WO2024074150A1

WO2024074150A1 - Micro-fluidic chip and oil injection method

Info

Publication number: WO2024074150A1
Application number: PCT/CN2023/123417
Authority: WO
Inventors: 杜佩; 苏阳
Original assignee: 江苏液滴逻辑生物技术有限公司
Priority date: 2022-10-08
Filing date: 2023-10-08
Publication date: 2024-04-11
Also published as: CN117884199A

Abstract

Provided in the present application are a micro-fluidic chip and an oil injection method. The micro-fluidic chip comprises: a cover plate and a substrate which are arranged opposite to each other and are spaced apart from each other, and a liquid injection shell. A fluid chamber is formed between the cover plate and the substrate, and the cover plate is provided with an oil inlet communicated with the fluid chamber. The liquid injection shell is provided with a first side and a second side which are opposite to each other, the second side being connected to the cover plate and/or the substrate. A first recess used for holding an oil bubble cap storing oil is formed in the surface of the first side of the liquid injection shell, and the surface of the second side of the liquid injection shell and the cover plate at least jointly form an oil injection chamber. The first recess is communicated with the oil injection chamber by means of an oil injection channel formed in the liquid injection shell, the oil injection chamber is communicated with the oil inlet, and a first exhaust channel via which the oil injection chamber is communicated with the outside of the first side is further formed in the liquid injection shell.

Description

Microfluidic chip and oil injection method

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Chinese Patent Application No. 2022112234527 filed on October 8, 2022, the contents of which are incorporated herein by reference in their entirety.

Technical Field

The present application belongs to the technical field of microfluidic chips and relates to a microfluidic chip and an oil injection method.

Background technique

Detection methods such as qPCR, LAMP, and immunoluminescence are widely used in the fields of biology and medicine to determine whether a sample carries genes related to genetic diseases, diagnose infectious diseases, detect gene replication, and conduct paternity testing. In traditional testing equipment, it is usually necessary to use a pipette to absorb a certain amount of liquid sample, align it with the injection port, and completely inject the liquid into the reaction chamber. Using a pipette to inject samples increases the cost of use and has a strong dependence on it.

Digital microfluidic chips use the principle of electrowetting technology, regulate the surface energy of solid and liquid through electric potential, and use the imbalanced state of surface energy to drive the liquid to move, so as to achieve precise control of microfluids. The main components of digital microfluidic chips include transparent conductive covers (such as ITO glass), electrode arrays with hydrophobic layers and dielectric layers on the surface, and fluid cavities for droplet movement between the transparent conductive covers and the electrode arrays. Digital microfluidic chips can integrate the operations often required in the fields of biology, chemistry, and medicine, such as sampling, dilution, reagent addition, reaction, separation, and detection. Compared with traditional control methods, this technology can achieve less sample consumption, and has the advantages of high sensitivity, high precision, high throughput, and high integration. It can quickly realize the full process of biochemical reactions with low cost. The full process reaction is fully enclosed without cross contamination and can be operated with one button, which greatly liberates the hands of operators.

In the process of using the microfluidic chip, in addition to injecting reagents, it is also necessary to inject oil into the fluid cavity. The role of the oil is to promote the flow of liquid reagents in the fluid cavity. However, in the related art, Oil is usually injected manually, which can easily introduce bubbles, thus affecting the use of digital microfluidic chips.

Summary of the invention

In view of the shortcomings of the prior art, the present application provides a microfluidic chip and an oil filling method, in which an oil filling chamber connected to a first exhaust channel is arranged in the liquid filling shell, so that during the oil filling process, the gas in the oil can be discharged through the first exhaust channel, thereby reducing the bubble content of the oil entering the fluid chamber.

According to one aspect of the present application, a microfluidic chip is provided, comprising: a cover plate and a substrate that are arranged oppositely and at intervals, a fluid cavity is formed between the cover plate and the substrate, the cover plate is provided with an oil inlet connected to the fluid cavity; and a liquid injection shell, the liquid injection shell having a first side and a second side that are opposite, the second side being connected to the cover plate and/or the substrate, wherein a first groove for placing an oil bubble for storing oil is formed on the first side surface of the liquid injection shell, the second side surface of the liquid injection shell and the cover plate at least jointly form an oil injection cavity, the first groove is connected to the oil injection cavity via an oil injection channel formed on the liquid injection shell, the oil injection cavity is connected to the oil inlet, and a first exhaust channel connecting the oil injection cavity and the outside of the first side is also formed inside the liquid injection shell.

