CN210496474U

CN210496474U - Micro-channel device

Info

Publication number: CN210496474U
Application number: CN201920840471.1U
Authority: CN
Inventors: 黄忠谔; 何信呈; 陈圣文; 陈明
Original assignee: Ce Biotechnology Inc
Current assignee: Ce Biotechnology Inc
Priority date: 2019-06-05
Filing date: 2019-06-05
Publication date: 2020-05-12
Anticipated expiration: 2029-06-05

Abstract

A microchannel device includes a lower shell and an upper shell. The lower shell comprises a base wall and two side walls, wherein the base wall is provided with an upper side, a lower side, two outer sides connecting the upper side and the lower side, and convex columns arranged at intervals. Each side wall of the lower shell extends upwards from each outer side of the base wall of the lower shell and is provided with a drainage channel which is sunken downwards from the top edge of each side wall, and each drainage channel extends back to the base wall of the lower shell along the flowing direction of the upstream side to the downstream side. The upper shell covers the lower shell and comprises a base wall and two side walls. The upper casing base wall has an upper and a lower side corresponding to the upper and the lower side of the lower casing base wall and the upper and the lower side of the two sides and the two sides. The side walls of the upper housing extend downwardly from the outer sides of the base wall to engage the side walls of the lower housing. A first gap through which large biological particles can pass is formed between the upper shell base wall and the top edge of the convex column, and a second gap through which small biological particles can pass is formed between the adjacent convex columns. The small biological particles of the liquid sample can settle to the lower shell due to gravity and flow through each drainage channel, so that the blockage is not easy to happen, the large biological particles are only limited to flow to the downstream side of the upper shell, and the sample treatment capacity is large.

Description

Micro-channel device

Technical Field

The present invention relates to a flow channel device, and more particularly to a microfluidic device.

Background

A micro flow channel device is used to supply a liquid sample (e.g. blood) to be measured to flow in its internal microstructure, and is aimed at capturing specific micro biological particles in the liquid sample or separating/filtering biological particles with specific size.

In microfluidics, marker-free isolation of circulating tumor cells from tumor samples (hereinafter referred to as "preamble 1"), disclosed in Nature protocols9, 694-710 (2014), Nezihi Murat Karabacak et al, see technical means related to the separation/filtration of cells of a specific size and the isolation of Circulating Tumor Cells (CTCs) from blood samples. The prior art 1 sequentially uses a Deterministic Lateral Displacement (DLD) program, an inertial focusing (inertial focusing) program and a magnetophoresis (WBC) program to discuss a technique for isolating non-labeled (marker-free) circulating tumor cells from blood samples, wherein 97% yield of rare Circulating Tumor Cells (CTCs) is obtained from blood samples through two stages of magnetophoresis and negative leukocyte enrichment (WBC).

Referring to fig. 1, the prior art 1 discloses a conventional microchannel device 1, which sequentially includes a first microchannel module 11 for executing the DLD procedure, a second microchannel module 12 for sequentially executing the inertial focusing procedure and the magnetophoresis procedure and communicating with the first microchannel module 11, and a pair of magnetic pillars (magnetcolumns) 13 along a flow direction f of a blood sample 8.

The first microchannel module 11 has an inlet channel 111 located on an upstream side 101 of the microchannel device 1, a buffer channel 112, a middle outlet channel 113 between the upstream side 101 and a downstream side 102 of the microchannel device 1, an upstream cell region 114 communicating the inlet channel 111, the buffer channel 112, and the middle outlet channel 113, and a plurality of micro-pillars 115 arranged at intervals in the upstream cell region 114.

The second microchannel module 12 has a microchannel (micro-channel)121, a downstream cell zone 122, a first downstream outlet channel 123, and a second downstream outlet channel 124, which are communicated with each other, in sequence along the flow direction f; the first downstream outlet channel 123 and the second downstream outlet channel 124 are respectively disposed on a first side 103 and a second side 104 of the micro flow channel device 1, which are opposite to each other. Each magnetic pillar 13 is disposed on the corresponding first side 103 and second side 104 of the micro flow channel device 1 respectively to be between the downstream cell regions 122, and the middle outlet flow channel 113 of the first micro flow channel module 11 and the micro channel 121 of the second micro flow channel module 12 are respectively adjacent to the first side 103 and second side 104 of the micro flow channel device 1.

