阅读说明：本技术 离心式微流控芯片及外泌体的提取方法 (Centrifugal micro-fluidic chip and exosome extraction method ) 是由 董鸣 王洪 赵靓 杨子仪 于 2020-11-02 设计创作，主要内容包括：本发明涉及一种离心式微流控芯片及外泌体的提取方法,离心式微流控芯片包括旋转中心、至少一个提取机构,提取机构包括进样单元、捕获释放单元以及富集单元；所述进样单元用于样本液的输入和存储；所述捕获释放单元与所述进样单元连接且位于所述进样单元的下游,用于捕获或释放样本液中的提取目标物；所述富集单元与所述捕获释放单元连接且位于所述捕获释放单元的下游,用于富集所述捕获释放单元释放的提取目标物。本发明利用该离心式微流控芯片仅需一次加样,通过控制芯片旋转,即可达到快速提取外泌体的目的,操作简便,提取速度快效率高,试剂用量低,提取得到的外泌体量大。(The invention relates to a centrifugal microfluidic chip and an extraction method of exosomes, wherein the centrifugal microfluidic chip comprises a rotating center and at least one extraction mechanism, and the extraction mechanism comprises a sample introduction unit, a capture release unit and an enrichment unit; the sample introduction unit is used for inputting and storing sample liquid; the capture and release unit is connected with the sample injection unit, is positioned at the downstream of the sample injection unit and is used for capturing or releasing an extraction target object in the sample liquid; the enrichment unit is connected with the capture and release unit and is positioned at the downstream of the capture and release unit and used for enriching the extraction target released by the capture and release unit. The centrifugal micro-fluidic chip can achieve the purpose of quickly extracting exosomes by only one-time sample adding and controlling the rotation of the chip, and has the advantages of simple and convenient operation, high extraction speed and efficiency, low reagent consumption and large amount of extracted exosomes.)

1. A centrifugal microfluidic chip is characterized by comprising a rotation center and at least one extraction mechanism, wherein the extraction mechanism comprises a sample introduction unit, a capture and release unit and an enrichment unit; the sample introduction unit is used for inputting and storing sample liquid; the capture and release unit is connected with the sample injection unit, is positioned at the downstream of the sample injection unit and is used for capturing or releasing an extraction target object in the sample liquid; the enrichment unit is connected with the capture and release unit and is positioned at the downstream of the capture and release unit and used for enriching the extraction target released by the capture and release unit.

2. The centrifugal microfluidic chip according to claim 1, wherein the capture and release unit comprises a loading solution pool for loading a loading solution containing a carrier capable of binding to an extraction target, an incubation pool, a carrier filtration pool, and an elution pool; the incubation pool is respectively connected with the sample introduction unit and the loading liquid pool; the eluent pool is used for loading an eluent capable of separating the extraction target object from the carrier; the carrier filtering tank is respectively connected with the incubation tank and the eluent tank, and a carrier filtering membrane for intercepting the carrier is arranged in the carrier filtering tank; the loading liquid pool, the incubation pool and the carrier filtering pool are sequentially distributed from the proximal end to the distal end of the rotating center;

preferably, catch release unit and still include the separating reservoir, advance kind of unit and pass through the separating reservoir with the incubation pool is connected, advance kind of unit, separating reservoir and the incubation pool is from the heart end of gyration center to heart end and distributes in proper order.

3. The microfluidic centrifugal chip according to claim 2, wherein the separation cell comprises a first chamber, a connection portion, and a second chamber, the first chamber is connected to the second chamber through the connection portion, and an inner diameter of the connection portion is smaller than inner diameters of the first chamber and the second chamber.

4. The centrifugal microfluidic chip according to claim 2 or 3, wherein from the proximal end to the distal end of the rotation center, the capture and release unit further comprises a diluent reservoir and a dilution mixing reservoir for loading a sample diluent, the diluent reservoir is connected with the dilution mixing reservoir, and the separation reservoir is connected with the incubation reservoir through the dilution mixing reservoir;

preferably, the capturing and releasing unit further comprises an impurity filtering tank, the diluting and mixing tank is connected with the incubation tank through the impurity filtering tank, and an impurity filtering membrane for intercepting impurities is arranged in the impurity filtering tank;

preferably, the capturing and releasing unit further comprises a buffer pool, the eluent pool is connected with the carrier filter pool through the buffer pool, and the eluent pool, the buffer pool and the carrier filter pool are sequentially distributed from the proximal end to the distal end of the rotating center.

5. The centrifugal microfluidic chip according to any one of the preceding claims, wherein the sample introduction unit comprises a sample introduction hole and a sample cell, the sample introduction hole is connected with the sample cell to input a sample liquid into the sample cell, and the sample cell is used for storing the sample liquid.

6. The centrifugal microfluidic chip according to any one of the preceding claims, wherein the enrichment unit comprises a target cell and a waste cell, which are respectively connected with the carrier filtration cell, the target cell is used for collecting the extracted target from the carrier filtration cell, and the waste cell is used for collecting waste liquid from the carrier filtration cell;

preferably, the capturing and releasing unit further comprises a flow direction selection tank, the target object tank and the waste liquid tank are respectively connected with the carrier filtration tank through the flow direction selection tank, and the liquid flows from the carrier filtration tank to the flow direction selection tank and then flows from the flow direction selection tank to the target object tank or the waste liquid tank.

