CN221268157U - Microfluidic device and support - Google Patents

Abstract

The utility model relates to a microfluidic device and a bracket, which are used for filtering whole blood, and comprise a body, a filtering mechanism arranged in the body and a collecting tank communicated with the filtering mechanism, wherein the filtering mechanism is used for filtering red blood cells, and the collecting tank is used for collecting plasma and further comprises: and the driving mechanism is used for driving the sample in the body to move from the side where the filtering mechanism is positioned to the side where the collecting tank is positioned. The driving mechanism can increase the flow speed of the sample, thereby increasing the whole blood filtering speed, shortening the whole blood separation time and reducing the possibility of hemolysis. The microfluidic device provided by the embodiment can obtain plasma without depending on a centrifugal machine, and has the advantages of small volume and simple operation.

Description

Microfluidic device and support

Technical Field

The utility model relates to the technical field of biology, in particular to a microfluidic device and a bracket.

Background

The biochemical detection of human blood can provide important information reflecting the health condition of human body. The samples for human blood testing in clinic are mostly blood plasma, and the extraction of blood plasma mostly depends on additional equipment such as a centrifuge and the like. Most of centrifuge equipment is large in volume and inconvenient to carry, so that the detection sites are limited, time is wasted, and rapid detection of diseases is not facilitated.

Among the prior art, the microfluidic device for whole blood filtration can solve above-mentioned technical problem, and current microfluidic device includes the body, and sets up whole blood separating mechanism, stock solution chamber and the liquid outlet on the chip body, and whole blood separating mechanism is used for obtaining plasma with blood filtration separation, and the stock solution chamber sets up between whole blood separating mechanism and liquid outlet to make the plasma inflow liquid outlet of separation.

However, the existing microfluidic devices have a slow whole blood filtration rate due to the capillary action of the microfluidic devices to allow plasma to flow.

In addition, in the prior art, red blood cells are often filtered through a micro-column array, and the whole blood moves slowly in the micro-column array, so that hemolysis often occurs, and the detection result is inaccurate. In addition, after the whole blood is filtered, air bubbles are present in the plasma, which is detrimental to the detection of the plasma sample.

Disclosure of utility model

An object of the present utility model is to provide a microfluidic device, which solves at least one of the above problems.

To achieve the above object, a first aspect of the present utility model provides a microfluidic device for whole blood filtration, including a body, a filtering mechanism disposed in the body, and a collecting tank in communication with the filtering mechanism, the filtering mechanism being for filtering red blood cells, the collecting tank being disposed in the body and being for collecting plasma, further comprising:

And the driving mechanism is used for driving the sample in the body to move from the side where the filtering mechanism is positioned to the side where the collecting tank is positioned.

Optionally, the driving mechanism is used for introducing compressed air into the filtering mechanism to drive the sample in the body to move towards the collecting tank.

Optionally, the driving mechanism is disposed at a side of the filtering mechanism away from the collecting tank.

Optionally, a driving cavity with an opening is formed on the body, the driving cavity is communicated with the filtering mechanism, the driving mechanism comprises a deformable membrane, and the deformable membrane covers the opening.

Optionally, the driving mechanism further includes a restoring driving member, where the restoring driving member is disposed in the driving cavity and is capable of driving the deformable film to restore the deformation.

Optionally, the restoring driving member is an elastic member.

Optionally, the elastic element is at least one of a sponge, a shrapnel and a spring.

Optionally, the driving mechanism comprises a suction member for creating a vacuum environment for the collection trough.

Optionally, the air pumping piece is an air pump or a syringe.

Optionally, offer on the body and hold the chamber, filter structure set up in hold the chamber, filtering mechanism includes the prefilter portion, the prefilter portion can backstop and adsorb partial erythrocyte.

Optionally, the primary filtration section comprises a filtration membrane.

Optionally, a flow guiding structure for guiding the sample is arranged at the bottom of the accommodating cavity.

Optionally, the body is last seted up with the notes liquid mouth that holds the chamber intercommunication, the water conservancy diversion structure includes buffer zone and filtration district, at least part the buffer zone with annotate the liquid mouth and set up relatively, the prefilter portion set up in filtration district upside.

Optionally, the buffer zone is disposed on a side of the filtration zone remote from the collection tank.

Optionally, the flow guiding structure includes a first flow guiding structure, and the first flow guiding structure is used for enabling the sample to flow to the side where the collecting tank is located.

Optionally, the first water conservancy diversion structure includes a plurality of first water conservancy diversion posts that the interval set up, first water conservancy diversion post connect in hold the chamber bottom in chamber, first water conservancy diversion post is followed filtering mechanism with the direction that the collecting vat set gradually extends.

Optionally, the flow guiding structure further includes a second flow guiding structure, in a first direction, at least one side of the first flow guiding structure is provided with the second flow guiding structure, the first direction is perpendicular to a direction in which the filtering mechanism and the collecting tank are sequentially arranged, and a thickness direction of the microfluidic device, and the second flow guiding structure is used for enabling the sample to flow towards the side where the first flow guiding structure is located.

Optionally, the second diversion structures are disposed on two sides of the first diversion structure along the first direction.

Optionally, the second flow guiding structure includes a plurality of second flow guiding columns that the interval set up, the second flow guiding column connect in hold the chamber bottom in chamber, the second flow guiding column extends along the first direction.

Optionally, the bottom of the accommodating cavity is connected with a first supporting part, and the first supporting part is used for supporting the primary filtering part, so that a first gap is formed between the primary filtering part and the flow guiding structure.

Optionally, a limiting part is further disposed in the accommodating cavity, and the limiting part is disposed on one side of the primary filtering part and is used for limiting the primary filtering part to move towards the buffer zone.

Optionally, the filtering mechanism further comprises a re-filtering part, wherein the re-filtering part is arranged at the downstream of the primary filtering part and is used for filtering red blood cells of the sample.

Optionally, a side of the re-filtering portion adjacent to the primary filtering portion is curved or broken line.

Optionally, the re-filtering part includes a first filtering area, and the first filtering area includes a plurality of first microcolumns arranged in an array.

Optionally, the re-filtering part further includes a second filtering area disposed downstream of the first filtering area, and the second filtering area includes a plurality of second microcolumns arranged in an array.

Optionally, the spacing between two adjacent first micropillars is greater than the spacing between two adjacent second micropillars, and/or the cross-sectional area of the first micropillars is greater than the cross-sectional area of the second micropillars.

Optionally, the distance between two adjacent second micropillars is 0.5 micrometers-2 micrometers; and/or, the distance between two adjacent first micropillars is 1 micrometers to 1.2 micrometers; and/or the maximum dimension at the cross section of the first microcolumn is 10 micrometers to 1000 micrometers; and/or the largest dimension at the cross section of the second microcolumn is 10 micrometers to 500 micrometers.

Optionally, a drainage part is further arranged between the primary filtering part and the secondary filtering part, and the drainage part is used for enabling the sample to flow from the primary filtering part to the side where the secondary filtering part is located.

