CN115957838B - Microfluidic chip - Google Patents

Abstract

The invention relates to a microfluidic chip comprising: an inlet region formed with a sample solution channel and a buffer solution channel; the sorting area is connected with the inlet area, the sorting area forms a sorting channel, a first micro-column array and a second micro-column array are arranged on the sorting channel, the first micro-column array is inclined towards the direction close to the central line of the sorting channel, and the second micro-column array is inclined towards the direction far away from the central line of the sorting channel; the outlet area is connected with the sorting area, a first outlet channel and a second outlet channel are formed on the outlet area, and the first outlet channel and the second outlet channel are communicated with the sorting channel. The microfluidic chip can obtain target cell collection liquid with higher purity, improves sorting precision, saves more purification work flow and time for workers, and further improves accurate purification of target cells by using the microfluidic chip.

Description

Microfluidic chip

Technical Field

The invention relates to the field of cell sorting, in particular to a microfluidic chip and a use method thereof.

Background

In the field of cell separation, microfluidic chips that accomplish cell separation based on various physical and chemical differences between different cells are widely used. Among them, label-free sorting techniques based on physical properties such as cell size and density are of great interest because of the potential for more downstream applications. Among the numerous label-free microfluidic sorting techniques, the deterministic lateral displacement technique has higher separation recovery rate and separation purity compared with other techniques such as inertial force, acoustic field force, etc., due to its structure and performance similar to that of filter screen filtration. Meanwhile, the deformation condition of the cells can be controlled by adjusting the pressure or flow of separation, and the method is particularly suitable for being used in a cell separation scene requiring the combination of rigidity and nuclear-mass ratio difference.

In the current lateral displacement micro-fluidic chip technology, the characteristic size of the micro-fluidic chip structure is matched with cells, so that the method has the advantages of high precision, high flux and low cost, but the sorting purity still needs to be improved, and in the current lateral displacement micro-fluidic chip, the lateral displacement micro-column array used for cell sorting is all provided with a critical separation size (target sample size) which is fixed but has a fluctuation interval by matching with fixed sorting pressure or sorting flow. When the sample difference is large or the cell sorting requirement changes, the sorting performance of the chip is directly reduced or lost, and the application of the lateral displacement technology in the field of cell separation is greatly limited.

Disclosure of Invention

Based on the method, the micro-fluidic chip is provided, and the sorting precision of the micro-fluidic chip in the cell sorting process is improved.

A microfluidic chip comprising: an inlet region formed with a sample solution channel and a buffer solution channel; the sorting area is connected with the inlet area, a sorting channel is formed by the sorting area, the sorting channel is communicated with the sample solution channel and the buffer solution channel, a first micro-column array and a second micro-column array are arranged on the sorting channel, the first micro-column array and the second micro-column array are respectively formed by micro-column array distribution, the first micro-column array is inclined towards the direction close to the central line of the sorting channel, the second micro-column array is inclined towards the direction far away from the central line of the sorting channel, and the first micro-column array is positioned at the solution inlet end and the solution outlet end of the sorting channel; the outlet area is connected with the sorting area, a first outlet channel and a second outlet channel are formed on the outlet area, the first outlet channel is located on the inner side of the second outlet channel, and the first outlet channel and the second outlet channel are communicated with the sorting channel.

The application discloses a microfluidic chip, a sample solution to be tested and a buffer solution enter the microfluidic chip through an inlet area, a sample solution channel and a buffer solution channel formed by the microfluidic chip respectively flow the sample solution to be tested and the buffer solution to a sorting area together, a sorting channel is arranged on the sorting area, a micro-column array is obliquely arranged on the sorting channel, wherein the first micro-column array is inclined towards the central line direction of the sorting channel, after the sample solution enters the sorting channel, the flowing direction of small-size cells is unchanged through the first micro-column array, the cells continuously migrate along the flowing direction of the liquid in the whole horizontal direction, and large cells laterally move along the inclined direction of the first micro-column array, namely the large cells are gathered towards the central direction of the sorting channel, and the small cells continuously flow along the central direction far away from the sorting channel; at this time, when the sample solution enriched by the first micro-column array flows into the second micro-column array, the macro-cells move along the inclined direction of the second micro-column array, namely, the macro-cells flow towards the central direction far away from the sorting channel and are mostly gathered on the side wall of the sorting channel, then enter the first micro-column array, pass through the second micro-column array of the previous stage so that the macro-cells enriched on the side wall of the sorting channel are gathered along the central direction of the sorting channel, the second micro-column array is positioned at the tail end of the sorting region, the macro-cells enriched by the sorting region flow to the macro-cell collecting end through the first outlet channel connected after being circularly sorted and enriched, and the rest of the solution flows out of the small-cell collecting end through the second outlet channel, so that the target cell collecting liquid with higher purity can be obtained, the sorting precision of the micro-fluidic chip is improved, more purification work flow and time are saved for workers, and the accurate purification of the target cells by using the micro-fluidic chip is further improved.

In one embodiment, the number of the first micro-pillar arrays and the second micro-pillar arrays is plural, and the second micro-pillar array is located between the two first micro-pillar arrays. Through being equipped with a plurality of first microcolumn arrays and second microcolumn arrays, select separately the passageway through the combination arrange first microcolumn array and second microcolumn array, and include the structure that a set of first microcolumn array and second microcolumn array crisscross set up at least, further, this first microcolumn array and the crisscross structure of second microcolumn array can set up the multiunit to reach the continuous further enrichment target cell of sample solution in the last level select separately the passageway, thereby improve the target cell content of first exit channel.

In one embodiment, the first micro-column array forms a first offset angle with the center line direction of the sorting channel, and the first offset angle ranges from 0.5 ° to 12.5 °.

In one embodiment, the second micro-column array forms a second offset angle with the center line direction of the sorting channel, and the second offset angle ranges from 0.5 ° to 12.5 °.

The offset angle range refers to an offset angle range between the first micro-column array and the second micro-column array and the central line of the sorting channel respectively, and the length of the sorting channel of the microfluidic chip and the circulation structure of the first micro-column array and the second micro-column array are more reasonable by setting the preferred offset angle range, so that the sorting efficiency and the sorting precision are further improved.

In one embodiment, the distance between the micropillars of the first micropillar array and/or the second micropillar array, which are adjacently distributed along the flow channel direction, is 6-25 micrometers. The flow channel direction refers to the liquid flow direction after the sample cells enter the sorting channel, the flow channel direction faces the liquid outlet end along the central line of the sorting channel, and the distance range between the microcolumns adjacently arranged in the flow channel direction is 6-25 micrometers.

In one embodiment, the distance between the micro pillars of the first micro pillar array and/or the second micro pillar array, which are adjacently distributed perpendicular to the direction of the flow channel, is 10-60 micrometers. The flow channel direction refers to the liquid flow direction of sample cells after entering the sorting channel, the flow channel direction faces the liquid outlet end along the center line of the sorting channel, and the distance range between microcolumns adjacently distributed in the direction perpendicular to the flow channel direction is 10-60 micrometers.