Before the blood sample 8 enters the microchannel device 1 from the inlet channel 111, a pretreatment process is performed on the blood sample 8. The pretreatment procedure is that a plurality of superparamagnetic beads (superparamagnetic beads)81 are combined with two antibodies (antibodies) of CD45 and CD66b, so that the surfaces of the superparamagnetic beads 81 are covered with antibodies of CD45 and CD66 b; subsequently, the blood sample 8 is mixed with the superparamagnetic beads 81 covered with the antibodies CD45 and CD66b, so that the antigen of the leukocyte 82 in the blood sample 8 is bound with the antibodies CD45, CD66b, etc., and the leukocyte 82 is bound with the superparamagnetic beads 81, thereby completing the pretreatment process of the blood sample 8.

When the blood sample 8 after the pretreatment process enters the first microchannel module 11 from the inlet channel 111 of the microchannel device 1, the blood sample 8 is deflected and aggregated cells (e.g., leukocytes 82 and circulating tumor cells 83) by the size-oriented microcolumns 115 disposed in the upstream cell region 114. Specifically, the DLD process executed by the first micro flow channel module 11 utilizes the concept that the hydrodynamic diameter of the cells is smaller than the critical deflection diameter (Dc) of each micro-column 115, so that the cells (e.g., the red blood cell 84 shown in fig. 1) with a size smaller than Dc do not deflect to flow toward the middle outlet channel 113 of the first micro flow channel module 11, and the white blood cell 82 and the circulating tumor cell 83 deflect toward the micro-channel 121 of the second micro flow channel module 12 because their hydrodynamic diameters are larger than Dc.

After the DLD procedure is performed to separate the cells with different sizes, the leukocyte 82 bound with the superparamagnetic beads 81 and the circulating tumor cells 83 not bound with the superparamagnetic beads 81 are along the flow direction f to sequentially perform the inertial focusing procedure and the magnetophoresis procedure in the second micro-channel module 12.

First, the leukocyte 82 bound with the superparamagnetic beads 81 and the circulating tumor cells 83 not bound with the superparamagnetic beads 81 are concentrated in the micro-channel 121 to enter the downstream cell region 122, and are subjected to a magnetic field generated by the pair of magnetic columns 13 while flowing through the downstream cell region 122

Influencing to form magnetophoresis by allowing the white blood cells 82 bound with the superparamagnetic beads 81 to follow the magnetic field

Flows toward the first downstream outlet channel 123, and the circulating tumor cells 83 not bonded with the superparamagnetic beads 81 are not subjected to the magnetic field

Towards the second downstream outlet flow passage 124.

Although the micro flow channel device 1 disclosed in the prior art 1 can separate/filter cells of different sizes in the DLD process performed by the first micro flow channel module 11. However, the micro-column 115 in the upstream cell region 114 of the first microchannel module 11 is a two-dimensional (2D) separation/filtration process, and is capable of processing a small amount of sample per unit time, and is inefficient.

As can be seen from the above description, it is a problem to be overcome by those skilled in the art of the present invention to improve the structure of the micro flow channel device to increase the amount of samples that can be processed per unit time and to improve the separation/filtration efficiency.

Disclosure of Invention

An object of the utility model is to provide a liquid sample handling capacity in the unit interval is big and the good miniflow channel device of filter effect.

The utility model discloses a micro-channel device for the separation contains a plurality of big biological particles and a plurality of size is less than the liquid sample of the little biological particle of big biological particle to catch specific target biological particle, it includes inferior valve and epitheca.

The lower case includes a base wall, and a pair of side walls. The base wall of the lower case has an upstream side, a downstream side far from the upstream side, two outer sides respectively connecting the upstream side and the downstream side, and a plurality of bosses upwardly projecting from the upper surface of the base wall at intervals. Each side wall of the lower shell extends upwards from the corresponding outer side of the base wall to define a lower channel together with the base wall, each side wall of the lower shell is provided with at least one drainage channel which is sunken downwards from the top edge of the corresponding side wall, and each drainage channel extends back to the base wall along the flowing direction from the upstream side to the downstream side.