Optionally, the drainage part is arranged at the bottom of the accommodating cavity;

Or the drainage part and the cavity bottom of the accommodating cavity are provided with a second gap, and/or the drainage part and the primary filtering part are of an integrated structure.

Optionally, when the drainage portion and the bottom of the accommodating cavity have a second gap, the body further includes a second supporting portion, where the second supporting portion is connected to the bottom of the accommodating cavity, and the second supporting portion is used to make the drainage portion and the bottom of the accommodating cavity have the second gap.

Optionally, the containment chamber tapers in size along the upstream side of the sample flow to the downstream side.

Optionally, a capillary channel is further arranged between the filtering mechanism and the collecting tank, and the capillary channel is used for enabling the blood plasma to flow into the collecting tank from the filtering mechanism.

Optionally, an antifoaming mechanism is disposed in the capillary channel, and the antifoaming mechanism is used for eliminating bubbles in plasma.

Optionally, the defoaming mechanism includes a plurality of blocking posts spaced along the length direction of the capillary channel, the blocking posts extending along the width direction of the capillary channel, the blocking posts and the top wall of the capillary channel having a third gap for passing plasma, the width direction of the capillary channel having a first side wall and a second side wall;

One end of the baffle column is connected with the first side wall, and the other end of the baffle column is connected with the second side wall; or (b)

The baffle column comprises a first baffle column and a second baffle column, one end of the first baffle column is connected with the first side wall of the capillary channel, and the other end of the first baffle column is spaced from the second side wall; the second baffle columns are connected with the second side wall of the capillary channel, the other end of the second baffle columns is spaced from the first side wall, and the first baffle columns and the second baffle columns are arranged in a staggered mode.

Optionally, one end of the defoaming mechanism, which is close to the collecting tank, is provided with a confluence notch.

Optionally, an accelerating mechanism for accelerating the blood plasma is further arranged in the capillary channel, and the accelerating mechanism is arranged at the downstream of the defoaming mechanism.

Optionally, the accelerating mechanism includes a plurality of third microcolumns arranged at intervals, the third microcolumns are connected to the bottom wall of the capillary channel, and the surface of the third microcolumns is provided with hydrophilic substances.

Optionally, the outlet end of the capillary channel is disposed obliquely downward.

Optionally, the body further comprises a sealing piece, and the sealing piece is used for closing or opening the liquid injection port.

Optionally, the body includes base member and lid, set up the holding tank on the base member, the lid is located the base member is in order to form hold the chamber.

Optionally, the cover body is single-sided adhesive tape.

Optionally, the surface of the collecting tank is provided with a hydrophilic layer.

Another object of the present utility model is to provide a microfluidic device, which solves one of the above-mentioned problems.

To achieve the object, the second aspect of the present utility model adopts the following technical scheme:

The support is used for enabling the microfluidic device to be placed at an acute angle or a right angle with the horizontal plane, and enabling the side of the collecting tank to be lower than the side of the filtering mechanism.

Optionally, the bracket includes:

A bottom plate;

at least one upright post, the lower end of which is connected with the bottom plate;

The inclined plate is connected to the bottom plate and is arranged at an included angle with the horizontal plane, one end of the microfluidic device, provided with the collecting groove, is abutted to the inclined plate, and the other end of the microfluidic device is abutted to the top end of the upright post.

Therefore, according to the technical scheme provided by the utility model, the driving mechanism can improve the flow speed of the sample, so that the whole blood filtering speed is improved, the whole blood separation time is shortened, and the possibility of hemolysis is reduced. The microfluidic device provided by the embodiment can obtain plasma without depending on a centrifugal machine, and has the advantages of small volume and simple operation.

The primary filter unit and the secondary filter unit cooperate to rapidly filter whole blood to obtain plasma. Wherein, the primary filter part can filter most red blood cells, so the sample can flow into the secondary filter part quickly, and the concentration of the sample can flow in the secondary filter part quickly due to the reduction of the concentration of the sample (because part of red blood cells are filtered by the primary filter part), so that the flow speed of the sample at the secondary filter part is improved, the whole blood separation time is shortened, and hemolysis is avoided.

And a defoaming mechanism is arranged in the capillary channel and is used for eliminating bubbles in blood plasma.

The microfluidic device is provided with a capillary channel, so that the flow of plasma is accelerated, and the separation time of whole blood is shortened; the outlet end of the capillary channel is obliquely arranged to form a backflow prevention pipeline for preventing the backflow of blood plasma.

Drawings

Fig. 1 is a schematic structural diagram of a first microfluidic device according to an embodiment of the present utility model;

Fig. 2 is an exploded view of a first microfluidic device according to an embodiment of the present utility model;

Fig. 3 is a schematic view of a portion of a first microfluidic device according to an embodiment of the present disclosure;

fig. 4 is a schematic structural diagram of a second microfluidic device according to an embodiment of the present utility model;

fig. 5 is a schematic diagram of a portion of a first microfluidic device according to an embodiment of the present utility model;

Fig. 6 is a cross-sectional view of a first microfluidic device provided by an embodiment of the present utility model;

FIG. 7 is a partial enlarged view at D in FIG. 6;

FIG. 8 is an enlarged view of a portion of FIG. 3 at A;

Fig. 9 is an exploded view of a second microfluidic device provided in an embodiment of the present utility model;

FIG. 10 is an enlarged view of a portion of FIG. 9 at E;

fig. 11 is a partial enlarged view at G in fig. 9;

fig. 12 is a partial enlarged view at B in fig. 4;

FIG. 13 is a schematic view of a structure of a bracket according to an embodiment of the present utility model;

fig. 14 is a schematic structural diagram of a rack-supported microfluidic device according to an embodiment of the present utility model;

fig. 15 is a schematic diagram of a second structure of a support-supported microfluidic device according to an embodiment of the present utility model.

In the figure:

1. A body; 11. a base; 111. a receiving chamber; 1111. a second subslot; 12. a cover body; 121. a through port; 122. a liquid injection port; 13. a drive chamber; 131. a driving groove; 14. a support bar; 15. a first support portion; 151. a support column; 16. a limit part; 17. a sealing member; 18. a communication groove; 19. a second supporting part;

2. A filtering mechanism; 21. a filtering membrane; 22. a re-filtering section; 221. a first filtration zone; 2211. a first microcolumn; 222. a second filtration zone; 2221. a second microcolumn; 23. a curve; 24. a folding line; 25. a first gap; 26. a second gap;

3. A capillary channel; 31. an outlet end; 32. a defoaming mechanism; 321. a baffle column; 322. a first stopper; 323. a second barrier post; 324. a confluence slit; 33. a first sidewall; 34. a second sidewall; 35. an acceleration mechanism; 351. a third microcolumn;

4. a driving mechanism; 41. a deformable membrane; 42. a sponge;

5. A flow guiding structure; 51. a first flow guiding structure; 511. a first flow directing column; 512. a first diversion trench; 52. a second flow guiding structure; 521. a second flow guiding column; 522. a second diversion trench; 53. a buffer area; 54. a filtration zone;

6. a collection tank;

100. A microfluidic device; 200. a bracket; 201. a bottom plate; 202. a column; 203. a sloping plate;

W, a first direction; l, the second direction; t, third direction.

