A device and method for droplet spotting

Abstract

This invention relates to an apparatus and method for droplet spotting. The apparatus includes a preparation mechanism and a spotting component. The preparation mechanism includes a first delivery component, a second delivery component connected in parallel with the first delivery component, and a microfluidic chip connected to both the first and second delivery components. The first and second delivery components are configured to deliver a first liquid and a second liquid to the microfluidic chip, respectively, thereby obtaining a droplet sequence. The spotting component is configured to spot the droplets in the droplet sequence. This apparatus separates the droplet generation and spotting process, allowing for greater controllability of the droplets. Each droplet can be considered a separate reaction space, satisfying the requirement of spotting liquids during the reaction process. Because the droplets are separated from each other, cross-contamination between droplets and between the droplets and the spotting head can be avoided during the spotting process, thus eliminating the need for washing the spotting head between adjacent spotting operations.

Description

Technical Field

[0001] This invention relates to the field of droplet spotting technology, and more specifically to an apparatus and method for droplet spotting. Background Technology

[0002] When spotting sensor materials, it is necessary to precisely manipulate and place tiny volumes of liquid (usually nanoliters or picoliters) on an extremely small scale. This process is also of great significance for the fabrication of biochips, chemical sensor arrays, microreactors, and more.

[0003] Current droplet spotting technologies include: inkjet printing (borrowing from printer technology, using heating, piezoelectric or electromagnetic excitation to precisely eject tiny droplets containing sensing materials from a nozzle and deposit them at a predetermined location); non-contact electrostatic spraying (using a high-voltage electrostatic field to charge and precisely guide tiny droplets, allowing them to deposit on the sensor surface without physical contact); microfluidic droplet spotting (integrating microchannels, microvalve and micropumps on a microfluidic chip to control the flow and distribution of micro-fluids, achieving precise control of droplet volume, position and velocity); piezoelectric micropump-driven spotting (using the deformation properties of piezoelectric materials under an electric field to drive liquid through microchannels and control droplet formation and discharge); laser-assisted droplet manipulation (using the photopressure or photothermal effect of a laser beam to non-contactly manipulate tiny droplets for precise positioning and deposition); and surface acoustic wave (SAW)-driven spotting (exciting sound waves on the surface of a MEMS sensor to induce droplet formation and movement, achieving precise spotting).

[0004] Microfluidic droplet spotting boasts advantages such as high throughput and efficiency, low sample consumption, high homogeneity and monodispersity, closed systems and reduced cross-contamination, stable reaction conditions, and high integration and automation, making it a promising technology for applications. However, in existing microfluidic droplet spotting technologies, the liquid remains in a continuous fluid form before entering the spotting head, making it difficult to separate the droplet formation process from the spotting process. Droplet volume is limited by the structure and size of the spotting head, and droplet composition is constrained by the composition of the continuous fluid, preventing flexible control. Summary of the Invention

[0005] In view of the above-mentioned problems existing in the prior art, the present invention provides an apparatus and method for droplet spotting, which can effectively separate the droplet generation and the spotting process, so as to improve the controllability during spotting.

[0006] A first aspect of the present invention: provides an apparatus for spotting liquid droplets, comprising,

[0007] A fabrication mechanism for fabricating a droplet sequence, the fabrication structure comprising a first delivery component, a second delivery component connected in parallel with the first delivery component, and a microfluidic chip connected to both the first and second delivery components. The first and second delivery components are configured to respectively deliver a first liquid and a second liquid to the microfluidic chip, thereby obtaining the droplet sequence; and

[0008] A dispensing assembly configured to dispense droplets in the droplet sequence.

[0009] Furthermore, the first delivery assembly includes a first container for holding the first liquid, a first delivery device for delivering the first liquid to the microfluidic chip, and a first conduit for connecting the first container and the microfluidic chip.

[0010] Furthermore, the second delivery assembly includes a second container for holding the second liquid, a second delivery device for delivering the second liquid to the microfluidic chip, and a second conduit for connecting the second container and the microfluidic chip.

[0011] Furthermore, while the first conveyor delivers the first liquid into the microfluidic chip, the second conveyor delivers the second liquid into the microfluidic chip, thereby obtaining the droplet sequence.

[0012] Furthermore, the first conveyor delivers the first liquid into the microfluidic chip at a first flow rate or a second flow rate, wherein the first flow rate is greater than the second flow rate.

[0013] Furthermore, the first liquid and the second liquid are immiscible.

[0014] Furthermore, the preparation mechanism also includes a third delivery component connected in parallel with the delivery component, the third delivery component being configured to deliver a third liquid into the microfluidic chip.

[0015] Furthermore, while the first delivery component delivers the first liquid into the microfluidic chip, the second delivery component delivers the second liquid into the microfluidic chip, and simultaneously the third delivery component delivers the third liquid into the microfluidic chip, thereby obtaining the droplet sequence.

