A programmable gravity self-driven microfluidic chip and a microfluidic detection system

Abstract

The application discloses a programmable gravity self-driven micro-fluidic chip and a micro-fluidic detection system, and belongs to the field of micro-fluidic chips, which comprises N-stage sample adding cavities, N-stage sample adding channels, a drainage channel, M reaction cavities and a waste liquid cavity; the top end of each sample adding cavity is in communication with the atmosphere; the first end of the N-stage sample adding channel is connected to the bottom end of the N-stage sample adding cavity in one-to-one correspondence, and the tail end is connected to a point to form a convergence point; the convergence point is lower than the bottom end of all the sample adding cavities; the first end of the drainage channel is connected with the convergence point, and the tail end is lower than the first end and is connected with the waste liquid cavity; the M reaction cavities are arranged along the drainage channel; during work, the liquid flows through the first-stage sample adding channel to the N-stage sample adding channel under the driving of gravity, and the time is increased gradually; wherein, N is a positive integer greater than 1, and M is a positive integer. The application realizes programmed control by means of gravity self-driven control of fluid sequential release, realizes programmed control, greatly simplifies operation on the basis of ensuring detection precision, and provides a new idea for instant diagnosis.

Description

Technical Field

[0001] This invention belongs to the field of microfluidic chips, and more specifically, relates to a programmable gravity-driven microfluidic chip and a microfluidic detection system. Background Technology

[0002] Infectious diseases pose a significant public health challenge globally, severely impacting human health and social stability. Accurate and rapid diagnosis and screening are the cornerstones of infectious disease control. However, existing diagnostic platforms heavily rely on complex laboratory equipment and highly skilled technicians, limiting their ability to respond to epidemics. Point-of-care testing (POCT) has emerged to address this need, providing rapid, portable, and real-time diagnostic tools for infectious disease control. Microfluidics, as an emerging fluid manipulation technology, offers even greater possibilities for POCT and represents a major trend for future development.

[0003] In microfluidic chips, "control" is typically achieved through precise channel design or by combining external actuators to control the reaction process accurately. Based on the presence or absence of external actuators, microfluidic chips can be categorized as active or passive. Active microfluidics generally utilizes external driving forces (including pressure, electrowetting, surface waves, and magnetism) for microfluidic manipulation, while passive microfluidics rely on self-driving forces, requiring no additional pump or energy source, and are characterized by portability and ease of operation. Passive driving forces mainly include capillary force, pressure, and gravity. Among these, gravity, being an inherent property of the fluid itself and independent of chip surface modification, shows promising application prospects.

[0004] Existing gravity-driven microfluidic chips can be mainly divided into three categories: the first category uses an external gravity source to replace a syringe pump for fluid injection; the second category uses a siphon structure for injection or completes the reaction within the chip; and the third category relies on the gravity of the fluid itself and the chip structure to achieve fluid manipulation. However, existing gravity-driven microfluidic chips can only achieve single-flow control, failing to achieve precise control or multi-directional flow, making it difficult to complete complex biochemical reactions. Furthermore, some microfluidic platforms even rely on external drives or capillary structures for fluid actuation. Summary of the Invention

[0005] To address the shortcomings and improvement needs of existing technologies, this invention provides a programmable gravity-driven microfluidic chip and a microfluidic detection system. Its purpose is to achieve programmable control by using gravity-driven control to release fluid sequentially, without relying on external drivers. This greatly simplifies operation while ensuring detection accuracy, and provides a new approach for real-time diagnosis.

[0006] To achieve the above objectives, according to one aspect of the present invention, a programmable gravity-driven microfluidic chip is provided, comprising: an N-stage sample loading chamber, an N-stage sample injection channel, a drainage channel, M reaction chambers, and a waste liquid chamber;

[0007] The top of each sample addition chamber is connected to the atmosphere;

[0008] The first end of the N-stage injection channel is connected to the bottom end of the N-stage sample dispensing chamber in a one-to-one correspondence, and the last end is connected to a single point to form a junction point; the junction point is lower than the bottom end of all sample dispensing chambers.

