Liquid drop split charging equipment

Abstract

The utility model provides liquid drop split charging equipment, and belongs to the field of micro-flow control. According to the liquid drop subpackaging equipment, air bubbles are used for pushing liquid drops to flow in the printing needle, so that the residence time of the liquid drops in the needle can be shortened, the time cost of production is reduced, the time of a single liquid drop passing through the printing needle is relatively fixed, then the single liquid drop is accurately dropped into a corresponding hole position by moving the pore plate, and the production efficiency is improved. In other words, each hole position only contains one liquid drop.

Description

Technical Field

[0001] The utility model relates to the field of microfluidic control, and particularly to a droplet dispensing device. Background Art

[0002] A droplet is a spherical liquid particle formed because one fluid is immiscible with another carrier fluid, and the essence of its formation is an emulsification phenomenon. According to the different roles of the two immiscible fluids during the droplet formation process, they are respectively called the continuous phase and the dispersed phase (discontinuous phase): the continuous phase is the fluid that acts as the droplet carrier, and the dispersed phase is the fluid that is dispersed into droplets. According to the different types of the single-layer emulsified dispersed phase, droplets can be divided into O / W (oil-in-water) type droplets and W / O (water-in-oil) type droplets. Among them, O / W type droplets refer to oil droplets with the oil phase as the dispersed phase and the water phase as the continuous phase, while W / O type droplets are the opposite.

[0003] In the biological field, droplets can encapsulate cells and serve as bioreactors, such as encapsulating cells and then culturing the cells into tissues or organoids; they can also be used for cell sorting, such as sorting cells such as sperm and fertilized eggs; due to characteristics such as small volume, low diffusion, no cross-contamination, and fast reaction speed, droplets are often used for high-throughput analysis, that is, each droplet can serve as an independent microreactor.

[0004] Currently, many scientific research experiments require distributing positive droplets into a well plate (such as a 96-well plate or a 384-well plate), and only one positive droplet is placed in one well of the well plate, and evidence (single droplet per well) can be left, which is beneficial for subsequent operations such as expansion culture, observation, and selection. However, most of the sorted positive droplets can only spontaneously flow out along with the oil phase, and it cannot be guaranteed that there is only one droplet in one well of the well plate; also, because the droplets are relatively small (with a diameter of dozens of micrometers) and there is a density difference between the droplets and the oil phase, the sorted droplets are likely to remain in the droplet channel and are difficult to drip out smoothly (as shown in Figure 1 ), this residual hysteresis phenomenon is also likely to cause the outflow time of the droplets to be inconsistent, making it difficult to accurately distribute them into the well plate, and it is also easy to cause the sorted droplets to lose the corresponding relationship with the wells of the well plate; even if there is no residual hysteresis phenomenon, the spontaneous outflow time of the droplets is very long (more than 2 minutes), which in turn leads to a long time to fill the entire well plate, increasing the production time cost; due to the inconsistent outflow time of the droplets, with some being long and some being short, it is impossible to predict the accurate time when the droplets drip out.

[0005] The existing product cytomine on the market first stores the sorted positive droplets in a storage cavity on an integrated chip, and then switches the output channel through a microvalve to sequentially export these positive droplets into a 96-well plate. This solution requires integrating a microvalve on the chip, increasing the difficulty of chip and system control.

[0006] Therefore, the above problems are still difficult to solve, so there is an urgent need to find a droplet output system that can prevent droplet residue and retardation and help individual droplets to be quickly and accurately dispensed into their corresponding positions on the microplate. Summary of the Invention

[0007] The utility model provides a droplet dispensing device, belonging to the field of microfluidic control. The droplet dispensing device uses air bubbles to push droplets to flow in the printing needle, which can not only reduce the residence time of droplets in the needle and lower the production time cost, but also the time for a single droplet to pass through the printing needle is relatively fixed. Then, by moving the microplate, individual droplets can be precisely dropped into the corresponding holes, that is, each hole contains only one droplet.

[0008] The utility model provides a droplet dispensing device, which comprises a chip for providing droplets and a droplet printing module for dispensing droplets into different holes, and each hole contains only one droplet.

[0009] Further, the droplet printing module comprises a droplet sorting chip. A droplet delivery channel is provided in the droplet preparation chip. The droplet delivery channel is the output channel for sorted positive droplets. At the same time, an air injection port is provided at the outlet of the droplet delivery channel for injecting air into the droplet delivery channel, and the air forms an air propulsion bubble after entering the droplet delivery channel.