[0016] Furthermore, when the first delivery component delivers the first liquid to the microfluidic chip at a third flow rate, the third delivery component delivers the third liquid to the microfluidic chip at a fourth flow rate. By changing the third flow rate and the fourth flow rate, the proportion of each component in the droplet obtained after the first liquid and the third liquid are miscible and / or react can be adjusted.

[0017] Furthermore, the first liquid and the third liquid are miscible and / or react with each other, while the third liquid and the second liquid are immiscible.

[0018] Furthermore, the dispensing assembly includes a dispensing platform, a dispensing head disposed above the dispensing platform, and an output tube of the microfluidic chip connected to the dispensing head. The dispensing platform is configured to move in both horizontal and vertical directions so that the dispensing head can dispense each droplet in the droplet sequence onto the substrate of the dispensing platform.

[0019] A second aspect of the present invention provides a method for spotting liquid droplets, using the apparatus for spotting liquid droplets as described in any of the preceding claims, comprising the following steps:

[0020] Step S1: Determine the type of microfluidic chip based on the quantity of different types of liquids;

[0021] Step S2: Prepare a droplet sequence using the preparation mechanism;

[0022] Step S3: The droplets in the droplet sequence are applied to the substrate using the spotting assembly.

[0023] The beneficial effects of this invention are as follows: This invention provides a device for droplet spotting, comprising a preparation mechanism for preparing a droplet sequence and a spotting component. The preparation mechanism includes a first delivery component, a second delivery component connected in parallel with the first delivery component, and a microfluidic chip connected to the first and second delivery components. The first and second delivery components are configured to deliver a first liquid and a second liquid to the microfluidic chip, respectively, thereby obtaining the droplet sequence. The spotting component is configured to spot the droplets in the droplet sequence. This device separates the droplet generation and spotting process, which can improve the controllability of the droplets. During the droplet generation process, the volume and composition of each droplet can be flexibly adjusted by controlling parameters such as flow rate and ratio. Furthermore, each droplet can be regarded as an independent reaction space, which can also meet the requirements of spotting liquids during the reaction process. In addition, since the droplets are separated from each other, cross-contamination between droplets and between droplets and the spotting head can be avoided during the spotting process, thus eliminating the need for washing the spotting head between adjacent spotting operations. Attached Figure Description

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] Figure 1 The diagram shows a schematic of a device for spotting liquid droplets.

[0026] In the figure, the reference numerals are as follows: 10, preparation mechanism; 11, first delivery assembly; 111, first container; 112, first conveyor; 113, first pipe; 12, second delivery assembly; 121, second container; 122, second conveyor; 123, second pipe; 13, microfluidic chip; 20, sample dispensing assembly; 21, sample dispensing platform; 22, sample dispensing head; 23, output tube; 30, substrate. Detailed Implementation

[0027] To make the technical problem to be solved, the technical solution, and the beneficial effects of this invention clearer, the invention will now be described in detail with reference to the accompanying drawings. This drawing is a simplified schematic diagram, illustrating only the basic structure of the invention, and therefore only shows the components relevant to the invention. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0028] Example 1

[0029] refer to Figure 1 As shown, the device for droplet spotting provided by the present invention includes a preparation mechanism 10 for generating a droplet sequence and a spotting component 20 connected to the preparation mechanism 10. The preparation mechanism 10 includes a first delivery component 11, a second delivery component 12 connected in parallel with the first delivery component 11, and a microfluidic chip 13 connected to the first delivery component 11 and the second delivery component 12.

[0030] The first delivery assembly 11 includes a first container 111 for holding a first liquid and a first delivery device 112 for delivering the first liquid to the microfluidic chip 13. The second delivery assembly 12 includes a second container 121 for holding a second liquid and a second delivery device 122 for delivering the second liquid to the microfluidic chip 13. The first liquid and the second liquid are immiscible. That is, the solubility of any component in the first liquid in the second liquid is zero. Similarly, the solubility of any component in the second liquid in the first liquid is also zero.

[0031] The first container 111 and the second container 121 are connected to the respective input ports of the microfluidic chip 13 via the first pipe 113 and the second pipe 123.

[0032] Preferably, the first conveyor 112 and the second conveyor 122 are electrically connected to the controller (not shown in the figure). The controller can control the start and stop of the first conveyor 112 and the second conveyor 122 according to a pre-set program, so as to prepare the desired droplet sequence within the flow channel of the microfluidic chip 13. Furthermore, the controller can also control the output power of the first conveyor 112 and the second conveyor 122 during operation according to a pre-set program, thereby controlling the flow rates of the first liquid and the second liquid. The preparation of droplets using the microfluidic chip 13 is well known to those skilled in the art and will not be elaborated upon further in this application.