The upper case covers the lower case and includes a base wall and a pair of side walls. The base wall of the upper shell has an upstream side, a downstream side, and two outer sides corresponding to the upstream side and the downstream side of the base wall of the lower shell, and the two outer sides of the lower shell, respectively. Each side wall of the upper shell extends downwards from the corresponding outer side of the base wall of the upper shell to be connected to the corresponding side wall of the lower shell, and the side walls and the base wall of the upper shell jointly define an upper channel so that the upper channel and the lower channel jointly define a micro-channel.

In the utility model, a first clearance which is enough for the big biological particles to pass through is arranged between the base wall of the upper shell and the top edge of each convex column, and a second clearance which is not enough for the big biological particles to pass through and is enough for the small biological particles to pass through is arranged between every two adjacent convex columns.

The micro-channel device of the utility model has the convex columns, the diameter of each column is larger than 1 μm, the length-diameter ratio is 8: 1.

The utility model discloses a miniflow passage device, the base wall of this inferior valve still have the block rib, and this block rib is protruding to be stretched and be close to the downstream side of the base wall of this inferior valve from the base wall of this inferior valve up, has between the apical margin of this block rib and the base wall of this epitheca and is enough to make the third clearance that the big biological particle passes through, and the size in this third clearance virtually equals this first clearance.

The utility model discloses a miniflow channel device, the projection is distinguished into a plurality of first districts and a plurality of second district, first district with the second district is arranged in turn each other along this flow direction to distribute from the inboard of the basic wall of this inferior valve towards two outsides of this inferior valve along this flow direction, and the height that highly is greater than the projection of each second district of the projection of each first district.

The utility model discloses a miniflow channel device, the base wall of this epitheca still have a plurality of drainage ribs, the drainage rib is along this flow direction interval arrangement each other, and each drainage rib is protruding the stretching downwards from the lower surface of the base wall of this epitheca to extend towards its these two outsides from the inboard of the base wall of this epitheca along this flow direction.

The utility model discloses a miniflow channel device, each lateral wall of this epitheca have an at least drainage way, and each drainage way of this epitheca is sunken up and extend along its basic wall of this flow direction dorsad from the bottom edge of the lateral wall that corresponds separately.

The utility model discloses a miniflow channel device, each projection has a plurality of nanometer hole.

The utility model discloses a miniflow channel device, each projection of the basic wall of this inferior valve have the body that links up the upper surface of its basic wall, and set up and be stained with glutinous coating in the resistance on the body that corresponds separately.

The micro-channel device of the utility model is modified with biotin end groups on each anti-sticky coating.

The utility model discloses a micro-channel device still contains a pair of electrode, and this inferior valve and this epitheca are arranged in to this pair of electrode.

The beneficial effects of the utility model reside in that: when the liquid sample enters the micro flow channel from each upstream side, the small biological particles can be settled to the convex pillars at the lower shell for circulation due to the influence of gravity, so that the settled small biological particles can directly flow through each drainage channel of the lower shell to leave, the blockage problem is not easy to cause, and the large biological particles are only limited to move along the flow direction at the upper channel and capture specific target biological particles, so that the large biological particles directly flow to the downstream side of the upper channel of the upper shell, a larger amount of sample can be processed in unit time, and the efficiency is better.

Drawings

Other features and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments with reference to the accompanying drawings, in which:

FIG. 1 is a schematic top view illustrating a conventional micro flow channel device;

FIG. 2 is an exploded perspective view illustrating a first embodiment of the microchannel device according to the present invention;

FIG. 3 is a perspective view showing the microchannel device according to the first embodiment of the present invention;

FIG. 4 is a partially enlarged perspective view showing a connection relationship between a pair of electrodes, a lower case and an upper case of the micro flow channel device according to the first embodiment of the present invention;

FIG. 5 is a partially enlarged view illustrating an embodiment of the micro flow channel device of the first embodiment of the present invention on a downstream side;

FIG. 6 is a schematic partial side view illustrating a micro flow channel device according to the first embodiment of the present invention, which separates/filters large biological particles from small biological particles on a downstream side;

FIG. 7 is an exploded perspective view illustrating a second embodiment of the microchannel device according to the present invention; and

FIG. 8 is a schematic partial side view illustrating a micro flow channel device according to the second embodiment of the present invention in which separation/filtration of large biological particles and small biological particles is performed on the downstream side.

