Microfluidic chip, liquid injection method therefor, and use thereof

Abstract

A microfluidic chip, a liquid injection method therefor, and uses thereof are provided. The microfluidic chip comprises a microfluidic chip substrate, a conductive cover, and a liquid injection housing, which are stacked in order from bottom to top. The liquid injection housing is provided with at least one liquid injection conduit and an oil intake conduit. The liquid injection housing comprises an oil injection cavity, a sample quantification cavity, and at least one liquid injection cavity arranged side by side, the oil injection cavity, the sample quantification cavity, and the at least one liquid injection cavity are configured to respectively arrange an oil bubble cap, a sample quantification plug, and at least one reagent bubble cap. A liquid injection column connected to a corresponding one of the at least one liquid injection conduit is disposed in each of the at least one liquid injection cavities, and each of the at least one liquid injection conduit forms a liquid injection channel. The oil injection column is disposed in the oil injection cavity and connected to the oil intake conduit. The surfaces of the oil injection cavity and the at least one liquid injection cavity are provided with spike parts correspondingly.

Description

[Technical Field]

[0001] The present disclosure relates to the technical field of microfluidic chips, and to microfluidic chips, liquid injection methods therefor, and uses thereof. [Background technology]

[0002] Microfluidic chips integrate basic operational units, such as sample preparation, reaction, separation, and testing, in biological, chemical, and medical analytical processes, onto a chip with microscale structures. The chip uses the principle of electrowetting technology to adjust the solid-liquid surface energy by electric potential, and move the liquid by the imbalance of surface energy, thereby realizing precise control of microfluidics.

[0003] During liquid injection into a microfluidic chip, an operator typically needs to draw up a certain amount of liquid sample with a pipette, align the pipette with the sample inlet, and inject the liquid completely into the reaction cavity. However, using a pipette to inject the sample increases the operating cost and has high requirements for the operator's operation precision.

[0004] Patent document CN209406357U discloses a microfluidic chip that facilitates liquid injection. The microfluidic chip includes a substrate and a cover plate. The substrate is provided with a plurality of microfluidic channels, and the substrate and the cover plate are joined together, with the microfluidic channels located between the substrate and the cover plate. The microfluidic chip further includes a connecting conduit, and the cover plate is provided with at least one guide hole, which communicates with the microfluidic channel, and the connecting conduit is detachably connected to the guide hole at one end.

[0005] CN107988070A discloses a microfluidic chip for microscale cell electroporation, a microscale cell electroporation and sorting device, and their uses. The microscale cell electroporation and sorting device includes an electroporation unit, a display screen, an outer case, a power supply unit, a microcontroller unit, and a primary sensor. The electroporation unit includes a chip. The display screen is configured to send instructions to the microcontroller unit and receive and display information fed back from the microcontroller unit and the primary sensor. The microcontroller unit is configured to receive instructions sent by the display screen and control the electroporation unit and the power supply unit. The electroporation unit is configured to complete the cell transfection process, and the primary sensor is configured to receive information fed back from the electroporation unit and send it to the display screen and the microcontroller unit. The microfluidic chip for microscale cell electroporation includes a sample inlet, a sample outlet, a negative pressure duct, a positive pressure duct, and a main channel. A 96-well plate is placed behind the sample outlet. This invention can ensure consistent conditions in the main channel during the transfection process, ensure transfection efficiency, ensure cell quality in 96-well plates, and facilitate later cell culture.

[0006] CN108148752A discloses an integrated drug screening and staining method based on a microfluidic chip. The microfluidic chip is configured with a liquid path control layer as an upper layer, a gas path control layer as a lower layer, and a blank glass base plate at the bottom. The integrated drug screening and staining method based on a microfluidic chip sequentially includes a chip pretreatment step, a cell seeding and culture step, a drug stimulation step, and a fluorescent staining step. The inlets of each liquid path layer are individually controlled by valves in the gas path layer, allowing for simultaneous cultivation of different types of cells, stimulation with different drugs, and staining with different antibodies. By utilizing microfluidic and microvalve technologies within the microfluidic chip, the present invention realizes drug screening and fluorescent staining on the microfluidic chip, thereby providing a completely new technological platform for cell culture, in situ fluorescent staining of cells, and drug screening research. This method is simple and convenient to operate, uses fewer cells and reagents, and has a high level of integration and wide application. Summary of the Invention [Problem to be solved by the invention]

[0007] Prior art technologies have used fully manual reaction plates, such as 96-well and 384-well plates, or continuous microfluidic devices equipped with syringe pumps and droplet microfluidics. However, these technologies have significant limitations in practical applications. Fully manual operation is time-consuming, labor-intensive, has low accuracy, and is prone to errors. Microfluidic device and droplet microfluidic operation relies heavily on syringe pumps, resulting in higher costs. In addition, prior art sample intake methods typically require the use of pipettes or external mechanical pumps, resulting in high manufacturing costs, complex operating procedures, low reproducibility, and limited operating environments. Furthermore, the liquid sample intake process involves tedious steps, leading to a high risk of waste and errors. Therefore, there is an urgent need to design and develop microfluidic chips and associated methods to meet the needs of practical production and daily life. [Means for solving the problem]