7. The centrifugal microfluidic chip according to any one of the preceding claims, wherein the separation pool is connected with the dilution mixing pool through a first channel, the diluent pool is connected with the dilution mixing pool through a second channel, the loading pool is connected with the incubation pool through a third channel, the eluent pool is connected with the buffer pool through a fourth channel, the buffer pool is connected with the carrier filtration pool through a fifth channel, and the incubation pool is connected with the carrier filtration pool through a sixth channel; the first channel, the second channel, the third channel, the fourth channel, the fifth channel and the sixth channel are bent towards the rotation center and the edge of the centrifugal microfluidic chip alternately, and capillary valves are arranged on the parts of the second channel, the third channel, the fourth channel and the fifth channel, which extend towards the rotation center, at each section.

8. The centrifugal microfluidic chip according to any one of the preceding claims, wherein the carrier filter tank has a membrane front inlet portion and a membrane rear outlet portion, a membrane placing groove is formed in a bottom wall between the membrane front inlet portion and the membrane rear outlet portion, and the carrier filter membrane is embedded in the membrane placing groove.

9. An extraction method of exosomes, using the centrifugal microfluidic chip according to any one of claims 1 to 8, comprising the steps of:

adding a sample liquid to the sample introduction unit; controlling the rotation speed of the centrifugal microfluidic chip, enabling the sample liquid to pass through the capture and release unit, and enabling the exosomes in the sample liquid to be captured;

releasing the exosomes captured by the capture-and-release unit to the enrichment unit.

10. The extraction method according to claim 9, wherein the step of controlling the rotation speed of the centrifugal microfluidic chip comprises:

(1) controlling the centrifugal microfluidic chip to centrifuge at a first speed so that the sample liquid flows into the separation pool from the sample pool;

(2) controlling the centrifugal microfluidic chip to centrifuge at a second speed in a direction opposite to the direction in the step (1), starting the centrifuge clockwise after stopping rotation until the centrifugal speed reaches a third speed, then starting the centrifuge anticlockwise until the centrifugal speed reaches the third speed, stopping the centrifugation and standing, enabling the liquid in the separation pool and the liquid in the diluent pool to flow into the dilution mixing pool to be mixed and flow into the impurity filtering pool, and then flow into the incubation pool through the impurity filtering membrane, and enabling the liquid in the loading liquid pool to flow into the incubation pool to be mixed with the filtered liquid;

(3) controlling the centrifugal microfluidic chip to centrifuge at a fourth speed in the same direction as the centrifugal microfluidic chip in the step (1), so that the liquid in the incubation pool flows into the carrier filter pool and reaches the waste liquid pool through the carrier filter membrane, the carrier is intercepted, and meanwhile, the liquid in the eluent pool flows into the buffer pool;

(4) and (3) controlling the centrifugal microfluidic chip to centrifuge at the fourth speed in the direction opposite to the step (1), so that the liquid in the buffer pool flows into the carrier filter pool and passes through the carrier filter membrane to reach the target object pool.

11. The extraction method according to claim 10, wherein the first speed is higher than the second speed, the second speed is higher than the third speed, and the fourth speed is higher than the third speed.

12. The extraction method according to claim 10, wherein the first speed is 4000 to 7000 revolutions/min, the second speed is 3000 to 5000 revolutions/min, the third speed is 1500 to 4000 revolutions/min, and the fourth speed is 7000 to 9000 revolutions/min; the centrifugation time of the step (1) is 10 s-3 min, the centrifugation time of the step (2) is 5 s-2 min, the centrifugation time of the step (3) is 10 s-1 min, and the centrifugation time of the step (4) is 10 s-1 min.

Technical Field

The invention relates to the technical field of microfluidics, in particular to a centrifugal microfluidic chip and an exosome extraction method.

Background

The exosome is an extracellular nano-scale vesicle formed by cells through an endocytosis-fusion-efflux process, has the size of 50-150 nm and high content in blood, and has the characteristics and functions of transferring nucleic acid (miRNA), protein, lipid and other bioactive molecules through a blood brain barrier. The exosome is used as a carrier for communicating and transmitting substances among cells, plays a role in regulation in receptor cells, and plays a vital role in a series of physiological and pathological processes through research. At present, the exosomes are extracted mainly from body fluids such as blood, saliva, urine, cerebrospinal fluid, semen, saliva, pleural effusion, milk and the like.

The exosome extraction method mainly comprises an ultracentrifugation method, a density gradient centrifugation method, a polymer precipitation method (PEG-base precipitation method), an ultrafiltration method, a magnetic bead immunization method, a kit extraction method and the like. The ultracentrifugation method is the most common exosome purification means, and can separate vesicle particles with similar sizes by alternately carrying out low-speed centrifugation and high-speed centrifugation. The density gradient centrifugation method is to form a density layer by ultracentrifugation and enrich exosomes. The PEG-base precipitation method, which previously applied to the collection of viruses from samples such as serum, is now also used to precipitate exosomes, by exploiting the property of polyethylene glycol (PEG) to co-precipitate with hydrophobic proteins and lipid molecules, the principle of which may be related to competitive binding of free water molecules. The ultrafiltration centrifugation method is to use ultrafiltration membranes with different relative molecular masses to carry out selective separation. The magnetic bead immunization method is characterized in that specific markers (such as CD63 and CD9 protein) are arranged on the surface of the exosome, and the exosome can be adsorbed and separated by using magnetic beads coated with anti-marker antibodies to be combined with exosome vesicles after incubation. However, the method for extracting exosomes usually needs multiple sample adding and changing, and has the defects of long time consumption, complicated operation process and the like.