Detailed Description

Before the present invention is described in detail, it should be noted that in the following description, similar components are denoted by the same reference numerals.

Referring to fig. 2, 3 and 4, a first embodiment of the micro flow channel device of the present invention for separating a liquid sample 9 containing a plurality of large biological particles 91 and a plurality of small biological particles 92 having a size smaller than the large biological particles 91 and capturing the liquid sample for a specific target biological particle includes a lower case 2, an upper case 3, and a pair of electrodes 4 sandwiching the lower case 2 and the upper case 3. It should be noted that the fluid sample 9 may be, for example, blood, lymph, urine, saliva, etc., which may be obtained from an animal subject or a human subject. In the first embodiment of the present invention, blood is taken as an example for explanation, but the present invention is not limited thereto.

The lower case 2 includes a base wall 21, and a pair of side walls 22. The base wall 21 of the lower case 2 has an upstream side 211, a downstream side 212 far from the upstream side 211, two outer sides 213 oppositely disposed and respectively connecting the upstream side 211 and the downstream side 212, and a plurality of protruding columns 215 protruding upward from an upper surface 214 of the base wall 21 at intervals. Preferably, each post 215 has a plurality of nano-scale holes (not shown), which are intended to increase the surface area of each post 215, thereby increasing the probability that each post 215 will contact a particular target biological particle. Preferably, each of the protruding pillars 215 of the base wall 21 of the lower case 2 has a body engaging with the upper surface 214 of the base wall 21, and an anti-sticking coating (not shown) disposed on the corresponding body, and each anti-sticking coating may be polyethylene glycol (PEG), but not limited thereto. In the first embodiment of the present invention, each anti-adhesion coating (not shown) is further modified with a biotin end group combined with streptavidin (streptavidin), so as to become a biotin-terminated polyethylene glycol (biotinylated PEG); the biotin end groups modified on each anti-stiction coating (i.e., polyethylene glycol) can facilitate capture of specific target biological particles. Specifically, the corresponding substance (e.g., biotin end group combined with streptavidin) coated on each of the pillars 215 having the nano-scale holes may act on the specific target biological particles flowing through the pillar 215 and further restrict the movement of the specific target biological particles, so that the specific target biological particles are attached to each of the pillars 215, and each anti-adhesion coating is selected according to the type or characteristics of the specific target biological particles to be captured. The first embodiment of the present invention is described by taking the biotin terminal group to which streptavidin is bonded as an example of the corresponding substance, but the corresponding substance may be a specific antibody, antigen, peptide, protein molecule, or the like, in order to make it easier for a specific target biological particle to be restrained from moving.

Each side wall 22 of the lower casing 2 extends upward from the corresponding outer side 213 of the base wall 21 to define a lower channel 20 together with the base wall 21, each side wall 22 of the lower casing 2 has at least one drainage channel 221 recessed downward from a top edge of the corresponding side wall 22, and each drainage channel 221 extends away from the base wall 21 in a flow direction F from the upstream side 211 toward the downstream side 212.

The upper case 3 covers the lower case 2 and includes a base wall 31 and a pair of side walls 32. The base wall 31 of the upper case 3 has an upstream side 311, a downstream side 312, and two outer sides 313 corresponding to the upstream side 211, the downstream side 212, and the two outer sides 213, respectively, of the base wall 21 of the lower case 2. Each side wall 32 of the upper housing 3 extends downward from the corresponding outer side 313 of the base wall 31 thereof to connect to the corresponding side wall 22 of the lower housing 2, and defines an upper channel 30 together with the base wall 31 thereof, so that the upper channel 30 and the lower channel 20 together define a micro channel C for the liquid sample 9 to flow through. Each side wall 32 of the upper casing 3 has at least one flow guide 321, and each flow guide 321 of the upper casing 3 is upwardly recessed from a bottom edge of the corresponding side wall 32 and extends away from the base wall 31 in the flow direction F like the lower casing 2.