[0008] According to a first aspect of an embodiment of the present disclosure, a microfluidic chip is provided, the microfluidic chip comprising a microfluidic chip substrate, a conductive cover, and a liquid injection housing, stacked in order from bottom to top. The liquid injection housing is provided with at least one liquid injection conduit and an oil intake conduit. The liquid injection housing comprises an oil injection cavity, a sample quantification cavity, and at least one liquid injection cavity arranged side by side, the oil injection cavity, the sample quantification cavity, and the at least one liquid injection cavity being configured to accommodate an oil bubble cap, a sample quantification plug, and at least one reagent bubble cap, respectively. A liquid injection column connected to a corresponding one of the at least one liquid injection conduit is disposed in each of the at least one liquid injection cavity, and each of the at least one liquid injection conduit forms a liquid injection channel. The oil injection column is disposed in the oil injection cavity, and the oil injection column is connected to the oil intake conduit. The surfaces of the oil injection cavity and the at least one liquid injection cavity are each provided with a corresponding spike component.

[0009] According to a second aspect of an embodiment of the present disclosure, there is provided a liquid injection method for a microfluidic chip, the liquid injection method including: during liquid injection, liquid injection columns successively enter corresponding reagent bubble caps to press the liquid in the reagent bubble caps, the reagent bubble caps form a seal with the liquid injection columns in the downward pressing process, and pierce the reagent bubble caps by their respective spike parts, the liquid in the reagent bubble caps flows into the closed cavity of the microfluidic chip through the liquid injection channel, adjusting the voltage of a microelectrode array arranged on a base plate of the microfluidic chip substrate so that the liquid flowing from the reagent bubble caps into the closed cavity reaches a designated position; During the downward pressing, the oil injection column continuously enters the oil bubble cap to press the liquid in the oil bubble cap, the oil bubble cap forms a seal with the oil injection column in the downward pressing process, and the oil bubble cap is perforated by each spike part, the liquid in the oil bubble cap flows into the closed cavity of the microfluidic chip through the oil suction hole, and the voltage of the microelectrode array arranged on the base plate of the microfluidic chip substrate is adjusted so that the oil liquid flowing from the oil bubble cap into the closed cavity reaches a specified position.

[0010] According to a third aspect of an embodiment of the present disclosure, there is provided an oil injection method for a microfluidic chip, the oil injection method including: during liquid injection, liquid injection columns successively enter corresponding reagent bubble caps to pressurize the liquid in the reagent bubble caps, the reagent bubble caps form seals with the liquid injection columns in a downward pressing process, the reagent bubble caps are pierced by their respective spike components, the liquid in the reagent bubble caps flows through the liquid injection channels into the closed cavities of the microfluidic chip, adjusting a voltage of a microelectrode array disposed on a base plate of a microfluidic chip substrate so that the liquid flowing from the reagent bubble caps into the closed cavities reaches a designated position; and during oil injection, the oil bubble caps are pierced by their respective spike components in a downward pressing process, the liquid in the oil bubble caps flows through the oil suction holes into the closed cavities of the microfluidic chip.

[0011] According to a fourth aspect of the present disclosure, there is provided a use of the microfluidic chip according to the first aspect, wherein the microfluidic chip is used in the field of digital microfluidic chips.

[0012] The microfluidic chip provided by the embodiments of the present disclosure is pre-embedded with reagents and integrated with a hole injection device, which avoids manual liquid injection and oil injection operations and is more reliable.