In one embodiment, the height range of the first micro-pillar array and/or the second micro-pillar array perpendicular to the direction of the flow channel is 5-50 micrometers. The height range of the first micro-column array and the second micro-column array in the direction vertical to the flow channel is 5-50 micrometers. The design of the size enables the micro-fluidic chip to have the advantages of compact structure, high sorting precision and good reproducibility.

In one embodiment, the cross-sectional shape of the micro-column is one of a circle, an ellipse, a triangle, a rectangle, a trapezoid, a diamond, an L-shape, a C-shape, and a T-shape.

In one embodiment, the height of the sorting channels perpendicular to the direction of the fluid can vary with different sorting pressures. The sample solution to be tested in the inlet area and the buffer solution flow on the sorting channel after entering the sorting area, and for the cells capable of generating deformation, the cells deform under the condition that the liquid is pressurized to enter the sorting channel, so that the height of the sorting channel, namely the height of the liquid channel formed on the sorting area, can change, therefore, the actual critical separation size of the sorting area can be adjusted by changing the sorting pressure for the cell sample capable of generating deformation, the fixed critical separation size is set by matching the fixed sorting pressure or the sorting flow with the micro-column array in the existing lateral displacement technology, and therefore, when the sample difference is large or the cell sorting requirement changes, the sorting performance of the micro-fluidic chip is reduced or lost.

In one embodiment, the height of the sorting channel perpendicular to the direction of the fluid is in the range of 15-60 microns. The separation channel, i.e. the separation region, is formed with a liquid channel, the height of which perpendicular to the fluid direction is larger than the height of the first micro-column array and the second micro-column array perpendicular to the fluid direction, and the height range value is 15-60 micrometers.

In one embodiment, the sorting area comprises a buffer flow channel area, a circulating sorting area and a small cell flow channel area, wherein a buffer supply channel is formed on the buffer flow channel area and is communicated with the buffer channel of the inlet area, the buffer flow channel area is positioned at the inner side of the circulating sorting area, the circulating sorting area is communicated with the sample solution channel and the buffer channel, the circulating sorting area forms the sorting channel, the first micro-column array and the second micro-column array are positioned on the circulating sorting area, the small cell flow channel area forms a small cell channel, and the small cell channel is communicated with the sorting channel. The buffer liquid flow channel region is arranged at the inner center of the sorting channel, the sorting channel is formed on the circulating sorting region, the small cell channel formed on the small cell flow channel region is positioned at the outer side of the circulating sorting region, after the fluid flows through the first micro-column array and the second micro-column array on the circulating sorting region to sort cells, most of cells collected by targets continue to flow forwards along the sorting channel, and most of small cells continue to flow forwards along the small cell flow channel region at the outer side, so that the cell sorting work is realized.

In one embodiment, the circulating sorting area comprises a first convergence area, a divergence area and a first separation part, the first convergence area and the divergence area are respectively provided with the first micro-column array and the second micro-column array, the first convergence area is adjacent to the inlet area, the divergence area is positioned at the liquid outlet end of the first convergence area, the small cell runner area is positioned at the outer side of the divergence area, the first separation part is arranged between the divergence area and the small cell runner area, and the small cell channel is communicated with the first convergence area. Through be equipped with first convergence district on the solution entry end of circulation separation district, be equipped with first microcolumn array on the first convergence district for big cell in the sample solution is enriched along the buffer runner district direction towards center department earlier, and the sample solution after the first convergence district flows into the divergence district, and the sample solution that cell concentration is high gets into the little cell runner district that is located the divergence district outside this moment, and the sample solution that contains more big cells through enrichment gets into the divergence district, makes the sample solution accomplish a purification. The purified sample solution flows through the second micro-column array arranged on the divergent zone and moves to the first separation part along the direction away from the flow channel, and further, elastic collision occurs between the large cells and the side wall of the first separation part, so that the large cells cannot be damaged, the cell structure of the collected target cell solution is complete and high in activity, and the next use and research are facilitated. In the process, most of the large cells in the sample solution obtained by the first purification are concentrated on the side wall of the first separation part, and then the large cells are moved to the next first convergence area along the direction close to the flow channel at the outlet of the divergence area, so that the cells in the sample solution are further purified, and the content of the target sorted large cells in the small cell channel is reduced.

In one embodiment, the number of the circulating separation zones is multiple, the critical separation size among the circulating separation zones distributed along the flowing direction of the liquid is increased progressively, and the critical separation size of the circulating separation zone of the next stage is 105% -200% of the critical separation size of the circulating separation zone of the previous stage. Further, by arranging a plurality of circulating separation areas in series to separate cells with different sizes step by step, the sample solution is continuously purified to obtain large cells with higher concentration. The sizes of the circulating separation zones which are adjacently arranged are different, specifically, the size of the circulating separation zone of the next stage is 105% -200% of the size of the circulating separation zone of the previous stage, and the critical separation size of the circulating separation zone along the flow channel direction is increased, so that the method is beneficial to further improving the separation precision and separation purity of large cells, increasing the resolution of cell separation and reducing the risk of flow channel blockage.

In one embodiment, the number of the first convergence region, the divergent region and the first partition is plural, and the first convergence region and the divergent region are staggered. The number of the first convergence areas and the divergence areas in the circulation separation area is multiple, and the first convergence areas and the divergence areas are arranged in a staggered mode, so that separation purity is improved, and the large cell content in the separation channel is further improved.

In one embodiment, the buffer flow channel region and the small cell flow channel region are provided with cylindrical arrays, and the distribution direction of the cylindrical arrays is the same as the liquid flow direction. By arranging the cylindrical arrays on the first convergence region and the divergence region, the arrangement direction of the cylinders in the cylindrical arrays is consistent with the flowing direction of the liquid, and the cylindrical arrays are used for stabilizing the flowing of the solution in the flow channel.

In one embodiment, the buffer flow channel further comprises a drainage part, a gap is arranged between the adjacent first convergence region and the adjacent divergence region, the drainage part is arranged on the outer side wall of the buffer flow channel region and/or the inner side wall of the first separation part, and the drainage part is positioned at the gap. Preferably, one side of the drainage part, which is close to the first convergence region, is inclined towards the direction of the central line, which is far away from the sorting channel, along the liquid flow direction, so that the solution converged towards the direction of the central line of the sorting channel is directed towards the direction flow channel of the divergent region, the drainage effect is achieved on the large cells, and one side of the drainage part, which is close to the divergent region, is inclined towards the direction of the central line, which is close to the sorting channel, along the liquid flow direction.

In one embodiment, the method further comprises a final sorting area, wherein the final sorting area is positioned at a liquid outlet end of the circulating sorting area, the first micro-column array is arranged on the final sorting area, the buffer runner area is positioned at the inner side of the final sorting area, the small cell runner area is positioned at the outer side of the final sorting area, and the sorting channel extends to the final sorting area. The solution flowing out from the circulating sorting area at one side close to the central line is further purified by arranging a final sorting area, and the final purification work is completed. The end of the final sorting area is connected with the outlet area, the final sorting area is positioned at the end of the circulating sorting area, the sorting channel extends to the final sorting area, and the buffer flow channel area at least partially extends to the end of the final sorting area, so that the buffer on the buffer flow channel area is communicated with the sorting channel on the final sorting area.