[0010] For the positive droplets and negative droplets of the utility model, they are only distinguished from the purpose of preparing droplets. Droplets that meet the preparation purpose are called positive droplets (or target droplets), and the rest are negative droplets (non-target droplets).

[0011] At the same time, an electrode is provided outside the droplet delivery channel, and the voltage generated by the electrode is 400 - 2,000V.

[0012] The electric field force generated by the electrode affects the movement trajectory of the positive droplets, and to a certain extent affects the time T1 for the droplets to pass through the droplet delivery channel, thereby affecting the droplet dispensing efficiency. In addition, when the set voltage is too high, the droplets will break, thus increasing the production cost.

[0013] Further, the droplet printing module further includes a printing tube, a waste liquid collection module and a droplet collection component; one end of the printing tube is connected to the droplet delivery channel, and the other end leads the positive droplets into the droplet collection component.

[0014] Further, the interval time between two sorted positive droplets by the droplet sorting chip is greater than the sum of the time for the positive droplets to pass through the droplet delivery channel and the printing tube.

[0015] The interval time is the time from the arrival of the first droplet at the end of the printing tube, about to or just dripping, to the arrival of the second droplet at the same position. In some specific embodiments, when the interval time is greater than or equal to 6 s, the droplet dispensing efficiency is as high as 99%. This may be because when collecting droplets each time, there is only one droplet moving in the printing tube, and there is no dripping of adjacent droplets. If the interval time is short, the well plate does not have enough time to move, which may lead to the phenomenon that two droplets are loaded into one well position. It should be noted that when the interval time is greater than 6 s, the entire sorting and printing time is longer, which affects the activity of microorganisms in the droplets and results in low experimental efficiency. Therefore, it is preferred that the interval time is equal to 6 s.

[0016] Further, the time for the positive droplet to pass through the droplet delivery channel is 10 ms to 1 s.

[0017] It can be understood that the time for the positive droplet to pass through the droplet delivery channel depends on multiple factors, such as the length of the droplet delivery channel and the flow rate of the droplet mentioned above. In some preferred embodiments, T1 is 1 s.

[0018] Further, the time T2 for the positive droplet to pass through the printing tube is 1 to 20 s. Preferably, T2 is 5 s.

[0019] Further, the length of the droplet delivery channel is 0.1 mm to 5 cm.

[0020] Further, the width of the droplet delivery channel is 50 μm to 1 mm; the depth is 30 μm to 1 mm.

[0021] Further, the diameter of the air injection port is 30 μm to 0.3 mm, and it is located 50 μm to 2 mm from the droplet delivery channel.

[0022] Further, the ratio of the radius of the air propulsion bubble to the radius of the droplet delivery channel is 0.1 to 5.

[0023] Further, the ratio of the number of air propulsion bubbles to the number of droplets passing through the droplet delivery channel is 10 to 1000.

[0024] Preferably, the ratio of the number of air propulsion bubbles to the number of droplets passing through the droplet delivery channel is 100. It can be understood that the presence of air propulsion bubbles can effectively shorten the droplet dispensing time, improve the stability of the droplet outflow speed, and reduce the error rate. However, when there are too many air bubbles, it will affect the dripping process of the droplets and shorten the service life of the syringe pump.

[0025] Further, the flow rate of the air propulsion bubbles delivered to the droplet delivery channel is 0.1 mL / hr to 20 mL / hr.

[0026] Further, the printing tube includes a capillary tube with a length of 5 - 40 cm and made of any one or more of Teflon, silicone, glass, stainless steel, polyethylene, and PEEK.

[0027] Further, the waste liquid collection module includes a flipping module and a waste liquid bottle. The flipping module includes a flipping stepper motor module and a ladle; the ladle is connected to the waste liquid bottle through a conduit and is used to receive waste liquid.

[0028] Among them, the flipping stepper motor module drives the ladle to flip. It can be understood that whether the positive droplets can smoothly enter the well plate and the removal of negative droplets or waste liquid require the flipping time of the ladle to match the times T1 and T2. The function of the ladle flipping is not to introduce the liquid flowing out of the printing tube into the waste liquid bottle. In some specific embodiments, if the flipping time interval of the ladle is approximately equal to T1 + T2, that is, when the positive droplets are about to be ready to drip or just starting to drip from the printing tube, the ladle flips, enabling the positive droplets to smoothly drip into the corresponding positions of the well plate.