Detailed Description

The technical scheme of the utility model is further described below by the specific embodiments with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are merely illustrative of the utility model and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the drawings related to the present utility model are shown.

In the present utility model, directional terms such as "upper", "lower", "left", "right", "inner" and "outer" are used for convenience of understanding, and thus do not limit the scope of the present utility model unless otherwise specified.

In the present utility model, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

In the description of the present utility model, unless explicitly stated and limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

The present embodiment provides a microfluidic device 100 for whole blood filtration, such as separating blood plasma from red blood cells in whole blood, and collecting the blood plasma to increase the separation speed of the blood plasma, but is not limited thereto, and can be used for separating other substances to be detected.

As shown in fig. 1-2, the microfluidic device 100 provided in this embodiment includes a body 1, a filtering mechanism 2 disposed in the body 1, and a collecting tank 6 in communication with the filtering mechanism 2, wherein the filtering mechanism 2 is used for filtering red blood cells to obtain plasma, and the collecting tank 6 is disposed in the body 1 and is used for collecting plasma.

Alternatively, in order to accommodate the sample and the filter mechanism 2, the body 1 is provided with an accommodating chamber 111, the sample can be injected into the accommodating chamber 111, and the filter mechanism 2 can be disposed in the accommodating chamber 111. It is understood that the sample in this embodiment may be whole blood, whole blood with some red blood cells filtered, or plasma, and those skilled in the art will understand the meaning of the sample according to the actual situation.

Specifically, as shown in fig. 2, the body 1 is provided with a filling port 122 communicating with the accommodating chamber 111, and a filling gun can penetrate through the filling port 122 to inject whole blood into the accommodating chamber 111. Preferably, the priming port 122 is positioned directly opposite the filter mechanism 2 so that whole blood enters the filter mechanism 2 directly.

Alternatively, the body 1 includes a base 11 and a cover 12, the base 11 is provided with a receiving groove, and the cover 12 is covered on the base 11 so as to cover the receiving groove to form the receiving cavity 111. The body 1 of this construction facilitates the processing of the accommodation chamber 111.

As shown in fig. 2, and in combination with fig. 1, the collection tank 6 is illustratively provided on the base 11 and is uncovered by the cover 12.

Optionally, the cover 12 is a single-sided adhesive, such as a pressure sensitive adhesive, and the cover 12 is connected to the body 1 by way of adhesion, and the cover 12 may facilitate processing of the microfluidic device 100, and may make the microfluidic device 100 small in size due to the small thickness of the pressure sensitive adhesive.

Optionally, the liquid injection port 122 is opened on the pressure sensitive adhesive. To seal the pouring spout 122, the body 1 may further comprise a closing member 17, the closing member 17 being adapted to close or open the pouring spout 122. The sealing member 17 is preferably a sticker that can be adhered to the body 1. The decal is small in thickness and relatively soft so that it can be better adhered to the pressure sensitive adhesive.

As shown in fig. 1 and 2, for convenience of description, a first direction W, a second direction L, and a third direction T are defined in this embodiment, where the first direction W, the second direction L, and the third direction T are perpendicular to each other, the third direction T is a thickness direction of the microfluidic device 100, and the second direction L is a setting direction of the filtering mechanism 2 and the collecting tank 6, that is, an overall flow direction of the sample is consistent with the second direction L. Illustratively, the first direction W coincides with the length direction of the microfluidic device 100 and the second direction L coincides with the width direction of the microfluidic device 100.

As shown in fig. 2, after the sample is injected into the accommodating cavity 111, in order to increase the downstream flow speed of the sample, optionally, a flow guiding structure 5 for guiding the sample is disposed at the bottom of the accommodating cavity 111, and the flow guiding structure 5 can guide the sample to flow in a preset direction, so as to increase the flow speed of the sample.

As shown in fig. 2, the flow guiding structure 5 comprises a buffer zone 53 and a filtering zone 54, at least part of the buffer zone 53 is arranged opposite to the liquid filling port 122, the filtering zone 54 is arranged opposite to at least part of the filtering mechanism 2, and optionally at least part of the filtering mechanism 2 is located on the upper side of the filtering zone 54. That is, the filter mechanism 2 is not arranged in the accommodating cavity 111 at the position opposite to the liquid injection port 122, so that the plasma can be rapidly dispersed into the accommodating cavity 111, and the plasma is prevented from overflowing from the liquid injection port 122. Meanwhile, the buffer zone 53 of the flow guiding structure 5 can guide whole blood to rapidly enter the filtering zone 54 provided with the filtering mechanism 2 and be adsorbed by the filtering membrane 21 positioned on the upper side of the filtering zone 54.

Preferably, the buffer zone 53 is disposed on a side of the filtering zone 54 away from the collection tank 6, so that after the sample enters the accommodating chamber 111, the whole sample flows along the second direction L, shortening the whole blood filtering time.

As shown in fig. 2, a limiting portion 16 is further disposed in the accommodating chamber 111, and the limiting portion 16 is disposed on one side of the filter mechanism 2 (specifically, a filter membrane 21 described below) and is used to limit the movement of the filter mechanism 2 (specifically, the filter membrane 21 described below) to the buffer zone 53, so as to ensure the buffering effect of the buffer zone 53. Specifically, the stopper 16 is connected to the bottom of the accommodating chamber 111. The stopper 16 may be a portion of a cylinder extending in the first direction W (i.e., the width direction of the accommodation chamber 111), and the tension between the surface of the cylinder and the sample is small, thereby reducing the residual amount of the sample on the stopper 16.

Referring to fig. 3 and 4, the flow guiding structure 5 includes a first flow guiding structure 51, and the first flow guiding structure 51 is used for enabling the sample to flow to the side of the collecting tank 6, so as to accelerate the flow speed of the sample along the second direction L.

Specifically, the first flow guiding structure 51 includes a plurality of first flow guiding columns 511 disposed at intervals, the first flow guiding columns 511 are connected to the bottom of the accommodating cavity 111, the first flow guiding columns 511 extend along the direction (i.e. the second direction L, i.e. the length direction of the microfluidic device 100) in which the filtering mechanism 2 and the collecting tank 6 are sequentially disposed, a first flow guiding groove 512 is formed between two adjacent first flow guiding columns 511, and the sample can flow along the first flow guiding groove 512.

The flow guiding structure 5 further comprises a second flow guiding structure 52, and in the first direction W, the second flow guiding structure 52 is disposed on at least one side of the first flow guiding structure 51, that is, the first flow guiding structure 51 and the second flow guiding structure 52 are disposed along the first direction W, and the second flow guiding structure 52 is used for making the sample flow to the side where the first flow guiding structure 51 is located. The second flow guiding structure 52 may concentrate the sample in the middle of the accommodating chamber 111 in the first direction W (i.e., the width direction of the accommodating chamber 111), thereby accelerating the flow velocity of the sample. In particular, when the sample amount in the accommodating cavity 111 is smaller, the second flow guiding structure 52 can guide the sample located at the edge to the middle of the accommodating cavity 111, so as to reduce the residual amount of the sample in the accommodating cavity 111.