According to another aspect of the present application, a method for filling a microfluidic chip with oil is also provided, comprising: installing an oil bubble cap into a first groove of a liquid filling shell, installing a freeze-dried bubble cap and a freeze-dried ball into each second groove of a first group of second grooves, and installing a reagent bubble cap into each second groove of a second group of second grooves; driving an oil filling pressure head located above the first groove to move toward the first groove to a first height relative to the microfluidic chip, so as to squeeze the oil bubble cap so that the oil flows into the fluid cavity and fills the first interval, wherein the first interval is a space in which the fluid cavity only covers the second group of liquid inlets; stopping the movement of the oil filling pressure head within a preset time period to allow the reagent to be injected into the fluid cavity through a plurality of second grooves; and after all the second grooves are filled with liquid, continuing to drive the oil filling pressure head toward the first groove to a second height relative to the microfluidic chip, so as to squeeze the oil bubble cap so that the oil fills the fluid cavity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a disassembled microfluidic chip according to a specific embodiment of the present application;

FIG2 is a schematic structural diagram of a cover plate and a substrate of a microfluidic chip according to a specific embodiment of the present application;

FIG3 is a side cross-sectional view of a microfluidic chip according to a specific embodiment of the present application;

FIG4 is a front view of a liquid injection housing of a microfluidic chip according to a specific embodiment of the present application;

FIG5 is a schematic diagram of the back side of a liquid injection housing of a microfluidic chip according to a specific embodiment of the present application;

FIG6 is a top view of a cover plate and a substrate according to a specific embodiment of the present application;

FIG7 is a flow chart of an oil injection method according to a specific embodiment of the present application;

FIG. 8 is a schematic diagram showing the first interval being filled with oil.

Description of reference numerals:
Cover plate 110, oil inlet 111, liquid inlet 112, first group 112a, second group 112b, sample injection port
113, exhaust hole 114;
Base plate 120;
Liquid injection housing 130, first groove 131, oil injection channel 132, spike 133, first exhaust channel
134a, second exhaust channel 134b, second groove 135, first group 135a, second group 135b, third groove 136, injection conduit 137a, sample conduit 137b, oil injection chamber 138, first chamber 138a, second chamber 138b, third chamber 138c, exhaust chamber 139, partition wall 1391, flange 1392, outer flange 1392a, inner flange 1392b;
Fluid chamber 140, first interval 141; electrode 150; dielectric layer 160; hydrophobic layer 170; gap glue 180;
Oil bubble cap 200; oil injection pressure head 300.

Detailed ways

It should be understood that, in the description of the present application, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

It should be noted that in the description of this application, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood by specific circumstances.

The technical solution of the present application is further illustrated below through specific implementation methods.

According to one aspect of the present application, an embodiment of the present application first provides a microfluidic chip. FIG1 is a disassembly schematic diagram of a microfluidic chip of a specific embodiment of the present application, FIG2 is a structural schematic diagram of a cover plate and a substrate of a microfluidic chip of a specific embodiment of the present application, and FIG3 is a side cross-sectional view of a microfluidic chip of a specific embodiment of the present application. As shown in the figure, the microfluidic chip includes: a cover plate 110 and a substrate 120 that are arranged oppositely and spaced apart, and a liquid injection housing 130.

As shown in FIGS. 2 and 3 , a fluid cavity 140 is formed between the cover plate 110 and the substrate 120, and the cover plate 110 is provided with an oil inlet 111 connected to the fluid cavity 140. The cover plate 110 and the substrate 120 can both be rectangular plates, and the two plates are similar in size and shape and are spaced a short distance apart, so that a very thin rectangular space, i.e., the fluid cavity 140, can be formed between them, and the reagents, samples, oil, etc. subsequently injected into the microfluidic chip will flow in the fluid cavity 140. As an example, the cover plate 110 can be a glass plate, more preferably ITO glass, and the cover plate 110 is further provided with a hydrophobic layer on the ITO conductive layer. The cover plate 110 can be transparent so that the external optical module used for detection can collect the amplification reaction products. The user can observe the flow of the internal liquid by generating fluorescent signals. An array of microelectrodes 150 is arranged on the substrate 120, and a dielectric layer 160 and a hydrophobic layer 170 are sequentially stacked on the array of microelectrodes 150. These microelectrodes 150 drive the liquid to move, thereby achieving precise control of the microfluid.

In some embodiments, the cover plate 110 and the substrate 120 are combined by the gap glue 180 provided at the periphery. The gap glue 180 is provided with high-precision gap beads of preset thickness, and the gap beads are spaced a certain distance from each other and are distributed in a ring shape, so that the cured gap glue 180 has a uniform and stable thickness, and the inner side of the gap glue 180 is provided with a safety distance from the microelectrode 150. The gap glue 180 enables the required fluid cavity 140 to be formed between the cover plate 110 and the substrate 120, and can ensure the airtightness of the fluid cavity 140. In other embodiments, the cover plate 110 and the substrate 120 can also be combined in other feasible ways, as long as a certain gap can be ensured between the cover plate 110 and the substrate 120.