In one embodiment, the final sorting region includes a second convergence region on which a plurality of the first micro-pillar arrays are disposed, and a second partition located outside the second convergence region. The last stage separation area is provided with a second convergence area, the second convergence area is provided with a first microcolumn array in a circulating way, the solution purified by the circulating separation area is purified again, the second separation part is arranged between the small cell runner area positioned on the last stage separation area and the second convergence area, the small cells in the solution after the circulating separation area are separated again, the last stage separation area is communicated with a first outlet channel of the outlet area, and the solution with high target cell concentration is obtained through the first outlet channel.

In one embodiment, the critical separation size of the final sorting area is higher than that of the circulating sorting area, and the critical separation size of the final sorting area is 120% -600% of that of the first circulating sorting area. The critical separation size of the final fraction separation zone is larger than that of the first circulation separation zone of the separation channel, so that the separation precision and separation purity of the large cells are further improved, and the risk of flow channel blockage is reduced.

In one embodiment, the buffer flow channel region extends at least partially through the final sorting region, the end of the buffer flow channel region being located on the final sorting region. The separation and purification are continuously carried out along the flow channel direction, so that the large cell content in the separation channel at the tail end is high, the buffer solution content is reduced, and the buffer solution flow channel region at least partially extends to the end part of the final separation region and is communicated with the separation channel, thereby being beneficial to maintaining the cell activity on the final separation region.

In one embodiment, the first partition includes a first partition body and a flow guiding end, the flow guiding end is disposed on the first partition body, the flow guiding end is located at the liquid outlet end of the first convergence zone, and the flow guiding end is used for guiding the liquid to flow to the small cell flow channel zone. The first separation part is provided with a flow guiding end which is used for guiding the solution outside the sorting channel of the previous stage to flow into the small cell flow channel area, while the solution positioned near the inner side of the sorting channel continuously enters the sorting channel of the next stage, the large cell content in the solution is high, and the large cell is offset along the array direction of the next stage, so that the circulating purification process is continuously carried out.

In one embodiment, the guide end has a guide arc surface, the guide arc surface is located at the outer side of the guide end, and the guide arc surface is offset towards the direction away from the center line of the sorting channel. The outside of the diversion end forms a diversion cambered surface which deviates towards the central line, which is beneficial to reducing the fluid resistance between the connection parts of the first micro-column array and the second micro-column array and achieves the effects of diversion and steady flow. Further, the second partition has the same structure as the first partition.

In one embodiment, the connection between the flow guiding end and the first partition body forms an angle.

In one embodiment, the buffer channel comprises a first buffer channel and a second buffer channel, the inlet region comprises a first buffer inlet region, a second buffer inlet region and a sample solution inlet region, the first buffer inlet region forms the first buffer channel, the second buffer inlet region forms the second buffer channel, and the second buffer channel is located inside the first buffer channel. Through being equipped with two buffer solution passageways, and sample solution passageway sets up between first buffer solution passageway and second buffer solution passageway, first buffer solution forms the sheath flow along first buffer solution passageway entering separation zone, be favorable to the partial sample cell solution of waiting to select separately of initial stage to flow to the middle sorting region of degree more, thereby reduce the loss rate of target sample cell, through being equipped with the second buffer solution passageway in the inboard of sample solution passageway, after second buffer solution enters the sorting region along two buffer solution passageways, the sample cell solution mixes and forms middle liquid flow of being convenient for, thereby guarantee that sample cell solution flows from the area that possesses the separation function of buffer solution make-up passageway outside, further, first buffer solution passageway of entry district, second buffer solution passageway and sample solution passageway are the same with the liquid flow direction in the separation channel respectively, be favorable to avoiding influencing the liquid flow direction after sample cell solution gets into the sorting region along with the buffer solution. The flow channel design of the buffer solution and the sample solution enables the sample cell solution to be sorted to be prevented from forming turbulence in the microfluidic chip, which is beneficial to improving the sorting efficiency and the sorting precision of the sample cell solution after passing through the sorting area and improving the sample cell recovery rate of the outlet area. In one embodiment, the outlet region includes a first outlet portion on which the first outlet channel is formed, the first outlet portion being adjacent to the liquid outlet end of the sorting channel, and a second outlet portion on which the second outlet channel is formed. The first outlet part of the outlet area is connected with the final-stage sorting area on the sorting area and is used for recycling the large cell solution collected by the target, and the second outlet part is communicated with the small cell flow channel area and is used for recycling the solution with high small cell content.

In one embodiment, the sample solution channel, the buffer solution channel, the first outlet channel and the second outlet channel are respectively provided with a cylindrical array, and the distribution direction of the cylindrical arrays is the same as the liquid flow direction. By providing a cylindrical array on the channels of the inlet and outlet areas, and the direction of the arrangement of the cylinders in the cylindrical array is consistent with the direction of the flow of the liquid, the cylindrical array is used for stabilizing the flow of the solution in the flow channel.

Specifically, the microstructure of the microfluidic chip can be manufactured by using thermosetting or thermoplastic polymers, glass, silicon and other materials, and a closed structure is formed by bonding, pressing, heat sealing/welding and other processes.

The second aspect of the application discloses a separation and purification method of a microfluidic chip, comprising the following steps: s1: with the microfluidic chip, the inlet area is connected with a sample solution to be processed and a buffer solution, the sample solution to be processed flows through the sample solution channel, the buffer solution flows through the buffer solution channel, the outlet area is connected with a large cell recovery liquid pipe and a small cell recovery liquid pipe, the first outlet channel is communicated with the large cell recovery liquid pipe, and the second outlet channel is communicated with the small cell recovery liquid pipe; s2: applying the same sorting pressure to the sample solution to be processed and the buffer solution, wherein the sample solution to be processed and the buffer solution pass through the sorting area, the target cell solution is recycled to the large cell recycling liquid pipe through the first outlet channel, and the rest solution is recycled to the small cell recycling liquid pipe through the second outlet channel; s3: after the sample solution to be treated is emptied or the recovery liquid is filled, the liquid inlet of the inlet area and the liquid outlet of the outlet area are interrupted, and the separation pressure applied by the sample solution to be treated and the buffer solution is contacted.

The second aspect of the application discloses a separation and purification method through the microfluidic chip, wherein a first buffer solution inlet area and a second buffer solution inlet area are connected with a buffer solution, a sample solution inlet area is connected with a sample to be processed, a first outlet part is connected with a large cell recovery liquid pipe, and a second outlet part is connected with a small cell recovery liquid pipe; applying equal sorting pressure to the buffer solution and the sample solution to be processed, so that the buffer solution and the sample flow into the microfluidic chip from the corresponding inlets respectively and cell sorting is completed; after the sample solution is emptied or the recovery solution is filled, the inflow and outflow of the microfluidic chip are interrupted, and the sorting pressure applied to the buffer solution and the sample solution to be processed is released, so that the sorting process is completed.