Disclosure of Invention

Therefore, it is necessary to provide a centrifugal microfluidic chip with simple operation and high exosome extraction efficiency.

A centrifugal microfluidic chip comprises a rotation center and at least one extraction mechanism, wherein the extraction mechanism comprises a sample introduction unit, a capture release unit and an enrichment unit; the sample introduction unit is used for inputting and storing sample liquid; the capture and release unit is connected with the sample injection unit, is positioned at the downstream of the sample injection unit and is used for capturing or releasing an extraction target object in the sample liquid; the enrichment unit is connected with the capture and release unit and is positioned at the downstream of the capture and release unit and used for enriching the extraction target released by the capture and release unit.

In one embodiment, the capture and release unit comprises a loading solution pool, an incubation pool, a carrier filtering pool and an eluent pool, wherein the loading solution pool is used for loading a loading solution containing a carrier capable of being combined with an extraction target; the incubation pool is respectively connected with the sample introduction unit and the loading liquid pool; the eluent pool is used for loading an eluent capable of separating the extraction target object from the carrier; the carrier filtering tank is respectively connected with the incubation tank and the eluent tank, and a carrier filtering membrane for intercepting the carrier is arranged in the carrier filtering tank; the loading liquid pool, the incubation pool and the carrier filtering pool are sequentially distributed from the proximal end to the distal end of the rotating center;

preferably, the capturing and releasing unit further comprises a separation pool, the sample pool is connected with the incubation pool through the separation pool, and the sample pool, the separation pool and the incubation pool are sequentially distributed from the proximal end to the distal end of the rotating center.

In one embodiment, the separation tank comprises a first chamber, a connecting part and a second chamber, wherein the first chamber is connected with the second chamber through the connecting part, and the inner diameter of the connecting part is smaller than the inner diameters of the first chamber and the second chamber.

In one embodiment, from the proximal end to the distal end of the rotation center, the capture and release unit further comprises a diluent pool and a dilution mixing pool for loading a sample diluent, the diluent pool is connected with the dilution mixing pool, and the separation pool is connected with the incubation pool through the dilution mixing pool;

preferably, the capturing and releasing unit further comprises an impurity filtering tank, the diluting and mixing tank is connected with the incubation tank through the impurity filtering tank, and an impurity filtering membrane for intercepting impurities is arranged in the impurity filtering tank;

preferably, the capturing and releasing unit further comprises a buffer pool, the eluent pool is connected with the carrier filter pool through the buffer pool, and the eluent pool, the buffer pool and the carrier filter pool are sequentially distributed from the proximal end to the distal end of the rotating center.

In one embodiment, the sample introduction unit comprises a sample introduction hole and a sample cell, wherein the sample introduction hole is connected with the sample cell and used for inputting a sample liquid into the sample cell, and the sample cell is used for storing the sample liquid.

In one embodiment, the enrichment unit comprises a target object pool and a waste liquid pool which are respectively connected with the carrier filtration pool, the target object pool is used for collecting the extracted target object from the carrier filtration pool, and the waste liquid pool is used for collecting waste liquid from the carrier filtration pool;

preferably, the capturing and releasing unit further comprises a flow direction selection tank, the target object tank and the waste liquid tank are respectively connected with the carrier filtration tank through the flow direction selection tank, and the liquid flows from the carrier filtration tank to the flow direction selection tank and then flows from the flow direction selection tank to the target object tank or the waste liquid tank.

In one embodiment, the separation pool is connected with the dilution mixing pool through a first channel, the diluent pool is connected with the dilution mixing pool through a second channel, the loading pool is connected with the incubation pool through a third channel, the eluent pool is connected with the buffer pool through a fourth channel, the buffer pool is connected with the carrier filtration pool through a fifth channel, and the incubation pool is connected with the carrier filtration pool through a sixth channel; the first channel, the second channel, the third channel, the fourth channel, the fifth channel and the sixth channel are bent towards the rotation center and the edge of the centrifugal microfluidic chip alternately, and capillary valves are arranged on the parts of the second channel, the third channel, the fourth channel and the fifth channel, which extend towards the rotation center, at each section.

In one embodiment, the carrier filter tank is provided with a membrane front inlet part and a membrane rear outlet part, a membrane placing groove is formed in the bottom wall between the membrane front inlet part and the membrane rear outlet part, and the carrier filter membrane is embedded in the membrane placing groove.

The invention also provides an extraction method of exosome, which uses the centrifugal microfluidic chip and comprises the following steps:

adding a sample liquid to the sample introduction unit; controlling the rotation speed of the centrifugal microfluidic chip, enabling the sample liquid to pass through the capture and release unit, and enabling the exosomes in the sample liquid to be captured;

releasing the exosomes captured by the capture-and-release unit to the enrichment unit.