[0013] Further embodiments of the present disclosure, as well as its features and advantages, will become more apparent by reference to the description herein in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic structural diagram of a microfluidic chip according to some embodiments of the present disclosure. [Figure 2] FIG. 1 is a front top view of a liquid injection housing according to some embodiments of the present disclosure. [Figure 3]FIG. 10 is a rear top view of a liquid injection housing according to some embodiments of the present disclosure. [Figure 4] 1A-1C are schematic structural diagrams of microfluidic chip substrates according to some embodiments of the present disclosure. [Figure 5] 1A and 1B are schematic structural diagrams of a liquid injection housing assembled with a conductive cover according to some embodiments of the present disclosure. [Figure 6] 1A-1C are schematic diagrams of gap sealant and adhesive bonding locations on a microfluidic chip according to some embodiments of the present disclosure. [Figure 7] 1 is a schematic structural diagram of a microfluidic chip according to some embodiments of the present disclosure. [Figure 8] 1A and 1B are schematic structural diagrams of microfluidic chips according to some other embodiments of the present disclosure. [Figure 9] 10A-10C are front and top views of a liquid injection housing according to some other embodiments of the present disclosure. [Figure 10] FIG. 10 is a rear top view of a liquid injection housing according to some other embodiments of the present disclosure. [Figure 11] 1A-1C are schematic structural diagrams of microfluidic chip substrates according to some other embodiments of the present disclosure. [Figure 12] 10A-10C are schematic structural diagrams of a liquid injection housing assembled with a conductive cover according to some other embodiments of the present disclosure. [Figure 13] 10A-10C are schematic diagrams of gap sealant and adhesive bonding locations of a microfluidic chip according to some other embodiments of the present disclosure. [Figure 14] 1 is a schematic cross-sectional view of a microfluidic chip according to some embodiments of the present disclosure. [Figure 15] 1A-1C are schematic cross-sectional views of microfluidic chips according to some other embodiments of the present disclosure. [Figure 16A] 1 is a schematic flow chart illustrating sample injection according to some embodiments of the present disclosure. [Figure 16B] 1 is a schematic flow chart illustrating sample injection according to some embodiments of the present disclosure. [Figure 17A]1 is a schematic flow chart illustrating liquid injection according to some embodiments of the present disclosure. [Figure 17B] 1 is a schematic flow chart illustrating liquid injection according to some embodiments of the present disclosure. [Figure 18A] FIG. 1 is a schematic diagram illustrating a liquid injection and oil injection process according to some embodiments of the present disclosure. [Figure 18B] FIG. 1 is a schematic diagram illustrating a liquid injection and oil injection process according to some embodiments of the present disclosure. [Figure 18C] FIG. 1 is a schematic diagram illustrating a liquid injection and oil injection process according to some embodiments of the present disclosure. [Figure 18D] FIG. 1 is a schematic diagram illustrating a liquid injection and oil injection process according to some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0015] In the figures, identical or similar elements are designated with the same reference numerals.

[0016] In describing this disclosure, directions or positional relationships indicated by terms such as "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" are based on directions or positional relationships shown in the accompanying drawings and do not indicate or imply that the referenced devices or elements must have a particular orientation or be configured and operated in a particular orientation. It should be understood that these terms are intended to facilitate and simplify the description of this disclosure and therefore cannot be construed as limiting this disclosure. In addition, terms such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or the numbering of depicted technical features. Thus, features defined as "first," "second," etc. may explicitly or implicitly include one or more features. In describing this disclosure, "plurality" means two or more unless clearly and specifically specified otherwise.

[0017] In the description of this disclosure, unless otherwise expressly specified and defined, the terms "disposed," "connected," and "connecting" should be understood in a broad sense, for example, they may be fixed, detachable, or integral connections, may be mechanical or electrical connections, may be direct connections, indirect connections through intermediates, or internal communication between two elements. For those skilled in the art, the specific meanings of the above terms in this disclosure should be interpreted according to the specific circumstances.

[0018] Those skilled in the art should understand that the present disclosure necessarily includes the pipelines, conventional valves, and general pumping equipment required to implement the complete process. However, the above content is not the main inventive point of the present disclosure. Those skilled in the art can add their own layout based on the selection of the technical process and the structural form of the equipment. In this regard, the present disclosure does not have any special requirements or specific limitations.

[0019] Digital microfluidic chips can integrate operational processes commonly required in biology, chemistry, medicine, and other fields, such as sample extraction, dilution, reagent addition, reaction, separation, and detection. Compared with traditional control methods, this technology allows for less sample consumption and has advantages such as high sensitivity, precision, high throughput, and high integration. It allows for the rapid implementation of fully automated integrated biochemical reaction processes at lower cost. The entire process can be carried out in a completely sealed environment without cross-contamination and can be operated with the push of a button, thereby significantly freeing up the operator's hands.

[0020] According to a first aspect of an embodiment of the present disclosure, a microfluidic chip is provided. Hereinafter, the technical solutions of the present disclosure will be further described in terms of specific embodiments with reference to the drawings.

[0021] Fig. 1 is a schematic structural diagram of a microfluidic chip according to some embodiments of the present disclosure. As shown in Fig. 1, the microfluidic chip includes a microfluidic chip substrate 1, a conductive cover 2, and a liquid injection housing 3, which are stacked from bottom to top. As shown in Fig. 7, the microfluidic chip substrate 1 includes, for example, a base plate. A microelectrode array 21 is disposed on the base plate, and a dielectric layer 23 and a hydrophobic layer 22 are stacked on the microelectrode array 21 in that order.