In one embodiment, the sort pressure is determined from a sort database, and the step of creating the sort database includes:

s1: under different sorting pressure conditions in a 0.5-2.5 Bar interval, sorting and testing polymer particle samples with the size of 2-25 microns, and confirming the critical separation size of the microfluidic chip according to test results;

s2: testing the sorting recovery rate of different cell samples under different sorting pressures by using the micro-fluidic chip with the critical separation size confirmed;

S3: and according to the test result, combining the micro-fluidic chip, critical separation size, cell type and characteristics, sorting pressure and corresponding sorting recovery rate, and establishing a cell sorting database.

The critical separation size is obtained by the set sorting recovery rate and the test data statistics, and comprises a positive critical separation size and a negative critical separation size. Further, the forward critical separation dimension is statistically derived from the minimum dimension data of the sample flowing into the first outlet portion at 100% recovery. The negative critical separation dimension is statistically derived from the minimum dimension data of the sample flowing into the second outlet portion at 100% recovery.

In one embodiment, the critical separation dimension ranges from 5 to 9 microns, from 8 to 13 microns, from 12 to 18 microns, or from 16 to 24 microns, with a corresponding separation pressure of from 0.5 to 2.5 Bar.

Drawings

FIG. 1 is a schematic diagram of the overall structure of a microfluidic chip;

FIG. 2 is a schematic view of the inlet region structure of a microfluidic chip;

FIG. 3 is a schematic view of the structure of the outlet region of the microfluidic chip;

FIG. 4 is a schematic diagram of the structure of a cyclic separation zone;

FIG. 5 is a schematic view of the structure of the first converging and diverging regions;

FIG. 6 is a schematic diagram of the structure of the final sorting section;

FIG. 7 is a schematic diagram of the final sorting section convergence zone with buffer replenishment channels;

FIG. 8 is a schematic diagram of the final sorting region convergence zone without buffer replenishment channels;

fig. 9 is a schematic view of the structure of the first outlet passage.

Wherein, the correspondence between the reference numerals and the component names is:

1 an inlet zone, 101 a sample solution channel, 102 a first buffer channel, 103 a second buffer channel, 11 a first buffer inlet zone, 12 a second buffer inlet zone, 13 a sample solution inlet zone;

the separation area 2, the gap 201, the buffer solution flow channel area 21, the cycle separation area 22, the first convergence area 221, the divergent area 222, the first division part 223, the first division part body 2231, the flow guiding end 2232, the small cell flow channel area 23, the non-point separation area 24, the second convergence area 241 and the second division part 242;

3 outlet zone, 301 first outlet channel, 302 second outlet channel, 31 first outlet portion, 32 second outlet portion;

4, a drainage part;

a local structure of the first micro-column array and B local structure of the second micro-column array.

Detailed Description

In order that the above-recited objects, features and advantages of the present application will be more clearly understood, a more particular description of the application will be rendered by reference to the appended drawings and appended detailed description. It should be noted that, without conflict, the embodiments of the present application and features in the embodiments may be combined with each other.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those described herein, and therefore the scope of the present invention is not limited to the specific embodiments disclosed below.

A microfluidic chip according to some embodiments of the present invention is described below with reference to the accompanying drawings.

Example 1

As shown in fig. 1 to 9, the present embodiment discloses a microfluidic chip, which includes an inlet region 1, wherein a sample solution channel 101 and a buffer channel are formed in the inlet region 1; the sorting area 2 is connected with the inlet area 1, the sorting area 2 forms a sorting channel, the sorting channel is communicated with the sample solution channel 101 and the buffer solution channel, a first micro-column array and a second micro-column array are arranged on the sorting channel and are respectively formed by the distribution of the micro-column arrays, the first micro-column array inclines towards the direction close to the central line of the sorting channel, the second micro-column array inclines towards the direction far away from the central line of the sorting channel, and the first micro-column array is positioned at the solution inlet end and the solution outlet end of the sorting channel; the outlet area 3, the outlet area 3 is connected with the sorting area 2, a first outlet channel 301 and a second outlet channel 302 are formed on the outlet area 3, the first outlet channel 301 is located on the inner side of the second outlet channel 302, and the first outlet channel 301 and the second outlet channel 302 are communicated with the sorting channel.

The application discloses a microfluidic chip, a sample solution to be tested and buffer solution enter the microfluidic chip through an inlet area 1, a sample solution channel 101 and a buffer solution channel formed by the microfluidic chip respectively flow the sample solution to be tested and the buffer solution to a sorting area 2 together, a sorting channel is arranged on the sorting area 2, the sorting channel comprises a micro-column array which is obliquely arranged, wherein a first micro-column array is inclined towards the central line direction of the sorting channel, after the sample solution enters the sorting channel, the flowing direction of small-size cells is unchanged through the first micro-column array, the whole liquid flowing direction is horizontally migrated continuously along the liquid flowing direction, and large cells are laterally moved along the inclined direction of the first micro-column array, namely, the large cells are gathered towards the central direction of the sorting channel, and the small cells continue to flow along the central direction far away from the sorting channel; at this time, when the sample solution enriched by the first micro-column array flows into the second micro-column array, the macro-cells move along the inclined direction of the second micro-column array, that is, the macro-cells flow in the direction far away from the center of the sorting channel and are mostly gathered on the side wall of the sorting channel, and then enter the first micro-column array, the macro-cells enriched on the side wall of the sorting channel through the second micro-column array of the previous stage are gathered along the center direction of the sorting channel, the first micro-column array is positioned at the tail end of the sorting area 2, the macro-cells enriched by the sorting area 2 flow to the macro-cell collecting end through the first outlet channel 301 connected after being circularly sorted and enriched, and the rest of the solution flows out of the small-cell collecting end through the second outlet channel 302, so that the target cell collecting liquid with higher purity can be obtained, the sorting precision of the micro-fluidic chip is improved, more purification work flow and time are saved for workers, and the accurate purification of the target cells by using the micro-fluidic chip is further improved.

As shown in fig. 4 to 7, this embodiment further defines, in addition to the features of the above-described embodiment: the first micro-column array and the second micro-column array are multiple in number, and the second micro-column array is located between the two first micro-column arrays. Through being equipped with a plurality of first micropillar arrays and second micropillar arrays, select separately the passageway through the combination arrange first micropillar array and second micropillar array, and include the structure that a set of first micropillar array and second micropillar array crisscross set up at least, further, this first micropillar array and the crisscross structure of second micropillar array can set up the multiunit to reach the continuous further enrichment target cell of sample solution in the last level select separately the passageway, thereby improve the target cell content of first exit channel 301.

In addition to the features of the above embodiments, the present embodiment further defines: the first micro-column array and the central line direction of the sorting channel form a first offset angle, and the range of the first offset angle is 0.5-12.5 degrees.

In addition to the features of the above embodiments, the present embodiment further defines: the second micro-column array forms a second offset angle with the central line direction of the sorting channel, and the range of the second offset angle is 0.5-12.5 degrees.

The offset angle range refers to an offset angle range between the first micro-column array and the second micro-column array and the central line of the sorting channel respectively, and the length of the sorting channel of the microfluidic chip and the circulation structure of the first micro-column array and the second micro-column array are more reasonable by setting the preferred offset angle range, so that the sorting efficiency and the sorting precision are further improved.