Preferably, the first flow guiding structure 51 is provided with second flow guiding structures 52 on both sides in the first direction W, thereby further concentrating the sample in the middle of the receiving chamber 111.

Specifically, the second flow guiding structure 52 includes a plurality of second flow guiding columns 521 disposed at intervals, the second flow guiding columns 521 are connected to the bottom of the accommodating cavity 111, and the second flow guiding columns 521 extend along the first direction W, so that a second flow guiding groove 522 is formed between two adjacent second flow guiding columns 521, and the sample can flow along the second flow guiding groove 522 to the first flow guiding structure 51.

Optionally, the first flow post 511 and the second flow post 521 are part of a cylinder, and the tension between the surface of the cylinder and the sample is small, so as to reduce the residual amount of the sample on the first flow post 511 and the second flow post.

As shown in fig. 2 and 5, the filter mechanism 2 includes a primary filter section capable of stopping and adsorbing a portion of red blood cells. When whole blood drips into and holds chamber 111, contains more red blood cells, and plasma can pass through the prefilter earlier, and the prefilter can filter partial red blood cells, and the prefilter can reduce the quantity of red blood cells in the sample through the physical adsorption effect on the one hand, has reduced the mechanical damage of red blood cells to reduce hemolysis probability. On the other hand, the primary filtering part plays a role of blood chromatography and transports blood into the micro-channel.

Optionally, the primary filtering portion includes a filtering membrane 21, and the water absorption of the filtering membrane 21 is higher than that of the flow guiding structure 5, so that whole blood is absorbed onto the filtering membrane 21 from the flow guiding structure 5, and most of red blood cells in the whole blood are blocked by the filtering membrane 21, so that the primary filtering sample, and the rest of the sample (containing plasma and part of red blood cells) continues to flow forward (i.e. downstream, i.e. on the side of the collecting tank 6). The filter membrane 21 may be a glass fiber filter membrane, a polyethersulfone filter membrane, a polytetrafluoroethylene filter membrane, or the like. Optionally, the filter membrane 21 may also be modified with a red blood cell trap, e.g., the red blood cell trap may be lectin, to prevent red blood cells from re-exiting the filter membrane 21.

Preferably, the filter membrane 21 is disposed above the filter zone 54.

As shown in fig. 4 and fig. 6 to fig. 7, the bottom of the accommodating chamber 111 is connected to a first supporting portion 15, and the first supporting portion 15 is used for supporting the filtering membrane 21, so that a first gap 25 is formed between the filtering membrane 21 and the flow guiding structure 5. In this embodiment, the filtering membrane 21 is substantially parallel to the flow guiding mechanism 5, and a first gap 25 is formed between the filtering membrane 21 and the flow guiding mechanism 5, and the first gap 25 serves to buffer whole blood and prevent the blood from overflowing.

Optionally, the first supporting portion 15 includes a plurality of supporting columns 151 disposed at intervals, and the supporting columns 151 are connected to the bottom of the accommodating cavity 111 and located at the first guiding structure 51. Still further, the first support 15 is located at the filtering section 54. Illustratively, the number of the support columns 151 is three, and the three support columns 151 are respectively located at three vertex angles of the triangle, thereby well supporting the filtering membrane 21. The support column 151 may be a cylinder.

To better support the filtering membrane 21, the body 1 may further include a support bar 14, the support bar 14 being connected to the bottom of the receiving chamber 111. Alternatively, both ends in the width direction of the cavity bottom of the accommodation cavity 111 are provided with the support bars 14, thereby avoiding influence on the sample flow.

To increase the flow rate of the sample, the filter means 2 may optionally further comprise a drainage portion arranged downstream of the primary filter portion for allowing the sample to flow from the filter membrane 21 to the side of the collection tank 6. It will be appreciated that a drain is also provided within the receiving chamber 111.

As shown in fig. 5 and 7, in the present embodiment, the second gap 26 is formed between the drainage portion and the bottom of the accommodating cavity 111, preferably, the drainage portion and the primary filtering portion are integrally formed, and the sample of the primary filtering portion directly flows onto the drainage portion, that is, a part of the filtering membrane 21 forms the drainage portion, but here, the main function of the filtering membrane 21 is not to filter the sample, but to drain the sample by capillary action and chromatographic action, so as to increase the flow rate of the sample.

As shown in fig. 3, 5 and 7, optionally, the body 1 further includes a second supporting portion 19, where the second supporting portion 19 is connected to the bottom of the accommodating cavity 111, and the second supporting portion 19 is used to make the filtering membrane 21 (i.e. the drainage portion) have a second gap 26 with the bottom of the accommodating cavity 111, so that the flowing effect of the sample can be better, and meanwhile, the filtering membrane 21 (i.e. the drainage portion) is prevented from contacting the bottom of the accommodating cavity 111, so that the sample is prevented from remaining at the bottom. The second support 19 may be a ring-shaped structure, and illustratively, the ring-shaped structure is a trapezoid, and further, the ring-shaped structure is an isosceles trapezoid, and the second support 19 is connected to a sidewall of the receiving chamber 111, thereby supporting an edge portion of the filtering membrane 21 (i.e., the drainage portion) and avoiding sample residue.

Of course, in other alternative embodiments, the drainage portion is provided at the bottom of the accommodating chamber 111, in which case the second support portion 19 may not be provided, but the drainage portion may be placed directly on the bottom. In this case, the drainage portion and the filtration membrane 21 may be integrally formed or may be separately formed.

As shown in fig. 4, the housing chamber 111 gradually decreases in size along the upstream side to the downstream side of the sample flow. More specifically, the cross section of the receiving chamber 111 corresponding to the flow guiding structure 5 and the flow guiding portion is isosceles trapezoid, and the lower bottom of the isosceles trapezoid is located upstream of the upper bottom, so that the sample gradually gathers toward the middle of the first direction W of the filtering membrane 21, and preparation is made for filtering the sample again.

As shown in fig. 3, 8 and 9 to 10, in order to filter out the sample again, the filtering mechanism 2 further includes a re-filtering portion 22, and the re-filtering portion 22 is disposed downstream of the filtering membrane 21 and is used to filter out the red blood cells of the sample. Downstream of the re-filtration section 22 may also include capillary channels 3. Illustratively, the primary filter portion, the drainage portion, the secondary filter portion 22, the collection tank 6 and the capillary channel 3 are disposed in this order along the second direction L. The primary filter unit receives most of the red blood cells, the drainage unit causes the sample to flow from the primary filter unit to the secondary filter unit 22, the secondary filter unit 22 filters the residual red blood cells, and the capillary channel 3 is used to flow the plasma from the secondary filter unit 22 into the collection tank 6, and the collection tank 6 collects the plasma.