[0022] 2 and 3 show front and rear top views, respectively, of a liquid injection housing according to some embodiments of the present disclosure. The liquid injection housing 3 includes an oil injection cavity 8, a sample metering cavity 9, and at least one liquid injection cavity 11 arranged side by side, e.g., six liquid injection cavities 11 uniformly arranged on one side of the liquid injection housing 3 as shown in FIG. 2. The oil injection cavity 8 is configured to receive an oil bubble cap 5, i.e., serves as a mounting location for an oil bubble cap (e.g., a silicone oil bubble cap). The sample metering cavity 9 is configured to receive a sample metering plug 4, and at least one liquid injection cavity 11 is configured to receive at least one reagent bubble cap 6. The liquid injection housing 3 is provided with at least one liquid injection conduit 14 and an oil intake conduit 12. As shown in FIG. 3 , at least one liquid injection conduit 14 and oil suction conduit 12 are provided on the back side of liquid injection housing 3, i.e., the side facing away from oil injection cavity 8 and at least one liquid injection cavity 11. A liquid injection column 10 connected to a corresponding one of the at least one liquid injection conduit 14 is disposed in each of at least one liquid injection cavity 11, each of at least one liquid injection conduit 14 forming a liquid injection channel 13, and the liquid injection conduits 14 collectively form a main liquid injection channel. An annular pit feature is provided in oil injection cavity 8. As shown in FIG. 2 , a raised oil injection column is disposed within the annular pit feature and communicates with oil suction conduit 12. The oil injection cavity 8 and each liquid injection cavity 11 are each provided with a spike member on their surfaces so that the oil or reagent bubble caps are pierced when the caps are depressed.

[0023] 1, the oil injection cavity 8, the sample quantification cavity 9, and the liquid injection cavity 11 of the liquid injection housing 3 may be used to place the oil bubble cap 5, the sample quantification plug 4, and the reagent bubble cap 6, respectively. Both the reagent bubble cap 6 and the oil bubble cap 5 are provided with a film (such as aluminum foil) for enclosing the reagent and oil (such as silicone oil).

[0024] According to some embodiments of the present disclosure, a microfluidic chip may be provided. The microfluidic chip includes a structure for disposing oil bubble caps and reagent bubble caps, spike components for puncturing the oil bubble caps and reagent bubble caps, and a hole structure for guiding oil and reagent into the corresponding channels. By pre-embedding the oil bubble caps and reagent bubble caps, liquid injection operations can be performed automatically, enabling fully automated application of the microfluidic chip. Therefore, the operator does not need to manually inject the required reagents, samples, and oils in sequence, freeing up the operator's hands. The microfluidic chip is highly reliable, portable, and highly efficient, making it suitable for widespread use.

[0025] The microfluidic chip provided by the present disclosure is mainly used as a digital microfluidic chip, and reagents and other substances (such as relevant liquids, solids, or solid-liquid mixtures) required for detection may be pre-sealed in a quantitative amount in a reagent kit, and the reagent kit is pre-embedded in a hole injection device sealed together with the digital microfluidic chip. As a result, the user does not need to perform manual operations when injecting samples, and inconveniences, failures, waste, etc. caused by manual operation errors can be effectively prevented.

[0026] In some embodiments, at least one vent conduit 15 is further disposed on the liquid injection housing 3. The liquid injection housing 3 is provided with at least one vent port, each connected to a respective vent conduit, which leads to a closed cavity for liquid flow within the microfluidic chip. By disposing the vent port, when a liquid (such as a reagent, oil, or sample) is injected into the closed cavity of the microfluidic chip, excess gas within the closed cavity can be exhausted, facilitating the flow of the liquid. In some other embodiments, multiple vent ports may be connected to one vent conduit.

[0027] 2, at least one first vent 7 is formed near the oil injection cavity 8 in the liquid injection housing 3, and the first vent 7 is in communication with a first vent conduit 15. In some other examples, as shown in FIGS. 8 and 9, in addition to the first vent 7, the liquid injection housing 3 is further provided with a second vent 25 located near the sample quantification cavity 9, a third vent 26 located between the sample quantification cavity 9 and the liquid injection cavity 11, a fourth vent 27 located between adjacent liquid injection cavities 11, and a fifth vent 28 located between the liquid injection cavity 11 and the edge of the liquid injection housing 3. Like the first vent 7, the second vent 25, the third vent 26, the fourth vent 27, and the fifth vent 28 may each be in communication with a vent conduit. For example, as shown in FIG. 10, the third vent port 26 communicates with a third vent column 34 .