In addition to the features of the above embodiments, the present embodiment further defines: the distance range between the microcolumns, which are adjacently distributed along the flow channel direction, of the first microcolumn array and/or the second microcolumn array is 6-25 micrometers. The flow channel direction refers to the liquid flow direction after the sample cells enter the sorting channel, the flow channel direction faces the liquid outlet end along the central line of the sorting channel, and the distance range between the microcolumns adjacently arranged in the flow channel direction is 6-25 micrometers.

In addition to the features of the above embodiments, the present embodiment further defines: the distance range between the microcolumns, which are adjacently distributed in the direction perpendicular to the flow channel, of the first microcolumn array and/or the second microcolumn array is 10-60 micrometers, the flow channel direction refers to the liquid flow direction after sample cells enter the sorting channel, the flow channel direction faces the liquid outlet end along the central line of the sorting channel, and the distance range between the microcolumns, which are adjacently distributed in the direction perpendicular to the flow channel, is 10-60 micrometers.

In addition to the features of the above embodiments, the present embodiment further defines: the height range of the first micro-column array and/or the second micro-column array perpendicular to the direction of the flow channel is 5-50 micrometers. The height range of the first micro-column array and the second micro-column array in the direction vertical to the flow channel is 5-50 micrometers. The design of the size enables the micro-fluidic chip to have the advantages of compact structure, high sorting precision and good reproducibility.

In addition to the features of the above embodiments, the present embodiment further defines: the section shape of the micro-column is one of a circle, an ellipse, a triangle, a rectangle, a trapezoid, a diamond, an L shape, a C shape and a T shape.

Further, in addition to the features of the above-described embodiments, the present embodiment further defines: the height of the sorting channels perpendicular to the direction of the fluid can vary with different sorting pressures. The sample solution to be tested in the inlet area 1 and the buffer solution flow on the sorting channel after entering the sorting area 2, and for the cells capable of generating deformation, the cells deform under the condition that the liquid is pressurized to enter the sorting channel, so that the height of the sorting channel, namely the height of the liquid channel formed on the sorting area 2, can change, therefore, the actual critical separation size of the sorting area 2 can be adjusted by changing the sorting pressure for the cell sample capable of generating deformation, and the fixed critical separation size is set by matching the fixed sorting pressure or the sorting flow with the existing lateral displacement micro-column array, so that when the sample difference is large or the cell sorting requirement changes, the sorting performance of the micro-fluidic chip is reduced or lost, and compared with the prior similar technology, the micro-fluidic chip has higher resolution and accuracy, and is convenient for workers to set up a sorting database and chip multiplexing in the later stage.

In addition to the features of the above embodiments, the present embodiment further defines: the height range of the sorting channel perpendicular to the direction of the fluid is 15-60 micrometers. The separation channel, i.e. the separation region 2, is formed with a liquid channel, the height of which perpendicular to the fluid direction is larger than the height of the first micro-column array and the second micro-column array perpendicular to the fluid direction, and the height range value is 15-60 micrometers.

In addition to the features of the above embodiments, the present embodiment further defines: the sorting area 2 comprises a buffer flow channel area 21, a circulating sorting area 22 and a small cell flow channel area 23, wherein a buffer supply channel is formed on the buffer flow channel area 21 and is communicated with the buffer channel of the inlet area 1, the buffer flow channel area 21 is positioned at the inner side of the circulating sorting area 22, the circulating sorting area 22 is communicated with the sample solution channel 101 and the buffer channel, the circulating sorting area 22 forms a sorting channel, the first micro-column array and the second micro-column array are positioned on the circulating sorting area 22, the small cell flow channel area 23 forms a small cell channel, and the small cell channel is communicated with the sorting channel. The buffer flow channel region 21 is arranged at the inner center of the sorting channel, the sorting channel is formed on the circulating sorting region 22, the small cell channel formed on the small cell flow channel region 23 is positioned at the outer side of the circulating sorting region 22, after the fluid flows through the first micro-column array and the second micro-column array on the circulating sorting region 22 for cell sorting, most of the cells collected by the targets continue to flow forwards along the sorting channel, and most of the small cells continue to flow forwards along the small cell flow channel region 23 at the outer side, so that the cell sorting work is realized.

As shown in fig. 4 and 5, this embodiment further defines, in addition to the features of the above-described embodiment: the circulation separation zone 22 comprises a first convergence zone 221, a divergence zone 222 and a first partition 223, the first convergence zone 221 and the divergence zone 222 are respectively provided with a first micro-column array and a second micro-column array, the first convergence zone 221 is adjacent to the inlet zone 1, the divergence zone 222 is positioned at the liquid outlet end of the first convergence zone 221, the small cell runner zone 23 is positioned at the outer side of the divergence zone 222, the first partition 223 is arranged between the divergence zone 222 and the small cell runner zone 23, and the small cell runner is communicated with the first convergence zone 221. Through being equipped with first convergence district 221 on the solution entry end of circulation separation zone 22, be equipped with first micropillar array on the first convergence district 221 for the big cell in the sample solution is first along the buffer flow channel district 21 direction enrichment towards center department, and the sample solution after first convergence district 221 flows into and diverges district 222, and the little cell flow channel district 23 that the sample solution of little cell concentration height is located the outside of dispersing district 222 is got into to the sample solution that is contained more big cell of enrichment this moment, and the sample solution is got into and diverges district 222, makes the sample solution accomplish a purification. The purified sample solution flows through the second micro-column array arranged on the divergent zone 222 and moves to the first separation part 223 along the direction away from the flow channel, and further, the large cells elastically collide with the side wall of the first separation part 223, so that the large cells are not damaged, the cell structure of the collected target cell solution is complete, the activity is high, and the next use and research are convenient. In the above process, most of the large cells in the sample solution obtained by the first purification are collected again on the side wall of the first partition 223, and then move to the next first convergence zone 221 along the direction close to the flow channel at the outlet of the divergence zone 222, so that the cells in the sample solution are further purified, and the content of the target sorted large cells in the small cell channel is reduced.

In addition to the features of the above embodiments, the present embodiment further defines: the number of the circulation separation zones 22 is plural, the critical separation size between the circulation separation zones 22 distributed along the flowing direction of the liquid is increased progressively, and the critical separation size of the next circulation separation zone 22 is 105% -200% of the critical separation size of the previous circulation separation zone 22. Further, by providing a plurality of circulating separation zones 22 in series to separate cells of different sizes step by step, the sample solution is continuously purified to obtain larger cells with higher concentration. The sizes of the circulation separation zones 22 adjacently arranged are different, specifically, the size of the circulation separation zone 22 of the next stage in the liquid outflow direction is 105-200% of the size of the circulation separation zone 22 of the previous stage, and the critical separation size of the circulation separation zone along the flow channel direction is increased, so that the separation precision and separation purity of large cells are improved, the resolution of cell separation is increased, and the risk of flow channel blockage is reduced.