The liquid injection housing 130 is used to assist various liquids (samples, reagents, oils, etc.) to be injected into the fluid cavity 140. FIG. 4 is a schematic diagram of the front side of the liquid injection housing of a microfluidic chip according to a specific embodiment of the present application; FIG. 5 is a schematic diagram of the back side of the liquid injection housing of a microfluidic chip according to a specific embodiment of the present application. As shown in FIG. 4 and FIG. 5, the liquid injection housing 130 has a first side and a second side (i.e., a front side and a back side) opposite to each other, the second side is connected to the cover plate 110 and/or the substrate 120, and the first side is away from the cover plate 110 and the substrate 120. The first side surface 130a of the liquid injection housing 130 is formed with a first groove 131 for placing the oil bubble 200 storing oil. The first groove 131 can be arranged in the center of the first side surface 130a and is a circular groove. In some other embodiments, the first groove 131 can also be arranged at other positions of the first side surface 130a, for example, at the edge of the first side surface 130a, and its shape can also be other shapes such as a rectangle, a triangle, etc. During the installation of the oil bubble cover 200, the periphery of the oil bubble cover 200 can be glued to the liquid injection housing 130 to ensure that the periphery of the oil bubble cover 200 is sealed with the liquid injection housing 130. After the oil bubble cover 200 is punctured, it can only flow to the second side surface 130b without overflowing. The second side surface 130b of the liquid injection housing 130 and the cover plate 110 at least jointly form an oil injection cavity 138. Since the upper surface of the cover plate 110 is flat, the oil injection cavity 138 has a flat bottom surface, which is convenient for unobstructed flow of oil. However, the second side surface 130b of the liquid injection housing 130 is not flat, that is, the oil injection cavity 138 is not flat. The heights of 138 at different positions are not consistent. As shown in FIG3 , the first groove 131 is connected to the oil injection chamber 138 via the oil injection channel 132 formed on the liquid injection housing 130, and the entrance of the oil injection channel 132 can be opened at the bottom of the center of the first groove 131. The oil injection chamber 138 is also connected to the oil inlet 111, that is, the cover plate forming the oil injection chamber 138 partially covers the oil inlet 111. A first exhaust channel 134a connecting the oil injection chamber 138 and the outside of the first side is also formed inside the liquid injection housing 130, and the first exhaust channel 134a is used to discharge the gas in the oil injection chamber 138 to the outside of the first side. The outlet of the first exhaust channel 134a should be set outside the first groove 131 to prevent oil from entering the first exhaust channel 134a. The extension direction of the first exhaust channel 134a can be perpendicular to the cover plate 110 to facilitate the exhaust of air.

The operating principle of the microfluidic chip of this embodiment during the oil filling process is as follows: when the oil bubble cap 200 disposed in the first groove 131 is ruptured by pressure, the oil flows out of the oil bubble cap 200 and flows into the oil filling chamber 138 through the oil filling channel 132. As the oil gradually fills the oil filling chamber 138, the air in the oil filling chamber 138 will be gradually discharged to the outside of the oil filling chamber 138 through the first exhaust channel 134a until the oil filling chamber 138 is completely filled with oil, and the oil in the oil filling chamber 138 then flows into the interior of the fluid chamber 140 through the oil inlet 111. In the process of oil flowing into the oil filling chamber 138, the microfluidic chip of this embodiment uses the first exhaust channel 134a to discharge the bubbles in the oil and the cavity, thereby avoiding the bubble content of the oil entering the fluid chamber 140.

In some embodiments, a spike 133 is disposed inside the first groove 131 for puncturing the oil bubble 200 when the oil bubble 200 placed inside the first groove 131 is subjected to pressure, so that the oil in the oil bubble 200 flows out.

As shown in FIG3, in some embodiments, the oil injection chamber 138 includes at least a first chamber 138a and a second chamber 138b arranged in a first direction a, and the first chamber 138a and the second chamber 138b are adjacent and connected. The first direction a is a direction from the oil injection channel 132 to the oil inlet 111, as shown in FIG3, and the first direction is indicated by the arrow a in the figure. The second side surface 130b of the injection housing 130 forming the first chamber 138a is farther away from the cover plate 110 than the second side surface 130b of the injection housing 130 forming the second chamber 138b. That is, as shown in FIG3, when the microfluidic chip is placed normally horizontally, The top of the first chamber 138a is higher than the second chamber 138b. The first exhaust passage 134a is connected to the first chamber 138a, and the oil inlet 111 is connected to the second chamber 138b.

The oil filling chamber 138 of the microfluidic chip of this embodiment includes a first chamber 138a and a second chamber 138b of different heights. After the oil enters the oil filling chamber 138, the lower second chamber 138b will be filled first. Therefore, the remaining air in the oil filling chamber 138 will be naturally discharged through the first exhaust channel 134a connected to the first chamber 138a. Therefore, such a setting is more conducive to the discharge of gas in the oil, and further reduces the air that can enter the fluid chamber 140.