[0009] The first end of the drainage channel is connected to the confluence point, and the second end is lower than the first end and connected to the waste liquid chamber;

[0010] M reaction chambers are arranged along the drainage channel;

[0011] During operation, the time it takes for the liquid to flow from the first-stage injection channel to the Nth-stage injection channel under the influence of gravity increases progressively.

[0012] Where N is a positive integer greater than 1, and M is a positive integer.

[0013] Furthermore, the liquid flow time is controlled in each injection channel in at least one of the following ways:

[0014] Adjust the length of the injection channel; adjust the width of the injection channel; adjust the height of the injection channel; adjust the local hydrophilicity or hydrophobicity of the injection channel.

[0015] In some alternative embodiments, the lengths of the first-stage injection channel to the Nth-stage injection channel increase progressively.

[0016] Furthermore, the sample loading cavity is triangular, with its base aligned with the chip edge to form the top of the sample loading cavity, and its vertex forming the bottom of the sample loading cavity.

[0017] Furthermore, in two adjacent sample loading chambers, the bottom of the previous sample loading chamber is not higher than the bottom of the next sample loading chamber.

[0018] Furthermore, there is partial overlap at the tail of the N-stage injection channels.

[0019] Furthermore, a waterproof and breathable membrane is provided between the first end of the drainage channel and the first reaction chamber.

[0020] Furthermore, the waste liquid chamber includes an upper waste liquid chamber and a lower waste liquid chamber; among the upper and lower waste liquid chambers, the upper waste liquid chamber has a smaller volume and a lower upper edge height;

[0021] Furthermore, the programmable gravity-driven microfluidic chip provided by this invention has five chip layers, which are, from top to bottom: top cap layer, reaction layer, channel layer, liquid storage layer and bottom cap layer.

[0022] A drainage channel and M reaction chambers are located in the reaction layer;

[0023] The N-level injection channel and the upper waste liquid chamber are located in the channel layer;

[0024] The N-level sample dispensing chamber and the lower waste liquid chamber are located in the liquid storage layer.

[0025] In some optional embodiments, M=1, and the reaction chamber is a filled reaction chamber;

[0026] Furthermore, the programmable gravity-driven microfluidic chip also includes: an amplification channel disposed between the filling reaction chamber and the waste liquid chamber and connected to the drainage channel, and K amplification chambers disposed along the amplification channel;

[0027] The amplification channel provides greater liquid resistance than the drainage channel; K is a positive integer.

[0028] According to another aspect of the present invention, a microfluidic detection system is provided, comprising: a chip holder, and a programmable gravity-driven microfluidic chip provided by the present invention;

[0029] The chip scaffold includes:

[0030] Stand base;

[0031] The bracket backplate is mounted on the bracket base;

[0032] And positioning posts set on the back plate of the bracket for fixing the chip.

[0033] In summary, the above-described technical solutions conceived in this invention can achieve the following beneficial effects:

[0034] (1) The programmable gravity-driven microfluidic chip provided by the present invention has its sample inlet channels connected to each sample inlet cavity converging at one point. The liquids flow through each sample inlet channel and reach the converging point at different times under gravity drive. This allows the liquids in the sample inlet cavity to enter the reaction cavity through the drainage channel in the expected order. When the liquid in the previous sample inlet cavity flows through the converging point, the liquids in the subsequent cavity will stop flowing. Thus, the liquids in the sample inlet cavity can be released step by step under gravity drive, thereby realizing programmable operation without relying on external drivers. This greatly simplifies the operation while ensuring detection accuracy and provides a new approach for real-time diagnosis.

[0035] (2) The programmable gravity-driven microfluidic chip provided by the present invention, in its preferred embodiment, adjusts the time for liquid to pass through the injection channel by adjusting the length of the injection channel, and has a simple structure; in its further preferred embodiment, the tails of adjacent injection channels partially overlap, thereby enabling the channel structure to be more compact and saving chip space while controlling the injection time.

[0036] (3) In the preferred embodiment of the programmable gravity-driven microfluidic chip provided by the present invention, the sample dispensing chamber is specifically triangular, with its base aligned with the edge of the chip and connected to the atmosphere, and its vertex forming the bottom end of the sample dispensing chamber connected to the sample injection channel, thereby ensuring that the sample dispensing chamber has a large contact area with the atmosphere and accelerating the release of liquid in the sample dispensing chamber.