In one embodiment, the step of controlling the rotation speed of the centrifugal microfluidic chip comprises:

(1) controlling the centrifugal microfluidic chip to centrifuge at a first speed so that the sample liquid flows into the separation pool from the sample pool;

(2) controlling the centrifugal microfluidic chip to centrifuge at a second speed in a direction opposite to the direction in the step (1), starting the centrifuge clockwise after stopping rotation until the centrifugal speed reaches a third speed, then starting the centrifuge anticlockwise until the centrifugal speed reaches the third speed, stopping the centrifugation and standing, enabling the liquid in the separation pool and the liquid in the diluent pool to flow into the dilution mixing pool to be mixed and flow into the impurity filtering pool, and then flow into the incubation pool through the impurity filtering membrane, and enabling the liquid in the loading liquid pool to flow into the incubation pool to be mixed with the filtered liquid;

(3) controlling the centrifugal microfluidic chip to centrifuge at a fourth speed in the same direction as the centrifugal microfluidic chip in the step (1), so that the liquid in the incubation pool flows into the carrier filter pool and reaches the waste liquid pool through the carrier filter membrane, the carrier is intercepted, and meanwhile, the liquid in the eluent pool flows into the buffer pool;

(4) and (3) controlling the centrifugal microfluidic chip to centrifuge at the fourth speed in the direction opposite to the step (1), so that the liquid in the buffer pool flows into the carrier filter pool and passes through the carrier filter membrane to reach the target object pool.

In one embodiment, the first speed is higher than the second speed, the second speed is higher than the third speed, and the fourth speed is higher than the third speed.

In one embodiment, the first speed is 4000-7000 rpm, the second speed is 3000-5000 rpm, the third speed is 1500-4000 rpm, and the fourth speed is 7000-9000 rpm; the centrifugation time of the step (1) is 10 s-3 min, the centrifugation time of the step (2) is 5 s-2 min, the centrifugation time of the step (3) is 10 s-1 min, and the centrifugation time of the step (4) is 10 s-1 min.

When the centrifugal microfluidic chip is used, sample liquid can be added into the sample injection unit, the loading liquid pool is provided with loading liquid, and the eluent pool is provided with eluent. And then, controlling the rotating speed of the centrifugal microfluidic chip to enable the sample liquid and the loading liquid to reach the incubation pool for incubation, wherein the carrier in the loading liquid is combined with the extraction target object in the sample liquid, such as exosome. And then releasing the sample liquid and the loading liquid from the incubation pool to the carrier filter pool through clockwise or anticlockwise rotating centrifugation, and enabling the carrier and the extraction target object combined with the carrier to be intercepted by the carrier filter membrane through the carrier filter membrane. And then, releasing the eluent to a carrier filter tank by rotating and centrifuging in the direction opposite to the previous step, separating the extraction target object from the carrier under the action of the eluent by a carrier filter membrane, and collecting the eluent to obtain the extraction target object. The centrifugal micro-fluidic chip can achieve the purpose of quickly extracting the exosome only by once sample adding and controlling the rotation of the chip, and can conveniently apply the extracted exosome at the later stage. The extraction process of the centrifugal microfluidic chip is simple and convenient to operate, the extraction speed is high, the efficiency is high, the reagent dosage is low, the amount of the exosome obtained by extraction is large, the defects that the traditional extraction mode is complex in operation, multiple samples are required to be added and changed, the consumed time is long and the like are overcome, the consumption of the reagent can be saved, the extraction time is shortened, and the extraction cost is reduced.

Drawings

FIG. 1 is a schematic structural diagram of a centrifugal microfluidic chip according to an embodiment;

FIG. 2 is a schematic top plate of a centrifugal microfluidic chip according to an embodiment;

FIG. 3 is a schematic diagram of centrifugation in the method for extracting exosomes according to an embodiment;

FIG. 4 is a particle size histogram of exosomes extracted experimentally;

FIG. 5 is an electron micrograph of exosomes extracted experimentally;

FIG. 6 is another electron micrograph of exosomes extracted experimentally.

Detailed Description

In order that the invention may be more fully understood, a more particular description of the invention will now be rendered by reference to specific embodiments thereof that are illustrated in the appended drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The centrifugal microfluidic chip 200 according to an embodiment of the present invention includes a rotation center, and at least one extraction mechanism including a sample introduction unit, a capture and release unit, and an enrichment unit. The sample introduction unit is used for inputting and storing sample liquid. The capture and release unit is connected with the sample injection unit and is positioned at the downstream of the sample injection unit and used for capturing or releasing the extraction target object in the sample liquid. The enrichment unit is connected with the capture and release unit and is positioned at the downstream of the capture and release unit and used for enriching the extraction target substances released by the capture and release unit.

As shown in fig. 1, in a specific example, the capture and release unit includes a loading solution pool 25, an incubation pool 26, a carrier filtration pool 27, and an eluent pool 28, and the loading solution pool 25 is used for loading a loading solution containing a carrier capable of binding to an extraction target. The incubation well 26 is connected to the sample well 10 and the loading solution well 25, respectively. The eluent pool 28 is used to load an eluent capable of separating the extraction target from the carrier. The carrier filtering tank 27 is connected with the incubation tank 26 and the eluent tank 28 respectively, and a carrier filtering membrane 271 for intercepting the carrier is arranged in the carrier filtering tank 27. The loading liquid pool 25, the incubation pool 26 and the carrier filtering pool 27 are distributed in sequence from the proximal end to the distal end of the rotating center.