The first embodiment of the present invention is described by taking the case where each side wall 22 of the lower casing 2 has the drainage channel 221 and each side wall 32 of the upper casing 3 has the drainage channel 321 as an example, but it is not limited thereto; that is, the first embodiment of the present invention may also be configured such that only the lower casing 2 has the flow guide 221 or only the upper casing 3 has the flow guide 321. In the first embodiment of the present invention, the number of the drainage channels 221 of the lower casing 2 and the number of the drainage channels 321 of the upper casing 3 are three, and the drainage channels 221 of the lower casing 2 and the drainage channels 321 of the upper casing 3 are arranged at intervals along the flowing direction F.

In addition, referring to fig. 5 and 6, a first gap G1 is formed between the base wall 31 of the upper case 3 and a top edge 2151 of each of the protruding pillars 215, and a second gap G2 is formed between each two adjacent protruding pillars 215, which is insufficient for the large biological particles 91 to pass through and sufficient for the small biological particles 92 to pass through. In the first embodiment of the present invention, the large biological particles 91 in the liquid sample 9 are white blood cells (white blood cells) with a size of 10 μm to 17 μm, and the small biological particles 92 in the liquid sample 9 are red blood cells (red blood cells) with a size of 6 μm to 8 μm, but not limited thereto. Therefore, the first gap G1 and the second gap G2 of the first embodiment of the present invention are between 10 μm and 17 μm and between 6 μm and 8 μm, respectively. In the first embodiment of the present invention, each post 215 is a cylinder, and each cylinder has a diameter greater than 1 μm and has a length to diameter ratio (aspect ratio), each of which is 8: 1. It should be noted that the sizes of the first gap G1 and the second gap G2 of the first embodiment of the present invention are determined by the sizes of the biological particles contained in the liquid sample 9, and the sizes are not limited to the aforementioned sizes.

It should be added here that the anti-sticking coatings (not shown) provided on the bodies of the pillars 215 are intended to prevent the large biological particles 91 in the liquid sample 9 from being caught between the first gaps G1 when the large biological particles 91 travel on the top edges 2151 of the pillars 215, thereby affecting the filtering effect of the large biological particles 91.

Referring again to fig. 1, 5 and 6, preferably, the base wall 21 of the lower housing 2 also has a stop rib 216 for stopping the small biological particles 92 from flowing out of the downstream side 212 of the lower passageway 20. The stopper rib 216 protrudes upward from the base wall 21 of the lower case 2 and is adjacent to the downstream side 212 of the base wall 21 to block the lower passage 20 of the downstream side 212. Specifically, the stopper rib 216 protrudes upward from the downstream side 212 of the base wall 21 of the lower case 2. In the first embodiment of the present invention, a third gap G3 is formed between a top edge 2161 of the stopping rib 216 and the base wall 31 of the upper shell 3, and the size of the third gap G3 is substantially equal to the first gap G1.

More preferably, in the first embodiment of the present invention, the base wall 31 of the upper shell 3 further has a plurality of flow guide ribs 315. The flow-inducing ribs 315 are arranged at intervals along the flow direction F, and each flow-inducing rib 315 protrudes downward from a lower surface 314 of the base wall 31 of the upper casing 3 and extends from an inner side of the base wall 31 of the upper casing 3 toward the two outer sides 313 of the upper casing 3 along the flow direction F. Specifically, in the first embodiment of the present invention, the first gap G1 is defined by the top edge 2151 of each protruding pillar 215 of the base wall 21 of the lower case 2 and a bottom edge of each drainage rib 315 of the base wall 31 of the upper case 3.