[0028] The microfluidic chip substrate 1, conductive cover 2, and liquid injection housing 3 are stacked and assembled from bottom to top to form a microfluidic chip. For example, the microfluidic chip substrate 1, conductive cover 2, and liquid injection housing 3 may be bonded to one another. In some embodiments, as shown in FIG. 4 , the microfluidic chip substrate 1 and conductive cover 2 are connected to one another using a gap sealant 17. The gap sealant 17 is circumferentially disposed between the microfluidic chip substrate 1 and the conductive cover 2, and a closed cavity 16 is formed by the microfluidic chip substrate 1, the conductive cover 2, and the gap sealant 17. The conductive cover 2 is bonded to the liquid injection housing 3 with an adhesive 40, and the edges of the liquid injection housing 3 are bonded to the edges of the microfluidic chip substrate 1 with an adhesive 24 to form a seal. FIG. 6 exemplarily illustrates the location of the adhesive 40 on the liquid injection housing 3 in the microfluidic chip for bonding the conductive cover to the liquid injection housing and the location of the adhesive 24 for bonding the liquid injection housing to the microfluidic chip substrate.

[0029] In some embodiments, the conductive cover 2 is a transparent conductive cover, for example, the conductive cover 2 is made of glass, such as ITO glass.

[0030] In some embodiments, the conductive cover 2 is provided with at least one through-hole. The through-hole communicates with the closed cavity 16 and includes a liquid inlet hole 19, a sample inlet hole 20, and an oil inlet hole 18. The liquid inlet hole 19 and the oil inlet hole 18 are aligned with the liquid inlet conduit 14 and the oil inlet conduit 12, respectively. In some other embodiments, the through-hole of the conductive cover 2 further includes at least one vent hole, and the vent holes are each aligned with a corresponding vent conduit 15 disposed on the liquid inlet housing 3.

[0031] For example, the liquid injection conduit 14 may extend a certain distance from the liquid suction hole 19. The distance the liquid injection conduit extends from the liquid suction hole may be, for example, 0.3 to 0.5 mm, or, for example, 0.55 to 0.7 mm. This distance may be, for example, 0.3 mm, 0.33 mm, 0.35 mm, 0.4 mm, 0.43 mm, or 0.5 mm, but is not limited to the listed values. Other values ​​not listed within this range are also applicable. Similarly, the oil suction conduit 12 and the vent conduit 15 may extend a certain distance from the oil suction hole 18 and the vent 7.

[0032] The through-holes may be positioned at a distance of 0.5 to 1 mm from the edge of the conductive cover. Here, the distance from the edge serves as a safety distance, which may be, for example, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1 mm, but it should be noted that the distance is not limited to the listed values. Other values ​​not listed within this range are also applicable. Additionally, the arrangement of the liquid intake holes 19 and sample intake holes 20 between the through-holes is related to the position of the electrodes on the microfluidic chip substrate 1, and the protrusions of the edges of the through-holes on the microfluidic chip substrate are separated from the electrodes on the microfluidic chip substrate by a safety distance of, for example, at least 0.5 mm. The oil intake hole 18 must be formed in an area of ​​the conductive cover corresponding to the non-electrode area of ​​the microfluidic chip substrate 1; that is, the protrusions of the oil intake hole 18 on the microfluidic chip substrate do not coincide with the electrodes on the microfluidic chip substrate 1.

[0033] It should be noted that embodiments of the present disclosure do not have specific requirements or special limitations on structural features such as the size, shape, and material of the through-holes. The through-holes are used to provide inlets for injecting samples, reagents, and oils. Therefore, it can be understood that other structures that enable such functions can be used in embodiments of the present disclosure, and that those skilled in the art can make adaptive adjustments to the size, shape, and material of the through-holes depending on the usage scenario and test conditions.

[0034] In some embodiments, the liquid injection conduit 14 in the liquid injection housing 3 extends from the lower surface of the transparent conductive cover by a distance of, for example, 0.55 to 0.7 mm. The liquid injection channel 13 includes a liquid intake end and a liquid discharge end. The liquid discharge end is provided with a notch configured to guide the flow. The liquid injection channel 13 has an inclination. Furthermore, the inclination of the liquid injection channel 13 is between 5° and 10°, and may be, for example, 5°, 6°, 7°, 8°, 9°, or 10°, but is not limited to the listed values. Other values ​​within this range are also applicable.

[0035] In some embodiments, the liquid injection channel 13 typically has a slope toward the electrode. The liquid injection channel 13 may be a straight hole, a sloped hole, a spiral hole, a tubular joint assembled with the liquid injection column 10, etc., and the shape of the channel is not limited to a circular shape as long as the upper part of the liquid injection column 10 communicates with the gap cavity of the chip. Those skilled in the art can make a selection according to the actual situation. The sloped hole of the liquid injection channel is designed to fit the through-hole of the transparent conductive cover, which ensures successful and stable liquid injection.

[0036] The microfluidic chip according to the embodiments of the present disclosure can inject multiple liquid reagents or samples simultaneously, has higher efficiency, good scalability, and convenience, and provides the basic feasibility of fully automating digital microfluidic chips, so that the operator does not need to manually inject the required reagents, samples, and oils in sequence, freeing up the operator's hands.

[0037] 8 to 13 show microfluidic chips according to some other embodiments of the present disclosure, in which elements having the same reference numbers as those in FIGS. 1 to 7 denote the same or similar elements.