[0029] Further, the waste liquid bottle is provided with a vacuum pumping component, and the vacuum pumping component is used to maintain a vacuum environment inside the waste liquid bottle.

[0030] Further, the droplet collection component includes a well plate for receiving droplets and a moving component. The moving component is used to drive the well plate to displace so as to receive droplets, and the well plate is provided with well positions for dispensing individual droplets.

[0031] The moving component also includes a waste liquid pool. The waste liquid pool is driven by the moving component. When the well plate has just collected a droplet, the next positive droplet can reach the end of the printing tube after T1 + T2 s. During this period, the waste liquid flowing out needs to be collected by the waste liquid pool and the ladle. The function of the waste liquid pool is to collect the waste liquid flowing out of the printing tube before the ladle returns to its original position. When the ladle returns from the flipped state to its original position, the waste liquid flows through the ladle and enters the waste liquid bottle. In summary, the collection of waste liquid and the dispensing of positive droplets require the mutual cooperation of the flipping module and the moving module, and the driving times of the two need to match T1 and T2, thereby improving the droplet dispensing efficiency.

[0032] Further, the moving component includes an X-axis module, a Y-axis module, and a Z-axis module; the X-axis module, Y-axis module, and Z-axis module respectively perform precise movements along the X-axis, Y-axis, and Z-axis.

[0033] Further, the distance between the end of the printing tube and the well plate is 0.5 mm - 20 mm.

[0034] It can be understood that when the distance between the end of the printing tube and the orifice plate is small, the air-propelled bubble comes out of the printing tube and enters the orifice plate along with the droplet before it has time to break. On the contrary, when the droplet drips from a high place, it is easy to splash onto other orifice positions on the orifice plate, thereby contaminating the droplets carried by the latter, and at the same time increasing the volume of the equipment.

[0035] Further, the orifice plate includes any one or more of an 8-well row, a 96-well plate, and a 384-well plate.

[0036] The beneficial effects of the present utility model include:

[0037] 1. A method for discharging droplets remaining in the printing tube by using air is provided, which shortens the time for the droplets to flow out and reduces the time cost of production;

[0038] 2. The equipment provided by the present utility model can accurately control the time for the droplets to flow out, and then can accurately distribute the droplets into the orifice plate, and the corresponding relationship between the sorted droplets and the orifice positions of the orifice plate is clear;

[0039] 3. The equipment provided by the present utility model can ensure that there is only one droplet in one orifice position. If the obtained droplets are to be used for subsequent experiments, this is conducive to analyzing the experimental results in combination with the characteristics of the droplets and saves the time for experimental trial and error. Description of the Drawings

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0041] Figure 1 : Schematic diagram of the droplet retention droplet channel

[0042] Figure 2 : Overall schematic diagram of the droplet dispensing equipment provided by the present utility model

[0043] Figure 3 : Overall schematic diagram of the droplet collection component of the droplet dispensing equipment

[0044] Figure 4 : Partially enlarged schematic diagram of the droplet collection component

[0045] Figure 5 : Schematic diagram of the flipping module

[0046] Figure 6 : Schematic diagram of the waste liquid bottle

[0047] Figure 7:Schematic diagram of air injection pump

[0048] Figure 8 :Partial enlarged schematic diagram of droplet printing module

[0049] Figure 9 :Schematic diagram of sorting and printing chip structure

[0050] Figure 10 :Partial enlarged structural schematic diagram of droplet introduction area of sorting and printing chip

[0051] Figure 11 :Partial enlarged structural schematic diagram of intersection of droplet delivery channel and droplet inlet

[0052] Figure 12 :Partial enlarged structural schematic diagram of end of droplet delivery channel

[0053] Figure 13 :Schematic diagram of working principle of droplet printing module