In addition, the entrance of the first exhaust channel 134a can be set at the position of the second side surface 130b of the liquid injection shell 130 forming the first cavity 138a that is farthest from the cover plate 110, that is, at the highest position of the top of the first cavity 138a. This arrangement can ensure that the air in the oil injection cavity 138 can be completely discharged when the oil completely fills the oil injection cavity 138, thereby avoiding oil mixing bubbles in the oil injection cavity 138.

It should be noted that, in another embodiment, the oil injection cavity 138 may include three or more cavities, which may be arranged along the first direction a, and their heights gradually decrease along the first direction a, the first exhaust channel 134a may be connected to the cavity with the highest height, and the oil inlet 111 may be connected to the cavity with the lowest height. The multiple cavities arranged in this way can also achieve the effect of naturally exhausting the air in the oil injection cavity 138 through the first exhaust channel 134a.

In some embodiments, the oil injection chamber 138 further includes a third chamber 138c extending along the first direction, one end of the third chamber 138c is connected to the oil injection channel 132, and the other end of the third chamber 138c is connected to the first chamber 138a. As shown in Figures 3 and 5, the third chamber 138c is approximately a long channel for transporting oil from the outlet of the oil injection channel 132 to the first chamber 138a without obstacles.

In some embodiments, at least a portion of the second side surface 130b of the injection housing 130 forming the first cavity 138a is inclined and extended along the first direction toward the cover plate 110. As shown in FIG3 , the top wall of the first cavity 138a is inclined downward along the first direction, and the closer to the second cavity 138b, the lower the top of the first cavity 138a. Since the density of gas is low, the bubbles in the oil tend to exist on the surface of the oil. The portion of the second side surface 130b where the oil is inclined is located when the oil flows out of the first cavity 138a. In the process of moving to the second chamber 138 b , it plays a role in blocking bubbles, thereby preventing bubbles from entering the fluid chamber 140 .

In order to rationally arrange the space on both sides of the liquid injection shell 130, the third cavity 138c can be arranged below the first groove 131, and the first cavity 138a is arranged on the side of the groove 131 and adjacent to the groove 131. Preferably, the first cavity 138a and the groove 131 can also share an inner wall of the liquid injection shell 130, as shown in FIG. 3 .

In some embodiments, as shown in FIG5 , the second side surface 130b of the liquid injection housing 130 and the cover plate 110 also form a venting chamber 139 together, and the venting chamber 139 and the oil injection chamber 138 can be isolated from each other by a partition wall 1391 provided on the second side of the oil injection housing. The venting chamber 139 can be provided to surround the oil injection chamber 138, and they are isolated by the partition wall 1391 formed on the second side and extending toward the cover plate 110. Therefore, the partition wall 1391 is used to define the area range of the oil injection chamber 138 and the venting chamber 139 on the horizontal plane. As shown in FIG5 , the oil injection chamber 138 is defined by the second side surface 130b of the oil injection housing, the upper surface of the cover plate 110, and the partition wall 1391, and the venting chamber 139 is defined by the second side surface 130b of the oil injection housing, the upper surface of the cover plate 110, the partition wall 1391, and the flange 1392 of the edge of the oil injection housing.

At least one second exhaust channel 134b is formed inside the liquid injection housing 130 to connect the exhaust chamber 139 and the outside of the first side. The second exhaust channels 134b can be multiple and can be discretely distributed on the liquid injection housing 130 to connect to the exhaust chamber 139 at different positions.

FIG6 is a top view of a cover plate 110 and a base plate 120 according to a specific embodiment of the present application. As shown in FIG6 , at least one exhaust hole 114 connected to the exhaust cavity 139 is provided on the cover plate 110. As shown in FIG6 , there may be multiple exhaust holes 114, and these exhaust holes 114 may also be discretely arranged on the cover plate to be connected to the fluid cavity 140 at different positions. For example, these exhaust holes 114 may be distributed at positions adjacent to the edge of the cover plate 110, that is, these exhaust holes 114 are connected to the edge space of the fluid cavity 140. This layout of the exhaust holes 114 is beneficial for the discharge of gas in the fluid cavity 140, because during the oil filling process, the oil will first fill the middle section of the fluid cavity 140, and the gas will be driven to the fluid cavity 140. The edge space of the cavity 140, therefore, arranging the exhaust hole 114 at a position adjacent to the edge of the cover plate is more convenient for the exhaust of gas in the final stage of oil filling.

The exhaust principle of the fluid cavity 140 during the oil injection process of this embodiment is as follows: when the oil is slowly injected into the fluid cavity 140, the oil will first fill the middle section of the fluid cavity 140, and the gas will be driven to the edge space of the fluid cavity 140, and then discharged into the exhaust cavity 139 through the exhaust hole 114 on the cover plate. Finally, the air in the exhaust cavity 139 is finally discharged to the outside of the microfluidic chip through the second exhaust channel 134b provided in the liquid injection housing 130.