[0037] (4) In the preferred embodiment of the programmable gravity-driven microfluidic chip provided by the present invention, a waterproof and breathable membrane is bonded between the first end of the drainage channel and the first reaction chamber. When the liquid being released flows into the reaction chamber through the drainage channel, excess gas can be discharged to avoid affecting the subsequent reaction and without affecting the release of the liquid. At the same time, the fluid reaction can be accelerated.

[0038] (5) The programmable gravity-driven microfluidic chip provided by the present invention, in its preferred embodiment, designs the volume of the waste liquid chamber based on the volume of the waste liquid generated in the reaction, and sets up an amplification channel and an amplification chamber, which can realize nucleic acid detection. Attached Figure Description

[0039] Figure 1 A schematic diagram of a programmable gravity-driven self-driving microfluidic chip provided in Embodiment 1 of the present invention;

[0040] Figure 2 A schematic diagram of the three-dimensional structure of the programmable gravity-driven self-driving microfluidic chip provided in Embodiment 1 of the present invention;

[0041] Figure 3 This is a schematic diagram of the chip layer of the programmable gravity-driven microfluidic chip provided in Embodiment 1 of the present invention.

[0042] Figure 4 This is a schematic diagram of the sample inlet channel in the programmable gravity-driven microfluidic chip provided in Embodiment 1 of the present invention;

[0043] Figure 5 This is a planar schematic diagram of a programmable gravity-driven self-driving microfluidic chip provided in Embodiment 2 of the present invention;

[0044] Figure 6 This is a flowchart illustrating the operation of a programmable gravity-driven self-driving microfluidic chip provided in Embodiment 2 of the present invention.

[0045] Figure 7 This is a planar schematic diagram of a programmable gravity-driven self-driving microfluidic chip provided in Embodiment 3 of the present invention;

[0046] Figure 8 This is a schematic diagram of the chip support in the microfluidic detection system provided in Embodiment 4 of the present invention;

[0047] In all the accompanying drawings, the same reference numerals are used to denote the same structures or elements, wherein:

[0048] 11-Top cover layer, 12-Reaction layer, 13-Channel layer, 14-Liquid storage layer, 15-Bottom cover layer, 16-Positioning hole;

[0049] 2-Sample addition cavity;

[0050] 3-Injection channel; 31-First-stage injection channel; 32-Second-stage injection channel; 33-Third-stage injection channel; 34-Fourth-stage injection channel; 35-Fifth-stage injection channel; 36-Sixth-stage injection channel;

[0051] 4- Drainage channel;

[0052] 5-Reaction chamber;

[0053] 6-Waste liquid chamber; 61-Upper waste liquid chamber; 62-Lower waste liquid chamber; 63-First vent;

[0054] 7- Waterproof and breathable membrane;

[0055] 81-Amplification channel, 82-Amplification chamber, 83-Second pore;

[0056] 91-Bracket base, 92-Bracket back plate, 93-Positioning post. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0058] In this invention, the terms "first," "second," etc. (if present) in the invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0059] To achieve programmable control and sequential release of fluids using gravity-driven self-propulsion, this invention provides a programmable gravity-driven self-propulsion microfluidic chip and microfluidic detection system. The overall concept is to improve the channel structure within the chip so that the injection channels connected to each sample chamber converge at a single point. The liquid, driven by gravity, reaches the convergence point at different times as it flows through each injection channel. The liquid that arrives at the convergence point first flows into the reaction chamber via the drainage channel. Simultaneously, because the convergence point is filled with liquid, a relatively sealed space is formed within the remaining injection channels, creating resistance and preventing subsequent liquid flow until the first arriving liquid is completely released. This allows for the stepwise release of liquid from the sample chambers under gravity-driven propulsion.

[0060] It should be noted that gravity-driven microfluidic chips often operate in a vertical or tilted state. Accordingly, the terms "top," "bottom," and "height" of the components are relative to the operating state. Specifically, in a vertical or tilted state, the uppermost point of the component is its "top," the lowermost point is its "bottom," and the distance between the top and bottom points is its "height." Furthermore, since the liquid in a gravity-driven microfluidic chip flows from top to bottom under gravity, the terms "start" and "end" of the channel are relative to the order in which the liquid flows. Specifically, the end where the liquid flows in is the "start," and the end where the liquid flows out is the "end."