When the centrifugal microfluidic chip 200 is used, a sample liquid can be added to the sample injection unit, a loading liquid is added to the loading liquid pool 25, and an eluent is added to the eluent pool 28. Then, by controlling the rotation speed of the centrifugal microfluidic chip 200, the sample liquid and the loading liquid reach the incubation pool 26 for incubation, and the carrier in the loading liquid is combined with the extraction target such as exosome in the sample liquid. The sample liquid and the loading liquid are then released from the incubation pool 26 to the carrier filtration pool 27 by rotating centrifugation clockwise or counterclockwise, and the carrier and the extraction target bound thereto are retained by the carrier filtration membrane 271 through the carrier filtration membrane 271. Then the eluent is released to the carrier filter tank 27 by rotating and centrifuging in the direction opposite to the previous step, the extracted target object is separated from the carrier under the action of the eluent by the carrier filter membrane 271, and then the eluent is collected to obtain the extracted target object. The invention can achieve the purpose of rapidly extracting the exosome by only one-time sample adding of the centrifugal microfluidic chip 200 and controlling the rotation of the chip, and can conveniently apply the extracted exosome at the later stage. The extraction process adopting the centrifugal microfluidic chip 200 is simple and convenient to operate, the extraction speed is high, the efficiency is high, the reagent dosage is low, the amount of the exosome obtained by extraction is large, the defects that the traditional extraction mode is complicated in operation, multiple times of sample adding and sample changing are needed, the consumed time is long and the like are overcome, the consumption of the reagent can be saved, the extraction time is shortened, and the extraction cost is reduced.

It can be understood that the center of the centrifugal microfluidic chip 200 is a rotation mounting portion, and the rotation center of the centrifugal microfluidic chip 200 is the rotation center during centrifugal operation. It will be appreciated that the extraction target may be captured on the carrier by coupling with a target capture substance, such that the extraction target and carrier are retained by the carrier filter 271, and the elution fluid may dissociate the extraction target from the carrier in the sample fluid, such that it is washed into the target reservoir 60.

Optionally, the centrifugal microfluidic chip 200 is substantially circular, and includes two extraction mechanisms uniformly distributed around the center of the circle, so that 2 samples can be extracted at the same time, and the centrifugal microfluidic chip is suitable for various liquid samples such as whole blood, plasma, saliva and the like. Of course, in other embodiments, the centrifugal microfluidic chip 200 may have other shapes, such as rectangular, polygonal, and so on. The number of extraction mechanisms on the microfluidic chip 200 can also be one, two, four, five, seven, and so on.

In a specific example, the sample introduction unit comprises a sample introduction hole 11 and a sample cell 10, the sample introduction hole 11 is connected with the sample cell 10 for inputting a sample liquid into the sample cell 10, and the sample cell 10 is used for storing the sample liquid.

In one particular example, the enrichment unit includes a target reservoir 60 and a waste reservoir 70 connected to the carrier filtration tank 27, respectively, the target reservoir 60 for collecting the extracted target from the carrier filtration tank 27 and the waste reservoir 70 for collecting the waste liquid from the carrier filtration tank 27. Preferably, the object tank 60 and the waste liquid tank 70 are provided on both sides of the carrier filtration tank 27 in the rotation direction, respectively, i.e., one on the clockwise side of the outlet of the carrier filtration tank 27 and the other on the counterclockwise side of the outlet of the carrier filtration tank 27.

In a specific example, the capture and release unit further comprises a separation pool 21, the sample pool 10 is connected with the incubation pool 26 through the separation pool 21, and the separation pool 21 and the incubation pool 26 of the sample pool 10 are sequentially distributed from the proximal end to the distal end of the rotation center. Thus, when whole blood or the like is used as the sample liquid, the sample liquid can be released to the separation cell 21, the whole blood is separated into plasma (close to the rotation center side) in the separation cell 21 by centrifugation, and the precipitate of blood cells or the like is located at the side far from the rotation center, which is beneficial to preventing the blood cells or the like from entering the incubation cell 26, and improves the extraction efficiency and sensitivity.

In a specific example, the separation tank 21 includes a first chamber, a connecting portion, and a second chamber, the first chamber is connected to the second chamber through the connecting portion, and the inner diameter of the connecting portion is smaller than the inner diameters of the first chamber and the second chamber, and the first chamber, the connecting portion, and the second chamber are sequentially distributed from the proximal end to the distal end. Thus, the separation tank 21 is composed of an upper chamber and a lower chamber, and the middle chamber is in a necking shape, which is beneficial to quantitative control of the first chamber (i.e. the upper chamber close to the rotation center), reduces the loss amount of plasma, and can effectively ensure that blood cells in the second chamber (i.e. the second chamber far from the rotation center) do not flow to the downstream, that is, if the necking design is not made, the interface between the upper part of plasma (near the rotation center) and the lower part of blood cells (far from the rotation center) after centrifugation is very large, and if 50 μ L of plasma is quantitatively taken from the upper part of the plasma, the outlet position of the separation tank 21 needs to be as close to the rotation center as possible to be far from the interface between the plasma and the blood cells, so as to prevent blood cells from being taken, and then there will. In addition, since the interface is large, the interface is unstable, and the amount of extraction may increase. Preferably, the downstream chamber is connected to a connection to the separation cell 21 to better bring the separated plasma to a subsequent extraction separation process. Alternatively, the sample cell 10 has a capacity of 140 μ L to 200 μ L, and the first chamber has a capacity of 50 μ L.