As shown in FIG3 , in some embodiments, the periphery of the second side of the liquid injection housing 130 is provided with a flange 1392 extending toward the cover plate 110, and one end of the flange 1392 extending is used to connect to the cover plate 110 or the substrate 120. The periphery of the second side of the liquid injection housing 130 can be provided with inner and outer flanges 1392, wherein the inner flange 1392b is used to connect to the cover plate 110 and form an outer wall defining the exhaust cavity 139, and the outer flange 1392a is used to connect to the substrate 120. By providing the inner and outer flanges 1392, the connection strength of the liquid injection housing 130 with the cover plate 110 and the substrate 120 as a whole can be further strengthened. The connection methods of the inner and outer flanges 1392 with the cover plate 110 and the substrate 120 include but are not limited to connection methods such as gluing, clamping or screw connection.

In addition to the configuration related to oil injection, the microfluidic chip also includes configurations related to sample injection and reagent injection, which will be described in detail below in conjunction with the accompanying drawings.

As shown in Fig. 6, at least one liquid inlet 112 connected to the fluid cavity is provided on the cover plate 110, and the liquid inlet 112 is used to inject reagents into the fluid cavity 140. There can be multiple liquid inlets 112, that is, different types of reagents can be injected into the fluid cavity 140 through the multiple liquid inlets 112 respectively.

As shown in FIG. 4 , at least one second groove 135 is further formed on the first side surface 130a of the liquid injection housing 130. Each second groove 135 corresponds to a liquid inlet 112 and is used to place a reagent bubble or a lyophilized ball storing a reagent. The second groove 135 can be a circular groove like the first groove 131. However, since the amount of injected reagent is less than the amount of injected oil, the size of the second groove 135 can be smaller than the first groove 131, and the size of the plurality of second grooves 135 can be the same. The plurality of second grooves 135 can be arranged along the The second straight line direction b is arranged, as shown in FIG. 4 , which shows six second grooves 135 , and the six second grooves 135 extend along a straight line direction parallel to the edge of the liquid injection housing 130 .

As shown in FIG5 , at least one injection conduit 137a is provided on the second side of the injection housing 130, and one end of each injection conduit 137a is connected to a second groove 135, and the other end is connected to a corresponding liquid inlet 112. The injection conduit 137a is preferably arranged to extend vertically, that is, each liquid inlet 112 is arranged directly below the corresponding second groove 135, so that the arrangement is convenient for the circulation of the reagent. The reagent injection principle of the microfluidic chip of this embodiment is that when the reagent flows into one of the second grooves 135, it will reach the corresponding liquid inlet 112 arranged on the cover plate 110 along the corresponding injection conduit 137a. Then, the reagent enters the corresponding position of the fluid cavity 140 through the liquid inlet 112, and an electrode 150 is arranged below the position. Before the liquid enters the corresponding position of the fluid cavity 140, the electrode 150 at the corresponding position needs to be opened, and the subsequent electrode 150 will be able to control the flow of the reagent above.

The same principle applies to the injection of samples. As shown in FIG4 , the cover plate 110 is provided with an injection port 113 connected to the exhaust cavity 139, and the first side surface 130a of the injection housing 130 is also formed with a third groove 136. The third groove 136 is used to place the sample, and the second side of the injection housing 130 is provided with a sample conduit 137b, one end of the sample conduit 137b is connected to the third groove 136, and the other end is connected to the injection port 113. The principle of sample injection of the microfluidic chip of this embodiment is that when the sample flows into the third groove 136, it will reach the corresponding injection port set on the cover plate along the corresponding sample conduit 137b. Then, the sample enters the corresponding position of the fluid cavity 140 through the injection port 113, and an electrode 150 is provided below the position. The subsequent electrode 150 will control the flow of the sample above.

In some embodiments, the plurality of second grooves 135 are grooves of different types, and a portion of the plurality of second grooves 135 is used to place the reagent blister, while another portion is used to place the freeze-dried ball. Both the reagent blister and the freeze-dried ball can produce reagents. Specifically, the principle of the reagent blister is similar to that of the oil blister 200. The reagent in the reagent blister is wrapped by the outer blister. When the reagent blister is squeezed and ruptured by external force, the reagent liquid inside it will flow out and further flow into the second groove 135. The freeze-dried ball freezes and stores the reagent. During use, the freeze-dried ball and the freeze-dried blister are used together. The dry blister stores diluent for flushing and diluting the freeze-dried ball. During use, the freeze-dried blister is squeezed and ruptured by external force, and the diluent inside it will flow out and contact the freeze-dried ball. The reagent in the freeze-dried ball melts and dilutes and then enters the corresponding injection tube 137a.