[0033] In some embodiments, a first conveyor 112 delivers a first liquid from a first container 111 to a microfluidic chip 13 via a first conduit 113. Simultaneously, a second conveyor 122 delivers a second liquid from a second container 121 to the microfluidic chip 13 via a second conduit 123, allowing both the first and second liquids to enter the flow channels within the microfluidic chip 13 simultaneously. With the flow rates of the first and second liquids remaining constant, a sequence of droplets of the first liquid…AAAA… can be formed within the microfluidic chip 13. A represents a droplet of the first liquid. The droplets in the sequence are separated by the second liquid. Generally, the flow channels of the microfluidic chip 13 are on the micrometer scale. Therefore, at the micrometer scale, the second liquid can encapsulate the first liquid under the influence of surface tension. This not only separates the droplets of the first liquid from each other but also prevents the droplets from contacting the flow channels of the microfluidic chip 13.

[0034] In other embodiments, a first conveyor 112 delivers a first liquid from a first container 111 to a microfluidic chip 13 via a first conduit 113. Simultaneously, a second conveyor 122 delivers a second liquid from a second container 121 to the microfluidic chip 13 via a second conduit 123. During this process, the controller continuously adjusts the flow rate of the first liquid using the first conveyor 112 at a certain frequency, making the flow rate either a first flow rate or a second flow rate. The first flow rate is greater than the second flow rate. With the flow rate of the second liquid remaining constant, a sequence of droplets of the first liquid can be formed within the microfluidic chip 13…AaAaAaA…, where A represents a large droplet of the first liquid and a represents a small droplet of the first liquid. Similarly, the droplets in the droplet sequence are separated by a second liquid.

[0035] In other embodiments and implementations, the fabrication mechanism 10 further includes a third delivery component (not shown) connected in parallel with the first delivery component 11, for delivering a third liquid to the microfluidic chip 13. The third liquid and the second liquid are immiscible.

[0036] The first conveyor 112 delivers the first liquid from the first container 111 to the microfluidic chip 13 through the first conduit 113. Simultaneously, the second conveyor 122 delivers the second liquid from the second container 121 to the microfluidic chip 13 through the second conduit 123. The third conveyor of the third delivery assembly delivers the third liquid from the third container to the microfluidic chip 13 through the third conduit, so that the first, second, and third liquids simultaneously enter the flow channels within the microfluidic chip 13. By continuously repeating the above process while maintaining constant flow rates of the first, second, and third liquids, a sequence of droplets of the first and third liquids can be formed within the microfluidic chip 13: ...ABABABA... where A represents a droplet of the first liquid and B represents a droplet of the third liquid. Similarly, in this droplet sequence, each droplet of the first liquid and each droplet of the third liquid are separated by a second liquid. Likewise, at the micrometer scale, the second liquid can also encapsulate the third liquid under the influence of surface tension. This not only separates the droplets of the third liquid from the droplets of the first liquid, but also prevents the droplets of the third liquid from contacting the flow channel of the microfluidic chip 13.

[0037] Understandably, in some other embodiments, the first conveyor 112 delivers the first liquid in the first container 111 to the microfluidic chip 13 at a third flow rate through the first conduit 113. Simultaneously, the third conveyor delivers the third liquid in the third container to the microfluidic chip 13 at a fourth flow rate through the third conduit, and the second conveyor 122 delivers the second liquid in the second container 121 to the microfluidic chip 13 through the second conduit 123. With the flow rate of the second liquid remaining constant, a droplet sequence of the solution obtained after the reaction and / or miscibility of the first and third liquids can be formed within the microfluidic chip 13…CCCC…, where C represents a droplet of the solution obtained after the reaction and / or miscibility of the first and third liquids.

[0038] Furthermore, by changing the ratio of the third flow rate to the fourth flow rate, the proportion of each component in the solution can be adjusted.

[0039] Recombined Figure 1 As shown, the dispensing assembly 20 includes a dispensing platform 21 for placing the substrate 30, a dispensing head 22 disposed above the dispensing platform 21, and an output tube 23 connecting the dispensing head 22 and the output port of the microfluidic chip 13. The dispensing platform 21 is configured to move in both horizontal and vertical directions to precisely adjust the positional relationship between the dispensing head 22 and the substrate 30. The dispensing platform 21 is well known to those skilled in the art and will not be described in detail in this application.

[0040] Preferably, the dispensing head 22 is perpendicular to the dispensing platform 21 to precisely dispense each droplet in the droplet sequence onto the substrate 30. Because the droplets in the droplet sequence are separated from each other, and because each droplet is encapsulated, it does not come into contact with the flow channels of the microfluidic chip 13 or the inner wall of the output tube 23. This not only avoids cross-contamination between droplets but also eliminates the need for washing the dispensing head 22 between any two adjacent dispensing operations.

[0041] Preferably, the dispensing platform 21 is also electrically connected to the controller. The controller can control the direction and distance of movement of the dispensing platform 21 according to a preset program, so that the dispensing head 22 can accurately dispense each droplet in the droplet sequence at a predetermined position on the substrate 30.