In addition to the features of the above embodiments, the present embodiment further defines: the number of the first convergence zones 221, the number of the divergence zones 222 and the number of the first separating portions 223 are plural, and the first convergence zones 221 and the divergence zones 222 are staggered. The number of the first convergence zones 221 and the divergence zones 222 in the circulation separation zone 22 is multiple, and the first convergence zones 221 and the divergence zones 222 are arranged in a staggered manner, so that the separation purity is improved, and the large cell content in the separation channel is further improved.

In addition to the features of the above embodiments, the present embodiment further defines: the buffer flow channel region 21 and the small cell flow channel region 23 are provided with cylindrical arrays, and the distribution direction of the cylindrical arrays is the same as the liquid flow direction. By providing a cylindrical array on the first converging region 221 and the diverging region 222, and the direction of the cylindrical arrangement in the cylindrical array is consistent with the direction of the liquid flow, the cylindrical array is used for stabilizing the solution flow in the flow channel.

In addition to the features of the above embodiments, the present embodiment further defines: the buffer liquid flow channel further comprises a drainage part 4, a gap 201 is arranged between the adjacent first convergence region 221 and the adjacent divergence region 222, the drainage part 4 is arranged on the outer side wall of the buffer liquid flow channel region 21 and/or the inner side wall of the first separation part 223, and the drainage part 4 is positioned at the gap 201. Specifically, the side of the drainage portion 4 near the first convergence region 221 is inclined in the liquid flow direction toward the center line direction away from the sorting channel, so that the solution collected toward the center line direction of the sorting channel is directed toward the direction flow channel of the divergent region 222, which has the effect of draining the large cells, and the side of the drainage portion 4 near the divergent region 222 is inclined in the liquid flow direction toward the center line direction near the sorting channel.

As shown in fig. 6 to 9, this embodiment further defines, in addition to the features of the above-described embodiment: the device further comprises a final sorting area 24, wherein the final sorting area 24 is positioned at the liquid outlet end of the circulating sorting area 22, a first micro-column array is arranged on the final sorting area 24, the buffer liquid flow passage area 21 is positioned at the inner side of the final sorting area 24, the small cell flow passage area 23 is positioned at the outer side of the final sorting area 24, and the sorting channel extends to the final sorting area 24. The solution exiting the recycle separation zone 22 on the side near the centerline is further purified by providing a final separation zone 24 and the final purification is accomplished. The end of the last sorting section 24 is connected to the outlet section 3, the last sorting section 24 is located at the end of the circulation sorting section 22, the sorting channels extend to the last sorting section 24, and the buffer flow channel section 21 extends at least partially to the end of the last sorting section 24, so that the buffer on the buffer flow channel section 21 communicates with the sorting channels on the last sorting section 24.

In addition to the features of the above embodiments, the present embodiment further defines: the final sorting area 24 includes a second convergence area 241 and a second partition 242, and a plurality of first micro-pillar arrays are disposed on the second convergence area 241, and the second partition 242 is located outside the second convergence area 241. The last sorting area 24 is provided with a second convergence area 241, the second convergence area 241 is provided with a first micro-column array in a circulating way, the solution purified by the circulating sorting area 22 is purified again, the second separation part 242 is arranged between the small cell runner area 23 positioned on the last sorting area 24 and the second convergence area 241, the small cells in the solution after passing through the circulating sorting area 22 are separated again, the last sorting area 24 is communicated with the first outlet channel 301 of the outlet area 3, and the solution with high target cell concentration is obtained through the first outlet channel 301.

In addition to the features of the above embodiments, the present embodiment further defines: the critical separation size of the final sorting zone 24 is higher than that of the circulating sorting zone 22, and the critical separation size of the final sorting zone 24 is 120% -600% of that of the first circulating sorting zone 22. The final separation zone 24 has a critical separation dimension greater than the first circulation separation zone 22 in the separation channel, which is advantageous for further improving the accuracy and purity of the large cell separation and reducing the risk of flow channel blockage.

In addition to the features of the above embodiments, the present embodiment further defines: the buffer flow path region 21 penetrates at least a part of the final sorting region 24, and the end of the buffer flow path region 21 is located on the final sorting region 24. Since the separation and purification are continuously carried out along the flow channel direction, the large cell content in the separation channel at the tail end is high, the buffer solution content is reduced, and the buffer solution flow channel region 21 at least partially extends to the end of the final separation region 24 and is communicated with the separation channel, so that the activity of cells on the final separation region 24 is favorably maintained.

As shown in fig. 4, this embodiment further defines, in addition to the features of the above-described embodiment: the first separator 223 includes a first separator body 2231 and a flow guiding end 2232, the flow guiding end 2232 is disposed on the first separator body 2231, the flow guiding end 2232 is located at the liquid outlet end of the first convergence zone 221, and the flow guiding end 2232 is used for guiding the liquid to flow toward the small cell flow channel zone 23. By providing the first separator 223 with a flow guide end 2232 for guiding the solution outside the sorting channel of the previous stage to flow into the small cell flow channel region 23, while the solution inside the sorting channel continues to enter the sorting channel of the next stage, the large cell content in the solution is high, and the large cell is offset along the array direction of the next stage, so that the process of circulating purification is continuously performed.

In addition to the features of the above embodiments, the present embodiment further defines: the diversion end 2232 has a diversion cambered surface, which is located outside the diversion end 2232 and is offset toward a direction away from a center line of the sorting channel. The outside of the diversion end 2232 forms a diversion cambered surface which deviates towards the central line, which is favorable for reducing the fluid resistance between the connection parts of the first micro-column array and the second micro-column array and achieves the effects of diversion and steady flow.

Further, the second partition 242 has the same structure as the first partition 223.

In addition to the features of the above embodiments, the present embodiment further defines: the junction of the deflector end 2232 and the first divider body 2231 forms a corner.

As shown in fig. 1 and 2, this embodiment further defines, in addition to the features of the above-described embodiment: the buffer channel comprises a first buffer channel 102 and a second buffer channel 103, the inlet zone 1 comprises a first buffer inlet zone 11, a second buffer inlet zone 12 and a sample solution inlet zone 13, the first buffer inlet zone 11 forms the first buffer channel 102, the second buffer inlet zone 12 forms the second buffer channel 103, and the second buffer channel 103 is located inside the first buffer channel 102. Through being equipped with two buffer solution channels, and sample solution channel 101 sets up between first buffer solution channel 102 and second buffer solution channel 103, first buffer solution forms the sheath flow when entering sorting region 2 along first buffer solution channel 102, be favorable to the partial sample cell solution of waiting to select separately of initial stage to flow to the middle sorting region 2 to a greater extent, thereby reduce the loss rate of target sample cell, through being equipped with second buffer solution channel 103 in the inboard of sample solution channel 101, second buffer solution is convenient for sample cell solution mix and form middle liquid stream after entering sorting region 2 along second buffer solution channel 103, thereby guarantee that sample cell solution flows to the region that possesses the sorting function outside the buffer replenishing channel, further, first buffer solution channel 102 of access region 1, second buffer solution channel 103 and sample solution channel 101 are the same with the liquid flow direction in the sorting channel respectively, be favorable to avoiding sample cell solution to influence liquid flow direction after entering sorting region 2 along with the buffer solution. The flow channel design of the buffer solution and the sample solution enables the sample cell solution to be sorted to be prevented from forming turbulence in the microfluidic chip, which is beneficial to improving the sorting efficiency and the sorting precision of the sample cell solution after passing through the sorting area 2 and improving the sample cell recovery rate of the outlet area 3.