In a specific example, from the proximal end to the distal end of the rotation center, the capturing and releasing unit further includes a diluent pool 22 and a dilution and mixing pool 23 for loading the sample diluent, the diluent pool 22 is connected with the dilution and mixing pool 23, and the separation pool 21 is connected with the incubation pool 26 through the dilution and mixing pool 23. Therefore, the diluent and the sample liquid can be released to the dilution mixing pool 23 for uniform mixing, and the sample liquid is diluted by the diluent in the diluent pool 22, so as to be better mixed and incubated with the loading liquid later.

In a specific example, the capturing and releasing unit further comprises an impurity filtering tank 24, the diluting and mixing tank 23 is connected with the incubation tank 26 through the impurity filtering tank 24, and an impurity filtering membrane 241 for intercepting impurities is arranged in the impurity filtering tank 24. In this way, the diluted sample solution can be released to the impurity filtering tank 24 and filtered by the impurity filtering membrane 241 to remove impurities such as mixed blood cells, so as to be mixed and incubated with the loading solution better.

Optionally, the pore diameter of the carrier filter film 271 is 0.22 μm, and the pore diameter of the impurity filter film 241 is 4-6 μm. It will be appreciated that the carrier particle size is larger than the pore size of the carrier filter film 271.

In a specific example, the capturing and releasing unit further comprises a buffer pool 29, the eluent pool 28 is connected with the carrier filter pool 27 through the buffer pool 29, and the eluent pool 28, the buffer pool 29 and the carrier filter pool 27 are sequentially distributed from the proximal end to the distal end of the rotation center. In this manner, by providing the buffer tank 29 between the eluent tank 28 and the carrier filtration tank 27, the fluid process control capability can be enhanced.

In one specific example, the capture and release unit further includes a remaining sample cell 30, and the remaining sample cell 30 is connected to one end of the separation cell 21 near the rotation center. Thus, when the sample solution is added to the sample cell 10 and centrifuged, the excess sample solution enters the remaining sample cell 30 beside the sample cell, thereby preventing the sample solution from being excessive.

In a specific example, the capture and release unit further comprises a flow direction selection tank 31, the target tank 60 and the waste liquid tank 70 are respectively connected with the outlet of the carrier filtration tank 27 through the flow direction selection tank 31, and the liquid flows from the carrier filtration tank 2 to the flow direction selection tank 31 and then flows from the flow direction selection tank 31 to the target tank 60 or the waste liquid tank 70. In this way, the liquid passes through the carrier filtration tank 27 and reaches the selection tank 31, and then flows to the object tank 60 or the waste liquid tank 70 better depending on the rotation direction of the centrifuge.

In one specific example, the carrier filter tank 27 has a membrane front inlet portion and a membrane rear outlet portion, a membrane placing groove is formed in a bottom wall between the membrane front inlet portion and the membrane rear outlet portion, and the carrier filter membrane 271 is embedded in the membrane placing groove, thereby facilitating effective stabilization of the filter membrane. Optionally, the impurity filtering tank 24 also has a membrane front inlet portion and a membrane rear outlet portion, a membrane placing groove is formed in the bottom wall between the membrane front inlet portion and the membrane rear outlet portion, and the impurity filtering membrane 241 is embedded in the membrane placing groove. Optionally, the carrier filter film 271 and the impurity filter film 241 are both attached to the hard substrate and embedded in the film placing groove together with the hard substrate, so that the problems of thin and easy deformation of the filter film can be overcome, the operation is simple, and the filter film is effectively and stably placed in the flow path. Optionally, the depth (chip thickness direction) of the film front inlet part and the film rear outlet part is 0.1mm to 7.8mm, the depth of the film groove is 0.2mm to 7.8mm, and the width of the film groove is 0.2mm to 5 mm.

In a specific example, the separation cell 21 is connected with the dilution and mixing cell 23 through a first channel 101, the diluent cell 22 is connected with the dilution and mixing cell 23 through a second channel 102, the loading cell 25 is connected with the incubation cell 26 through a third channel 103, the eluent cell 28 is connected with the buffer cell 29 through a fourth channel 104, the buffer cell 29 is connected with the carrier filtration cell 27 through a fifth channel 105, and the incubation cell 26 is connected with the carrier filtration cell 27 through a sixth channel 106. Therefore, during high-speed centrifugation, the centrifugal force is large and is greater than the capillary force, the channel cannot be filled with sample liquid, the siphonage cannot be triggered, and when the centrifugal force is reduced within a proper range, the capillary force is greater than the centrifugal force to trigger the siphonage, so that the flow of the liquid can be controlled through centrifugation.