[0054] Reference numerals: droplet collection component 1, X-axis module 11, Y-axis module 12, Z-axis module 13, orifice plate stage 14, waste liquid pool 15, wetting pool 16; flipping module 2, waste liquid bottle connection port 21, strainer 22, printing tube fixing cylinder 23, flipping stepper motor module 24, printing tube 25; waste liquid bottle 3, waste liquid bottle body 31, waste liquid bottle cap 32, waste liquid inlet 33, vacuum docking head 34; injection pump 4, air storage 41, injection pump drive 42, injection pump connecting pipe 43; sorting and printing chip 5, droplet introduction channel 51, intersection of droplet delivery channel and droplet inlet 52, outlet of droplet delivery channel 53, air injection port 54, droplet inlet 55, inlet of droplet delivery channel 56, electrode 57. Detailed implementation manners

[0055] The preferred embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. It should be noted that the following embodiments are intended to facilitate the understanding of the present invention and do not limit it in any way. The raw materials and equipment used in the specific embodiments of the present invention are all known products and are obtained by purchasing commercially available products.

[0056] Embodiment 1: Droplet dispensing equipment provided by the present invention

[0057] The positive droplets and negative droplets described in the present invention are only distinguished from the purpose of preparing droplets. The droplets that meet the preparation purpose are called positive droplets (or target droplets), and the rest are negative droplets (non-target droplets).

[0058] The droplet dispensing device provided by the present utility model includes a chip for providing droplets and a droplet printing module. The chip for providing droplets can synthesize droplets and / or perform preliminary screening on the droplets, enabling target droplets with uniform size to enter the droplet printing module; the droplet printing module includes a sorting and printing chip 5, a printing tube 25, a waste liquid collection module, and a droplet collection component 1; the waste liquid collection module includes a flipping module 2 and a waste liquid bottle 3, and the droplet collection component includes a orifice plate carrier 14 for receiving the orifice plate and a moving component.

[0059] As Figure 2 shown, the droplet collection component 1 is located on the first layer (counting from bottom to top) of the device provided by the present utility model, the flipping module 2 is located above the droplet collection component 1, between the first-layer clamping plate and the second-layer clamping plate; the waste liquid bottle 3 is embedded on the second-layer clamping plate, close to the flipping module 2; the injection pump 4 is located on the topmost layer. Since there is a sorting and printing chip 5 containing a droplet delivery channel between the injection pump 4 and the flipping module 2 and the waste liquid bottle 3, the distance between the injection pump 4 and the latter two is relatively far.

[0060] Figure 3 As the overall schematic diagram of the above-mentioned droplet collection component 1, it can be seen that the droplet collection component 1 is composed of a moving component and an orifice plate carrier 14. The moving component includes an X-axis module 11, a Y-axis module 12, and a Z-axis module 13. These three modules are mainly composed of a lead screw stepping motor, a guide rail, a sensor, etc., and respectively perform precise movements in the X / Y / Z-axis directions to drive any one or more of an 8-well row, a 96-well plate, and a 384-well plate (in this embodiment, a 96-well plate is preferably used) to move in three-dimensional space. The orifice plate is used to receive positive droplets flowing out of the printing tube; the orifice plate carrier 14 is mainly used for loading the orifice plate and cleaning liquid, and the latter is used to clean the tip of the printing tube before printing the 96-well plate. During use, driven by the moving component, the orifice plate carrier 14 moves in coordination with the frequency of droplets flowing out of the printing tube 25 to ensure that each orifice plate hole contains only one droplet, and by moving the Z-axis module 13, the distance between the orifice plate and the end of the printing tube 25 is adjusted to prevent some liquid from splashing onto the adjacent orifice plate hole when the droplet drops onto the target orifice plate hole, causing contamination of the latter.

[0061] Furthermore, a waste liquid pool 15 and a wetting pool 16 are designed beside the orifice plate carrier 14 (as Figure 4 shown). The former is used for temporarily storing waste liquid in case of emergency, that is, when the ladle 22 is too late to flip and receive the waste liquid, the moving component is moved to make the waste liquid pool 15 located directly below the printing tube 25; the latter is filled with a wetting agent, which is used to wet and clean the end of the printing tube 25 to enable the droplets to flow out smoothly and reduce the probability of cross-contamination. The wetting agent includes one or more of deionized water, fluorinated oil, ethanol, and isopropanol. In this embodiment, deionized water is preferably used.