[0061] The following is an example.

[0062] Example 1:

[0063] A programmable gravity-driven self-driving microfluidic chip, such as Figure 1 , Figure 2 and Figure 3 As shown, it includes: a 6-stage sample loading chamber 2, a 6-stage sample injection channel 3, a drainage channel 4, 9 reaction chambers 5, and a waste liquid chamber 6;

[0064] The top of each sample addition chamber 2 is connected to the atmosphere;

[0065] The first end of the 6-stage sample injection channel 3 is connected to the bottom end of the 6-stage sample dispensing chamber 2 in a one-to-one correspondence, and the last end is connected to a point to form a junction point; the junction point is lower than the bottom end of all sample dispensing chambers.

[0066] The first end of the drainage channel 4 is connected to the confluence point, and the second end is lower than the first end and connected to the waste liquid chamber 6;

[0067] Nine reaction chambers 5 are arranged along the drainage channel 4;

[0068] During operation, the time it takes for the liquid to flow through the first to sixth stage injection channels under gravity increases progressively. To control the time it takes for the liquid to flow through each stage of the injection channel, as a preferred implementation method, such as... Figure 1 and Figure 4 As shown in this embodiment, the lengths of the first-stage sample inlet channel 31, the second-stage sample inlet channel 32, the third-stage sample inlet channel 33, the fourth-stage sample inlet channel 34, the fifth-stage sample inlet channel 35, and the sixth-stage sample inlet channel 36 increase progressively. Specifically, the first-stage sample inlet channel 31 is a straight channel, while the second-stage to sixth-stage sample inlet channels 32 and 36 are all meandering channels with increasing degree of meandering. At the same time, the tails of adjacent sample inlet channels 32 to 36 partially overlap, which allows for more compact channel structures and saves chip space while controlling the sample inlet time.

[0069] It should be noted that this embodiment controls the injection time by controlling the length of the injection channel, while avoiding liquid cross-contamination. The specific length can be adjusted, and this is only a preferred embodiment, but should not be construed as a sole limitation of the invention. In other embodiments of the invention, the injection time can also be controlled by adjusting the width of the injection channel, adjusting the height of the injection channel, adjusting the local hydrophilicity or hydrophobicity of the injection channel, adjusting the contact angle between the liquid and the injection channel, or a combination of these methods. In practical applications, the injection time can also be controlled by adjusting the viscosity, density, and other properties of the liquid.

[0070] Based on the channel structure design of this embodiment, after the reaction reagents are horizontally added to each sample loading chamber, the chip is placed vertically. Since the first-stage sample loading channel is the shortest, the reaction reagents in the first-stage sample loading chamber will reach the junction point first and flow into each reaction chamber sequentially through the drainage channel. Finally, the excess reagents will flow into the waste liquid chamber. At the same time, since the junction point is filled with the reagents flowing out of the first-stage sample loading chamber, a relatively sealed environment is formed in the second-stage to sixth-stage sample loading channels. The reagents in the channels will no longer flow due to the resistance formed by the gas pressure. After the reagents in the first-stage sample loading channel have completely flowed out, the reagents in the subsequent sample loading channels will continue to flow towards the junction point and flow into each reaction chamber sequentially through the drainage channel. Similarly, during this process, the liquid in the subsequent sample loading channels will no longer flow. And so on, the reagents in the third-stage to sixth-stage sample loading channels will flow into each reaction chamber sequentially.

[0071] As a preferred implementation method, such as Figure 1 , Figure 2 ,and Figure 3 As shown in this embodiment, to facilitate reagent flow, the sample application chamber 2 is specifically triangular, with its base aligned with the chip edge to form the apex of the sample application chamber, and its vertex forming the bottom of the sample application chamber. This ensures a large contact area between the sample application chamber and the atmosphere, accelerating the flow of liquid within the sample application chamber in the channel. It should be noted that in practical applications, the shape of the sample application chamber can also be set to other shapes besides triangle, as long as its apex is connected to the atmosphere.