As shown in fig. 9, to more clearly show the positional relationship among the primary filter portion, the drainage portion, and the secondary filter portion 22, the accommodating groove is divided into a first sub-groove in which the guide structure 5, the primary filter portion, the stopper portion 16, the first support portion 15, and the support bar 14 are disposed, the drainage portion and the second support portion 19 are disposed in the second sub-groove 1111, and the secondary filter portion 22 is disposed in the third sub-groove in which the first sub-groove, the second sub-groove 1111, and the third sub-groove are disposed in this order along the second direction L. Alternatively, the depth of the second subslot 1111 is greater than the depth of the third subslot, such that the filtering membrane 21 is defined between the limiting portion 16 and the sidewall of the second subslot 1111, preventing the filtering membrane 21 from being displaced in the second direction L.

As shown in fig. 8 and 10, the size of the re-filtering portion 22 gradually decreases along the upstream side to the downstream side of the sample flow to guide the sample to flow into the capillary channel 3.

As shown in fig. 8 and 10, the side of the re-filtering part 22 adjacent to the filtering membrane 21, that is, the side of the re-filtering part 22 adjacent to the filtering membrane 21 is a fold line 24 (as shown in fig. 8) or a curve 23 (as shown in fig. 10), so that the sample can flow to the re-filtering part 22.

Optionally, the re-filtering part 22 includes a first filtering area 221, and the first filtering area 221 includes a plurality of first micro-columns 2211 arranged in an array to re-filter the red blood cells through the plurality of first micro-columns 2211 arranged at intervals.

The re-filtering portion 22 further includes a second filtering area 222 disposed downstream of the first filtering area 221, and the second filtering area 222 includes a plurality of second micro-columns 2221 arranged in an array so as to re-pass red blood cells through the plurality of second micro-columns 2221 disposed at intervals.

The spacing between adjacent two first micro-pillars 2211 is greater than the spacing between adjacent two second micro-pillars 2221, and/or the cross-sectional area of the first micro-pillars 2211 is greater than the cross-sectional area of the second micro-pillars 2221. The present embodiment further filters red blood cells through an array of micropillars of different pitch sizes and/or micropillars of different sizes.

Optionally, the spacing between two adjacent second micropillars 2221 is 0.5 micrometers-2 micrometers; and/or, the spacing between two adjacent first micropillars 2211 is 1 micrometer to 1.2 micrometers; and/or, the largest dimension at the cross-section of the first micropillars 2211 is 10 micrometers to 1000 micrometers; and/or the largest dimension at the cross section of the second micropillar 2221 is 10 micrometers-500 micrometers.

The shape of the first micro-column 2211 and/or the second micro-column 2221 includes, but is not limited to, at least one of a cylinder, a cube, a cuboid, a prism.

In this embodiment, the primary filter unit and the secondary filter unit 22 cooperate to rapidly filter whole blood to obtain plasma. Wherein, the primary filter part filters most of the red blood cells, so that the sample can rapidly flow into the secondary filter part 22, and the secondary filter part 22 further filters the red blood cells by the steric hindrance of the microcolumn (i.e., the first filter region 221 and the second filter region 222) to avoid hemolysis.

As shown in fig. 9, optionally, a capillary channel 3 is provided between the filter means 2 and the collection tank 6, the capillary channel 3 being used for letting plasma flow from the filter means 2 into the collection tank 6. The capillary channel 3 can accelerate the blood plasma flow through capillary action, improve the filtering speed and shorten the whole blood separation time.

As shown in fig. 11, the outlet end 31 of the capillary channel 3 is inclined downward, so that the distance between the bottom wall at the outlet end 31 of the capillary channel 3 and the cover 12 increases, to allow air to circulate between the inside of the capillary channel 3 and the accommodation chamber 111 and the collection tank 6 during the inflow of plasma into the collection tank 6.

As shown in fig. 9, the capillary channel 3 extends in the second direction L, and the length direction of the capillary channel 3 coincides with the second direction L, and the width direction of the capillary channel 3 coincides with the first direction W, as an example. It is understood that the capillary channel 3 is not limited to extend in the second direction L, but may be a curved channel, and the width direction of the capillary channel 3 is perpendicular to both the flow direction of the plasma in the capillary channel 3 and the thickness direction of the microfluidic device 100, and thus, is not limited to coincide with the first direction W.

In the process of filtering whole blood and in the process of fast flow of plasma, bubbles exist in the plasma due to the flow of the whole blood and the like, which is unfavorable for detecting the plasma sample, and in order to eliminate the bubbles in the plasma, as shown in fig. 8 and 12, a defoaming mechanism 32 is optionally arranged in the capillary channel 3, and the defoaming mechanism 32 is used for eliminating the bubbles in the plasma. Still further, the defoaming mechanism 32 is located at an end upstream of the capillary channel 3.

The defoaming mechanism 32 may include a plurality of blocking posts 321 disposed at intervals along the length direction of the capillary channel 3, the blocking posts 321 extending along the width direction (i.e., the first direction W) of the capillary channel 3, the blocking posts 321 and the top wall of the capillary channel 3 having a third gap for passing plasma, i.e., a third gap between the blocking posts 321 and the cover 12, and the capillary channel 3 having a first side wall 33 and a second side wall 34 in the width direction.

As shown in fig. 8, in the present embodiment, the stopper 321 includes a first stopper 322 and a second stopper 323, one end of the first stopper 322 is connected to the first side wall 33 of the capillary passage 3, and the other end is spaced from the second side wall 34; the second barrier 323 is connected to the second sidewall 34 of the capillary passage 3, and the other end is spaced apart from the first sidewall 33, and the first barrier 322 and the second barrier 323 are alternately arranged.

When the amount of plasma in the capillary passage 3 is small, the plasma slowly flows forward in the space formed between the first barrier 322 and the second barrier 323, between the first barrier 322 and the second side wall 34, and between the second barrier 323 and the first side wall 33, i.e., the trajectory of the plasma flow is substantially serpentine, which is equivalent to slowing down the plasma flow velocity, thereby reducing the bubbles generated during the rapid plasma flow.

When the amount of plasma in the capillary passage 3 is large, since the first barrier column 322 and the second barrier column 323 are of a cross column structure, the forward direction of the plasma is blocked, and when the plasma is gathered to a height higher than the first barrier column 322 (or the second barrier column 323), the plasma flows to the next second barrier column 323 (or the first barrier column 322), which is equivalent to slowing down the flow speed of the plasma, thereby reducing the bubbles generated in the rapid flow process of the plasma.

In another alternative embodiment, as shown in fig. 12, the barrier 321 does not include the first barrier 322 and the second barrier 323, but rather, one end of the barrier 321 is connected to the first sidewall 33 and the other end is connected to the second sidewall 34, the barrier 321 and the top wall of the capillary channel 3 have a third gap for passing the plasma, the plasma passes through the third gap, the barrier 321 is in a cross-pillar structure (i.e., extends along the width direction of the capillary channel 3 along the barrier 321), the forward direction of the plasma is blocked, and when the plasma gathers to a higher level than the barrier 321, the plasma flows to the next barrier 321, which is equivalent to slowing down the plasma flow rate, thereby reducing the bubbles generated during the rapid plasma flow.