[0042] Understandably, in some embodiments, by controlling the movement direction and distance of the spotting platform 21 through the controller, the spotting head 22 can prevent some droplets in the droplet sequence from being placed onto the substrate 30, thereby discarding some droplets in the droplet sequence. This can make the droplet sequence generated by the preparation mechanism 10 different from the actual droplet sequence, thereby further improving the flexibility of the device.

[0043] Example 2

[0044] Based on the apparatus for droplet spotting in Embodiment 1, this embodiment provides a method for droplet spotting, including the following steps.

[0045] In step S1, the type of the microfluidic chip 13 is determined based on the quantity of different types of liquids.

[0046] In some embodiments, the liquids are of at least two types, and the two liquids are immiscible. The liquids may also be of three, four, or more types, and at least one of these liquids is immiscible with the other liquids.

[0047] In some implementations, the microfluidic chip 13 can be classified into two-inlet-one-outlet type and three-inlet-one-outlet type, depending on the number of inlet ports and outlet ports. Based on the arrangement of the internal flow channels, the microfluidic chip 13 can also be classified into T-shaped, cross-shaped, Y-shaped, etc.

[0048] In step S2, the droplet sequence is prepared using the preparation mechanism 10.

[0049] In some embodiments, the desired droplet sequence is generated by the various preparation components of the preparation mechanism 10.

[0050] In step S3, the droplets in the droplet sequence are applied to the substrate 30 by the spotting component 20.

[0051] Example 3

[0052] Based on the apparatus and method for droplet spotting described in Examples 1 and 2, this example prepares a sensor chip for detecting hydrogen sulfide gas.

[0053] In this embodiment, the apparatus for droplet spotting includes a preparation mechanism 10 for generating a droplet sequence and a spotting component 20 connected to the preparation mechanism 10. The preparation mechanism 10 includes a first delivery component 11, a second delivery component 12 connected in parallel with the first delivery component 11, and a microfluidic chip 13 connected to the first delivery component 11 and the second delivery component 12.

[0054] The first delivery assembly 11 includes a first container 111 for holding a first liquid and a first delivery device 112 for delivering the first liquid to the microfluidic chip 13. The second delivery assembly 12 includes a second container 121 for holding a second liquid and a second delivery device 122 for delivering the second liquid to the microfluidic chip 13. The first liquid and the second liquid are immiscible. That is, the solubility of any component in the first liquid in the second liquid is zero. Similarly, the solubility of any component in the second liquid in the first liquid is also zero. The first container 111 and the second container 121 are respectively connected to the respective input ports of the microfluidic chip 13 via a first conduit 113 and a second conduit 123.

[0055] In this embodiment, both the first container 111 and the second container 121 are syringes. The first liquid is an aqueous solution of molybdenum dioxide nanocrystals containing a stabilizer, and the second liquid is cyclohexane. The microfluidic chip 13 is a two-inlet, one-outlet type.

[0056] In this embodiment, both the first delivery device 112 and the second delivery device 122 are syringe pumps, and are electrically connected to the controller (not shown in the figure). The controller can control the start and stop of the first delivery device 112 and the second delivery device 122 according to a pre-set program to prepare the desired droplet sequence within the flow channel of the microfluidic chip 13. Furthermore, the controller can also control the output power of the first delivery device 112 and the second delivery device 122 during operation according to a pre-set program, thereby controlling the flow rate of the molybdenum dioxide solution and cyclohexane.

[0057] In this embodiment, the first conveyor 112 delivers the molybdenum dioxide solution from the first container 111 to the microfluidic chip 13 via the first conduit 113 at a flow rate of 0.125 cm / min. Simultaneously, the second conveyor 122 delivers cyclohexane from the second container 121 to the microfluidic chip 13 via the second conduit 123 at a flow rate of 1.000 cm / min. With the flow rates of the molybdenum dioxide solution and cyclohexane remaining constant, a sequence of molybdenum dioxide droplets can be formed within the microfluidic chip 13.

[0058] In this embodiment, the dispensing assembly 20 includes a dispensing platform 21 for placing the substrate 30, a dispensing head 22 disposed above the dispensing platform 21, and an output tube 23 connecting the dispensing head 22 and the output port of the microfluidic chip 13. The dispensing platform 21 is provided with an electronic scale located below the substrate 30 for weighing the mass of a certain number of droplets dispensed onto the substrate 30.

[0059] In this embodiment, the spotting assembly 20 sequentially drops a molybdenum dioxide solution onto the substrate 30, weighing the solution after each 20 drops. After the spotting is complete and the molybdenum dioxide solution droplets have dried, the substrate 30 is aged to obtain a sensor chip for detecting hydrogen sulfide gas. The sensor chip is connected to electrodes to obtain its detection limit for hydrogen sulfide gas. The weighing results and detection limit results are shown in Table 1 below.