As shown in fig. 1 and 3, this embodiment further defines, in addition to the features of the above-described embodiment: the outlet zone 3 comprises a first outlet portion 31 and a second outlet portion 32, the first outlet portion 31 being provided with a first outlet channel 301, the first outlet portion 31 being provided adjacent to the liquid outlet end of the sorting channel, and the second outlet portion 32 being provided with a second outlet channel 302. The first outlet section 31 of the outlet section 3 is connected to the final sorting section 24 of the sorting section 2 for recovering the target collected large cell solution, and the second outlet section 32 is connected to the small cell flow path section 23 for recovering the small cell-containing high solution.

In addition to the features of the above embodiments, the present embodiment further defines: the sample solution channel 101, the buffer solution channel, the first outlet channel 301 and the second outlet channel 302 are respectively provided with a cylindrical array, and the distribution direction of the cylindrical array is the same as the flowing direction of the liquid. By providing a cylindrical array on the channels of the inlet zone 1 and the outlet zone 3, and the direction of the cylindrical arrangement in the cylindrical array is consistent with the direction of the liquid flow, the cylindrical array is used for stabilizing the solution flow in the flow channel.

Specifically, the microstructure of the microfluidic chip can be manufactured by using thermosetting or thermoplastic polymers, glass, silicon and other materials, and the closed structure is formed by bonding, pressing, heat sealing/welding and other processes.

Example 2

The second embodiment of the application discloses a separation and purification method of a microfluidic chip. Comprising the following steps:

s1: with the microfluidic chip, the inlet area 1 is connected with a sample solution to be processed and a buffer solution, the sample solution to be processed flows through the sample solution channel 101, the buffer solution flows through the buffer solution channel, the outlet area 3 is connected with a large cell recovery liquid pipe and a small cell recovery liquid pipe, the first outlet channel 301 is communicated with the large cell recovery liquid pipe, and the second outlet channel 302 is communicated with the small cell recovery liquid pipe;

s2: applying the same sorting pressure to the sample solution to be processed and the buffer solution, wherein the sample solution to be processed and the buffer solution pass through the sorting area 2, the target cell solution is recycled to the large cell recycling liquid pipe through the first outlet channel 301, and the rest solution is recycled to the small cell recycling liquid pipe through the second outlet channel 302;

s3: after the sample solution to be treated is emptied or the recovery liquid is filled, the liquid inlet of the inlet area 1 and the liquid outlet of the outlet area 3 are interrupted and contact with the sorting pressure applied by the sample solution to be treated and the buffer solution is applied.

The second aspect of the present application discloses a separation and purification method using the microfluidic chip, wherein the first buffer inlet region 11 and the second buffer inlet region 12 are connected with a buffer, the sample solution inlet region 13 is connected with a sample to be processed, the first outlet portion 31 is connected with a large cell recovery liquid tube, and the second outlet portion 32 is connected with a small cell recovery liquid tube; applying equal sorting pressure to the buffer solution and the sample to be processed, so that the buffer solution and the sample flow into the microfluidic chip from the corresponding inlets respectively and cell sorting is completed; after the sample is emptied or the recovery liquid is filled, the inflow and outflow of the microfluidic chip are interrupted, and the sorting pressure applied to the buffer liquid and the sample to be processed is relieved, so that the sorting process is completed.

Example 3

In addition to the features of the foregoing embodiments, the present embodiment further defines that the sorting pressure is determined from a sorting database, and the library construction of the sorting database includes the steps of S1: under different sorting pressure conditions in a 0.5-2.5 Bar interval, sorting and testing polymer particle samples with the size of 2-25 microns, and confirming the critical separation size of the microfluidic chip according to test results; s2: using the micro-fluidic chip with the critical separation size, testing the separation recovery rate of different cell samples under different separation pressures, and determining the optimal separation pressure; s3: and according to the test result, combining the micro-fluidic chip, critical separation size, cell type and characteristics, sorting pressure and corresponding sorting recovery rate, and establishing a cell sorting database.

For better explanation of an improvement, the present invention adopts the micro-fluidic chip with the following specification to build the sorting database: the first micro-column array and the second micro-column array in the micro-fluidic chip are respectively provided with isosceles triangle micro-columns, wherein the angle of the vertex angle of the triangle is 120 degrees, the offset angle of the sorting channels of the micro-column arrays in the first convergence region 221 and the second convergence region 241 is 3.17 degrees, the offset angle of the sorting channels of the micro-column arrays in the divergence region 222 is 5.22 degrees, the distance range between the micro-columns adjacently distributed in the direction perpendicular to the flow channel of the first micro-column array and the second micro-column array is 50 micrometers, and the critical separation sizes from front to back are 4 micrometers, 5.6 micrometers and 7 micrometers. The whole critical separation size range of the chip is 8-13 microns under the sorting pressure of 0.5-2.5 Bar.

Wherein: the forward critical separation dimension is statistically derived from the minimum dimension data of the sample flowing into the first outlet section 31 at 100% recovery. The negative critical separation dimension is statistically derived from the minimum dimension data of the sample flowing into the second outlet portion 32 at 100% recovery. The first outlet 31 is used for recovering the large cell solution after sorting, and the second outlet 32 is used for recovering the small cell solution.

(1) Particle testing:

for 5 different specifications of microfluidic chips with critical separation dimension design values of 2-16 microns, respectively using polystyrene particle samples with particle diameters of 1 micron, 3 microns, 5 microns, 7 microns, 9 microns, 11 microns, 13 microns, 15 microns, 17 microns and 19 microns for sorting test, and obtaining actual positive critical separation dimension and negative critical separation dimension, as shown in the positive critical separation dimension test data in table 1 and the negative critical separation dimension test data in table 2.

TABLE 1

TABLE 2

(2) Cell testing: using a size 2 chip with positive and negative critical separation dimensions of 5 microns and 3 microns, respectively, different cells with minimum dimensions of 2 microns, 4 microns, 6 microns, 8 microns and 10 microns were tested for cell recovery at a sorting pressure of 0.5 Bar, 0.75 Bar, 1 Bar, 1.25 Bar, 1.5 Bar, 1.75 Bar, 2 Bar, 2.25 Bar and 2.5 Bar, respectively, and the best sorting pressure data for the different sized cells shown in tables 3 and 4 were obtained.