[0072] It is easy to understand that, to facilitate control of the sample addition sequence, in adjacent sample addition chambers, the bottom of the previous sample addition chamber is not higher than the bottom of the next sample addition chamber. In this embodiment, as... Figure 1 and Figure 2 As shown in this embodiment, the bottom height of each sample addition chamber is the same, which facilitates both control of the sample addition sequence and processing.

[0073] To achieve the aforementioned chamber and channel structure, this embodiment employs a 5-layer chip structure design, such as... Figure 3As shown, the five chip layers contained in the chip, from top to bottom, are: top cap layer 11, reaction layer 12, channel layer 13, liquid reservoir layer 14, and bottom cap layer 15.

[0074] Drainage channel 4 and reaction chamber 5 are located in reaction layer 12;

[0075] Sample introduction channel 3 is located in channel layer 13;

[0076] Sample addition chamber 2 is located in the liquid storage layer 14;

[0077] Furthermore, in this embodiment, the waste liquid chamber 6 includes an upper waste liquid chamber 61 and a lower waste liquid chamber 62; of the upper waste liquid chamber 61 and the lower waste liquid chamber 62, the upper waste liquid chamber 61 has a smaller volume and a lower upper edge height; the upper waste liquid chamber 61 is located in the channel layer 13; the lower waste liquid chamber 62 is located in the storage layer 14; based on this structural design, liquid will not stagnate at the inlet of the waste liquid chamber and will be continuously released under the action of gravity and surface tension. Figure 1 As shown, in order to balance the air pressure, the waste liquid chamber 6 is also provided with a first air hole 63 in this embodiment.

[0078] like Figure 3 As shown, the same positioning hole 16 is provided at the same position in each chip layer.

[0079] The chip provided in this embodiment can be processed using CNC (Computerized Numerical Control), CO2 laser cutting, 3D printing, and injection molding, etc.; the chip material is not limited to single-crystal silicon wafers, quartz, glass, PDMS (Polydimethylsiloxane), PMMA (Polymethyl methacrylate), PC (Polycarbonate), transparent resin, and hydrogel, etc.

[0080] It should be noted that the number of sample loading chambers, sample injection channels, and reaction chambers in this embodiment is merely illustrative and should not be construed as the sole limitation of the present invention. In other embodiments, the number of chambers can be set according to the types of reagents involved in the actual detection task and the specific detection target. Furthermore, the specific chip layering scheme is only one optional implementation method, and other chip layering schemes may also be used in other embodiments.

[0081] Example 2:

[0082] A programmable gravity-driven self-driving microfluidic chip, such as Figure 5 As shown, this embodiment is similar to the above embodiment 1, except that in this embodiment, a waterproof and breathable membrane 7 is bonded between the first end of the drainage channel and the first reaction chamber.

[0083] Since gas can pass through the waterproof and breathable membrane while liquid cannot, based on this waterproof and breathable membrane, when the liquid being released flows into the reaction chamber through the drainage channel, excess gas can be discharged to avoid affecting subsequent reactions without affecting the release of liquid, and at the same time, the fluid reaction can be accelerated.

[0084] The following explanation uses colorimetric immunoassay as an example to further illustrate the working process of the programmable gravity-driven microfluidic chip provided in this embodiment. The colorimetric immunoassay process is as follows:

[0085] (1) Capture antibody incubation: There are multiple similar capture antibody incubation strips on a chip, and different types of capture antibodies are incubated at the bottom of the reaction chamber by means of membrane strips, covalent bonds, physical adsorption, etc.

[0086] (2) Chip packaging: The fabricated microfluidic chip, such as Figure 5 The package is shown as a single unit and bonded by pressure.

[0087] (3) Horizontal sample loading: Add incubation buffer, sample, washing solution 1, enzyme-labeled antibody, washing solution 2, and chromogenic substrate to the 6 sample loading chambers on the chip respectively;

[0088] (4) Chromogenic Immunoassay: After all reagents are added horizontally to the microfluidic chip, the chip is placed vertically to trigger the "gravity switch," which drives the sequential release of fluids. The incubation buffer, sample, washing solution 1, enzyme-labeled antibody, washing solution 2, and chromogenic substrate will enter the reaction chamber in sequence. This process is as follows: Figure 6 As shown;

[0089] (5) Results analysis: After the chip is placed vertically, no other operation is required. Wait for a certain reaction time (several minutes) and the color development result can be observed after the reaction is completed.