Alternatively, the post 321 is a rectangular solid post 321, which breaks the bubble more easily when the edge comes into contact with the bubble. The shape of the stopper 321 is not limited thereto, and may be a hexahedral, pentahedral, or other polygonal column or cylinder, etc.

As shown in fig. 8 and 12, the defoaming mechanism 32 is provided with a confluence slit 324 at one end near the collecting tank 6, that is, the confluence slit 324 is provided at one end downstream of the defoaming mechanism 32, so that the flow speed can be increased and the amount of plasma remaining on the substrate 11 can be reduced when the plasma is gathered and flows forward again and the plasma flows forward as a whole.

Alternatively, the dimension of the confluence slit 324 in the width direction (i.e., the first direction W) of the capillary passage 3 is gradually increased from the upstream side to the downstream side, and the confluence slit 324 is exemplified as a triangular slit.

As shown in fig. 12, an acceleration mechanism 35 for accelerating plasma is further provided in the capillary passage 3, and the acceleration mechanism 35 is provided downstream of the defoaming mechanism 32. The acceleration mechanism 35 can increase the flow rate of plasma and thereby shorten the whole blood separation time.

Illustratively, the accelerating mechanism 35 includes a plurality of third microcolumns 351 disposed at intervals, the third microcolumns 351 being connected to the bottom wall of the capillary channel 3, the surface of the third microcolumns 351 having a hydrophilic substance. The third microcolumn 351 may increase a surface area in contact with plasma, and the surface of the third microcolumn 351 is covered with a hydrophilic substance having a hydrophilic group, so that when plasma is in contact with the hydrophilic group, the plasma is subjected to an attractive force, which pushes the plasma to flow forward, thereby shortening a whole blood separation time.

Alternatively, the third microcolumns 351 are arranged in an array, and the third microcolumns 351 may be cylinders having a diameter of 30 micrometers to 1000 micrometers, and a distance between two adjacent third microcolumns 351 is 20 micrometers to 1500 micrometers.

Of course, as shown in fig. 5, the acceleration mechanism 35 may not be provided.

As shown in fig. 1 and 2, the microfluidic device 100 provided in this embodiment further includes a driving mechanism 4, where the driving mechanism 4 is used to drive the sample in the body 1 to move from the side of the filtering mechanism 2 to the side of the collecting tank 6. The driving mechanism 4 can increase the flow speed of the sample, thereby increasing the whole blood filtering speed, shortening the whole blood separation time and reducing the possibility of hemolysis. The microfluidic device 100 provided in this embodiment can obtain plasma without depending on a centrifuge, and has a small device size and simple operation. In an alternative embodiment, the drive mechanism 4, the filter mechanism 2 and the collecting tank 6 are arranged in sequence in the second direction L.

Optionally, the drive mechanism 4 is used to introduce compressed air into the filter mechanism 2 to drive the sample within the body 1 towards the collection well 6. The driving mechanism 4 increases the pressure at the filtering mechanism 2 by introducing compressed air into the filtering mechanism 2, thereby pushing the sample at the filtering mechanism 2 to move to the side of the collecting tank 6.

Further, the driving mechanism 4 is provided at a side of the filtering mechanism 2 away from the collecting tank 6, and is used for driving the sample in the body 1 to move toward the collecting tank 6. By arranging the drive mechanism 4 on the side of the filter mechanism 2 remote from the collecting tank 6, the compressed air can push the sample on the side of the filter mechanism 2 remote from the collecting tank 6, i.e. apply a force to the sample towards the collecting tank 6 side, thereby increasing the downstream flow speed of the sample.

It will be appreciated that the sample flows from the side of the filter means 2 to the side of the collection tank 6, and therefore the sample flows upstream and downstream, with the filter means 2 being located upstream of the collection tank 6 as illustrated.

As shown in fig. 2, the body 1 is provided with a driving cavity 13 with an opening, illustratively, the base 11 is provided with a driving groove 131, the cover 12 is provided with a through hole 121 opposite to the driving groove 131, the cover 12 is covered on the base 11, and the driving groove 131 is communicated with the through hole 121 to form the driving cavity 13. The driving mechanism 4 includes a deformable film 41, and the deformable film 41 covers the opening, thereby sealing the opening.

The drive chamber 13 communicates with the filter mechanism 2, i.e. the drive chamber 13 communicates with the space in which the filter mechanism 2 is located. By pressing the deformable membrane 41, the deformable membrane 41 moves into the driving cavity 13, so that air in the driving cavity 13 is compressed, the pressure in the driving cavity 13 is increased, and then the compressed air in the driving cavity 13 enters the filtering mechanism 2, so that a sample in the filtering mechanism 2 is driven to move towards the collecting tank 6.

Alternatively, the deformable film 41 is an elastic film, and the material of the elastic film may be selected from polyethylene film, polypropylene film, polyvinyl chloride film, PDMS film, thermoplastic polyurethane elastomer rubber film (i.e., TPU film), and the like.

As shown in fig. 2, in order to communicate the drive chamber 13 with the housing chamber 111, that is, to communicate the drive chamber 13 with the filter mechanism 2, the base 11 is provided with a communication groove 18, and the notch of the communication groove 18 is sealed by the cover 12. Illustratively, the bottom of the communication groove 18 is higher than the bottom of the receiving chamber 111 to avoid the sample in the receiving chamber 111 from flowing from the communication groove 18 into the driving chamber 13.

To allow the deformable membrane 41 to resume deformation, the driving mechanism 4 optionally further comprises a resume driving member that is provided to the driving chamber 13 and is capable of driving the deformable membrane 41 to resume deformation. Preferably, the restoring driving member is an elastic member, and when the deformable membrane 41 is pressed, the elastic member is compressed, and the elastic member restores the deformation under the action of restoring force by releasing the deformable membrane 41, and brings the deformable membrane 41 into restoring deformation. The elastic member is illustratively a sponge 42, although in other alternative embodiments, the elastic member may be a dome, a spring, or at least two of the sponge 42, dome, spring.

In this embodiment, when the deformable wall resumes its deformation, air enters the microfluidic device 100 from the capillary channel 3 due to the inclined arrangement of the outlet end 31 of the capillary channel 3, thereby preventing the plasma in the collection tank 6 from being sucked back, i.e. the outlet end 31 of the capillary channel 3 forms an anti-reflux channel.