TABLE 3 Table 3

TABLE 4 Table 4

(3) Establishing a database sub-library according to the test result:

counting the particle test and cell test data results to obtain a sorting database sub-library of comprehensive micro-fluidic chip specifications, sorting pressure and cell size characteristics shown in Table 5;

TABLE 5

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(4) Repeating the above operation to establish a database: repeating the above operations for other chip specifications, sorting conditions and cell size characteristics, and finally summarizing all the data to obtain a finished sorting database.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims (11)

1. A microfluidic chip, comprising:

an inlet region (1), the inlet region (1) being formed with a sample solution channel (101) and a buffer channel;

the sorting area (2) is connected with the inlet area (1), the sorting area (2) forms a sorting channel, the sorting channel is communicated with the sample solution channel (101) and the buffer solution channel, a first micro-column array and a second micro-column array are arranged on the sorting channel and are respectively formed by micro-column arrays in a distributed mode, the first micro-column array is inclined towards the direction close to the central line of the sorting channel, the second micro-column array is inclined towards the direction far away from the central line of the sorting channel, and the first micro-column array is positioned at the solution inlet end and the solution outlet end of the sorting channel;

the sorting area (2) comprises a buffer flow passage area (21), a circulating sorting area (22) and a small cell flow passage area (23), wherein a buffer supply passage is formed on the buffer flow passage area (21), the buffer supply passage is communicated with the buffer passage of the inlet area (1), the buffer flow passage area (21) is positioned at the inner side of the circulating sorting area (22), the circulating sorting area (22) is communicated with the sample solution passage and the buffer passage, the circulating sorting area (22) forms the sorting passage, the first micro-column array and the second micro-column array are positioned on the circulating sorting area (22), and the small cell flow passage area (23) forms the small cell passage, and the small cell passage is communicated with the sorting passage;

The circulating separation zone (22) comprises a first convergence zone (221), a divergence zone (222) and a first partition (223), the first convergence zone (221) and the divergence zone (222) are respectively provided with the first micro-column array and the second micro-column array, the first convergence zone (221) is adjacent to the inlet zone (1), the divergence zone (222) is positioned at the liquid outlet end of the first convergence zone (221), the small cell flow channel zone (23) is positioned at the outer side of the divergence zone (222), the first partition (223) is arranged between the divergence zone (222) and the small cell flow channel zone (23), and the small cell channel is communicated with the first convergence zone (221)

The outlet area (3), outlet area (3) with separation area (2) is connected, form first exit channel (301) and second exit channel (302) on outlet area (3), first exit channel (301) are located the inboard of second exit channel (302), first exit channel (301) and second exit channel (302) with separation channel intercommunication.

2. The microfluidic chip according to claim 1, wherein,

the number of the first micro-column arrays and the second micro-column arrays is a plurality, and the second micro-column arrays are positioned between the two first micro-column arrays; and/or

The first micro-column array forms a first offset angle with the central line direction of the sorting channel, and the range of the first offset angle is 0.5-12.5 degrees; and/or

The second micro-column array forms a second offset angle with the central line direction of the sorting channel, and the range of the second offset angle is 0.5-12.5 degrees.

3. The microfluidic chip according to claim 1, wherein,

the distance range between the microcolumns, which are adjacently distributed along the flow channel direction, of the first microcolumn array and/or the second microcolumn array is 6-25 micrometers; and/or

The distance between the microcolumns, which are adjacently distributed in the direction perpendicular to the flow channel, of the first microcolumn array and/or the second microcolumn array is 10-60 micrometers; and/or

The height range of the first micro-column array and/or the second micro-column array perpendicular to the direction of the flow channel is 5-50 micrometers; and/or

The section shape of the micro-column is one of a circle, an ellipse, a triangle, a rectangle, a trapezoid, a diamond, an L shape, a C shape and a T shape.

4. The microfluidic chip according to claim 1, wherein the height of the sorting channels perpendicular to the direction of the fluid can be varied with different sorting pressures.

5. The microfluidic chip according to claim 1 or 4, wherein the sorting channels have a height perpendicular to the direction of the fluid in the range of 15 to 60 microns.

6. The microfluidic chip according to claim 1, wherein the number of the circulation sorting areas (22) is plural, the critical separation size between the circulation sorting areas (22) distributed along the liquid flow direction is increased, and the critical separation size of the circulation sorting area (22) of the next stage is 105% -200% of the critical separation size of the circulation sorting area (22) of the previous stage; and/or

The number of the first convergence regions (221), the divergence regions (222) and the first separating portions (223) is a plurality, and the first convergence regions (221) and the divergence regions (222) are staggered; and/or

The buffer liquid flow channel region (21) and the small cell flow channel region (23) are provided with cylindrical arrays, and the distribution direction of the cylindrical arrays is the same as the liquid flow direction; and/or

Still include drainage portion (4), adjacent first convergence district (221) with have clearance (201) between the district that diverges (222), drainage portion (4) set up on the lateral wall of buffer runner district (21) and/or the inside wall of first partition portion (223), drainage portion (4) are located clearance (201) department.

7. The microfluidic chip according to claim 1, further comprising a final sorting zone (24), wherein the final sorting zone (24) is located at a liquid outlet end of the circulation sorting zone (22), wherein the final sorting zone (24) is provided with the first micro-column array, wherein the buffer flow channel zone (21) is located inside the final sorting zone (24), wherein the small cell flow channel zone (23) is located outside the final sorting zone (24), and wherein the sorting channel extends to the final sorting zone (24).

8. The microfluidic chip according to claim 7, wherein the final sorting region (24) comprises a second convergence region (241) and a second partition (242), the second convergence region (241) is provided with a plurality of the first micro-column arrays, and the second partition (242) is located outside the second convergence region (241); and/or

The critical separation size of the final-stage separation zone (24) is higher than that of the circulating separation zone (22), and the critical separation size of the final-stage separation zone (24) is 120% -600% of that of the first circulating separation zone (22); and/or

The buffer flow channel region (21) penetrates at least part of the final sorting region (24), and the tail end of the buffer flow channel region (21) is positioned on the final sorting region (24).

9. The microfluidic chip according to claim 1, wherein the first partition (223) comprises a first partition body (2231) and a flow guiding end (2232), the flow guiding end (2232) being arranged on the first partition body (2231), the flow guiding end (2232) being located at a liquid outlet end of the first convergence zone (221), the flow guiding end (2232) being arranged for guiding a liquid flow towards the small cell flow channel zone (23).

10. The microfluidic chip according to claim 9, wherein the flow guiding end (2232) has a flow guiding cambered surface, which is located outside the flow guiding end (2232) and is offset towards a direction away from a center line of the sorting channel; and/or

The connection of the flow guiding end (2232) and the first partition body (2231) forms a bent angle.

11. The microfluidic chip according to claim 1, wherein the buffer channels comprise a first buffer channel (102) and a second buffer channel (103), the inlet region (1) comprising a first buffer inlet region (11), a second buffer inlet region (12) and a sample solution inlet region (13), the first buffer inlet region (11) forming the first buffer channel (102), the second buffer inlet region (12) forming the second buffer channel (103), the second buffer channel (103) being located inside the first buffer channel (102); and/or

The outlet zone (3) comprises a first outlet part (31) and a second outlet part (32), the first outlet part (31) is provided with the first outlet channel (301), the first outlet part (31) is adjacent to the liquid outlet end of the separation channel, and the second outlet part (32) is provided with the second outlet channel (302); and/or

The sample solution channel, the buffer solution channel, the first outlet channel and the second outlet channel are respectively provided with a cylindrical array, and the distribution direction of the cylindrical arrays is the same as the liquid flow direction.