[0060] Table 1:

[0061]

[0062] Example 4

[0063] Based on the apparatus and method for droplet spotting described in Examples 1 and 2, this example prepares a sensor chip for detecting hydrogen sulfide gas.

[0064] In this embodiment, the apparatus for droplet spotting includes a preparation mechanism 10 for generating a droplet sequence and a spotting component 20 connected to the preparation mechanism 10. The preparation mechanism 10 includes a first delivery component 11, a second delivery component 12 connected in parallel with the first delivery component 11, and a microfluidic chip 13 connected to the first delivery component 11 and the second delivery component 12.

[0065] The first delivery assembly 11 includes a first container 111 for holding a first liquid and a first delivery device 112 for delivering the first liquid to the microfluidic chip 13. The second delivery assembly 12 includes a second container 121 for holding a second liquid and a second delivery device 122 for delivering the second liquid to the microfluidic chip 13. The first liquid and the second liquid are immiscible. That is, the solubility of any component in the first liquid in the second liquid is zero. Similarly, the solubility of any component in the second liquid in the first liquid is also zero. The first container 111 and the second container 121 are respectively connected to the respective input ports of the microfluidic chip 13 via a first conduit 113 and a second conduit 123.

[0066] In this embodiment, both the first container 111 and the second container 121 are syringes. The first liquid is an aqueous solution of tungsten trioxide nanocrystals containing a stabilizer, and the second liquid is cyclohexane. The microfluidic chip 13 is a two-inlet, one-outlet type.

[0067] In this embodiment, both the first delivery device 112 and the second delivery device 122 are syringe pumps, and are electrically connected to the controller (not shown in the figure). The controller can control the start and stop of the first delivery device 112 and the second delivery device 122 according to a pre-set program to prepare the desired droplet sequence within the flow channel of the microfluidic chip 13. Furthermore, the controller can also control the output power of the first delivery device 112 and the second delivery device 122 during operation according to a pre-set program, thereby controlling the flow rate of the tungsten trioxide solution and cyclohexane.

[0068] In this embodiment, the first conveyor 112 delivers the tungsten trioxide solution from the first container 111 to the microfluidic chip 13 via the first conduit 113 at a flow rate of 0.125 cm / min. Simultaneously, the second conveyor 122 delivers cyclohexane from the second container 121 to the microfluidic chip 13 via the second conduit 123 at a flow rate of 1.000 cm / min. With the flow rates of the tungsten trioxide solution and cyclohexane remaining constant, a sequence of tungsten trioxide droplets can be formed within the microfluidic chip 13.

[0069] In this embodiment, the dispensing assembly 20 includes a dispensing platform 21 for placing the substrate 30, a dispensing head 22 disposed above the dispensing platform 21, and an output tube 23 connecting the dispensing head 22 and the output port of the microfluidic chip 13. The dispensing platform 21 is provided with an electronic scale located below the substrate 30 for weighing the mass of a certain number of droplets dispensed onto the substrate 30.

[0070] In this embodiment, the spotting assembly 20 sequentially drops tungsten trioxide solution onto the substrate 30, weighing the solution after each 20 drops. After the spotting is complete and the tungsten trioxide solution droplets have dried, the substrate 30 is aged to obtain a sensor chip for detecting hydrogen sulfide gas. The sensor chip is connected to electrodes to obtain its detection limit for hydrogen sulfide gas. The weighing results and detection limit results are shown in Table 2 below.

[0071] Table 2:

[0072]

[0073] Example 5

[0074] Based on the apparatus and method for droplet spotting described in Examples 1 and 2, this example prepares a sensor chip for detecting hydrogen sulfide gas.

[0075] In this embodiment, the apparatus for droplet spotting includes a preparation mechanism 10 for generating a droplet sequence and a spotting component 20 connected to the preparation mechanism 10. The preparation mechanism 10 includes a first delivery component 11, a second delivery component 12 connected in parallel with the first delivery component 11 and the third delivery component, and a microfluidic chip 13 connected to the first delivery component 11, the second delivery component 12 and the third delivery component.

[0076] The first delivery assembly 11 includes a first container 111 for holding a first liquid and a first delivery device 112 for delivering the first liquid to the microfluidic chip 13. The second delivery assembly 12 includes a second container 121 for holding a second liquid and a second delivery device 122 for delivering the second liquid to the microfluidic chip 13. The third delivery assembly includes a third container for holding a third liquid and a third delivery device for delivering the third liquid to the microfluidic chip 13. The first liquid and the second liquid are immiscible, and the third liquid and the second liquid are immiscible. That is, the solubility of any component in the first liquid in the second liquid is zero. Similarly, the solubility of any component in the third liquid in the second liquid is also zero. The first container 111, the second container 121, and the third container are connected to the respective input ports of the microfluidic chip 13 via a first conduit 113, a second conduit 123, and a third conduit, respectively.