In alternative embodiments, as shown in fig. 9, the drive mechanism 4 may not be of the construction described above, but the drive mechanism 4 may comprise a suction member for creating a vacuum environment for the collection trough 6. It is understood that the vacuum environment refers to a gaseous state in which the pressure of the collection tank 6 is lower than one atmosphere, and since the pressure in the filter mechanism 2 is not lower than one atmosphere, the sample of the filter mechanism 2 can automatically flow into the collection tank 6. Alternatively, the air extracting member may be an air pump or a syringe, and an air inlet end of the air pump or an air inlet end of the syringe is covered at a notch of the collecting tank 6 in a sealing manner, so that part of air in the collecting tank 6 is extracted, and a vacuum environment is formed in the collecting tank 6.

To make the collection tank 6 easier to collect plasma, the surface of the collection tank 6 is provided with a hydrophilic layer, such as the surface of the collection tank 6 is coated with a hydrophilic agent or a hydrophilic coating is cured by ultraviolet light, or the surface of the collection tank 6 is subjected to plasma hydrophilic treatment to make the surface more hydrophilic, and the plasma automatically flows into the plasma collection tank 6 without an air pump.

Illustratively, the process of filtering whole blood using the microfluidic device 100 provided by the present embodiment is as follows:

1. Opening the sealing piece 17, enabling the liquid injection gun to pass through the liquid injection opening 122 so as to inject whole blood into the accommodating cavity 111, enabling the whole blood to enter the buffer zone 53 of the flow guiding structure 5, and covering the sealing piece 17 again after liquid injection is finished;

2. The drive mechanism 4 operates to accelerate the flow of whole blood;

3. the sample passes through the filter membrane 21, the first filter zone 221, the second filter zone 222 and the capillary channel 3 in this order, and finally flows into the collection tank 6.

As shown in fig. 13-15, the present embodiment further provides a support 200 adapted to the microfluidic device 100, where the support 200 is used to place the microfluidic device 100 at an acute angle or a right angle to the horizontal, and the side of the collection tank 6 is lower than the side of the filtering mechanism 2. The rack 200 may further increase the flow rate of the sample within the microfluidic device 100 under the force of gravity, thereby further shortening the whole blood separation time.

Optionally, the support 200 includes a bottom plate 201, an inclined plate 203 and at least one upright 202, the lower end of the upright 202 is connected to the bottom plate 201, the inclined plate 203 is connected to the bottom plate 201 and forms an included angle with the horizontal plane, preferably, the inclined plate 203 is inclined towards the side where the upright 202 is located, one end of the microfluidic device 100, where the collecting tank 6 is disposed, is abutted to the inclined plate 203, and the other end of the microfluidic device 100 is abutted to the top end of the upright 202, so that the collecting tank 6 is lower than the filtering mechanism 2. The support 200 provided in this embodiment has a simple structure and is convenient for supporting the microfluidic device 100.

Alternatively, a plurality of columns 202 may be disposed at intervals along a direction in which the inclined plate 203 extends, so that a plurality of microfluidic devices 100 may be supported at the same time, and illustratively, the inclined plate 203 extends along the first direction W, and a plurality of columns 202 are disposed at intervals along the first direction W.

The present embodiment also provides a plasma separation method adapted to the microfluidic device 100 and the rack 200 described above, for separating plasma from whole blood by gravity induction and capillary action. Illustratively, during whole blood filtration, the microfluidic device 100 is tilted with the collection tank 6 below the filtration mechanism 2, achieving gravity induction. The filter membrane 21 and the capillary channel 3 perform capillary action.

While the utility model has been described in detail in the foregoing general description, embodiments and experiments, it will be apparent to those skilled in the art that modifications and improvements can be made thereto. Accordingly, such modifications or improvements may be made without departing from the spirit of the utility model and are intended to be within the scope of the utility model as claimed.

Claims (41)

1. A micro-fluidic device for whole blood filters, including body (1), set up in filtering mechanism (2) in body (1) and with collecting vat (6) of filtering mechanism (2) intercommunication, filtering mechanism (2) are used for filtering red blood cells, collecting vat (6) set up in body (1) to be used for collecting plasma, its characterized in that still includes:

The driving mechanism (4) is used for driving the sample in the body (1) to move from the side where the filtering mechanism (2) is positioned to the side where the collecting tank (6) is positioned;

The body (1) is provided with a containing cavity (111), and the bottom of the containing cavity (111) is provided with a flow guiding structure (5) for guiding a sample;

The flow guiding structure (5) comprises a first flow guiding structure (51), and the first flow guiding structure (51) is used for enabling a sample to flow to the side where the collecting groove (6) is located;

The flow guiding structure (5) further comprises a second flow guiding structure (52), the second flow guiding structure (52) is arranged on at least one side of the first flow guiding structure (51) in a first direction (W), the first direction (W) is perpendicular to the direction in which the filtering mechanism (2) and the collecting tank (6) are sequentially arranged and the thickness direction of the microfluidic device, and the second flow guiding structure (52) is used for enabling a sample to flow towards the side where the first flow guiding structure (51) is located.

2. The microfluidic device according to claim 1, wherein the drive mechanism (4) is adapted to introduce compressed air into the filter mechanism (2) to drive the sample within the body (1) towards the collection well (6).

3. Microfluidic device according to claim 2, characterized in that the drive mechanism (4) is arranged at the side of the filter mechanism (2) remote from the collection tank (6).

4. A microfluidic device according to claim 2 or 3, characterized in that the body (1) is provided with a drive chamber (13) having an opening, the drive chamber (13) being in communication with the filter means (2), the drive means (4) comprising a deformable membrane (41), the deformable membrane (41) covering the opening.

5. The microfluidic device according to claim 4, wherein the driving mechanism (4) further comprises a restoring driver arranged in the driving chamber (13) and capable of driving the deformable membrane (41) to restore deformation.

6. The microfluidic device of claim 5, wherein the recovery driver is an elastic member.

7. The microfluidic device of claim 6, wherein the elastic member is at least one of a sponge (42), a shrapnel, and a spring.

8. Microfluidic device according to claim 1, characterized in that the drive mechanism (4) comprises a suction element for creating a vacuum environment for the collection tank (6).

9. The microfluidic device of claim 8, wherein the air extraction member is an air pump or a syringe.

10. The microfluidic device according to claim 1, wherein the filter means (2) is arranged in the receiving chamber (111), the filter means (2) comprising a primary filter portion capable of stopping and adsorbing part of the erythrocytes.

11. The microfluidic device according to claim 10, wherein the primary filter portion comprises a filter membrane (21).

12. The microfluidic device according to claim 11, wherein the body (1) is provided with a liquid injection port (122) communicated with the accommodating cavity (111), the flow guiding structure (5) comprises a buffer area (53) and a filtering area (54), at least part of the buffer area (53) is arranged opposite to the liquid injection port (122), and the primary filtering part is arranged on the upper side of the filtering area (54).

13. Microfluidic device according to claim 12, characterized in that the buffer zone (53) is arranged at the side of the filtration zone (54) remote from the collection tank (6).

14. The microfluidic device according to claim 1, wherein the first flow guiding structure (51) comprises a plurality of first flow guiding columns (511) arranged at intervals, the first flow guiding columns (511) are connected to the cavity bottom of the accommodating cavity (111), and the first flow guiding columns (511) extend along the direction in which the filtering mechanism (2) and the collecting tank (6) are arranged in sequence.