[0090] Example 3:

[0091] A programmable gravity-driven self-driving microfluidic chip, this embodiment is similar to embodiment 1 above, except that, as Figure 7 As shown, in this embodiment, M=1, and the reaction chamber is a filled reaction chamber;

[0092] Furthermore, the programmable gravity-driven microfluidic chip also includes: an amplification channel 81 disposed between the filling reaction chamber and the waste liquid chamber and connected to the drainage channel, and three amplification chambers 82 disposed along the amplification channel 81;

[0093] The amplification channel provides greater liquid resistance than the drainage channel.

[0094] The programmable gravity-driven microfluidic chip provided in this embodiment can also achieve sequential release of liquids. Ultimately, the liquids in each sample application chamber will flow sequentially into the filling reaction chamber. Furthermore, the chip provided in this embodiment is mainly used for nucleic acid detection. The filling reaction chamber can be encapsulated with a silicone membrane or magnetic beads, and amplification reagents are pre-embedded in the amplification chambers. Figure 7 As shown, in this embodiment, the chip specifically integrates 5 sample loading chambers for adding nucleic acid extraction reaction reagents and blocking agents;

[0095] After each reagent enters the reaction chamber in sequence and reacts, it first flows into the waste liquid chamber through a drainage channel with low resistance. The volume of the waste liquid chamber is designed so that it is filled with waste liquid and washing solution after the reaction. Then, the nucleic acid that can be extracted after the reaction will flow into each amplification chamber through the amplification channel to complete nucleic acid detection and analysis. For example... Figure 7 As shown, to balance the gas pressure, each amplification chamber in this embodiment is also provided with a second vent 83. It should be noted that in practical applications, the number of amplification chambers and the number of sample loading chambers can be adjusted accordingly based on the actual detection and analysis task.

[0096] like Figure 7 As shown, to ensure the amplification channel has greater resistance than the drainage channel, excess liquid enters the waste liquid chamber before it is filled, and the nucleic acid extracted from the reaction enters the amplification chamber after the waste liquid chamber is filled. In this embodiment, the drainage channel connecting the filling reaction chamber and the waste liquid chamber is a vertical channel, while the amplification channel is an inclined channel. It should be noted that in other embodiments of the present invention, the channel resistance can also be set by adjusting local hydrophobicity, channel width, or valves, etc.

[0097] The following explanation further illustrates the working process of the programmable gravity-driven self-driving microfluidic chip provided in this embodiment, using a specific nucleic acid detection process as an example. The nucleic acid detection process is as follows:

[0098] (1) Reagent pre-embedding: Silicone film or magnetic beads are encapsulated in the filling reaction chamber, and amplification reagents are pre-embedded in the amplification chamber.

[0099] (2) Chip packaging: The processed microfluidic chip is packaged into a whole and bonded by pressure.

[0100] (3) Horizontal sample loading: Add the sample and lysis mixture, washing solution 1, washing solution 2, elution solution and mineral oil respectively from the 5 sample loading chambers integrated on the chip.

[0101] (4) Sample nucleic acid extraction: After all the reagents are added to the microfluidic chip, the chip is placed vertically to trigger the "gravity switch" to drive the fluid to be released sequentially. The mixture, washing solution 1, washing solution 2, elution solution, and mineral oil enter the filling reaction chamber in sequence. After four steps of sample lysis, two washings and one elution, the extracted nucleic acid enters the amplification chamber.

[0102] (5) Nucleic acid amplification: Mineral oil is released into the amplification chamber to achieve the oil sealing function, and the nucleic acid amplification and sample analysis are completed in conjunction with the supporting temperature control system.

[0103] Example 4:

[0104] A microfluidic detection system includes: a chip scaffold, and a programmable gravity-driven microfluidic chip provided in any one of embodiments 1 to 3 above;

[0105] like Figure 8 As shown, the chip scaffold includes:

[0106] Stand base 91;

[0107] The bracket back plate 92 is mounted on the bracket base 91;

[0108] and positioning posts 93 disposed on the back plate 91 of the bracket for fixing the chip; correspondingly, such as Figure 1 , Figure 5 and Figure 7 As shown, a positioning hole is provided on the chip at the position corresponding to the positioning post 93.