[0038] 8 and 9, a groove is provided at the bottom of the oil injection cavity 8 for placing the oil bubble cap, and the oil outlet 30 is located in the center of the groove. A spike part, such as a perforation feature 31 having a protruding portion, is placed around the oil outlet 30, and the oil bubble cap 5 is placed in the oil bubble cap placement position so that the oil bubble cap is aligned with the oil injection cavity 8. When the oil bubble cap 5 is pressed down, the perforation feature 31 perforates the film (e.g., aluminum foil) of the oil bubble cap 5, and oil flows from the oil outlet 30 through the oil injection channel and the oil inlet 33 (as shown in FIG. 10) into the closed cavity 16 of the microfluidic chip.

[0039] As described above, in addition to the first vent port 7, the liquid injection housing 3 is further provided with a second vent port 25, a third vent port 26, a fourth vent port 27, and a fifth vent port 28, as shown in Figures 8 and 9. The second vent port 25, the third vent port 26, the fourth vent port 27, and the fifth vent port 28 may each communicate with a vent conduit. For example, as shown in Figure 10, the third vent port 26 communicates with a third vent column 34.

[0040] 11 and 12, the conductive cover 2 is further provided with a plurality of vents 35 to 37. The sixth vent 35 is typically located in an area diagonally opposite the oil inlet hole 18, and the corresponding area of ​​the microfluidic chip substrate 1 is free of electrodes, while the seventh vent 36 and the eighth vent 37 are typically located near the sample inlet hole 20. During sample injection, gas is exhausted outward from the seventh vent 36 and the eighth vent 37 to maintain the air pressure in the closed cavity 16 and prevent bubbles from entering the closed cavity 16.

[0041] In some embodiments, as shown in FIG. 14, after the microfluidic chip is assembled, the liquid injection conduit 14 is provided with a cutout feature 38 toward the closed cavity 16 to facilitate the flow of liquid into the closed cavity, and the depth of the cutout may be, for example, 0.24 mm.

[0042] According to a second aspect of an embodiment of the present disclosure, there is provided a liquid injection method for a microfluidic chip.

[0043] As shown in Figures 17A and 17B, during liquid injection, the reagent bubble cap 6 is pressed down, the liquid injection column 10 enters the reagent bubble cap 6 continuously, the liquid (e.g., reagent) in the reagent bubble cap 6 is pressed, the reagent bubble cap 6 forms a seal with the liquid injection column 10 in the downward pressing process and is pierced by the corresponding spike part, the liquid in the reagent bubble cap flows through the liquid injection channel 13 into the closed cavity 16 of the microfluidic chip, and the voltage of the microelectrode array 21 is adjusted, so that the liquid flowing from the reagent bubble cap to the closed cavity 16 reaches the designated position.

[0044] During oil injection, the oil bubble cap 5 is pressed down, the oil injection column enters the oil bubble cap 5 continuously, and the liquid (e.g., oil) in the oil bubble cap 5 is pressed. The oil bubble cap 5 forms a seal with the oil injection column during the downward pressing process (e.g., ensures that the oil flows only through the oil injection column to the underside of the liquid injection housing, preventing oil from leaking into the oil injection cavity 8 for placing the oil bubble cap), and is pierced by the corresponding spike part, causing the liquid in the oil bubble cap to flow through the oil suction hole 18 into the closed cavity 16 of the microfluidic chip, and the voltage of the microelectrode array 21 is adjusted, thereby allowing the liquid flowing from the oil bubble cap into the closed cavity 16 to reach the specified position.

[0045] Alternatively, during oil injection, the oil bubble cap 5 is pressed down, and the oil bubble cap 5 is pierced by the spike parts in the downward pressing process, so that the liquid (e.g., oil) in the oil bubble cap 5 flows through the oil suction holes 18 into the closed cavity 16 of the microfluidic chip. There is no need to adjust the voltage of the microelectrode array 21.

[0046] In some embodiments, the liquid injection method comprises: depressing the oil bubble cap at a first speed such that liquid within the oil bubble cap enters the closed cavity and occupies a portion of a bottom area of ​​the closed cavity; Press down on the reagent bubble cap to release the liquid in the reagent bubble cap into the closed cavity; and depressing the oil bubble cap at a second speed, the second speed being less than the first speed, so that the liquid in the oil bubble cap occupies the entire bottom area of ​​the closed cavity.

[0047] In some embodiments, the liquid injection method comprises: The method further includes, after depressing the oil bubble cap at a first speed, stopping the depression of the oil bubble cap and lifting the oil bubble cap upward by a distance of, for example, 2 mm.