15. The microfluidic device according to claim 1, wherein the first flow guiding structure (51) is provided with the second flow guiding structure (52) along both sides of the first direction (W).

16. The microfluidic device according to claim 1, wherein the second flow guiding structure (52) comprises a plurality of second flow guiding posts (521) arranged at intervals, the second flow guiding posts (521) being connected to the bottom of the receiving cavity (111), the second flow guiding posts (521) extending along the first direction (W).

17. Microfluidic device according to claim 12 or 13, characterized in that the bottom of the receiving chamber (111) is connected with a first support (15), the first support (15) being adapted to support the primary filter so that there is a first gap (25) between the primary filter and the flow guiding structure (5).

18. The microfluidic device according to claim 12, wherein a limiting portion (16) is further provided in the accommodating chamber (111), the limiting portion (16) being provided at one side of the prefilter portion and being configured to limit movement of the prefilter portion toward the buffer region (53).

19. The microfluidic device according to any one of claims 10-13, wherein the filtering means (2) further comprises a re-filtering portion (22), the re-filtering portion (22) being arranged downstream of the primary filtering portion and being adapted to filter erythrocytes of the sample.

20. The microfluidic device according to claim 19, wherein the side of the re-filtration section (22) adjacent to the primary filtration section is curved (23) or broken line (24).

21. The microfluidic device according to claim 19, wherein the re-filtration section (22) comprises a first filtration zone (221), the first filtration zone (221) comprising a plurality of first micro-columns (2211) arranged in an array.

22. The microfluidic device according to claim 21, wherein the re-filtration section (22) further comprises a second filtration zone (222) disposed downstream of the first filtration zone (221), the second filtration zone (222) comprising a plurality of second micropillars (2221) arranged in an array.

23. The microfluidic device according to claim 22, wherein a spacing between two adjacent first micropillars (2211) is larger than a spacing between two adjacent second micropillars (2221), and/or a cross-sectional area of the first micropillars (2211) is larger than a cross-sectional area of the second micropillars (2221).

24. The microfluidic device according to claim 22, wherein a pitch of two adjacent second micropillars (2221) is 0.5-2 microns; and/or, the distance between two adjacent first micropillars (2211) is 1 micrometers-1.2 micrometers; and/or the maximum dimension at the cross section of the first micropillar (2211) is 10 micrometers to 1000 micrometers; and/or the largest dimension at the cross section of the second micropillar (2221) is 10 micrometers to 500 micrometers.

25. The microfluidic device according to claim 19, wherein a drainage portion is further provided between the primary filter portion and the re-filter portion (22), the drainage portion being adapted to allow a sample to flow from the primary filter portion to the side of the re-filter portion (22).

26. The microfluidic device according to claim 25, wherein the drainage portion is provided at a cavity bottom of the receiving cavity (111);

or the drainage part and the cavity bottom of the accommodating cavity (111) are provided with a second gap (26), and/or the drainage part and the primary filtering part are of an integrated structure.

27. The microfluidic device according to claim 26, wherein when the drainage portion and the bottom of the receiving chamber (111) have a second gap (26), the body (1) further comprises a second support portion (19), the second support portion (19) being connected to the bottom of the receiving chamber (111), the second support portion (19) being adapted to have the drainage portion and the bottom of the receiving chamber (111) having the second gap (26).

28. Microfluidic device according to any of claims 10-13, characterized in that the receiving chamber (111) tapers in size along the upstream side of the sample flow to the downstream side.

29. Microfluidic device according to anyone of claims 1-3, 8-13, characterized in that a capillary channel (3) is further provided between the filter means (2) and the collection tank (6), the capillary channel (3) being adapted for letting plasma flow from the filter means (2) into the collection tank (6).

30. Microfluidic device according to claim 29, characterized in that a defoaming mechanism (32) is arranged in the capillary channel (3), the defoaming mechanism (32) being used for eliminating bubbles in the plasma.

31. The microfluidic device according to claim 30, wherein the defoaming mechanism (32) comprises a plurality of blocking posts (321) arranged at intervals along the length direction of the capillary channel (3), the blocking posts (321) extending along the width direction of the capillary channel (3), the blocking posts (321) having a third gap with the top wall of the capillary channel (3) for passing plasma, the capillary channel (3) having a first side wall (33) and a second side wall (34) in the width direction;

one end of the baffle post (321) is connected with the first side wall (33), and the other end of the baffle post is connected with the second side wall (34); or (b)

The baffle column (321) comprises a first baffle column (322) and a second baffle column (323), one end of the first baffle column (322) is connected with the first side wall (33) of the capillary channel (3), and the other end of the first baffle column is spaced from the second side wall (34); the second baffle columns (323) are connected with the second side wall (34) of the capillary channel (3), the other end of the second baffle columns is spaced from the first side wall (33), and the first baffle columns (322) and the second baffle columns (323) are arranged in a staggered mode.

32. The microfluidic device according to claim 30, wherein the defoaming mechanism (32) is provided with a confluence slit (324) at an end near the collection tank (6).

33. Microfluidic device according to claim 30, characterized in that an acceleration mechanism (35) for accelerating the plasma is further arranged in the capillary channel (3), which acceleration mechanism (35) is arranged downstream of the defoaming mechanism (32).

34. The microfluidic device according to claim 33, wherein the acceleration mechanism (35) comprises a plurality of third micro-pillars (351) arranged at intervals, the third micro-pillars (351) are connected to the bottom wall of the capillary channel (3), and the surface of the third micro-pillars (351) is provided with hydrophilic substances.

35. Microfluidic device according to claim 29, characterized in that the outlet end (31) of the capillary channel (3) is arranged obliquely downwards.

36. The microfluidic device according to claim 12, wherein the body (1) further comprises a closure (17), the closure (17) being adapted to close or open the filling opening (122).

37. The microfluidic device according to any one of claims 10 to 13, wherein the body (1) comprises a base body (11) and a cover body (12), the base body (11) is provided with a containing groove, and the cover body (12) is covered on the base body (11) to form the containing cavity (111).

38. The microfluidic device according to claim 37, wherein the cover (12) is a single sided adhesive tape.

39. Microfluidic device according to any of claims 1-3, 8-13, characterized in that the surface of the collection tank (6) is provided with a hydrophilic layer.

40. A holder adapted for use with a microfluidic device according to any one of claims 1-39, wherein the holder is adapted to place the microfluidic device at an acute or right angle to the horizontal and with the side of the collection trough (6) lower than the side of the filter means (2).

41. The stent of claim 40, wherein the stent comprises:

A bottom plate (201);

-at least one upright (202), the lower end of said upright (202) being connected to said base plate (201);

The inclined plate (203) is connected to the bottom plate (201) and is arranged at an included angle with the horizontal plane, one end of the microfluidic device, provided with the collecting tank (6), is abutted to the inclined plate (203), and the other end of the microfluidic device is abutted to the top end of the upright post (202).