[0062] As Figure 5As shown in the figure, the flipping module 2 includes a waste liquid bottle connection port 21, a strainer 22, a printing tube fixing cylinder 23, a flipping stepper motor module 24, and a printing tube 25. The waste liquid bottle connection port 21 is connected to the waste liquid inlet 33 through a conduit, allowing the excess oil phase without droplets to enter the waste liquid bottle 3. The strainer is connected to the waste liquid bottle connection port 21 and is used to receive the waste liquid. The printing tube fixing cylinder 23 can not only fix the printing tube 25 on the sorting and printing chip 5 but also prevent the printing tube 25 from folding and being damaged, thus ensuring that the droplets flow out continuously within a certain period of time. The sorting and printing chip 5 includes a droplet delivery channel. The flipping stepper motor module 24 is used to drive the strainer 22 to flip 90°, enabling the latter to receive the waste liquid without obstructing the positive droplets from dripping into the well plate. The printing tube 25 is a capillary tube with a length of 5 - 40 cm and a material of any one or more of Teflon, polyethylene, silicone, glass, stainless steel, and PEEK (preferably a Teflon capillary tube in this embodiment), which is used to transport the sorted positive droplets of the sorting and printing chip 5 and the air propulsion bubbles for spacing and pushing the positive droplets, and then print the droplets onto the well positions. In summary, the flipping module 2 mainly performs the following actions: 1) When not printing, the liquid passes through the strainer 22 and enters the waste liquid bottle for unified collection; 2) When printing, the flipping stepper motor module 24 drives the strainer 22 to flip 90°, allowing the liquid to fall into the well plate.

[0063] As Figure 6 shown in the figure, the waste liquid bottle 3 includes a waste liquid bottle body 31, a waste liquid bottle cap 32, a waste liquid inlet 33, and a vacuum docking head 34, and is mainly used to receive the waste liquid generated when not printing. The waste liquid contains the excess oil phase without droplets. The waste liquid bottle body 31 is one or more of a cuboid, a cube, and a cylinder (preferably a cuboid in this embodiment), with a volume of 10 mL - 500 mL (preferably 200 mL in this embodiment), which is convenient for replacement and removal of the waste liquid. The waste liquid inlet 33 and the vacuum docking head 34 are inserted into the waste liquid bottle cap. The former is connected to the waste liquid bottle connection port 21 of the flipping module 2, and the latter is connected to the vacuum pumping component. The vacuum pumping component is one or more of a vacuum pump and a vacuum generator (preferably a vacuum pump in this embodiment). By means of the vacuum pumping component, the vacuum environment inside the waste liquid bottle 3 is maintained, and then, by using the pressure difference between the waste liquid bottle 3 and the waste liquid delivery pipeline, the waste liquid flows into the waste liquid bottle 3 continuously and at a certain speed.

[0064] As Figure 7As shown in the figure, the injection pump 4 includes an air storage 41 and an injection pump drive 42. The air storage 41 can be any one or more of syringes with specifications of 1 mL, 5 mL, 10 mL, 50 mL, and 100 mL. In this embodiment, 10 mL is preferably selected. The air storage 41 conveys air for the droplet delivery channel, and different-capacity air storages can be selected and replaced according to the amount of dispensed droplets. The injection pump drive 42 includes a closed-loop stepper motor, a lead screw module, a sensor, etc., and is used to precisely control the volume and frequency of the air conveyed from the air storage 41 to the droplet delivery channel.

[0065] Figure 8 It is a partial enlarged schematic diagram of the droplet printing module. One end of the injection pump connecting pipe 43 is connected to the air storage 41, and the other end is connected to the sorting and printing chip 5, injecting air into the droplet delivery channel in the sorting and printing chip 5 to form an air propulsion bubble.

[0066] Figure 9 It is a schematic diagram of the structure of the sorting and printing chip 5. The generated or processed droplets enter the droplet delivery channel inlet 56 through the droplet introduction channel 51, (see the partial enlarged view in Figure 10 ), the droplet inlet 55, and the intersection 52 of the droplet delivery channel and the droplet inlet. As can be seen from Figure 11 , there is an electrode 57 outside the intersection of the droplet delivery channel and the droplet inlet; at the end of the delivery channel, there are a droplet delivery channel outlet 53 and an air injection port 54 ( Figure 12 ).