[0048] For example, as shown in FIGS. 18A to 18D, during the oil injection process, the oil bubble cap is depressed to allow oil to enter the closed cavity through the oil suction hole. As shown in FIG. 18A, when the oil flowing into the closed cavity occupies approximately half of the bottom area of ​​the closed cavity, the oil bubble cap is stopped from being depressed and lifted upward, for example, by a distance of 2 mm. In this case, the liquid (reagent) injection operation begins, and the liquid enters the closed cavity through the liquid injection conduit. After the liquid injection operation is completed, the oil bubble cap continues to be depressed, and the downward pushing speed of the oil bubble cap is lower than the downward pushing speed before the liquid injection. This continuously expels air from the closed cavity through the vents (e.g., the sixth vent, the seventh vent, and the eighth vent). Finally, the closed cavity 16 is filled, as shown in FIGS. 18B to 18D.

[0049] In some embodiments, a sample injection method is provided, as shown in Figures 16A-16B: By depressing the sample quantitation plug, the sample flows through a channel in the sample injection column into a closed cavity.

[0050] According to a third aspect of the present disclosure, there is provided a use of the microfluidic chip described in the first aspect, wherein the microfluidic chip is used in the field of digital microfluidic chips.

[0051] In the embodiment of the present disclosure, by embedding reagents in advance and cooperating with a hole injection device, the liquid injection operation can be performed automatically, and a fully automated application of the microfluidic chip can be realized. Therefore, the operator does not need to manually inject the necessary reagents, samples, and oils in order, freeing the operator's hands. The microfluidic chip has high reliability and injection efficiency, is portable, and is suitable for widespread use.

[0052] The applicant notes that the above description is merely a specific embodiment of the present disclosure, and the scope of protection of the present disclosure is not limited thereto. Those skilled in the art will understand that any variations or replacements that can be easily conceived by those skilled in the art within the technical scope disclosed in the present disclosure will fall within the scope of protection of the present disclosure. [Explanation of symbols]

[0053] 1. Microfluidic Chip Substrate 2 Conductive cover 3 Liquid injection housing 4. Sample Quantitation Plug 5 Oil Bubble Caps 6 Reagent Bubble Caps 7 First Vent 8 Oil injection cavity 9. Sample quantification cavity 10 Liquid injection column 11 Liquid injection cavity 12 Oil intake pipe 13 Liquid injection channel 14 Fluid injection conduit 15 Ventilation duct 16 Closed Cavity 17 Gap sealant 18 Oil intake hole 19 Liquid suction hole 20 Sample intake hole 21 Microelectrode Array 22 Hydrophobic layer 23 Dielectric layer 24, 40 Adhesive 25 Second Vent 26 Third Vent 27 Fourth Vent 28 Fifth Vent 30 Oil outlet 31 Perforation Features 33 Oil inlet 34 Ventilated column 35 Sixth Vent 36 Seventh Vent 37 Eighth Vent 38 Cutout feature

Claims

1. A microfluidic chip, comprising a microfluidic chip substrate, a conductive cover, and a liquid injection housing, which are stacked in order from bottom to top, and the liquid injection housing is provided with at least one liquid injection conduit and an oil suction conduit; the liquid injection housing comprises an oil injection cavity, a sample metering cavity, and at least one liquid injection cavity arranged side by side, the oil injection cavity, the sample metering cavity, and the at least one liquid injection cavity being used to place an oil bubble cap, a sample metering plug, and at least one reagent bubble cap, respectively; a liquid injection column connected to a corresponding one of the at least one liquid injection conduit is disposed in each of the at least one liquid injection cavity, and each of the at least one liquid injection conduit forms a liquid injection channel; an oil injection column disposed within the oil injection cavity and connected to the oil suction conduit; a spike component is provided on a surface of the oil injection cavity and the at least one liquid injection cavity, respectively; the microfluidic chip substrate and the conductive cover are connected to each other by using a gap sealant circumferentially disposed between the microfluidic chip substrate and the conductive cover, and a closed cavity is formed by the microfluidic chip substrate, the conductive cover, and the gap sealant; the conductive cover is provided with at least one through-hole, the at least one through-hole communicating with the interior of the closed cavity, the at least one through-hole comprising at least one liquid inlet hole, a sample inlet hole, and an oil inlet hole, the at least one liquid inlet hole and the oil inlet hole being aligned with the at least one liquid injection conduit and the at least one oil inlet conduit, respectively; the at least one through hole is disposed at a distance of 0.5 to 1 mm from the edge of the conductive cover; Microfluidic chip.

2. 2. The microfluidic chip of claim 1, wherein at least one vent conduit is disposed on the liquid injection housing, and the liquid injection housing is provided with at least one vent hole, each of the at least one vent hole communicating with one of the at least one vent conduit.

3. 2. The microfluidic chip of claim 1, wherein the conductive cover is provided with at least one through-hole, the at least one through-hole communicating with the interior of the closed cavity, the at least one through-hole comprising an air vent, the air vent aligned with a corresponding air vent conduit arranged on the liquid injection housing.