In a specific example, the first channel 101, the second channel 102, the third channel 103, the fourth channel 104, the fifth channel 105 and the sixth channel 106 are all alternately bent towards the rotation center and the edge of the centrifugal microfluidic chip 200, thereby forming one or more inverted U-shaped structures, and the second channel 102, the third channel 103, the fourth channel 104 and the fifth channel 105 are provided with capillary valves at each section extending towards the rotation center. It will be appreciated that the location where each channel is bent towards the edge of the microfluidic chip 200 is closer to the centre of rotation than the chamber upstream thereof. Alternatively, the depth (chip thickness direction) of each channel may be 0.2mm, the shape of the capillary valve may be circular, square or various polygons, the diameter is 1.5mm, and the depth (chip thickness direction) may be 0.5 mm.

In the embodiment shown in fig. 1, the first channel 101, the second channel 102, the third channel 103, the fifth channel 105 and the sixth channel 106 are bent toward the rotation center 1 time, that is, 1 inverted U-shaped structure is formed, respectively, and the fourth channel 104 is bent toward the rotation center 2 times, that is, two inverted U-shaped structures are formed. The fourth channel 104 adopts two-stage bending and is matched with a buffer tank 29 to realize the process control of the fluid time domain, namely, the time of delaying the fluid flowing into the carrier filter tank 27. The reason why two-stage bending is adopted to match with one buffer pool 29 in the embodiment is as follows: (1) if three-stage bending is adopted, the overall design is simple, but the defect is that the bending structure mainly depends on the matching of the capillary force of the channel and the centrifugal force to realize the functionalization, but when the flow path is longer, for example, the three-stage bending structure is difficult to ensure that the capillary force plays a role each time, and the surface property (hydrophilicity) of the channel is slightly changed, the function of a valve cannot be realized; (2) if one-level bending is adopted to match with the two buffer pools, the design structure of the chip becomes complicated, and the two buffer pools need more spatial layouts. Therefore, on the premise of ensuring the effectiveness of the capillary valve, only two-stage bending design is selected, and the two-stage bending design is matched with one buffer pool to realize fluid time domain control, so that the distributed sample adding process is completed.

Preferably, the bent portion of the first channel 101 is located on the clockwise side of the separation cell 21, and the bent portion of the second channel 102 is located on the clockwise side of the diluent cell 22. In this way, the diluent reservoir 22 can be better synchronized with the separation reservoir 21, i.e. the plasma is taken out of the separation reservoir 21 by rotating it counterclockwise, and the solution in the diluent reservoir 22 flows out simultaneously.

In a specific example, the centrifugal microfluidic chip 200 has a rotation hole 201 formed at the center thereof for being sleeved on a centrifugal rotation shaft of a centrifugal instrument, thereby facilitating the centrifugation of the centrifugal microfluidic chip 200. Optionally, the loading liquid pool 25, the eluent liquid pool 28 and the diluent liquid pool 22 are provided with corresponding sample adding holes so as to add corresponding solutions. Alternatively, the centrifugal microfluidic chip 200 may be processed by CNC, laser engraving, soft lithography, 3D printing, and injection molding, but is not limited thereto.

In a specific example, the centrifugal microfluidic chip 200 includes a bottom plate and a top plate, wherein the bottom plate is provided with a corresponding sample cell 10, a loading liquid cell 25, an incubation cell 26, a carrier filter cell 27, an eluent cell 28, a target cell 60, a waste liquid cell 70, a separation cell 21, a diluent cell 22, a dilution mixing cell 23, an impurity filter cell 24, a residual sample cell 30, a buffer cell 29, and the like, the depth (in the thickness direction of the chip) of the sample cell can be 2mm, and two chambers connected with each other are connected by a microchannel. In addition, as shown in FIG. 2, the top plate is provided with a fixing groove 202 corresponding to the membrane placing groove, so that the filter membrane is better sealed and fixed when the top plate and the bottom plate are attached.

The method for extracting exosomes according to an embodiment of the present invention, using the centrifugal microfluidic chip 200, includes the following steps:

adding the sample liquid to a sample introduction unit; controlling the rotating speed of the centrifugal microfluidic chip to enable the sample liquid to pass through the capture and release unit and enable the exosomes in the sample liquid to be captured;

the exosomes captured by the capture release unit are released to the enrichment unit.

In one specific example, the step of controlling the rotational speed of the centrifugal microfluidic chip 200 comprises:

(1) controlling the centrifugal microfluidic chip 200 to centrifuge at a first speed to enable the sample liquid to flow from the sample cell 10 into the separation cell 21;

(2) controlling the centrifugal microfluidic chip 200 to centrifuge at a second speed in a direction opposite to the direction in the step (1), starting the centrifuge clockwise after stopping rotation until the centrifugal speed reaches a third speed, then starting the centrifuge anticlockwise until the centrifugal speed reaches the third speed, stopping the centrifugation and standing, enabling the liquid in the separation tank 21 and the liquid in the diluent tank 22 to flow into the dilution mixing tank 23 to be mixed and flow into the impurity filtering tank 24, and then flow into the incubation tank 26 through the impurity filtering membrane 241, and enabling the liquid in the loading liquid tank 25 to flow into the incubation tank 26 to be mixed with the filtered liquid;

(3) controlling the centrifugal microfluidic chip 200 to centrifuge at a fourth speed in the same direction as the centrifugal microfluidic chip in the step (1), so that the liquid in the incubation pool 26 flows into the carrier filter pool 27 and reaches the waste liquid pool 70 through the carrier filter membrane 271, the carrier is intercepted, and meanwhile, the liquid in the eluent pool 28 flows into the buffer pool 29;

(4) and (3) controlling the centrifugal microfluidic chip 200 to centrifuge at a fourth speed in the direction opposite to the step (1), so that the liquid in the buffer tank 29 flows into the carrier filter tank 27 and reaches the target object tank 60 through the carrier filter membrane 271.