More specifically, the upstream side 211 of the base wall 21 of the lower case 2 and the upstream side 311 of the base wall 31 of the upper case 3 are used as an inlet for supplying the liquid sample 9 into the microchannel device according to the first embodiment of the present invention, and the downstream side 212 of the base wall 21 of the lower case 2 and the downstream side 312 of the base wall 31 of the upper case 3 are used as an outlet of the microchannel device according to the first embodiment of the present invention. When the liquid sample 9 containing the large biological particles (e.g., leukocytes) 91 and the small biological particles (e.g., erythrocytes) 92 enters the microchannel C from the respective

upstream sides

211, 311, the small biological particles 92 sink down into the lower channel 20 of the lower casing 2 and travel between the second gaps G2 formed by the adjacent pillars 215 in the flow direction F as they stay in the microchannel C due to the turbulence of the flow guide ribs 315 on the upstream side 311 of the upper casing 3 and the influence of gravity, thereby being guided out of the microchannel device of the first embodiment from the respective

flow guide channels

221, 321; the large biological particles 91 are allowed to travel toward the downstream side 312 of the base wall 31 of the upper casing 3 in the flow direction F by the flow guide ribs 315 only in the first gap G1 in the upper channel 30 on the basis of the size restriction thereof, and are guided from the downstream side 312 of the upper channel 30 of the upper casing 3 to the outside of the micro flow channel device of the first embodiment.

It should be noted that the purpose of the pair of electrodes 4 sandwiching the lower case 2 and the upper case 3 is that the ohmic contact formed by the pair of electrodes 4 can adjust the micro-potential of the micro flow channel device of the first embodiment of the present invention when a bias voltage is applied to the pair of electrodes 4, and effectively improve the capture rate of specific target biological particles.

As can be seen from the above detailed description of the first embodiment of the present invention, when the liquid sample 9 enters the micro flow channel C of the first embodiment from the

upstream sides

211 and 311, the small biological particles 92 can settle to the convex pillars 215 of the lower shell 2 to circulate due to the turbulence and gravity of the drainage ribs 315 of the upstream side 311 of the upper shell 3, so that the settled small biological particles 92 can flow through the drainage channels 221 of the lower shell 2 to leave the micro flow channel device of the first embodiment of the present invention, and the large biological particles 91 are only limited to move to the downstream side 312 of the upper channel 30 along the flow direction F near the upper channel 30 of the upper shell 3 to leave the micro flow channel device of the first embodiment of the present invention. Therefore, the first embodiment of the present invention is specifically a three-dimensional (3D) mode of the filtering process, which allows the large biological particles 91 to flow directly to the downstream side 312 of the upper channel 30 of the upper shell 3, while the small biological particles 92 flow directly to the

respective drainage channels

221, 321 at the

upstream sides

211, 311, and are influenced by gravity to flow directly to the drainage channel 221 adjacent to the downstream side 212 of the base wall 21 of the lower shell 2 at the

downstream sides

212, 312, thereby preventing the micro-channel device from being clogged. In addition, based on the filtering process of the first embodiment of the present invention in the three-dimensional (3D) mode, the amount of samples that can be processed per unit time is much larger than that of the micro flow channel device 1 disclosed in the prior art 1, and the efficiency is better.

Referring to fig. 7 and 8, a second embodiment of the micro flow channel device of the present invention is substantially the same as the first embodiment, except that the base wall 31 of the upper case 3 of the second embodiment of the present invention does not have the flow guide rib 315, and the protruding pillar 215 is divided into a plurality of first regions 2152 and a plurality of second regions 2153. Specifically, the first areas 2152 and the second areas 2153 are alternately arranged along the flow direction F and are distributed from an inner side of the base wall 21 of the lower case 2 to the two outer sides 213 thereof along the flow direction F, and the height of the boss 215 of each first area 2152 is greater than the height of the boss 215 of each second area 2153. In other words, the second embodiment of the present invention replaces the drainage ribs 315 of the upper shell 3 of the first embodiment with the arrangement of the protruding columns 215 in the first regions 2152.

To sum up, in the micro flow channel device of the present invention, when the liquid sample 9 enters the micro flow channel C from the

upstream sides

211, 311, the small biological particles 92 can gradually settle to the convex pillars 215 of the lower shell 2 due to the influence of gravity, so that the settled small biological particles 92 can directly flow through the drainage channels 221 of the lower shell 2 to leave and capture the specific target biological particles, thereby preventing the blockage problem, and the large biological particles 91 are only limited to the upper channel 30 to move along the flow direction F to the downstream side 312 of the upper channel 30 to leave, so that the large biological particles 91 directly flow to the downstream side 312 of the upper channel 30 of the upper shell 3, and can process a larger amount of samples in unit time, and the efficiency is better, thereby achieving the purpose of the present invention.

