure, a micro-fluidic chip connected with a glass capillary or a metal needle head, and a collecting vessel; the micro-fluidic chip connected with the glass capillary or the metal needle is fixed on the crank connecting rod structure, the tip of the glass capillary or the metal needle is driven by the stepping motor to do circular motion on the surface of the external phase liquid, and micro-droplets with different sizes are prepared by controlling the rotating speed; different micro-fluidic chips are additionally arranged to generate liquid drops with different components.

Furthermore, the crank connecting rod structure drives the whole micro-fluidic chip to do uniform-speed circular motion.

Furthermore, the step motors are two step motors with the same specification, and the two step motors are respectively connected with the two cranks.

Furthermore, the two stepping motors are connected to the same drive controller, so that the rotation synchronism of the two motors is ensured.

Furthermore, continuous phase fluid flows out from the glass capillary or the metal needle, external phase liquid is contained in the collecting vessel, the glass capillary or the metal needle is driven by the connecting rod structure to do circular motion in the external phase liquid, and liquid drops are generated under the shearing action of the external phase liquid.

Furthermore, the microfluidic chip is made of PDMS material.

Furthermore, the crank connecting rod structure is processed by adopting an aluminum alloy material.

Further, the tip of the glass capillary is just immersed in the oil phase on the surface of the collection vessel.

Compared with the prior art, the invention has the following remarkable advantages:

(1) the rotary liquid drop generator has the advantages of reasonable design, simple structure and low cost.

(2) The invention utilizes two stepping motors with the same specification to be connected with the same stepping motor driving controller, on one hand, the rotating speed of the motors can be well controlled, on the other hand, the stability of circular motion can be ensured, and simultaneously, the dead point problem of the crank connecting rod structure can be well solved.

(3) Compared with the traditional micro-fluidic chip for preparing liquid drops, the rotary type liquid drop generator has no external phase injection, the requirement for generating the liquid drops is reduced to a certain extent, and the cost is saved.

(4) Compared with the traditional micro-fluidic chip, the rotary type liquid drop generator directly leads the continuous phase liquid into the open type external phase liquid, so that an external phase liquid channel is omitted, the complexity of the micro-fluidic chip is reduced to a certain extent, and the blocking condition of the micro-fluidic chip is reduced.

(5) The rotary type droplet generator can generate water-in-oil droplets and oil-in-water droplets, and different multi-component droplets can be prepared by additionally arranging different microfluidic chips.

Drawings

FIG. 1 is a schematic view of a crank in an embodiment of the present invention.

Fig. 2 is a schematic view of a connecting rod in an embodiment of the invention.

Fig. 3 is an overall assembly diagram in an embodiment of the invention.

Fig. 4 is a schematic diagram of a droplet generation process in an embodiment of the invention.

FIG. 5 is a schematic view of a microchannel in an embodiment of the invention.

Fig. 6 is a schematic view of a microfluidic chip in an embodiment of the present invention.

Detailed Description

The invention provides a rotary type liquid drop generating device, which is characterized in that on the basis of a traditional micro-fluidic chip, the whole micro-fluidic chip is enabled to do circular motion through a connecting rod structure, and a liquid drop is generated by a tip under the shearing action of an external phase liquid. Since the droplet generation method has no injection of external phase, the requirement for droplet generation is reduced to a great extent.

As shown in fig. 1 to 3, the rotary droplet generator mainly comprises two stepping motors 1, crank connecting rod structures 5 and 6, a microfluidic chip 2 with a glass capillary 4 or a metal needle, and a collecting vessel 3; fixing a micro-fluidic chip 2 connected with a glass capillary tube 4 or a metal needle on connecting rod structures 5 and 6, making the tip end of the glass capillary tube or the metal needle do circular motion on the surface of an external phase liquid by the driving of a stepping motor 1, and preparing micro-droplets with different sizes by controlling the rotating speed, wherein the faster the rotating speed is, the smaller the size of the generated droplet is, and otherwise, the larger the size of the generated droplet is; different micro-fluidic chips are additionally arranged to generate liquid drops with different components.

The connecting rod structures 5 and 6 can drive the whole microfluidic chip to do uniform-speed circular motion, so that the winding of the injection tube is effectively avoided.

The two step motors are connected to the same drive controller, so that the rotating synchronism of the two motors can be guaranteed.

The micro-fluidic chip is fixed on the connecting rod structure, so that the whole micro-fluidic chip can do uniform circular motion.

Compared with the traditional micro-fluidic chip, the rotary type liquid drop generator has the advantages that continuous phase fluid flows out of the glass capillary or the metal needle, external phase liquid is contained in the collecting vessel, the glass capillary or the metal needle is driven by the connecting rod structure to do circular motion in the external phase liquid, liquid drops are generated under the shearing action of the external phase liquid, the injection of the phase fluid is omitted, and liquid drops with different components are generated by additionally arranging different micro-fluidic chips.

Compared with the existing rotary liquid drop generation mode, the novel rotary liquid drop generation mode provided by the invention solves the problem that continuous phases cannot be continuously injected in the rotary liquid drop generation process. The liquid drop generating method has no injection of external phase, the generation of liquid drops is controlled by controlling the rotating speed of the motor, and meanwhile, the requirement for generating the liquid drops is reduced to a certain extent. The invention not only can realize the generation of water-in-oil (W/O) and oil-in-water (O/W) type droplets, but also can prepare a plurality of complex multicomponent droplets.

The tip of the glass capillary or the metal needle is driven by the connecting rod structure to do circular motion on the surface of the external phase liquid, and liquid drops are generated under the shearing action of the external phase liquid.