[0077] In this embodiment, the first container 111, the second container 121, and the third container are all syringes. The first liquid is an aqueous solution of molybdenum dioxide nanocrystals containing a stabilizer, the second liquid is cyclohexane, and the third liquid is an aqueous solution of tungsten trioxide nanocrystals containing a stabilizer. The microfluidic chip 13 is a three-inlet, one-outlet type.

[0078] In this embodiment, the first delivery device 112, the second delivery device 122, and the third delivery device are all syringe pumps, and are electrically connected to the controller (not shown in the figure). The controller can control the start and stop of the first delivery device 112 and the second delivery device 122 according to a pre-set program, so as to prepare the desired droplet sequence within the flow channel of the microfluidic chip 13. Furthermore, the controller can also control the output power of the first delivery device 112, the second delivery device 122, and the third delivery device during operation according to a pre-set program, thereby controlling the flow rates of the tungsten trioxide solution, cyclohexane, and molybdenum dioxide solution.

[0079] In this embodiment, the first conveyor 112 delivers the molybdenum dioxide solution from the first container 111 to the microfluidic chip 13 via the first pipe 113 at a flow rate of 0.125 cm / min. The third conveyor delivers the tungsten trioxide solution from the third container to the microfluidic chip 13 via the third pipe at a flow rate of 0.125 cm / min. Simultaneously, the second conveyor delivers cyclohexane from the second container 121 to the microfluidic chip 13 via the second pipe 123 at a flow rate of 1.000 cm / min. With the flow rates of the molybdenum dioxide solution, tungsten trioxide solution, and cyclohexane remaining constant, a droplet sequence of a mixed solution obtained by the mutual dissolution of molybdenum dioxide and tungsten trioxide solutions can be formed within the microfluidic chip 13.

[0080] In this embodiment, the dispensing assembly 20 includes a dispensing platform 21 for placing the substrate 30, a dispensing head 22 disposed above the dispensing platform 21, and an output tube 23 connecting the dispensing head 22 and the output port of the microfluidic chip 13. The dispensing platform 21 is provided with an electronic scale located below the substrate 30 for weighing the mass of a certain number of droplets dispensed onto the substrate 30.

[0081] In this embodiment, the spotting assembly 20 sequentially spots the mixed solution onto the substrate 30, and weighs the solution after every 20 drops. After the spotting is complete and the droplets of the mixed solution have dried, the substrate 30 is aged to obtain a sensor chip for detecting hydrogen sulfide gas. The sensor chip is connected to electrodes to obtain its detection limit for hydrogen sulfide gas. The weighing results and detection limit results are shown in Table 3 below.

[0082] Table 3:

[0083]

[0084] Example 6

[0085] Based on the apparatus and method for droplet spotting described in Examples 1 and 2, this example prepares a sensor chip for detecting hydrogen sulfide gas.

[0086] In this embodiment, the apparatus for droplet spotting includes a preparation mechanism 10 for generating a droplet sequence and a spotting component 20 connected to the preparation mechanism 10. The preparation mechanism 10 includes a first delivery component 11, a second delivery component 12 connected in parallel with the first delivery component 11 and the third delivery component, and a microfluidic chip 13 connected to the first delivery component 11, the second delivery component 12 and the third delivery component.

[0087] The first delivery assembly 11 includes a first container 111 for holding a first liquid and a first delivery device 112 for delivering the first liquid to the microfluidic chip 13. The second delivery assembly 12 includes a second container 121 for holding a second liquid and a second delivery device 122 for delivering the second liquid to the microfluidic chip 13. The third delivery assembly includes a third container for holding a third liquid and a third delivery device for delivering the third liquid to the microfluidic chip 13. The first liquid and the second liquid are immiscible, and the third liquid and the second liquid are immiscible. That is, the solubility of any component in the first liquid in the second liquid is zero. Similarly, the solubility of any component in the third liquid in the second liquid is also zero. The first container 111, the second container 121, and the third container are connected to the respective input ports of the microfluidic chip 13 via a first conduit 113, a second conduit 123, and a third conduit, respectively.

[0088] In this embodiment, the first container 111, the second container 121, and the third container are all syringes. The first liquid is an aqueous solution of molybdenum dioxide nanocrystals containing a stabilizer, the second liquid is cyclohexane, and the third liquid is an aqueous solution of tungsten trioxide nanocrystals containing a stabilizer. The microfluidic chip 13 is a three-inlet, one-outlet type.

[0089] In this embodiment, the first delivery device 112, the second delivery device 122, and the third delivery device are all syringe pumps, and are electrically connected to the controller (not shown in the figure). The controller can control the start and stop of the first delivery device 112 and the second delivery device 122 according to a pre-set program, so as to prepare the desired droplet sequence within the flow channel of the microfluidic chip 13. Furthermore, the controller can also control the output power of the first delivery device 112, the second delivery device 122, and the third delivery device during operation according to a pre-set program, thereby controlling the flow rates of the tungsten trioxide solution, cyclohexane, and molybdenum dioxide solution.