The above-mentioned embodiments are only examples of the present invention, and the scope of the present invention should not be limited thereby, and all the simple equivalent changes and modifications made according to the claims and the contents of the specification should be included in the scope of the present invention.

Claims

1. A micro flow channel device for separating a liquid sample containing a plurality of large biological particles and a plurality of small biological particles having a size smaller than that of the large biological particles and capturing the liquid sample with respect to a specific target biological particle, comprising: which comprises the following steps:

a lower casing including a base wall and a pair of side walls, the base wall having an upstream side, a downstream side remote from the upstream side, two outer sides respectively connecting the upstream side and the downstream side, and a plurality of pillars protruding upward from an upper surface of the base wall at intervals, each side wall extending upward from a corresponding outer side of the base wall to define a lower channel together with the base wall, each side wall having at least one drainage channel recessed downward from a top edge of the corresponding side wall, and each drainage channel extending away from the base wall in a flow direction from the upstream side toward the downstream side; and

an upper case covering the lower case and including a base wall and a pair of side walls, the base wall of the upper case having an upstream side, a downstream side, and two outer sides respectively corresponding to the base wall of the lower case, the upstream side, the downstream side, and the two outer sides of the lower case, each side wall of the upper case extending downward from the respective corresponding outer side of the base wall thereof to be joined to the respective corresponding side wall of the lower case, and defining an upper channel together with the base wall of the upper case so that the upper channel and the lower channel define a microchannel together;

wherein, a first gap which is enough for the large biological particles to pass through is arranged between the base wall of the upper shell and the top edge of each convex column; and

wherein, a second gap which is not enough for the large biological particles to pass through and is enough for the small biological particles to pass through is arranged between every two adjacent convex columns.

2. The micro flow channel device according to claim 1, wherein: each convex column is a cylinder, the diameter of each cylinder is more than 1 mu m, and the length-diameter ratio is 8: 1.

3. The micro flow channel device according to claim 1, wherein: the base wall of the lower casing further has a stopper rib protruding upward from the base wall of the lower casing and adjacent to the downstream side of the base wall of the lower casing, a third gap having a size substantially equal to the first gap is provided between the top edge of the stopper rib and the base wall of the upper casing, and the third gap is sufficient for the passage of the large biological particles.

4. The micro flow channel device according to claim 1, wherein: the convex columns are divided into a plurality of first areas and a plurality of second areas, the first areas and the second areas are alternately arranged along the flow direction and distributed from the inner side of the base wall of the lower shell to the two outer sides of the lower shell along the flow direction, and the height of the convex columns of the first areas is greater than that of the convex columns of the second areas.

5. The micro flow channel device according to claim 1, wherein: the base wall of the upper shell is also provided with a plurality of drainage ribs which are arranged at intervals along the flow direction, and each drainage rib protrudes downwards from the lower surface of the base wall of the upper shell and extends from the inner side of the base wall of the upper shell to the two outer sides along the flow direction.

6. The micro flow channel device according to claim 1, wherein: each side wall of the upper shell is provided with at least one drainage channel, and each drainage channel of the upper shell is upwards sunken from the bottom edge of the corresponding side wall and extends back to the base wall of the upper shell along the flowing direction.

7. The micro flow channel device according to claim 1, wherein: each convex column is provided with a plurality of nanometer holes.

8. The micro flow channel device according to claim 7, wherein: each convex column of the base wall of the lower shell is provided with a body connected with the upper surface of the base wall and an anti-sticking coating arranged on the body corresponding to each convex column.

9. The micro flow channel device according to claim 8, wherein: each anti-sticking coating is further modified with biotin end groups.

10. The micro flow channel device according to claim 1, wherein: the micro flow channel device further comprises a pair of electrodes disposed on the lower case and the upper case.