In one particular example, the first speed is higher than the second speed, the second speed is higher than the third speed, and the fourth speed is higher than the third speed. Preferably, the first speed is 4000-7000 rpm, the second speed is 3000-5000 rpm, the third speed is 1500-4000 rpm, and the fourth speed is 7000-9000 rpm. Preferably, the centrifugation time of step (1) is 10 s-3 min, the centrifugation time of step (2) is 5 s-2 min, the centrifugation time of step (3) is 10 s-1 min, and the centrifugation time of step (4) is 10 s-1 min.

Specifically, an example of a method for extracting exosomes from whole blood is as follows:

first, the sample cell 10 is filled with whole blood, the diluent cell 22 is filled with PBS solution (due to the presence of the capillary valve on the second channel 102, the PBS solution fills the flow path between the capillary valve and the diluent cell 22 only by capillary force), the loading cell 25 is filled with carrier liquid (due to the presence of the capillary valve on the third channel, the loading liquid fills the flow path between the capillary valve and the loading cell 25 only by capillary force), and the eluent cell 28 is filled with eluent (due to the presence of the capillary valve on the fourth channel, the eluent fills the flow path between the first downstream capillary valve and the eluent cell 28 only by capillary force).

Then, as shown in the section 0 to t1 in fig. 3, the centrifugal microfluidic chip 200 is controlled to rotate clockwise 5000 rpm for 1min and then stops, the whole blood solution flows into the separation cell 21 from the sample cell 10, the surplus whole blood flows into the residual sample cell 30, and plasma is obtained by separation in the separation cell 21, the plasma is located in a first chamber of the separation cell 21 close to the rotation center, and a second chamber far away from the rotation center is filled with blood cells, white blood cells and the like. Meanwhile, in high-speed rotation, one capillary valve on the second channel 102, the third channel 103 and the fourth channel 104 breaks through, and when the centrifugal chip stops rotating, the middle flow paths of the two capillary valves of the second channel 102, the third channel 103 and the fourth channel 104 are filled under the action of capillary force.

Then, as shown in the section t 2-t 4 in fig. 3, the centrifuge is started, the control chip stops rotating after rotating for 1min at 4000 rpm anticlockwise, starts to start forward to reach 3000 rpm and then stops decelerating, and starts to accelerate backward to 3000 rpm and then stops decelerating. During the high-speed rotation process, the plasma in the separation pool 21 flows into the dilution mixing pool 23 under the action of siphon force, is mixed with the PBS diluent solution flowing out of the diluent pool 22 in the dilution mixing pool 23 and flows into the impurity filtering pool 24, the mixed solution passes through the membrane and then enters the incubation pool 26 to stay, the carrier liquid in the loading liquid pool 25 also flows into the incubation pool 26 to be mixed with the diluted plasma solution, and the plasma and the carrier liquid are incubated completely during the mixing process.

Then, as shown at t5 to t6 in FIG. 3, the chip rotation is stopped after the completion of the mixing, and the mixture is left to stand for a while, at this time, the sixth channel 106 is filled with the mixture by the capillary force, and the fourth channel 104 is completely filled with the eluent. The chip is started and stopped after rotating for 30s at 8000 rpm, and the mixed solution in the incubation pool 26 flows through the carrier filter film 271 and is selected to enter the waste solution pool 70 in the flow direction selection pool 31. Meanwhile, under high-speed rotation, the eluent in the eluent pool 28 flows into the buffer pool 29 and breaks through the capillary valve on the fifth channel 105, and after stopping for a period of time, the eluent in the buffer pool 29 fills the fifth channel 105.

Then, as shown at t 7-t 8 in FIG. 3, the chip is started and stopped after rotating at 8000 rpm for 30s, and the eluent in the buffer pool 29 flows through the carrier filter membrane 271 and is selected to enter the target pool 60 in the flow direction selection pool 31.

Through experimental tests, about 95 μ L of sample collection liquid is finally obtained in the target object pool 60 by eluting with 100 μ L of eluent. The sample solution was subjected to NTA (nanoparticle Tracking analysis) to track exosomes at a particle size of around 110nm and an exosome concentration of 3E +6 per ml as shown in FIG. 4. The sample solution was examined by electron microscopy (SEM), and the exosome electron micrographs were observed under different visual fields as shown in fig. 5 and 6.

The method for extracting the exosome adopts the centrifugal microfluidic chip 200, realizes the quick extraction of the exosome by controlling the rotation of the chip, can achieve the purpose of extracting the exosome only by once sample adding, and can conveniently apply the extracted exosome at the later stage. The extraction process adopting the centrifugal microfluidic chip 200 is simple and convenient to operate, the extraction speed is high, the efficiency is high, the reagent dosage is low, the amount of the exosome obtained by extraction is large, the defects that the traditional extraction mode is complicated in operation, multiple times of sample adding and sample changing are needed, the consumed time is long and the like are overcome, the consumption of the reagent can be saved, the extraction time is shortened, and the extraction cost is reduced.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.