[0090] In this embodiment, the first conveyor 112 delivers the molybdenum dioxide solution from the first container 111 to the microfluidic chip 13 via the first pipe 113 at a flow rate of 0.0625 cm / min. The third conveyor delivers the tungsten trioxide solution from the third container to the microfluidic chip 13 via the third pipe at a flow rate of 0.0625 cm / min. Simultaneously, the second conveyor 122 delivers cyclohexane from the second container 121 to the microfluidic chip 13 via the second pipe 123 at a flow rate of 1.000 cm / min. With the flow rates of the molybdenum dioxide solution, tungsten trioxide solution, and cyclohexane remaining constant, a droplet sequence of a mixed solution obtained by the mutual dissolution of molybdenum dioxide and tungsten trioxide solutions can be formed within the microfluidic chip 13.

[0091] In this embodiment, the dispensing assembly 20 includes a dispensing platform 21 for placing the substrate 30, a dispensing head 22 disposed above the dispensing platform 21, and an output tube 23 connecting the dispensing head 22 and the output port of the microfluidic chip 13. The dispensing platform 21 is provided with an electronic scale located below the substrate 30 for weighing the mass of a certain number of droplets dispensed onto the substrate 30.

[0092] In this embodiment, the spotting assembly 20 sequentially spots the mixed solution onto the substrate 30, and weighs the solution after every 20 drops. After the spotting is complete and the droplets have dried, the substrate 30 is aged to obtain a sensor chip for detecting hydrogen sulfide gas. The sensor chip is connected to electrodes to obtain its detection limit for hydrogen sulfide gas. The weighing results and detection limit results are shown in Table 4 below.

[0093] Table 4:

[0094]

[0095] Example 7

[0096] Based on the apparatus and method for droplet spotting described in Examples 1 and 2, this example prepares a sensor chip for detecting hydrogen sulfide gas.

[0097] In this embodiment, the apparatus for droplet spotting includes a preparation mechanism 10 for generating a droplet sequence and a spotting component 20 connected to the preparation mechanism 10. The preparation mechanism 10 includes a first delivery component 11, a second delivery component 12 connected in parallel with the first delivery component 11 and the third delivery component, and a microfluidic chip 13 connected to the first delivery component 11, the second delivery component 12 and the third delivery component.

[0098] The first delivery assembly 11 includes a first container 111 for holding a first liquid and a first delivery device 112 for delivering the first liquid to the microfluidic chip 13. The second delivery assembly 12 includes a second container 121 for holding a second liquid and a second delivery device 122 for delivering the second liquid to the microfluidic chip 13. The third delivery assembly includes a third container for holding a third liquid and a third delivery device for delivering the third liquid to the microfluidic chip 13. The first liquid and the second liquid are immiscible, and the third liquid and the second liquid are immiscible. That is, the solubility of any component in the first liquid in the second liquid is zero. Similarly, the solubility of any component in the third liquid in the second liquid is also zero. The first container 111, the second container 121, and the third container are connected to the respective input ports of the microfluidic chip 13 via a first conduit 113, a second conduit 123, and a third conduit, respectively.

[0099] In this embodiment, the first container 111, the second container 121, and the third container are all syringes. The first liquid is an aqueous solution of molybdenum dioxide nanocrystals containing a stabilizer, the second liquid is cyclohexane, and the third liquid is an aqueous solution of tungsten trioxide nanocrystals containing a stabilizer. The microfluidic chip 13 is a three-inlet, one-outlet type.

[0100] In this embodiment, the first delivery device 112, the second delivery device 122, and the third delivery device are all syringe pumps, and are electrically connected to the controller (not shown in the figure). The controller can control the start and stop of the first delivery device 112 and the second delivery device 122 according to a pre-set program, so as to prepare the desired droplet sequence within the flow channel of the microfluidic chip 13. Furthermore, the controller can also control the output power of the first delivery device 112, the second delivery device 122, and the third delivery device during operation according to a pre-set program, thereby controlling the flow rates of the tungsten trioxide solution, cyclohexane, and molybdenum dioxide solution.

[0101] In this embodiment, the first conveyor 112 delivers the molybdenum dioxide solution from the first container 111 to the microfluidic chip 13 via the first pipe 113 at a flow rate of 0.250 cm / min. The third conveyor delivers the tungsten trioxide solution from the third container to the microfluidic chip 13 via the third pipe at a flow rate of 0.250 cm / min. Simultaneously, the second conveyor 122 delivers cyclohexane from the second container 121 to the microfluidic chip 13 via the second pipe 123 at a flow rate of 1.000 cm / min. With the flow rates of the molybdenum dioxide solution, tungsten trioxide solution, and cyclohexane remaining constant, a droplet sequence of a mixed solution obtained by the mutual dissolution of molybdenum dioxide and tungsten trioxide solutions can be formed within the microfluidic chip 13.