[0067] The working principle of the droplet printing module is as shown in Figure 13 . There is a laser at the droplet inlet 55 to detect the presence of positive droplets; the air injection port 54 provided at the end of the droplet delivery channel is used to inject air into the droplet delivery channel. The other end of the air injection port is connected to the air storage 41. After the air enters the droplet delivery channel, an air propulsion bubble is formed. There is an electrode 57 outside the channel to change the movement trajectory of the droplets. When a single droplet flows through the laser detection device, if it is identified and judged as a positive droplet, the electrode 57 is energized to generate an electric field. Under the action of the electric field force, the movement trajectory of the positive droplet deviates and flows into the droplet delivery channel inlet 56. When the droplet flows to the end of the delivery channel, the air injection port 54 continuously injects air into the droplet delivery channel, and the generated air propulsion bubble follows the positive droplet into the printing tube 25; at the same time, the flipping stepper motor module 24 drives the ladle 22 to flip 90° (to prevent positive droplets from entering the waste liquid bottle), and the moving part drives the orifice plate stage 14, and then moves the orifice plate so that an orifice position without droplets is aligned with the end of the printing tube 25; with the cooperation of the sorting and printing chip 5, the flipping module 2, and the droplet collection component 1, the positive droplets successfully drop into the orifice plate, and there is only one droplet in one orifice plate hole position.

[0068] It is understandable that, under a certain voltage, according to the dielectrophoretic force formula For a specific flow rate and droplet size, by selecting an appropriate voltage, it is ensured that the positive droplets are stably deflected to the entrance 56 of the positive droplet delivery channel, and the time T1 for the droplets to pass through the droplet delivery channel is calculated, and the droplets and the air propulsion bubbles enter the printing tube 25 in a certain proportion; it is understandable that, with the assistance of air propulsion bubbles with a certain initial velocity, the droplets can pass through the printing tube 25 at a relatively fast speed. According to the length of the printing tube 25 and the flow rate of the droplets, the climbing tube time T2 of the droplets can be calculated. In order to improve the efficiency of dispensing individual droplets into independent holes, the time interval for dispensing positive droplets is greater than or equal to T1 + T2, that is, when a positive droplet flows into the entrance 56 of the droplet delivery channel, there are no droplets in the droplet delivery channel and the printing tube 25; it is understandable that when the droplets drop into the holes, the air propulsion bubbles are released from the printing tube 25 and then automatically burst, and will not drop into the orifice plate along with the droplets.

[0069] When the droplet dispensing device provided by the present utility model executes the printing operation, the process is as follows:

[0070] 1) Loading consumables: Loading the sorting and printing chip - Loading the orifice plate - Loading the consumables for wetting - Connecting the injection pump connecting tube 43 on the sorting and printing chip to the syringe of the injection pump;

[0071] 2) Wetting and cleaning: Moving the wetting pool 16 under the printing tube 25 - Executing the wetting and cleaning operation of the printing tube 25;

[0072] 3) Printing: The injection pump 4 works stably - Positive signal recognition - The colander 22 is lifted - The orifice plate moves to the corresponding position to receive the positive droplets.

[0073] In some embodiments, the droplet dispensing device provided by the present utility model is applicable to the dispensing of droplets with a particle size of 20 μm to 0.2 mm. Among them, the flow rate of the droplets is 0.1 mL / hr to 20 mL / hr; the length of the droplet delivery channel is 0.1 mm to 5 cm, the width is 50 μm to 1 mm, the depth is 30 μm to 1 mm, and the time T1 for the droplet to pass through this channel is 10 ms to 1 s; the voltage generated by the outer electrode of the droplet delivery channel is 400 to 2,000 V, and the distance between the two is 20 μm to 0.2 mm; the diameter of the air injection port is 30 μm to 0.3 mm, and it is located 50 μm to 2 mm from the droplet delivery channel; the ratio of the radius of the air propulsion bubble to the radius of the droplet delivery channel is 0.1 to 5, the flow rate entering the droplet delivery channel is 0.1 mL / hr to 20 mL / hr, and the ratio to the number of positive droplets passing through the droplet delivery channel is 10 to 1,000; the length of the printing tube is 5 to 40 cm, the time T2 for the positive droplet to pass through the printing tube is 1 to 20 s, and the distance between the end of the printing tube and the orifice plate is 0.5 mm to 20 mm.