According to the type of consumables for storing reagents placed, the plurality of second grooves 135 are divided into two groups. The plurality of second grooves 135 include a first group 135a of second grooves 135 and a second group 135b of second grooves 135, each second groove 135 in the first group 135a of second grooves 135 is used to place freeze-dried blisters and freeze-dried balls, and each second groove 135 in the second group 135b of second grooves 135 is used to place reagent blisters. Correspondingly, a plurality of liquid inlets 112 are provided on the cover plate 110, and the plurality of liquid inlets 112 include a first group of liquid inlets 112 and a second group of liquid inlets 112, wherein each liquid inlet 112 in the first group 112a of liquid inlets 112 is connected to a corresponding second groove 135 in the first group of second grooves 135, and each liquid inlet 112 in the second group 112b of liquid inlets 112 is connected to a corresponding second groove 135 in the second group of second grooves 135, and the second group of liquid inlets 112 is closer to the oil inlet 111 than the first group of liquid inlets 112.

As shown in FIG. 4 , the six second grooves 135 shown in the figure are divided into two groups, namely, the first group 135a second grooves 135 and the second group 135b second grooves 135, each group contains three second grooves 135. Correspondingly, the six liquid inlets 112 shown in FIG. 6 are also divided into two groups, namely, the first group 112a liquid inlets 112 and the second group 112b liquid inlets 112, each group contains three liquid inlets 112. The plurality of second grooves 135 and the plurality of liquid inlets 112 shown in the figure are arranged along the second direction b, and each group of second grooves 135 or each group of liquid inlets 112 are three adjacently arranged second grooves 135 or liquid inlets 112. In some other embodiments, the plurality of second grooves 135 may not necessarily be arranged along a straight line, and the plurality of second grooves 135 may also be arranged in a circular shape or distributed in a cluster, but no matter how the arrangement is, the plurality of grooves include the first group 135a second grooves 135 and the second group 135b second grooves 135 divided into two groups.

The second group 112b of liquid inlets 112 is closer to the oil inlet 111 than the first group 112a of liquid inlets 112. As shown in FIG6 , when the oil inlet 111 is disposed at a corner of the cover plate, the second group 112b of liquid inlets 112 is closer to the corner while the first group 112a of liquid inlets 112 is farther from the corner. Therefore, during the oil filling process, the oil will first fill the space where the second group 112 b of the liquid inlets 112 of the fluid chamber 140 are located, and then fill the space where the first group 112 a of the liquid inlets 112 of the fluid chamber 140 are located.

When the consumables for storing reagents are freeze-dried balls, the freeze-dried balls are placed in the opening of the corresponding second groove 135 connected to the injection conduit 137a. It can be understood that since the freeze-dried balls are solid, the joint of the opening of the injection conduit 137a is not tight, so it is easy to produce more bubbles during the injection process, and if bubbles are injected here, it is easy to affect the subsequent amplification reaction. And for the reagent bubble for storing reagents, the reagent bubble can directly provide liquid reagent to the injection conduit 137a, and this situation is not easy to produce bubbles or produce acceptable, smaller bubbles. Therefore, in the process of oil injection, when the oil just fills the space at the position of the second group 112b of the fluid chamber 140, the oil injection can be stopped and the injection operation can be performed at this time. For the second group 135b second groove 135 where the reagent bubble is located, the space at the corresponding liquid inlet 112 has been filled with oil, but because the reagent bubble is not easy to produce bubbles, the reagent can be injected when the oil already exists without bringing in bubbles or only injecting acceptable small bubbles. For the second grooves 135 of the first group 135a where the freeze-dried balls are located, the space where the corresponding liquid inlet is located has not been filled with oil, so even if bubbles are introduced during the liquid injection process, they can be discharged from the exhaust holes 114 during the subsequent oil injection process. Therefore, the arrangement and layout of the second grooves 135 and the corresponding liquid inlet 112 in this embodiment will help avoid the generation of bubbles in the fluid chamber 140.

According to another aspect of the present disclosure, a method for injecting oil into a microfluidic chip is also provided, and the method is applicable to a microfluidic chip having the above two sets of second grooves 135 and two sets of liquid inlets 112. As shown in FIG. 7 , the injection method 700 includes:

Step 710, installing the oil bubble cap 200 into the first groove 131 of the liquid injection housing 130, installing the freeze-dried bubble cap and the freeze-dried ball into each second groove 135 of the first group of second grooves 135, and installing the reagent bubble cap into each second groove 135 of the second group of second grooves 135;

Step 720: drive the oil injection head 300 located above the first groove 131 to move toward the first groove 131 to a first height relative to the microfluidic chip to squeeze the oil bubble cap 200 so that the oil flows into the fluid cavity. 140 and fills the first interval 141, wherein the first interval 141 is a space where the fluid cavity 140 only covers the second group of liquid inlets 112;

Step 730 , stopping the oil injection head 300 from moving within a preset period of time to allow the reagent to be injected into the fluid chamber 140 through the plurality of second grooves 135 ; and

Step 740 , after all the second grooves 135 are filled with liquid, continue to drive the oil injection head 300 to move toward the first groove 131 to a second height relative to the microfluidic chip to squeeze the oil bubble cap 200 so that the oil fills the fluid cavity 140 .