[0109] Considering that in actual detection and analysis, the chip only needs to be tilted at a certain angle to trigger the "gravity switch," causing the reagents in the sample dispensing chamber within the chip to be released sequentially, this embodiment also includes an angle adjustment mechanism for adjusting the tilt angle between the support backplate and the vertical direction. Based on this angle adjustment mechanism, the tilt angle range of the chip can be adjusted to 0-90 degrees, preferably 90 degrees. Simultaneously, the fluid release rate can be controlled by adjusting the chip tilt angle, thereby adjusting the reaction time and controlling the reaction process.

[0110] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A programmable gravity-driven self-driving microfluidic chip, characterized in that, include: N Level plus sample cavity, N Multistage injection channel, drainage channel M One reaction chamber and one waste liquid chamber; The top of each sample loading chamber is connected to the atmosphere; the sample loading chamber is triangular, with its base aligned with the edge of the chip, forming the top of the sample loading chamber, and the vertex forming the bottom of the sample loading chamber; The N The first end of each injection channel is connected to a corresponding terminal. N The bottom end of each sample dispensing chamber is connected to a single point, forming a junction point; this junction point is lower than the bottom ends of all the sample dispensing chambers. N There is partial overlap at the tail end of the injection channels; The first end of the drainage channel is connected to the confluence point, and the second end is lower than the first end and connected to the waste liquid chamber; The M A reaction chamber is arranged along the drainage channel; During operation, the liquid flows through the first-stage injection channel under the influence of gravity to the second stage. N The time for each injection channel increases progressively; in, N It is a positive integer greater than 1. M It is a positive integer.

2. The programmable gravity-driven self-driving microfluidic chip as described in claim 1, characterized in that, The liquid flow time is controlled in each of the following ways: Adjust the length of the injection channel; adjust the width of the injection channel; adjust the height of the injection channel; adjust the local hydrophilicity or hydrophobicity of the injection channel.

3. The programmable gravity-driven self-driving microfluidic chip as described in claim 2, characterized in that, First-stage sample inlet channel to... N The length of the injection channels increases progressively.

4. The programmable gravity-driven self-driving microfluidic chip as described in claim 1, characterized in that, In two adjacent sample loading chambers, the bottom of the previous sample loading chamber is not higher than the bottom of the next sample loading chamber.

5. The programmable gravity-driven self-driving microfluidic chip as described in any one of claims 1 to 4, characterized in that, A waterproof and breathable membrane is provided between the first end of the drainage channel and the first reaction chamber.

6. The programmable gravity-driven self-driving microfluidic chip according to any one of claims 1 to 4, characterized in that, The waste liquid chamber includes an upper waste liquid chamber and a lower waste liquid chamber; of the upper and lower waste liquid chambers, the upper waste liquid chamber has a smaller volume and a lower upper edge height; Furthermore, the programmable gravity-driven microfluidic chip has five chip layers, from top to bottom: top cap layer, reaction layer, channel layer, liquid storage layer and bottom cap layer; The drainage channel and the M A reaction chamber is disposed in the reaction layer; The N The primary injection channel and the upper waste liquid chamber are located in the channel layer; The N The sample addition chamber and the lower waste liquid chamber are located in the liquid storage layer.

7. The programmable gravity-driven self-driving microfluidic chip according to any one of claims 1 to 4, characterized in that, M =1, the reaction chamber is a filled reaction chamber; Furthermore, the programmable gravity-driven microfluidic chip also includes: an amplification channel disposed between the filling reaction chamber and the waste liquid chamber and connected to the drainage channel, and a [missing information - likely a feature or feature] disposed along the amplification channel. K One amplification chamber; The amplification channel provides greater liquid resistance than the drainage channel. K It is a positive integer.

8. A microfluidic detection system, characterized in that, include: A chip scaffold, and a programmable gravity-driven microfluidic chip as described in any one of claims 1 to 7; The chip scaffold includes: Stand base; The bracket backplate is mounted on the bracket base; And positioning posts disposed on the back plate of the bracket for fixing the chip.

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