4. 2. The microfluidic chip of claim 1, wherein a protrusion on an edge of the at least one through-hole on the microfluidic chip substrate is spaced apart from an electrode on the microfluidic chip substrate by a distance of at least 0.5 mm, and the oil suction hole of the at least one through-hole is formed in an area of ​​the conductive cover corresponding to an electrode-free area of ​​the microfluidic chip substrate.

5. The microfluidic chip according to any one of claims 1 to 2, wherein the conductive cover is a transparent conductive cover.

6. A microfluidic chip described in any one of claims 1 to 2, wherein the conductive cover is made of ITO glass.

7. 3. The microfluidic chip of claim 1, wherein the conductive cover is bonded to the liquid injection housing by an adhesive, and an edge of the liquid injection housing is bonded to an edge of the microfluidic chip substrate by an adhesive to form a seal.

8. 3. The microfluidic chip according to claim 1, wherein the microfluidic chip substrate comprises a base plate, a microelectrode array is disposed on the base plate, and a dielectric layer and a hydrophobic layer are stacked in that order on the microelectrode array.

9. 3. The microfluidic chip according to claim 1, wherein the at least one liquid injection conduit each extends from a corresponding through-hole formed in the conductive cover.

10. A microfluidic chip as described in claim 9, wherein the distance that each of the at least one liquid injection conduit extends from the corresponding through hole is 0.55 to 0.7 mm.

11. A microfluidic chip as described in any one of claims 1 to 2, wherein the liquid injection channel has a liquid intake end and a liquid discharge end, and the liquid discharge end is provided with a notch configured to guide flow.

12. A microfluidic chip as described in claim 11, wherein the liquid injection channel has a slope.

13. A microfluidic chip as described in any one of claims 12, wherein the inclination of the liquid injection channel is 5° to 10°.

14. A microfluidic chip as claimed in any one of claims 1 to 2, wherein an aluminum foil is provided within each of the at least one reagent bubble cap and the oil bubble cap.

15. 3. A liquid injection method for a microfluidic chip according to claim 1, comprising: During liquid injection, the liquid injection columns successively enter the corresponding reagent bubble caps to press the liquid in the reagent bubble caps, the reagent bubble caps form a seal with the liquid injection columns in the downward pressing process, and the reagent bubble caps are pierced by their respective spike parts, the liquid in the reagent bubble caps flows through the liquid injection channel into the closed cavity of the microfluidic chip, and the voltage of the microelectrode array arranged on the base plate of the microfluidic chip substrate is adjusted so that the liquid flowing from the reagent bubble caps into the closed cavity reaches a designated position; a liquid injection method including: during oil injection, the oil injection column continuously enters the oil bubble cap to press the liquid in the oil bubble cap; the oil bubble cap forms a seal with the oil injection column in the downward pressing process, and each spike part pierces the oil bubble cap; the liquid in the oil bubble cap flows into the closed cavity of the microfluidic chip through an oil suction hole; and adjusting the voltage of the microelectrode array arranged on the base plate of the microfluidic chip substrate so that the liquid flowing from the oil bubble cap to the closed cavity reaches a designated position.

16. depressing the oil bubble cap at a first speed so that the liquid in the oil bubble cap enters the closed cavity and occupies a portion of a bottom area of ​​the closed cavity; depressing the reagent bubble cap to force the liquid in the reagent bubble cap into the closed cavity; 16. The liquid injection method of claim 15, further comprising: depressing the oil bubble cap at a second speed such that the liquid in the oil bubble cap occupies an entire bottom area of ​​the closed cavity, the second speed being less than the first speed.

17. 17. The liquid injection method of claim 16, further comprising: after the oil bubble cap has been depressed at the first speed, stopping the depression of the oil bubble cap and lifting the oil bubble cap upward by a distance of 2 mm.

18. 3. An oil injection method for a microfluidic chip according to claim 1, comprising: During liquid injection, the liquid injection columns successively enter the corresponding reagent bubble caps to press the liquid in the reagent bubble caps, the reagent bubble caps form a seal with the liquid injection columns in the downward pressing process, and the reagent bubble caps are pierced by their respective spike parts, the liquid in the reagent bubble caps flows through the liquid injection channel into the closed cavity of the microfluidic chip, and the voltage of the microelectrode array arranged on the base plate of the microfluidic chip substrate is adjusted so that the liquid flowing from the reagent bubble caps into the closed cavity reaches a designated position; During oil injection, the oil bubble cap is pierced by each spike part in a downward pressing process, and the liquid in the oil bubble cap flows into the closed cavity of the microfluidic chip through an oil suction hole.

19. Use of the microfluidic chip according to any one of claims 1 to 2, wherein said microfluidic chip is used in the field of digital microfluidic chips.

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