The present invention will be described in detail with reference to the following examples and drawings.

Example 1

A rotary liquid drop generating device is mainly composed of a stepping motor 1, a stepping motor drive controller, crank connecting rod structures 5 and 6 and a micro-fluidic chip 2 with a glass capillary 4 or a metal needle.

The inner phase liquid is introduced into the micro-fluidic chip 2 and then flows out from the glass capillary tube 4 or the metal needle, the tip of the glass capillary tube or the metal needle is contacted with the surface of the outer phase liquid, the micro-fluidic chip 2 with the glass capillary tube 4 or the metal needle makes circular motion through the crank connecting rod structures 5 and 6, and uniform liquid drops are generated under the shearing action of the outer phase liquid. The size of the generated droplets is controlled by adjusting the rotational speed of the stepping motor 1.

With reference to fig. 1, the present invention designs and manufactures a specific model of a crank. The connection problem of the crank, the stepping motor and the connecting rod structure in the figure 2 needs to be fully considered, and a proper aperture and a proper pitch are designed. Fig. 2 is a concrete model of a connecting rod structure, which fully considers the connection problem of the connecting rod and the crank in fig. 1, and also designs a plane for facilitating the installation of the microfluidic chip.

Referring to fig. 3, a first step is to perform a needle drawing process on the glass capillary. The glass capillary is drawn into a micro needle by a needle drawing instrument, redundant parts at the tip end are cut off by a ceramic chip, a fracture is ground to be flat by the ceramic chip, and the glass capillary is subjected to needle forging treatment, so that the fracture is forged to be a proper size. And the second step is to perform hydrophilic or hydrophobic treatment on the glass capillary. And thirdly, connecting the glass capillary or the metal needle subjected to hydrophilic or hydrophobic treatment to the microchannel, fixing the whole microfluidic chip on the railing structure, and adjusting the height of the collecting vessel or increasing or decreasing the oil in the collecting vessel 3 to ensure that the needle point just sinks over the surface of the oil.

Referring to fig. 4, when the liquid reaches the glass capillary 4 or the metal needle, the switch is turned on, the connecting rod structure 5 drives the whole microfluidic chip to make uniform-speed circular motion, and the liquid flowing out of the glass capillary generates liquid drops under the shearing action of the external phase liquid, and the liquid drops are annularly arranged in the collecting vessel 3. When the complex multicomponent liquid drops are prepared, the complex multicomponent liquid drops can be accurately wrapped by controlling the rotating speed of a motor.

Example 2

This example presents a rotary droplet generator, taking the fabrication of a water-in-oil droplet preparation chip as an example.

(1) With reference to fig. 1 and 2, the whole crank connecting rod structure is made of aluminum alloy materials, so that the rigidity of the crank connecting rod structure is guaranteed while the crank connecting rod structure is light in weight. Firstly, the crank and the connecting rod structure are fixed together by nuts, and then the crank is fixed on the stepping motor by bolts.

(2) Fixing a glass capillary tube with the outer diameter of 1.3mm and the inner diameter of 1mm on a needle drawing instrument to obtain a microneedle, cutting out a part by using a ceramic cutting piece, grinding a fracture flat by using the plane of the ceramic piece, washing off redundant white powder by using clear water, then placing under a microscope to observe whether the fracture is flat or not, continuing to grind flat if the fracture is not flat, and then forging the needle. The fracture was forged to 300 μm using a glass capillary tube with a pin forging apparatus. The glass capillary tip is then subjected to a hydrophobic treatment.

(3) The micro-fluidic chip is made of PDMS (polydimethylsiloxane) material, and a 1.3mm circular micro-channel is prepared by a pouring method. And then inserting the hydrophobized glass capillary into the microfluidic chip, and connecting the other end of the glass capillary with a Teflon tube. And finally, fixing the whole microfluidic chip on the connecting rod structure.

(4) And adding a proper amount of oil into the collector vessel, adjusting the height of the collector vessel or increasing or decreasing the oil phase in the collector vessel, so that the tip of the glass capillary inserted into the microfluidic chip is just immersed into the surface oil phase.

(5) Ultrapure water is used as a dispersion phase and is introduced into the microfluidic chip by a syringe pump, a motor is turned on to rotate a switch, the tip of the glass capillary does uniform-speed circular motion on the surface of the oil phase, the dispersion phase is twisted under the action of the viscous force of the oil, and when the viscous force is greater than the interfacial tension, the dispersion phase is broken to generate micro-droplets.

Example 3

This embodiment proposes a rotary droplet generator, taking the example of making dual-core droplets.

(1) Steps 1 and 2 are the same as those in example 1.

(2) PDMS was used to cast a cross-shaped microchannel, one of which was 1.3mm in diameter and the others were 1mm, as shown in FIG. 5. Then the hydrophobized glass capillary tube was inserted into a 1.3mm channel, two channels perpendicular to it were inserted into teflon tubes, and the last channel was inserted into two needles with an outer diameter of 0.45mm and an inner diameter of 0.24, as shown in fig. 6. The entire microfluidic chip is then fixed on the link structure.

(3) The oil is dyed into red and blue colors respectively as an internal phase, the aqueous solution (added with a proper amount of thickening agent) is used as an intermediate phase, and the undyed oil is used as an external phase. The collection vessel was adjusted so that the oil just passed the tip.

And introducing the liquid into the micro-fluidic chip by using an injection pump, regulating the flow of the injection pump to stably generate red and blue alternating liquid drops, and then regulating the rotating speed to stably generate dual-core liquid drops.