[0102] In this embodiment, the dispensing assembly 20 includes a dispensing platform 21 for placing the substrate 30, a dispensing head 22 disposed above the dispensing platform 21, and an output tube 23 connecting the dispensing head 22 and the output port of the microfluidic chip 13. The dispensing platform 21 is provided with an electronic scale located below the substrate 30 for weighing the mass of a certain number of droplets dispensed onto the substrate 30.

[0103] In this embodiment, the spotting assembly 20 sequentially spots the mixed solution onto the substrate 30, and weighs the solution after every 20 drops. After the spotting is complete and the droplets of the mixed solution have dried, the substrate 30 is aged to obtain a sensor chip for detecting hydrogen sulfide gas. The sensor chip is connected to electrodes to obtain its detection limit for hydrogen sulfide gas. The weighing results and detection limit results are shown in Table 5 below.

[0104] Table 5:

[0105]

[0106] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0107] It should be understood that the terms "length", "width", "up", "down", "front and back", "left and right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0108] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An apparatus for spotting liquid droplets, comprising: A preparation mechanism (10) for preparing a droplet sequence includes a first delivery component (11), a second delivery component (12) connected in parallel with the first delivery component (11), and a microfluidic chip (13) connected to the first delivery component (11) and the second delivery component (12). The first delivery component (11) and the second delivery component (12) are configured to deliver a first liquid and a second liquid to the microfluidic chip (13) respectively, thereby obtaining the droplet sequence. A spotting assembly (20) configured to spot droplets in the droplet sequence.

2. The apparatus for droplet spotting according to claim 1, characterized in that, The first delivery assembly (11) includes a first container (111) for holding the first liquid, a first delivery device (112) for delivering the first liquid to the microfluidic chip (13), and a first conduit (113) for connecting the first container (111) and the microfluidic chip (13).

3. The apparatus for droplet spotting according to claim 2, characterized in that, The second delivery assembly (12) includes a second container (121) for holding the second liquid, a second delivery device (122) for delivering the second liquid to the microfluidic chip (13), and a second conduit (123) for connecting the second container (121) and the microfluidic chip (13).

4. The apparatus for droplet spotting according to claim 3, characterized in that, While the first delivery device (112) delivers the first liquid into the microfluidic chip (13), the second delivery device (122) delivers the second liquid into the microfluidic chip (13), thereby obtaining the droplet sequence.

5. The apparatus for droplet spotting according to claim 4, characterized in that, The first delivery device (112) delivers the first liquid into the microfluidic chip (13) at a first flow rate or a second flow rate, and the first flow rate is greater than the second flow rate.

6. The apparatus for spotting liquid droplets according to any one of claims 1-5, characterized in that, The first liquid and the second liquid are immiscible.

7. The apparatus for spotting liquid droplets according to any one of claims 1-5, characterized in that, The preparation mechanism (10) further includes a third delivery component connected in parallel with the delivery component, the third delivery component being configured to deliver a third liquid into the microfluidic chip (13).

8. The apparatus for droplet spotting according to claim 7, characterized in that, While the first delivery component (11) delivers the first liquid into the microfluidic chip (13), the second delivery component (12) delivers the second liquid into the microfluidic chip (13), and at the same time the third delivery component delivers the third liquid into the microfluidic chip (13), thereby obtaining the droplet sequence.

9. The apparatus for droplet spotting according to claim 7, characterized in that, While the first delivery component (11) delivers the first liquid into the microfluidic chip (13) at a third flow rate, the third delivery component delivers the third liquid into the microfluidic chip (13) at a fourth flow rate.

10. The apparatus for droplet spotting according to claim 9, characterized in that, The first liquid and the third liquid are miscible and / or react, while the third liquid and the second liquid are immiscible. By changing the third flow rate and the fourth flow rate, the proportion of each component in the droplet obtained after the first liquid and the third liquid are miscible and / or react can be adjusted.

11. The apparatus for spotting liquid droplets according to any one of claims 1-5, characterized in that, The dispensing assembly (20) includes a dispensing platform (21), a dispensing head (22) disposed above the dispensing platform (21), and an output tube (23) of the microfluidic chip (13) connected to the dispensing head (22). The dispensing platform (21) is configured to move in both horizontal and vertical directions so that the dispensing head (22) can dispense each droplet in the droplet sequence onto a substrate (30) on the dispensing platform (21).

12. A method for spotting liquid droplets, characterized in that, Using the apparatus for droplet spotting as described in any one of claims 1-11, the method includes the following steps: Step S1: Determine the type of the microfluidic chip (13) based on the quantity of different types of liquids; Step S2: Prepare droplet sequences using the preparation mechanism (10); Step S3: Droplets from the droplet sequence are applied onto the substrate (30) using the spotting assembly (20).

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