[0074] Preferably, the droplet particle size is 50 μm and the flow rate is 0.1 mL / hr; the length of the droplet delivery channel is 15 mm, the width is 50 μm, the depth is 90 μm, and the time T1 for the droplet to pass through this channel is 1 s; the voltage generated by the outer electrode of the droplet delivery channel is 1,000 V, and the distance between the two is 40 μm; the diameter of the air injection port is 90 μm, and it is located 300 μm from the droplet delivery channel; the ratio of the radius of the air propulsion bubble to the radius of the droplet delivery channel is 0.1, the flow rate entering the droplet delivery channel is 5 mL / hr, and the ratio to the number of positive droplets passing through the droplet delivery channel is 10; the length of the printing tube is 20 cm, the time T2 for the positive droplet to pass through the printing tube is 5 s, and the distance between the end of the printing tube and the orifice plate is 10 mm.

[0075] Example 2: Influence of the lengths of the droplet delivery channel and the printing tube on droplet dispensing

[0076] The lengths of the droplet delivery channel and the printing tube largely determine the time for droplets to pass through them, thereby affecting the efficiency of dispensing droplets. On the other hand, based on the time for positive droplets to pass through the droplet delivery channel, the time for generating air propulsion bubbles needs to be set. Therefore, in this embodiment, droplets with a particle size of 50 μm and a flow rate of 0.1 mL / hr are used as the experimental objects, and the droplet dispensing device provided in Embodiment 1 is adopted to explore the influence of the lengths of the droplet delivery channel and the printing tube on the droplet dispensing of this device. Among them, except for the different lengths of the droplet delivery channel and the printing tube, other parameters of the droplet dispensing device are the same as the optimal parameters. The number of droplets in the hole positions is detected by a microscope. Each experimental group is designed with 3 replicates. The specific results are shown in Table 1. Error rate = the number of hole positions containing 2 or more droplets / 96 × 100%.

[0077] Table 1 Influence of the lengths of the droplet delivery channel and the printing tube on droplet dispensing

[0078]

[0079] As can be seen from Table 1, the error probability of experimental group A is relatively large. The main reason is that the droplet sorting and printing rates are too fast, and the movement of the 96-well plate and the sieve cannot keep up with the printing rate, resulting in incorrect dropping into the holes. The error rates of experimental groups B - F are all less than 5%, indicating that the ratios of the droplet delivery channels to the printing tubes corresponding to experimental groups B - F are all applicable to the droplet dispensing device provided by the present utility model. Among them, when T1 = 1 s and T2 = 5 s, the efficiency of filling the 96-well plate is the highest. Therefore, this condition is preferentially adopted.

[0080] Embodiment 3: Influence of droplet dispensing interval on its dispensing

[0081] To ensure that there is only one droplet in each pore diameter, in this embodiment, droplets with a particle size of 50 μm and a flow velocity of 0.1 mL / hr are used as the experimental objects. The droplet dispensing device provided in Embodiment 1 is adopted, with T1 = 1 s and T2 = 5 s. The time interval between the arrival of two consecutive droplets at the end of the printing tube is explored. The method for detecting the number of droplets in the hole positions is the same as that described in Embodiment 2. Error rate = the number of hole positions containing 2 or more droplets / 96 × 100%.

[0082] Table 2 Influence of droplet dispensing interval on its dispensing

[0083] Interval time / s Error rate / % 4 <15％ 5 <10％ 6 <1％ 7 <1％ 8 <1％

[0084] As can be seen from Table 2, when the interval time is greater than or equal to 6 s, the droplet dispensing efficiency is as high as 99%. This is because when collecting droplets each time, there is only one droplet moving in the printing tube, and there is no phenomenon that two droplets are loaded into one well due to the short interval time between adjacent droplet drips and the well plate not having enough time to move. It should be noted that when the interval time is greater than 6 s, the sorting and printing time of the entire well plate will increase significantly, affecting the experimental efficiency. Therefore, an interval time of 6 s is preferably selected.

[0085] Example 4: Influence of the ratio of air propulsion bubbles to droplet number on droplet dispensing

[0086] Air propulsion bubbles not only push the droplets forward with their inherent initial velocity but also space each droplet, so that there is only one droplet in each well on the well plate. It can be understood that the more air propulsion bubbles there are, the greater the driving force on the droplets, the faster they move, and the higher the droplet dispensing efficiency. However, when the number of bubbles is too large, it may lead to abnormal droplet dripping processes and bubbles that have not had time to dissipate entering the well plate with the droplets, affecting subsequent experiments. Combining the results of Examples 2 and 3, in this example, droplets with a particle size of 50 μm and a flow rate of 0.1 mL / hr were used as the research object. Based on the droplet dispensing equipment provided in the example, the lengths of the droplet delivery channel and the printing tube were 10 mm and 20 cm respectively. The influence of the ratio of air propulsion bubbles to droplet number on droplet dispensing was explored. The method for detecting the number of droplets in the detection wells was as described in Example 2. Each experimental group was designed with three replicates. The specific results are shown in Table 3.