In the method of this embodiment, the oil injection head 300 can be used to press down the oil bubble 200 so that the oil flows out of the oil bubble 200. The oil injection head 300 can be driven by a motor to move in the vertical direction. In step 720, the oil injection head 300 moves downward from an initial position above the first groove 131, and then squeezes the oil pressure bubble 200, and the oil flows into and gradually fills the fluid cavity 140. When the oil injection head 300 is pressed down to the first height, the oil fills the first interval 141, and the above-mentioned first interval 141 is the space of the fluid cavity 140 covering the second group of liquid inlets 112. As shown in Figure 8, Figure 8 shows a schematic diagram of the oil filling the first interval 141.

In step 730, since the oil injection pressure head 300 stops pressing down, the oil filling state will remain in the state shown in Figure 8. At this time, the reagent bubbles or lyophilized balls in the plurality of second grooves 135 inject reagents into the fluid chamber 140. Similar to the oil injection process, for each second groove 135, a liquid injection head can also be used to squeeze the reagent bubble or the lyophilized bubble used to dilute the lyophilized ball to release the reagent.

In step 740 , after the injection is completed, the oil injection head 300 is driven downward to a second height relative to the microfluidic chip, so that the fluid cavity 140 is completely filled with oil. As described above, using such an oil injection sequence will help avoid bubbles in the fluid cavity 140 .

In some embodiments, before the oil injection head 300 stops moving within a preset time period: the oil injection head 300 is moved a preset distance in a direction away from the first groove 131. During the injection, the liquid and oil in the fluid chamber 140 will be further filled, which may cause the oil to cover the first group of liquid inlets 112. Therefore, before the injection, the oil injection head 300 can be retreated a short distance upwards. This can provide a certain margin for the reagent injected into the fluid chamber 140 and prevent the oil from covering the first group 112a of liquid inlets 112.

In some embodiments, the speed at which the oil injection head 300 moves from the first height to the second height is less than the speed at which the oil injection head 300 moves from the initial height to the first height. Since the second stage of the oil injection operation (step 740 in method 700) needs to fill the entire fluid cavity 140 and exhaust all air, the movement speed of the oil injection head 300 in this stage can be slightly less than the movement speed of the first stage of the oil injection operation (step 720 in method 700) to prevent excessive pressure from causing oil to overflow from the microfluidic chip.

After the oil injection is completed and before the microfluidic chip is operated, it is necessary to ensure that the oil injection head 300 is slowly lifted off the surface of the oil bubble cover 200 to prevent the pressure applied to the microfluidic chip by the oil injection head 300 from affecting the movement of the liquid.

The applicant declares that the above is only a specific implementation method of the present application, but the protection scope of the present application is not limited thereto. Technical personnel in the relevant technical field should understand that any changes or substitutions that can be easily thought of by technical personnel in the relevant technical field within the technical scope disclosed in the present application are within the protection scope and disclosure scope of the present application.

Claims

A microfluidic chip, comprising:

A cover plate and a base plate are arranged opposite to each other and spaced apart, a fluid cavity is formed between the cover plate and the base plate, and the cover plate is provided with an oil inlet connected to the fluid cavity; and

A liquid injection shell, the liquid injection shell having a first side and a second side opposite to each other, the second side being connected to the cover plate and/or the base plate, wherein a first groove for placing an oil bubble for storing oil is formed on the first side surface of the liquid injection shell, and the second side surface of the liquid injection shell and the cover plate at least jointly form an oil injection cavity, the first groove is connected to the oil injection cavity via an oil injection channel formed on the liquid injection shell, the oil injection cavity is connected to the oil inlet, and a first exhaust channel connecting the oil injection cavity and the outside of the first side is also formed inside the liquid injection shell.
The microfluidic chip according to claim 1, wherein

The oil injection chamber at least includes a first chamber and a second chamber arranged in a first direction, the first direction being a direction from the oil injection passage to the oil inlet, wherein a second side surface of the injection shell forming the first chamber is further away from the cover plate than a second side surface of the injection shell forming the second chamber, the first exhaust passage is connected to the first chamber, and the oil inlet is connected to the second chamber.
The microfluidic chip according to claim 2, wherein:

The oil injection cavity further includes a third cavity extending along the first direction, one end of the third cavity is connected to the oil injection channel, and the other end of the third cavity is connected to the first cavity.
The microfluidic chip according to claim 2, wherein:

The inlet of the exhaust passage is arranged at a position of the second side surface of the liquid injection housing forming the first cavity that is farthest from the cover plate.
The microfluidic chip according to claim 2, wherein:

At least a partial section of the second side surface of the liquid injection housing forming the first cavity is arranged to extend obliquely toward the cover plate along the first direction.
The microfluidic chip according to any one of claims 1 to 5, wherein:

The second side surface of the liquid injection housing and the cover plate also form an exhaust cavity together, the exhaust cavity and the oil injection cavity are isolated from each other, and at least one second exhaust channel connecting the exhaust cavity and the outside of the first side is also formed inside the liquid injection housing, wherein

The cover plate is provided with at least one exhaust hole connected to the exhaust cavity.
The microfluidic chip according to claim 6, wherein:

The second side of the liquid injection housing further forms a partition wall extending toward the cover plate to separate the exhaust chamber from the oil injection chamber.
The microfluidic chip according to claim 6, wherein:

The cover plate is rectangular, and the oil inlet is arranged at a first corner adjacent to the cover plate.
The microfluidic chip according to claim 8, wherein:

One of the at least one exhaust hole is disposed at a second corner adjacent to the cover plate, wherein the second corner and the first corner are two corners on a diagonal line of the cover plate.
The microfluidic chip according to any one of claims 1 to 5, wherein:

A sharp thorn is arranged inside the first groove, which is used to puncture the oil bubble cover when the oil bubble cover placed inside the first groove is subjected to pressure, so that the oil in the oil bubble cover flows out.
The microfluidic chip according to any one of claims 1 to 5, wherein:

The cover plate is provided with at least one liquid inlet connected to the fluid cavity; and

At least one second groove is also formed on the first side surface of the liquid injection shell, wherein each of the second grooves corresponds to a liquid inlet and is used to place a reagent blister or a freeze-dried ball storing a reagent, and at least one liquid injection conduit is provided on the second side of the liquid injection shell, and one end of each of the liquid injection conduits is connected to a second groove, and the other end is connected to a corresponding liquid inlet.
The microfluidic chip according to claim 11, wherein the at least one second groove is a plurality of second grooves, and the plurality of second grooves are arranged along the second direction.
The microfluidic chip according to any one of claims 1 to 5, wherein:

The cover plate is provided with a sample injection port connected to the exhaust cavity; and

A third groove is also formed on the first side surface of the liquid injection housing, wherein the third groove is used to place the sample. A sample conduit is provided on the second side of the liquid injection housing, one end of the sample conduit is connected to the third groove, and the other end is connected to the sample injection port.
The microfluidic chip according to any one of claims 1 to 5, wherein:

The cover plate and the base plate are bonded together by adhesive through a gap arranged at the periphery.
The microfluidic chip according to any one of claims 1 to 5, wherein:

The periphery of the second side of the liquid injection housing is provided with a flange extending toward the cover plate, and one end of the flange extending is used to be connected to the cover plate or the base plate.
The microfluidic chip according to claim 11, wherein the at least one second groove is a plurality of second grooves, the plurality of second grooves include a first group of second grooves and a second group of second grooves, each second groove in the first group of second grooves is used to place a freeze-dried blister and a freeze-dried ball, each second groove in the second group of second grooves is used to place a reagent blister, and,

The cover plate is provided with a plurality of liquid inlets, the plurality of liquid inlets comprising a first group of liquid inlets and a second group of liquid inlets, wherein each liquid inlet in the first group of liquid inlets is connected to the first group of second liquid inlets. The corresponding second groove in the groove, each liquid inlet in the second group of liquid inlets is connected to the corresponding second groove in the second group of second grooves, and the second group of liquid inlets is closer to the oil inlet than the first group of liquid inlets.
A method for injecting oil into the microfluidic chip according to claim 16, comprising:

Installing the oil bubble cap into the first groove of the liquid injection housing, installing the freeze-dried bubble cap and the freeze-dried ball into each second groove of the first group of second grooves, and installing the reagent bubble cap into each second groove of the second group of second grooves;

driving an oil injection pressure head located above the first groove to move toward the first groove to a first height relative to the microfluidic chip, so as to squeeze the oil bubble cover so that the oil flows into the fluid cavity and fills a first interval, wherein the first interval is a space where the fluid cavity only covers the second group of liquid inlets;

stopping the movement of the oil injection head within a preset period of time to allow the reagent to be injected into the fluid chamber through the plurality of second grooves; and

After all the second grooves are filled with liquid, the oil injection head is continuously driven to move toward the first groove to a second height relative to the microfluidic chip to squeeze the oil bubble cap so that the oil fills the fluid cavity.
The oil injection method according to claim 17, further comprising:

Before stopping the oil injection pressure head from moving within a preset time period:

The oil injection pressure head is moved a preset distance in a direction away from the first groove.
The oil injection method according to claim 17, wherein:

The speed at which the oil injection pressure head moves from the first height to the second height is less than the speed at which the oil injection pressure head moves from the initial height to the first height.