[0087] Table 3 Influence of the ratio of air propulsion bubbles to droplet number on droplet dispensing

[0088]

[0089] As can be seen from Table 3, the presence of air propulsion bubbles can effectively shorten the droplet dispensing time, improve the stability of the droplet outflow speed, and reduce the error rate. That is, when the ratio of the number of air propulsion bubbles to the number of droplets is greater than or equal to 100:1, the droplet dispensing efficiency is the highest. However, when the ratio of the two numbers is greater than 100, due to too many air bubbles affecting the droplet dripping process and shortening the life of the injection pump, etc., it is preferably that the ratio of the number of air propulsion bubbles to the number of droplets is equal to 100.

[0090] The above-described embodiments have detailed the technical solutions of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, supplements, or substitutions in a similar manner within the principle scope of the present invention should be included within the protection scope of the present invention.

Claims

1. A droplet dispensing device, characterized in that It includes a chip for providing droplets and a droplet printing module. The droplet printing module is used to dispense droplets into different pore positions, and each pore position contains only one droplet.

2. The device according to claim 1, wherein The droplet printing module includes a droplet sorting chip. There is a droplet delivery channel in the droplet preparation chip. The droplet delivery channel is the output channel for sorted positive droplets. At the same time, an air injection port is provided at the outlet of the droplet delivery channel for injecting air into the droplet delivery channel. After the air enters the droplet delivery channel, an air propulsion bubble is formed.

3. The device according to claim 2, characterized in that, The droplet printing module further includes a printing tube, a waste liquid collection module, and a droplet collection component. One end of the printing tube is connected to the droplet delivery channel, and the other end leads the positive droplets into the droplet collection component.

4. The device according to claim 3, characterized in that, The time for the positive droplets to pass through the droplet delivery channel is 10 ms to 1 s.

5. The device according to claim 3, wherein The time for the positive droplets to pass through the printing tube is 1 to 20 s.

6. The device according to claim 3, characterized in that, The length of the droplet delivery channel is 0.1 mm to 5 cm.

7. The device according to claim 3, characterized in that, The width of the droplet delivery channel is 50 μm to 1 mm; the depth is 30 μm to 1 mm.

8. The device according to claim 3, characterized in that, The diameter of the air injection port is 30 μm to 0.3 mm, and it is located 50 μm to 2 mm from the droplet delivery channel.

9. The device according to claim 3, wherein The ratio of the radius of the air propulsion bubble to the radius of the droplet delivery channel is 0.1 to 5.

10. The device according to claim 3, characterized in that, The ratio of the number of air propulsion bubbles to the number of droplets passing through the droplet delivery channel is 10 to 1000.

11. The device according to claim 3, characterized in that, The flow rate of the air propulsion bubbles delivered to the droplet delivery channel is 0.1 mL / hr to 20 mL / hr.

12. The device according to claim 3, characterized in that The waste liquid collection module includes a flipping module and a waste liquid bottle. The flipping module includes a flipping stepping motor module and a ladle. The ladle is connected to the waste liquid bottle through a conduit and is used to receive waste liquid.

13. The device according to claim 12, characterized in that, The waste liquid bottle is provided with a vacuum pumping component, which is used to maintain a vacuum environment inside the waste liquid bottle.

14. The device according to claim 12, wherein, The droplet collection component includes an orifice plate for receiving droplets and a moving component. The moving component is used to drive the displacement of the orifice plate to receive droplets. The orifice plate is provided with pore positions for dispensing individual droplets.

15. The device according to claim 14, characterized in that, The moving component includes an X-axis module, a Y-axis module, and a Z-axis module. The X-axis module, Y-axis module, and Z-axis module respectively perform precise movements along the X-axis, Y-axis, and Z-axis.

16. The device according to claim 3, characterized in that, The distance between the end of the printing tube and the orifice plate is 0.5 mm to 20 mm.

17. The device according to claim 16, characterized in that, The orifice plate includes any one or more of 8-well strips, 96-well plates, and 384-well plates.

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